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14 Νοε 2013 (πριν από 4 χρόνια και 6 μήνες)

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Hong Lim, Ph.D.

1420 Seamans Center

5810 (office);



David Wilder, PhD and Nicole Grossland, PhD

Office Hours:

M, W, F: 4:00

5:00 PM






Mechanics of Deformable Bodies




Text and Grading


“The Mechanical Design Process, 3


David G. Ullman

Hill (ISBN: 0



Homework and Quiz


Individual Design Notebook


Reverse engineering report


Team Project


Final Exam

Final exam will be a short answer exam covering the terminology and concepts studied
throughout this course


Individual Design Notebooks

You are to keep a design notebook for use in this course.

This is to be a spiral bound notebook.

Every page must be numbered at the beginning of the term.

No pages can be removed and each page must be dated and initialed when used.

All work related to this course (homework and design project) will be entered into
this note book.

Each notebook will be collected at the end of the term and graded on the number of
“quality entries” it contains.

A quality entry is a significant sketch or drawing of some aspect of design; a listing of
functions, ideas or other features; a table such as morphology or decision matrix; or a
page of text.

Unintelligible entries are not quality entries.


Team Project

Design Team:

Design teams will be organized by the instructor.

Team members will determine the leader (CEO).

Team Project:

Each team will determine a design problem (new invention or modification) related to
biomechanical devices through discussion with the instructor.

The team project will be considered completed by obtaining final product documentation
(drawings, part list with specified materials, and assembly instructions).

No final product in physical form is required.

Each team should record the whole history of the design in the
Product Development



Documents in the PDF

Problem Appraisal Phase

Understanding the Problem:

Description of Customers

Customer’s Requirements

Weighting of Customer’s

Competition’s Benchmarks vs.
Customer’s Requirements

Engineering Requirements

Competition’s Benchmarks vs.
Engineering Requirements

Engineering Targets

Planning the Project

Task Titles

Objectives of Each Task

Personnel Required for Each

Time Required for Each Task

Schedule of Tasks

Conceptual Design Phase

Concept Generation:

Function Decomposition

Literature and Patent Search
Process and Results

Concept Mapping

Sketches of Overall Concepts

Concept Evaluation and

Assessment of Tech. Readiness:

Identification of Failure Modes

Identification of Critical

Concept Selection:

Decision Matrices to Determine
Best Concepts

Analsysi, Experiments and
Models Supporting Evaluation

Product Design Phase

Product Generation:

Usable off
shelf Products

Shape Development Driven by

Materials Selection

Manufacturing Process

Product Evaluation:

Comparison to Engineering

Functional Changes Noted

Design for Assembly Evaluation

Cost Evaluation

Analysis, Experiments and
Models Supporting Evaluation

Final Product Documentation:

Layout Drawings

Detail Drawings of
Manufactured Parts

Parts List (Bill of Materials)

Assembly Instructions


The file is to be maintained by the group in a binder. This PDF, when completed, is effectively a
final report. It will be graded on completeness and quality of both the design and the
documentation itself.


Biomechanical Design


Deliberate purposive planning

A mental project or scheme in which means to an end are laid out

A preliminary sketch or outline showing the main features of something to be executed: DELINEATION

The arrangement of elements or details in a product or work of art

The creative art of executing aesthetic or functional designs

Biomechanical Design:

Design something related to biomechanics, such as:

Biomechanical devices

Medical devices: orthopedic implants, scissors, scalpers, staplers, etc.

Exercising devices: treadmill, weight
lifting, helmets, wrist
guards, etc.

Rehabilitation devices: wheel
chairs, canes, etc.

Biomechanical activities

Exercises for fitness or strengthening body parts

Biomechanical design includes

Development (or invention) of new biomechanical stuffs; and

Modification of existing biomechanical stuffs


What will we learn in this class?

Typical design process:

Identification of design problems


Evaluation of the design

Decision making

Final report

Techniques helping generate better quality designs in less time:

Concurrent engineering

Computer aided drawing

Legal and regulation issues:

Safety and liability

Patent, FDA, CE, and UL

Importance of communication of design data:

Records of design data, design process, and final report

Oral presentations


The Life of A Product

*Process of idea development,
production, use, and end of product

*The whole process must be
considered in the design process.


Design Process

What is the design process?

Design process is the organization and management of people and the information they develop in the
evolution of the product.

Why study the design process?

Design process determines the efficiency of new product development.

85% of the problems with new products not working as intended, taking too long to bring to market, or costing
too much are the result of poor design process.

The design process needs to improved consistently and executed for developing better products because:

There is a continuous need for new, cost
effective, high
quality products.

Most products require a team of people from diverse areas of expertise to develop an idea into hardware.

We will study the design process to get the tools to develop an efficient design process regardless of the
product being developed.

3 types of knowledge used by designers:

Knowledge to generate ideas

Experience and natural ability

Knowledge to evaluate ideas

Experience and formal training (focus of most engineering education)

Knowledge to structure the process

specific knowledge

What we will study in this class


One person, with sufficient knowledge of the physics, materials and manufacturing
processes to manage all aspects of the design and construction of the project, could
design and manufacture an entire product in the past.

By the middle of the 20

century, products and manufacturing processes had become
too complex for one person to have sufficient knowledge or time to focus on all
aspects of the evolving product.

Different groups of people for marketing, design, manufacturing and overall management

way communication over the wall:

What is manufactured is not often what the customer had in mind.

Inefficient, costly, and greater possibility for making poor
quality products

History of the Design Process


Simultaneous Engineering (in late 1970s and early 1980s):

Simultaneous development of the manufacturing process with the evolution of the product by assigning
manufacturing representatives to be members of design team

Concurrent Engineering (in late 1980s):

Integrated Product and Process Design (IPPD) in the 1990s

A greater refinement in thought about what it takes to efficiently develop a product

Primarily focusing on the integration of teams of people, design tools and techniques, and information about
the product and the processes used to develop and manufacture it.

10 Key Features of Concurrent Engineering

Focus on the entire product life (chap 1)

Use and support of design team (chaps 3 and 5)

Realization that the processes are as important as the product (chaps 4 and 5)

Attention to planning for information
centered tasks (chap 5)

Careful product requirements development (chap 6)

Encouragement of multiple concept generation and evaluation (chaps 7 and 8)

Awareness of the decision
making process (chap 8)

Attention to designing in quality during every phase of the design process (throughout)

Concurrent development of product and manufacturing process (chaps 9

Emphasis on communication of the right information to the right people at the right time (throughout)

A key point of concurrent engineering is a concern for information.

