MEM23061A Test Mechanical Engineering Materials

tobascothwackUrban and Civil

Nov 15, 2013 (3 years and 6 months ago)

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Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


1


MEM23061A Test Mechanical Engineering Materials

Lab
.

BEAM BENDING

Report

Answers

1. Use Solid Edge to calculate Ixx for each beam. Also determine the weight on CAD. Draw up the cross
-
section (either in part

mode or as a draft). While you are still in the

profile sketch (i.e. before going to a
solid) go to top menu:

Inspect > Area... > Click "Area Information" button in Ribbonbar > (click inside the
area you want to inspect) > Click on the green arrow in Ribbonbar. > You should see a table like this...



Ixx is the Second Moment of Area in bending with

a vertical load.

Sorry there is something wrong and
I

cannot figure it out !

Aluminium Channel

Command: MASSPROP


Select objects: 1 found


Select objects:



----------------

REGIONS
----------------


Ar
ea: 0.1837

Perimeter: 4.5203

Bounding box: X:
-
0.0037
--

0.8092

Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


2



Y: 0.0000
--

0.7632

Centroid: X: 0.3876


Y: 0.2965

Moments of inertia: X: 0.0270



Y: 0.0468

Product of inertia: XY: 0.0205

Radii of gyration: X: 0.3836


Y: 0.5049

Principal moments and X
-
Y directions about centroid:


I: 0.0108 along [0.9976
-
0.0691]


J: 0.01
93 along [0.0691 0.9976]


Aluminium Beam

Command: MASSPROP


Select objects: 1 found


Select objects:



----------------

REGIONS
----------------


Area: 0.2503

Perimeter: 4.5829

Bounding box: X:
-
0.0059
--

0.77
00


Y: 0.0000
--

0.8689

Centroid: X: 0.3790


Y: 0.4301

Moments of inertia: X: 0.0740


Y: 0.0447

Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


3


Product of inertia: XY: 0.0401

Radii of gyration: X: 0.5436



Y: 0.4225

Principal moments and X
-
Y directions about centroid:


I: 0.0087 along [0.0356
-
0.9994]


J: 0.0277 along [0.9994 0.0356]

Calculation for Aluminium Beam:

E1 & E2: Top and Bottom

Height = (hi
-
h2) / 2 =
(22.1
-
19.1) = 1.5mm

d1 = 19.1/2+(1.5/2)=10.3mm

Ic1=bd^3/12=18*1.5^3/12=5.0625mm4

I1=Ic1+Ad^2


= 5.0625+(18.1*1.5)*(10.3^2)=2869.4925mm4

E2:

Ic2=bh^3/12=1.5*19.1^3/12=870.983875mm4

Total I=I1+I2+I3


= 2.69.4925+2869.4925=870.983875=6609.968875mm4

20120809 Test results:


Specimen

I Second
Moment

of
Area (mm4)

Modulus of Elasticity
E

Maximum Stress f( Mpa)

Aluminium Channel




2 kg + 1 lb Hook




5kg + 1 lb Hook




7 kg + 1 lb Hook








Aluminium Channel




2 kg + 1 lb Hook




5kg + 1
lb Hook




7 kg + 1 lb Hook








Tas Oak Timber




100 g Hook

154.1

67665.77494

7.042383193

300 g Hook

154.1

102545.0404

21.12714958

500 g Hook

154.1

109788.8401

35.21191596





Steel Flat Bar




Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


4


1 lb hook only

260.42

183935.1456

10.59466439

500 g + Hook

260.42

195682.5346

22.36651371

1 kg + Hook

260.42

191251.3335

34.13836303





Steel Square Bar




2 kg + 1 lb Hook

894.73

174339.9121

34.18226867

5 kg + 1 lb Hook

894.73

176330.554

76.03810786

6 kg + 1 lb Hook

894.73

181666.4088

89.99005
426





Aluminium Beam




5 kg + 1 lb Hook

6609.97

67403.86114

18.19904251

8 kg + 1 lb Hook

6609.97

65316.81498

28.21686407

10 kg + 1 lb Hook

6609.97

68022.24518

34.89541178





Tas Oak Timber




200 g

977.96

20898.09399

2.106527874

400 g

977.96

2
0876.79114

4.208761095

600 g

977.96

20898.09399

6.319583623



2. Write a short

report on the beam bending results. Each beam must have at least 3 weights. Make sure the
deflection does not exceed the travel of the dial indicator (if so, use a lighter we
ight).


Testing:
In our test, the specimen are supported at both ends in a
simply supported
beam configuration. Th
e
supports are placed on the rig or pivots
.

Small weights (
masses
) are used to load the beams and
deflections measured with a vernier calipe
r and recorded.

Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


5



Specimen

Start

5

kg + Hook
2.2
kg

8 kg + Hook 2.2
kg

10

kg + Hook
2.2
kg

Aluminium Beam
18.0
0
mm wide x
50.50 mm

48.00 mm

46.50 mm

45.75 mm

Stud
ent: Jagdishwar Kishor 264964237 Teacher: Tim Love
tt


6


22.10 mm height x
1.50 mm cross
-
section






Specimen

Start

100 g + Hook 100g

300 g + Hook 100g

5
00 g + Hook 100g

Tas Oak Timber
19.80 mm wide x
8.40 mm height

37.00 mm

35.00 mm

33.00 mm

31.00 mm



3. Using the equations above, calculate the value of E. Compare these values to the values obtained from

the
internet. E.g. Matweb. Show the working for
1 example calculation, but only give the rest of the answers in
a table. Use Excel to do your calculations.

Modulus of Elasticity
E =


W * L
3

/ (48 * z * I)





= 1.962*1000^3 / (48* 2*977.96)





=
20898.09399

Please refer to table above in Q1
.:


4. D
etermine the maximum stress

for each mass (load) added to the beams.

Please refer to table above in Q1.:


5. Discuss any sources of error in the experiment
-

esp.

measurements
-

and how they might affect the
results. Specify an overall error for your calc
ulation of E.

During this procedure, a few

measurement uncertainties did

affect the results. First, the