Drawings, plans, concept sketches, meeting notes, etc.

History of the Design Process


Controllable Variables in Concurrent Engineering


Overview of the Design Process


Design Problems

What size SAE grade 5 bolt should be
used to fasten together two pieces of
1045 sheet steel (4 mm thick and 6 cm
wide) which are lapped over each other
and loaded with 100 N?


Well defined analysis problem finding
the diameter of the bolt

Design a joint to fasten together two
pieces of 1045 sheet steel (4 mm thick
and 6 cm wide), which are lapped over
each other and loaded with 100 N?

defined design problem with number
of potential problems

How to connect the sheets? (Bolted,
glued, welded, etc.?)

Disassembly required later?

What working environment?



Change a problem from one of your engineering science classes into a design problem by
changing as few words as possible. Do your home work in your design notebook. Due is
one week.


Design problems have many satisfactory solutions and no clear
best solution.

Design problems

are ill

have no correct answer;

have no clear best answer.

Design process knowledge is based
upon the domain knowledge.

Mechanical design problems begin
with an ill
defined need and result in
a piece of machinery that behaves in
a certain way.


A designer must develop a machine
that has the capabilities to meet
some need that is not fully defined.


Basic Actions of Design Problem Solving


the need or realize that there is a problem to be solved.

New needs also can be established throughout the design effort because new design
problems arise as the product evolves. Design of these details poses new subproblems.


how to solve the problem.

Planning occurs mainly at the beginning of a project. Plans are always updated because
understanding is improved as the process progresses.


the problem by developing requirements and uncovering existing
solutions for similar problems.

Formal efforts to understand new design problems continue throughout the process. Each
new subproblem requires new understanding.


alternative solutions.

Concept Generation vs. Product Generation


the alternatives by comparing them to the design requirements and to
each other.

Evaluation techniques also depend on the design phase; there are differences between the
evaluation techniques used for concepts and those used for products.


and acceptable solutions

Decision making requires a commitment based upon incomplete evaluation.

Decision requires a consensus of team members.


the results

Communication of the information developed to others on the design team and to
management is an essential part of concurrent design.


Basic Terminologies used to describe the Design Process

“Communication” as a one key feature of concurrent engineering

Communication depends on a shared understanding of terminology.


What a product or a system is supposed to do;

Described using action verbs and a noun describing the object on which the
action occurs:

Record images; quantify the blood pressure; fix an unstable spine segment; etc.


A grouping of objects that perform a specific function;

Shutter system; timer system; CD
R system; cooling system; etc.

A system can be decomposed into another subsystems or further into individual
components (or parts).

Multiple systems can be assembled into a higher level system or further into a
final product.

Feature: the important form and function aspects of mechanical devices

dimensions, material properties, shapes, or functional details (speed of opening and
closing for shutter system)

Decomposition of design disciplines

In general, during the design process, the
function of the system and its
decomposition are considered first. After
the function has been decomposed to the
finest subsystems possible, assemblies and
components are developed to provide
these functions.


Function, Behavior, and Performance


describes what a device does.

But, function provides no information about how a device accomplishes the function.


The term “form” relates to any aspect of physical shape, geometry, construction, material,
or size.

provides some information on how a device accomplishes the function.

Behavior and Performance in association with Function.

Function is the desired output from a
system yet to be designed.

Behavior is the actual output, the response
of the system’s physical properties to the
input energy or control.

Performance is the measure of function
and behavior

how well the device does
what it is designed to do.

A clear picture of desired performance
should developed in the beginning of the
design process.


Types of Mechanical Design Problems

Selection Design:

choosing one item (or more) from a list of similar items

choosing a bearing, bolt, motor, etc. from a catalog

Configuration Design:

How to assemble all the components into the completed product

Parametric Design:

Finding values for the features that characterize the object being studied or that meet the

Design a cylindrical tank: V =



for known V

Original Design:

Design a process, assembly or component not previously in existence


Redesign of an existing product

Most design problems are redesign problems since they are based on prior,
similar solutions. Conversely, most design problems are original as they contain
something new that makes prior solutions inadequate.


Languages of Mechanical Design

A mechanical object can be described by:

Semantic language:

Verbal or textual representation of the object

“bolt” or “The shear stress is equal to the shear forces on the bolt divided by the
sectional area.”

Graphical language:

drawing of the object

Sketches, scaled representations of orthogonal drawings, or artistic renderings

Analytical Language:

Equation, rules, or procedures representing the form of function of the object

= F/A

Physical Language:

Hardware or physical model of the project


In most cases, the initial need is expressed in a semantic language as a
written specification or a verbal request by a customer or supervisor, and
the final result of the design process is a physical product.


Design, State, Constraints and Decision

Design State:

Collection of all the knowledge, drawings, models, analyses and notes thus far

In the beginning, design state is just the problem statement

Design Constraints:

Factors limiting the design process

Examples: size, strength of material, corrosion properties, anatomy, etc.

In the beginning, the design requirements effectively constrains the possible
solutions to a subset of all possible product designs.

Two sources of constraints added during the design process:

Designer’s knowledge of mechanical devices and the specific problem being solved

Result of design decisions

Design Decision:

Continuous comparison between design state and the goal (requirements for the
product given in the problem statement)

The difference controls the process.

Design is the successive development and application of constraints until only
one unique products remains.

Each design decision changes the design state.

The design progresses in increment punctuated by design decisions.


The Value of Information

*The most valuable information is the decisions that are communicated to others.


Design as Refinement of Abstract Representations

Graphical Refinement

See Table 2.2 for levels of abstraction in
other languages.


processing Model of Human Problem Solving

Processing System used by the human mental system
in solving any type of problem


Chunks of Information


processing Model of Human Problem Solving

Types of Knowledge that might be in a chunk of information:

General knowledge

Information that most people know and apply without regard to a specific domain

“red is a color.” “4 is bigger than 3.”

Gained through everyday experiences and basic schooling

Domain Specific Knowledge:

Information on the form or function of an individual object or a class of objects

Bolts are used to carry shear or axial stress

The proof stress of a grade 5 bolt is 85 kpsi.

Gained from study and experience in the specific domain

It may take about 10 years to gain enough specific knowledge to be considered an expert in a domain

Procedural Knowledge:

The knowledge of what to do next

If there is no answer to problem X, then decompose X into two independent subproblems of x1 and x2 that
are easier to solve.

Gained mostly from experience

Required for solving mechanical design problems


The size of STM is a major limiting factor in the ability to solve problem.

To accommodate this limitation, breakdown problems into finer and finer subproblems
until we can “get our mind around it”

in other word, manage the info in our STM

Human designers are quite limited although our expertise about the constraints and
potential solutions increases and our configuration of chunks becomes more efficient as we
solve problems.

These limitations would preclude our ability to solve complex problems.

Implications of the Information
processing Model


Mental Processes that Occur during Design

Understanding the problem:

A problem is understood by comparing the requirements on the desired function to information in the
term memory.

Every designer’s understanding of the problem is different, we need to develop a method to ensure that
the problem is fully understood with minimal bias from the designer’s own knowledge.

Generating a solution:

Use the information stored in LTM that meets the design requirements.

If no solution found from LTM, then use a three step approach

Decompose the problem into subproblems

Try to find partial solutions to the subproblems

Recombine the subsolutions to fashio a total solution

Creative part of this approach is in knowing how to decompose and recombine cognitive chunks

Evaluating the solution:

Evaluation requires comparison between generated ideas and the laws of nature, the capability of
technology and the requirements of the design problem itself.

Evaluation requires modeling the concept to see how it performs.

The ability to model is usually a function of knowledge in the domain.


A decision is made at the end of each problem
solving activity to accept the generated and evaluated
idea or to address another topic that is related to the problem.

Controlling the design process:

Path from initial problem to solution seemed random.


Solving Behavior

A person’s problem
solving behavior affects how problems are solved individually and has a significant
impact on team effectiveness.

Four Personal
Problem Solving Dimensions (or styles):

Individual Problem
solving Style:


Solve problem internally (reflective); a good listener; think and speak; enjoy having time alone for problem solving


Sociable; tend to speak and think

About 75% Americans and 48% of engineering students and executives

Individual Preference to work with Facts or Possibilities:

Facts oriented people:

literal, practical, and realistic

75 % of Americans, 66% of top executives, 34% of all engineering students

Possibility oriented people:

Like concepts and theories and look for relationship between pieces of information and meaning of the information

Objectivity with which decisions are made:


Logical, detached and analytical

Taking objective approach to make decisions

51% of Americans, 68% of engineering students, 95% of top executives


Make decisions based on an interpersonal involvement, circumstances, and the “right thing to do”

Need to Make Decisions:


Tend to make decisions with a minimum of stress and like an ordered, scheduled, controlled and deliberate environment

50% of Americans, 64 % of engineering students, and 88% of top executives


People goes with flow is flexible, adaptive, and spontaneous, and finds making and sticking with decisions difficult

Please make sure to read section 3.3.6 carefully for better design team activities.


Characteristics of a Creative Designer

Problem solving involves:

Understanding the problem, generating solutions, evaluating the solutions, deciding on the best one, and
determining what to do next

Criteria of Creative Solution:

It must solve the design problem.

It must be original.

Originality and creativity are assessed by society.

Creativity in relation to other Attributes

Intelligence: no correlation with creativity

Visualization Ability:

Creative engineers have good ability to visualize, to generate and manipulate visual images in their head.

The ability to manipulate complex images can be improved with practice and experience.


A person must have knowledge of existing products to be a creative designer

A firm foundation in bioengineering science is essential to being a creative biomechanical designer.

Partial Solution Manipulation: important attribute

Risk Taking: certainly required

Conformity: Creative people tend to be nonconformists.

Constructive nonconformists take a stand because they think they are right and might generate a good idea.

Obstructive nonconformists take a stand just to have an opposing view and will slow down the design progress.


Creative designers have more than one approach to problem solving.


Higher creativity when the work environment allows risk taking and nonconformity and encourages new ideas.


Creativity comes with practice.

Practice enhances the number and quality of ideas.


Creative Designer

A creative designer is a:


Hard worker; and

Constructive nonconformist with knowledge about the domain and
ability to dissect things in his or her head

Good News:

Designers with no strong natural ability can develop creative methods by
using good problem
solving techniques to help decompose the problems
in ways that maximize the potential for understanding it, for generating
good solutions, for evaluating the solutions, for deciding which solution is
best and for deciding what to do next

A design project requires:

much attention to detail and convention;

demands strong analytical skills; and thus

People with a variety of skills.

There are many good designers who are not particularly creative


Engineering Design Team

A team is a group of people working toward a common understanding.

Team vs. Individual Problem Solving

There are social aspects of team work.

Each team member may have different understanding of the problem, different alternatives for solving
it, and different knowledge for evaluating it. (more solutions but also more confusion)

Team Goals:

A small number of people with complementary skills who are committed to a common purpose, common
performance goals and a common approach for which team members hold themselves mutually
accountable are required for an effective team.

Team members must:

learn how to collaborate with each other, i.e., to get the most out of other team members.

Comprise to reach decisions through consensus rather than by authority.

Establish communications.

Be committed to the good of the team.

Team Roles:

Organizer; Creator; Resource
investigator; Motivator; Evaluator; Team worker; Solver; Completer
(finisher or pusher)

Building Team Performance:

For developing productive teams;

Keep the team productive

Select team members on the basis of skills in both primary and secondary roles

Establish clear rule of behavior

Set and seize upon a few immediate performance
oriented goals.

Spend time together.

Develop a common understanding


Overview of the Design Process

An Ideal Flow Chart of Activities During Design Process


What initiates a Design Project?

Need for a New Design:


About 80% of new product development is market

Assessment of the market is most important in understanding the design problem
because there is no way recover the costs of design and manufacture without market

Incorporation of the latest technology can improve its perception as a high quality

New product idea without market demand

To use new technologies whose development requires an extensive amount of capital
investment and possibly years of scientific and engineering time

High financial risk but greater profit due to uniqueness

Examples of successful products: sticky notes; Walkman

Need for Redesign

By market demand for a new model

Desire to include a new technology

Fix a problem with an existing product

Redesign process can be applied to the subproblems that result from the
decomposition of a higher
level system.


Project Planning:

to allocate the resources of money, people, and equipment to accomplish the design activities:

Planning should precede any commitment of resources although requiring speculations about the

Easier to plan a project similar to earlier projects than to plan a totally new one

Plans are often updated whenever unknown demands become certain with the progress of design

Specifications Definition:

Goal is to understand the problem and to lay the foundation for the remainder of the design project.

Identify the customers: Generate the customer’s requirements: Evaluate the competition: Generate engineering
specifications: Set targets for its performance

Design Review:

formal meeting for progress report and design
decision making

Conceptual Design:

To generate and evaluate the concepts for the product

Generate concepts based on the defined specifications for developing a functional model of the product

Evaluate concepts by comparing the concepts generated to the targets for its performance

Design Review

Product Development:

Evaluate the product for performance, cost, and production

Make product decisions

Documentation and Communication

BOM (Bill of Materials), Drawings, etc.

Product Support:

Support for vendors, maintenance of engineering change, customer, manufacturing and assembly, and
retirement of the product

Overview of the Design Process


Why Do We Have to Follow The Design Process Techniques?


Techniques in the design process may imply “RIGIDITY” whereas the creativity implies

Following the techniques in the design process helps the designers develop a quality
product that meets the needs of the customer by several ways:

Eliminating expensive changes later

Developing creative solutions to design problems systematically

Creativity does not spring from randomness.

“Genius is 1 percent inspiration and 99 percent perspiration.”

The inspiration for creativity can only occur if the perspiration occur early is properly directed
and focused.

The techniques that make up the the design process are only an attempt to organize the

Forcing documentation of the progress of the design (record of the design’s evolution) that
will be useful later in the design process.


Design Process Examples

Simple Process

Complex Process


Communication during the Design Process

Design Records:

Importance of documents in design file:

To demonstrate the state
art design practices

To prove originality in case of patent application

To demonstrate professional design procedures in case of a lawsuit

Design Notebook:

A diary of the design tracking the ideas development and the decision made in a design notebook

Name; Affiliation; Title of the problem; Problem Statement; and all sketches, notes and calculations that concerns the design

A design notebook sequentially numbered, signed and dated pages is considered good documentation whereas
random bits of information scrawled on bits of papers are not.

Good evidences for legal purposes (patent or lawsuit) as well as a reference to the history of the designer’s own work

Documents Communicating with Management:

Needed for periodic presentations to managers, customers, and other team members for design review

Regardless of its form (oral or written);

Make it understandable (consider the recipients’ level of knowledge about the design problem)

Carefully consider the order of presentation (whole


whole: 3
step approach: gradual
introduction of new ideas)

Be prepared with quality material (good visual and written documentation; following the agenda;
being ready for questions)

Documents Communicating the Final Design:

Material describing the final design, e.g, Drawings (or data files) of individual components and of

Written documentation to guide

manufacture, assembly, inspection, installation, maintenance, recruitment, and quality control


Team Project

Select an original design problem to solve throughout the
remainder of the course.

The problem should concern biomechanical devices in which some of
the design team members have some knowledge or training.

The final product will be data from analyses and evaluation and final
drawings, not an actual hardware.

Design Team Activity :

Each student should start gathering the design ideas immediately and
recording the ideas in the design notebook.

Start the team meeting ASAP for:

Organization of the team

Planning the design process to finish the project by the end of April.

Each team will present their design project in May.

Any discussion about the design project with the instructor is welcome.


Project Definition and Planning

Concurrent engineering encourages involvement
through out the entire product life cycle from the
project definition to product retirement.

Project definition and planning is the first phase of
the mechanical design process.


Project Definition

Why developing new products?

To fill some market need

Mostly driven by the customer

To exploit a technological development

Driven by new technologies and what is learned during the design

Project Definition:

the challenges of choosing from the many suggestions as to which products to
spend time and money on to develop or refine

“Fuzzy front end” of dealing with vague design ideas

Specific Questions in Project Definition Phase:

Is there a good potential return on investment (ROI)?

Does the new product or improvement fit the company image?

Does it fit the distribution channels?

Is there sufficient production capacity in
house or with known vendors?

What will the project cost?


Project Planning

Planning is like trying to measure the smile of the Cheshire cat; you are
trying to quantify something that isn’t there.

Planning is the process used to develop a scheme for scheduling and
committing the resources of time, money, and people.

Producing a map showing how product design process activities are scheduled.

The whole activities of specification definition, conceptual design, and product
development must be scheduled and have resources committed to them

Planning generates a procedure for developing needed information and
distributing it to the correct people at the correct time.

Important information: product requirements, concept sketches, system
functional diagrams, component drawings, assembly drawings, material
selections, and any other representation of decisions made during the
development of the product.

Typical Master Plan (a generic process) of a Company for Specific Products:

A blue print for a process:

product development process; delivery process; new product development plan; or
product realization plan, etc.

We will refer to this generic process as the product development process



A quality management system of the International Standard Organization

First issued in 1987 and now adopted by over 150 countries

Over 350,000 companies worldwide and 8500 U.S. companies have the ISO

9000 registration means that the company has a quality system that:

Standardizes, organizes, and controls operations.

Provides for consistent dissemination of information.

Improves various aspects of the business
based use of statistical data and analysis.

Enhances customer responsiveness to products and services.

Encourage improvement.

To receive certification,

One should develop a process that describes how to develop products, handle product
problems, and interact with customers and vendors.

Required written procedures that:

Describe how most work in the organization gets carried out (i.g., the design of new products, the
manufacture of products, and the retirement of products).

Control distribution and reissue of documents.

Design and implement a corrective and protective action system to prevent problems from recurring.

Evaluation of the effectiveness of the process by an accreditted external auditor

Certification expires in 3 years and audits at 6
month intervals to maintain the currency of
the certificate.

9000 requires a company to have a documented development process on which
the plan for a particular product can be based.


Background for Developing a Design Project Plan

A plan tells how a project will be initiated, organized, coordinated, and monitored, e.g.,
managerial activities.

Types of Design Projects:

Variation of existing product:

Improvement of existing product:

Redesign of some features of an existing product due to:

Customers request; no longer supply of materials or components from the vendor; needed improvement in
manufacturing; or New technology or new understanding of an existing technology

Development of a new product for a single (or small) run or for mass production

Members of the Design Team:

Product design engineer:

Product manager (product marketing engineer):

Manufacturing engineer; Detailer; Drafter; Technician; Materials specialist; QC/QA specialist;
Analyst; Industrial engineer; Assembly manager; Vendor’s or supplier’s representatives

Structure of Design Teams:

Functional Organization (13 %):

Each project is assigned to a relevant functional area, focusing a single discipline

Functional Matrix (26 %):

project manager with limited authority is designated to coordinate the project across different functional areas

Balanced Matrix

(16 %):

A project manager is assigned to oversee the project and shares the responsibility and authority with functional

Project Matrix

(28 %):

A project manager oversees the whole project and functional managers assign personnel as needed.

Project Team

(16 %)

Organize the talent around the project whenever possible.

Structures focus on the project are more successful than those built around the functional areas in the company.


Planning for Deliverables


All models of the product, such as drawings, prototypes, bills of materials, analysis results, test results,
and other representations of the information generated in the project

Measure of the progress in design project

Models vs. Prototypes:

Models are analytical and/or physical representations of design information.

Prototypes are physical models. Solid models in CAD can replace the physical models these days.

4 Purposes of Prototypes:


Developing function of the product to compare with the goals

Learning tool


Refine the components and assemblies

Geometry, materials and manufacturing processes are as important as functions

Rapid prototyping and CAD models have greatly improved the time and cost efficiency in building prototypes.


Verify both the geometry and manufacturing process.

Exact materials and manufacturing processes are used to build sample for functional testing.


Verify the entire production product.

The result of preproduction run.


Types of Models



(Form and Function)



(mainly Function)


(mainly Form)


Final Product

concept prototype

product prototype

process and proof
production prototype

the envelope

Engineering science analysis

Finite element analysis;
detailed simulation


Layout drawings

Detail and assembly
drawings; solid models

An important decision in planning the project:

How many models and prototypes should be scheduled in the design process?

Because of cost effectiveness, there is a strong move toward replacing physical prototypes with
computer models. But not always right.

Be sure to set realistic goals for the time required and the information learned.


Five Steps in Planning

Step 1: Identify the Tasks

Tasks in terms of the activities that need to be performed (generate concepts,
producing prototypes, etc.)

Make the tasks as specific as possible.

Step 2: State the Objective for Each Task

Each task must be characterized by a clearly stated objective

The results of the tasks (or activities) should be the stated objectives.

Task objectives should be:

Defined as information to be refined or developed and communicated to others.

This information should be contained in deliverables

Easily understood by all in the design team.

Specific in terms of exactly what information is to be developed. If concepts are
required, then tell how many are sufficient.

Feasible, given the personnel, equipment, and time available

Step 3: Estimate the Personnel, Time, and Other Resources Needed to meet
the Objectives

Step 4: Develop a sequence for the tasks

Step 5: Estimate the Product Development Costs


Step 3: Estimate the Personnel, Time, and Other
Resources Needed to Meet the Objective

Necessary Identification for each Task:

Who on the design team will be responsible for meeting the objectives?

What percentage of their time will be required?

Over what period of time they will be needed?

Time (in hours) = A x PC x D

A = a constant based on past projects

A = 30 for a small company with good communication

A = 150 for a large company with average communication

PC = product complexity based on function

PC =

(j = the level in the functional diagram; F

= the number of functions at that level)

D = project difficulty

D = 1, not too difficult; D = 2, difficult; D = 3, extremely difficult

Time estimation = (o + 4m + p)/6

O = optimistic estimate; m = most
likely estimate; p = pessimistic estimate

Time Distribution across the Phases of the Design Process

Project Planning (3

5 %); Specifications Definition (10

15%); Conceptual Design (15

35%); Product Development (50

70%); Product Support (5



Step 4: Develop a Sequence for the Tasks

The goal is to have each task accomplished before its result is needed and to make
use of all of the personnel, all of the time.

For each task, it is essential to identify its precessors and successors.

Tasks are often interdependent

two tasks need decisions from each other in order to be

Sequential vs. Parallel (uncoupled and coupled) tasks

Bar Chart (or Gantt Chart)

best way to develop a schedule for a fairly simple

Design Structure Matrix (DSM)

for a complex project with coupled tasks

Showing the relationship (or inter
dependence) among tasks (example: see page 104

Useful tool for to help sequence the tasks (Page 104)


Step 5: Estimate the Product Development Cost

The planning document can serve as a basis for estimating the cost of
designing the new product in terms of:

Personnel cost

Resources (supplies and equipment)

Team Project:


Planning must be done and written in the PDF.


Read examples in pages from 105

109 for planning.


Gantt chart or DSM should be good entries.


Understanding the Problem and

the Development of Engineering Specifications

Importance of finding the right problem to be solved:

Unnecessary effort to design a retarder (dampener) determining the final
position of the solar panels in the Mariner IV satellite

Finding the right problem to be solved is often not easy although it may seem a
simple task.

Creeping Specifications:

Specifications changing during the design process

More features can be added as more is learned during the process

New technologies or competitive products introduced during the design (ignore,
incorporate or start all over?)

Changes in any spec. affecting the previous decisions depedent upon that spec

Engineering Specifications (requirements) should be:


Reveal the difference between alternatives.

Measurable (most important and major topic of chap 6)


Each specification should identify a unique feature of the alternative.

“Product must give smooth ride over rough road.” vs. “Product should reduce shocks from bumps.”


Characterizing an important attribute of all the proposed alternatives


Only external features are observable.


Quality Function Deployment (QFD)

Most popular technique used to generate engineering
specifications in an organized manner

Developed in Japan in the mid
1970s and introduced to the US in the late

69% of the US companys use the QFD method recently

Important Points

Employ QFD no matter how well the design team thinks it understands a

QFD takes time to complete, but time spent for QFD saves time later.

QFD can be applied to the entire problem and also any subproblems.

QFD helps overcome our cognitive limitation.

We tend to try to assimilate the customer’s functional requirement (what is
to be designed) in terms of form (how it will look).


Quality Function Deployment (QFD)

House of Quality


Example of QFD

Step 1: identify the customers

Step 2: determine the requirements

Step 3: determine the relative

importance of requirements

Step 4: identify and evaluate the


Step 5: generate engineering specification

Step 6: Relate customers’ requirements to

engineering specifications

Step 7: Set engineering targets

Step 8: identify the relationships between

engineering requirements


QFD Step 1: Identify the Customers: Who are they?

For general products:

Who are the customers?


Designers’ management

Manufacturing personnel

Sales staff

Service personnel

Standard organizations


For many products,

there are 5 or more
classes of customers
whose voices need to be

For a spinal implant system:

Who are the customers?

Orthopaedic surgeons





Sales Reps

Patients ?


QFD Step 2: Determine the Customer’s Requirements: What
do the customers want



works as it should,


lasts long,


is easy to maintain,


looks attractive,


incorporates the latest technology,


and has many features.

Production Customer:


is easy to produce (both manufacture and assemble),


uses available resources (human skills, equipment, and raw materials),


uses standard parts and methods,


uses existing facilities,


produces a minimum scraps and rejected parts.

Marketing/Sales Customer:


easy to package, store, and transport,


attractive and suitable for display

Types of Requirements:

Basic features: neutral satisfaction with existence

basic assumed functions; not included in QFD


Performance Features: good satisfaction with existence


verbalized in the form that the better the performance, major part of QFD


Excitement (or WOW) Features: high satisfaction with existence


How to collect customer’s requirements

Observation of customers

Surveys: mail, telephone, face

group technique

A group of surgeons for orthopaedic implants

Steps for developing useful data for requirements

Specify the information needed:

Reduce the problem to a single statement. If impossible, more than one data collecting effort may be warranted.

Determine the type of data
collection method to be used:

Depending on the use of data collection methods

Determine the content of individual questions:

Write a clear goal for the results expected from each question.

Design the questions:

Each question should seek unbiased, unambiguous, clear and brief information.

Do not: assume that the customers have more than common knowledge; use jargon; lead the customer toward the answer
you want; tangle two questions together.

Do use complete sentences

Order the questions:

Order them to give context

Take data:

Any set of questions should be considered a test or verification.

Repeated application is required to generate usable information.

Reduce the data:

Make a list of customer’s requirements in the customer’s own word (easy; fast; other abstract terms).

The list should be in positive terms, i.e., wanted, not unwanted

QFD Step 2: Determine the Customer’s Requirements:

What do the customers want?


Types of Customers’ Requirements:

Functional Performance

Performance about the product’s desired behavior

Flow of energy, information, or materials; Operational steps; operation sequence

Human Factors

Required in any products that is seen, touched, heard, tasted, smelled or controlled by a human

Appearance; Force and motion control; Ease of controlling and sensing state

Physical Requirements

Available spatial envelope; Physical properties


Mean time between failures; Safety (hazard assessment)


Distribution (shipping); Maintainability; Diagnosability; Repairability; Testability; Cleanability; Installability;

Resources Concerns

Time; Cost; Capital; Unit; Equipment; Standards; Environment

Manufacturing Requirements

Materials; Quantity; Company capabilities

**For Spinal Implants:

Functional performance (flow of energy, operational steps and operation sequence)

Human Factors

Physical Requirements

Reliability (mechanical failure, corrosion, biocompatibility, and complications due to the failure)

Other requirements are not as critical as for other common products

QFD Step 2: Determine the Customer’s Requirements:

What do the customers want?


Resource Concerns

Time requirements:

Timing to introduce a new product

Cost Requirements:

Capital Cost:

Cost per Unit:

Cost estimation will be covered in Chap 12.

Standards (Codes):

Types of Standards:

Performance: seat
belt strength, helmet durability

Product Standards Index

lists US standards that apply to various products.

American National Standards Institute (ANSI) does not write standards but is a clearing house for
standards written by other organizations

Test Methods:

American Society for Testing and Materials (ASTM
) publishes over 4000 individual standards covering the
properties of materials, specifying equipment test the properties and outlining the procedures for testing.

Underwriters Laboratories (UL)

testing standards.

Codes of Practice:

Give parameterized design methods for standard mechanical components, such as pressure vessels, welds,
elevators, piping and heat exchangers

Knowledge of which standards apply to the current situation are important to
requirements and must be noted from the beginning of the project

Environment Concerns:


Evaluate the importance of each of the customers’

Generate a weighting factor for each requirement considering

To whom is the requirement important

How is a measure of importance developed for this diverse group of

How to determine the weight factor

Customer’s rating from 1 (unimportant) to 10 (important)

Fixed Sum Method:

Distribute the importance on all the listed requirements

QFD Step 3: Determine the Relative Importance of the
Requirements: Who vs. What


Determine how the customer perceives the competition’s ability
to meet each of the requirements.

1 The product does not meet the requirement at all.

2 The product meets the requirement slightly.

3 The product meets the requirement somewhat.

4 The product meets the requirement mostly.

5 The product meets the requirement completely.

Why studying existing products?

It creates an awareness of what already exists.

It reveals opportunities to improve on what already exists.

This process is called “Competition Benchmarking.”

QFD Step 4: Identify and Evaluate the Competition:

How satisfied is the customer now?


Engineering Specifications:

Restatement of the design problems in terms of parameters that can be measured and have target

Measurable behaviors of the product

If units for an engineering parameter can not be found, the parameter is not measurable and must
be readdressed.


Easy to attach

The number of steps; time to attach; number of parts; number of tools used

Every effort must be made to find as many ways as possible to measure customer’s

Carefully check each entry to see what nouns are or noun phrases have been used
because each noun refers to an object that is part of the product or its environment
and should be considered to see if new objects are being assumed.

“easy to adjust suspension system …” then “an adjustable suspension system” has been
assumed as part of the solution.

QFD Step 5: Generate Engineering Specifications:

How will the customers’ requirements be met?


QFD Step 6: Relate Customers’ Requirements to Engineering
Specifications: How to measure what?

Strong, medium, weak, and no relationship

QFD Step 7: Set Engineering Targets: How much is good

Ascertain how the competition meets the engineering goal.

Establish targets for the new product.



Set the target early.


Too tight target may eliminate new ideas.


If a target is much different than the values achieved by the competition, it should be

Strong negative; negative; Positive; Strong positive

QFD Step 8: Identify Relationships between Engineering
Requirements: How are the “HOWS” dependent to each


Example of QFD

Step 1: identify the customers

Step 2: determine the requirements

Step 3: determine the relative

importance of requirements

Step 4: identify and evaluate the


Step 5: generate engineering specification

Step 6: Relate customers’ requirements to

engineering specifications

Step 7: Set engineering targets

Step 8: identify the relationships between

engineering requirements


Basic Methods for Idea Generation


Record all the ideas generated.

Generate as many ideas as possible, then visualize them.

Think wild.

Do not allow evaluation of the ideas

5 Method (Brainwriting):

Brainwriting to force equal participation by all.

6 (optimal number of members); 3 (number of ideas); 5 (minute interval)

No verbal communication allowed until the end.

Use of Analogies in Design:

Consider needed function and then ask, What else provides this function?

Use of Extremes and Inverses:

Transform current concepts into others by taking them to extremes or considering

Finding Ideas in Reference Books and Trade Journals:

Using Experts to Help Generate Concepts:

Needed to design in a new domain


Guideline for Team Project

Use Brainstorming Method to determine a design item.

Make sure to write your own ideas in an individual notebook and finalized
team project item in PDF with minutes of brainwriting.

Do not try to make a fancy and complete product. Any improvement in a
small component can be a product for the design team project as long as the
techniques introduced in this class are well executed.

Make sure to follow all the steps suggested in this book and
produce a good design records.


Concept Generation


An idea that is sufficiently developed to evaluate the
physical principles that govern its behavior.

Goal of concept generation is to confirm that the proposed
product will operate as anticipated and that, with
reasonable further development, it will meet the targets

Concepts must be refined enough to evaluate the
technologies needed to realize them, to evaluate the
basic architecture (form) of them, and to evaluate the
manufacturability to some extent

Concepts can be represented in deliverables (sketch,
flow diagram, a set of calculations, prototypes, etc)

Examples of weak methodology

Start design with a concept to be developed into a

There is a tendency for designers to take their first
idea and start to refine it toward a product.

If you generate one idea, it is probably a poor one. If you
generate twenty ideas, you may have a good one. (or,
alternatively, he who spends too much time developing a single
concept realizes only that concept.

Main goal of this chapter is to learn techniques
for the generation of many concepts.

Functional decomposition

Concept variant generation


Understanding the Function of Existing Devices

Bench marking (review of existing devices) is always a good practice because:

There is nothing so new that ideas for it can not be borrowed from other devices.

Lots of engineering hours have been spent developing the features of existing products (it is
foolish to ignore it).

Defining Function:

Remember that


the product must do, whereas its


product will do it.

Develop the

and then map the

as we mapped

the customer required into

requirements were to be measured in QFD.

Function is the logical
flow of energy (including static forces), material, or information between

or the change of state of an object caused by one or more of the flows.

Functions required to attach any component to another are GRASP, POSITION, ATTACH. In
undertaking these actions, human provides information and energy in controlling movement and in
applying force to it. (Flow of energy, material, and information)

Functions associated with flow of energy:

Types of energy: mechanical, electrical, fluid and thermal

Its action: transformed, stored, transferred (conducted), supplied, and dissipated

Functions associated with flow of material:

flow: position, lift, hold, support, move, translate, rotate and guide

Diverging flow: disassemble, separate

Converging flow: assembling or joining materials (mix, attach, and position relative to)

Functions associated with flow of information:

In the form of mechanical signals, electrical signals or software

Generally used as part of automatic control or to interface with a human operator

Function associated with the change of state of an object:

Changes in energy storage, kinetic or potential energy, material properties, form or information content


Using Product Decomposition to

understand the Function of Existing Product

Step 1: For the whole device, examine interfaces with other objects.

Examine the flows of energy, information and material into and out of the device

Step 2: Remove a component for more detailed study.

Carefully note how it was fastened to the rest of the device and also any relationship it
has to other parts that may not contact.

It may have a clearance with some other parts in order to function.

Step 3: Examine each interface of the component to find the flow of energy


How the functions identified in step 1 are transformed by the component;

How the parts are fastened together;

How forces are transformed and flow from one component to anther; and

The purpose of each feature of component


Patents as a Source of Ideas

Patent Literature:

Good source of ideas although
hard to read

Sources for Patent Searches


for European and other foreign

Types of Patents:

Utility Patents:

Claiming how an idea operates or
is used

Design Patents:

Covering only the look or form of
the idea


Technique for Designing with Function

Goal of Functional Modeling:

To decompose the problem in terms of flow of energy, material, and

Decomposition forces a detailed understanding of what the product
be is to

4 Basic Steps:

Find the overall function that needs to be accomplished.

The goal is to generate a single statement of the overall function on the basis of
the customer requirements.

Create subfunction descriptions.

The goal is to decompose the overall function.

Order the subfunctions.

Refine subfunctions.


Step 1: Find the overall function

Most important functions must be
reduced to a simple clause and put it in
a black box.

Inputs into and outputs out of this black
box are all flows of the energy, material
and information.


Energy must be conserved.

Material must be conserved

All interfacing objects and known, fixed
parts of the system must be identified.

List all the objects (all features,
components, assemblies, humans, etc)
that interact, or interface, with the

Ask how will the customer know if the
system performing?

Answers to this question will help
identify information flows that are

Use action verbs to convey flow.

Typical mechanical design functions:

See Table 7.1

The BikeE suspension Example:

Overall function:

transfer and absorb

To transfer forces between wheel,
chain, and frame and absorb peak
loads between wheel and frame

Goal: alter the energy flow

Make sure to state the overall function
of your design in individual design
notebook (personal ideas) and finalized
overall function in the PDF.


Step 2: Create subfunction description

Goal is to decompose the overall function into subfunctions.

Reasons for Decomposition:

The resulting decomposition controls the search for solution to the design problem.

Since concepts follow function and products follow concepts, we must fully understand the function
before wasting time generating products that solve the wrong problem.

Decomposition into functional detail leads to a better understanding of the problem.

Most good ideas come from fully understanding the functional needs of the design problem.

It is useful to begin function decomposition before the QFD and use the functional development to help
determine the engineering specifications.

Decomposition may lead to the realization that there are some already existing components that
can provide some of the functionality required.


Consider what needs to happen (the function) not how.

Detailed, structured
oriented how consideration must be suppressed as they add detail too soon, which
limit the number of possible concepts too early.

Use only objects described in the problem specification or overall function.

Use only “nouns” previously used to describe the material flow or interfacing objects to avoid the new
components creeping into the product.

Break the function down as finely as possible.

Let each function represent a change or transformation in the flow of material, energy, or information.

Use standard notation when possible.

Whenever available, use common notations, such as block diagrams used to represent elec. circuits,
piping system, or transfer functions in systems dynamics and control, although there is no standard
notation for general mechanical product design.

Consider all operational sequences.

Think of each function in terms of its preparation, use, and conclusion.


Functional Decomposition for the Space Shuttle aft Field Joint


Step 3: Order the Subfunctions

Order the functions found in step 2 to accomplish the overall function in step


The flows must be in logical or temporal order.

Arrange the subfunctions in independent group (preparation, use, and conclusion).

In each group, arrange them so that the output of one function is the input of another.

Redundant functions must be identified and combined.

Similar subfunctions must be combined into one.

Functions not within the system boundary must be eliminated.

This step helps the team come to mutual agreement on the exact system boundary; it is
often not as simple as it sounds.

Energy and material must be conserved as they flow through the system.

Inputs to each function must match the outputs of the previous function.


Step 4: Refine Subfunctions

Examine each subfunction to see if it can be further divided
into sub

This step should be continued until:

‘atomic’ functions are developed; or

“atomic” implies that the function can be fulfilled by existing objects.

new objects are needed for further refinement.

It is a struggle to develop the suggested diagram of function

It is a fact that the design can be only as good as the understanding of the
functions required by the problem.

This exercise is both the first step in developing ideas for solutions and
another step in understanding the problem.

The functional decomposition diagrams are intended to be
updated and refined as the design progresses.


Concept Generation

Concepts are the means for providing function.

Any form that gives an indication how the function can be achieved.

What to do

Function vs. How to do

Concepts (forms)

Remember that the idea is often not original.

Many methods for concept generation are available, but no
single method is best.

A good designer is familiar with these methods and uses them, or a
combination of them, as needed.


Basic Methods for Concept Generation


Morphological Method

This technique uses the functions identified
to foster ideas.

Powerful method that can be used formally or
informally as part of everyday thinking

2 step approach

Step 1

Developing Concepts for Each

Goal is to find as many concepts as possible
that can provide each function identified in the

How to store mechanical energy: springs,
elastomers (rubbers or plastics), etc.

If there is a function with only one conceptual
idea, this function must be re

Situations explaining the lack of more concepts.

The designer has made a fundamental

The function is directed at how, not what.

“store energy in coil spring” rather than “store

Domain knowledge is limited.

Keep the concepts as abstract as possible and at
the same level of abstraction for better
comparison of developed concepts.

The force required for moving an object can be
provided by a hydraulic piston, a linear electric
motor, the impact of another object, or magnetic

Refined mechanical components vs. basic physical

Morphology for BikeE Suspension System


Morphological Method

Step 2

Combining Concepts:

to combine these individual concepts into
overall concepts to meet all the functional

Select one concept for each function and
combine those into a single design.


This method may generate too many ideas.

It erroneously assumes that each function of
the design is independent and that each
function satisfies only one function.

The results may not make any sense.

Concept generation process is the time
that back
envelope sketches begin

We remember functions by their forms

Only way to design an object with any
complexity is to use sketches to extend the
term memory.

Sketches made in the design notebook
provide a clear record of the development of
the concept and the product.

Combined Concepts for BikeE Suspension System


Logical Methods for Concept Generation

The Theory of Inventive Machines, TRIZ:

Developed by Genrikh Altshuller (a ME engineer, inventor, and Soviet patent
investigator) in Soviet Union in the 1950s based on patterns found in patented

Goal of TRIZ:

Find the major contradiction that is making the problem hard to solve, then

Use TRIZ’s 40 inventive ideas for overcoming the contraindication

With TRIZ, we can systematically innovate; we don’t have to wait for an
inspiration or use the trial and error common to other methods.

Axiomatic Design:

Evolved in MIT by Prof. Nam Suh in an effort to make the design process



Maintain the independence.

Then, a change in a specific design parameter should have an effect only on a single function.



Minimize the information content of the design.

The simplest design has the highest probability of success and is the best alternative.


Concept Evaluation

How to choose the best of the concepts generated for
development into a quality product?

Goal is to expend the least amount of resources on deciding which concepts
have the highest potential for becoming a quality product.

It is difficult to evaluate concepts, or to choose which concepts to spend time,
particularly when we still have very limited knowledge and data on which to
base this selection.

Design is learning, and resources are limited.

Techniques for systematic evaluation of rough concepts.

Evaluation implies both “comparison” and “decision making.”

It is the comparisons between alternative concepts and the requirements that they
must meet that gives the information necessary to make decisions.

For all design decisions:

Itemizing the alternatives and the criteria for their evaluation

Comparing the alternatives to the criteria to each other

For comparisons:

Alternatives and criteria must be in the same language and they must exist at the
same level of abstraction


Concept Evaluation Techniques

Be ready during concept
evaluation to abandon your
favorite idea, if you can not
defend it in a rational way.

Abandon if necessary “the
way things have always have
been done around here”.


Information Presentation in Concept Evaluation

Design Evaluation Cycles


Evaluation based on Feasibility Judgment

Three Immediate Reactions of a Designer as a concept is generated based on
designer’s “gut feel”:

It is not Feasible.

It might work if something else happens.

It is worth considering.

Implications of Each of these Reactions:

It Is Not Feasible.

Before discarding an idea, ask “Why is it not feasible?”

Make sure not to discard an idea because:

a concept is similar to ones that are already established, or

a concept is not invented here (less ego

It is Conditional.

To judge a concept workable if something else happens.

Factors are the readiness of technology, the possibility of obtaining currently unavailable
information, or the development of some other part of the product.

It is Worth Considering.

The hardest concept to evaluate is one that is not obviously a good idea or a bad one, but
looks worth considering.

Such a concept requires engineering knowledge and experience. If sufficient knowledge is
not immediately available, it must be developed using models or prototypes that are easily


Evaluation based on GO/NO
GO Screening

Measures for deciding to go or no

Criteria defined by the customer requirements:

Absolute evaluation by comparing each alternative concept with the customer

A concept with a few no
go responses may be worth modifying rather than

This type of evaluation not only weeds out designs that should not be considered
further, but also helps generates new ideas.

Readiness of the technologies used:

This technique refines the evaluation by forcing an absolute comparison with
art capabilities.

6 Measures for a Technology’s Maturity:

Are the critical parameters that control the function identified?

Are the safe operating latitude and sensitivity of the parameters known?

Have the failure modes been identified?

Can the technology be manufactured with known process?

Does hardware exist that demonstrates positive answers to the preceding four questions?

Is the technology controllable throught the product’s life cycle?

If these questions are not answered in the positive, a consultant or vendor is
added to the team.


Evaluation based on a Basic Decision Matrix

Matrix Method (or Pugh’s

effective comparison of alternative concepts
(basic form Table 8.2)

Iteratively test the completeness and
understanding of requirements, rapidly
identifies the strongest

Step 1: Choose the criteria for Comparison.

Criteria are the functional requirements and
engineering specification determined in QFD.

The concepts must be refined enough to
compare with the engineering targets for
evaluation (mismatch in the level of

Step 2: Develop Relative Importance

Step 3 in QFD should provide the data for
relative importance.

Step 3: Select the Alternatives to be

Step 4: Evaluate Alternatives.

Relative evaluation among alternatives

Step 5: Compute the Satisfaction.


This method is most effective if
each member performs it
independently and the individual
results are then compared.


have BDM in individual notebook.


Decision Matrix for Energy Management System

S indicates “Same as datum”


Robust Decision Making

Robust decision refers to make decisions that are as insensitive
as possible to the uncertainty, incompleteness, and evolution of
the information that they are based on.

For robust decision making, we need to improve the method
used to evaluate the alternatives (step 4 in decision

Word Equations used for Robust Decision Making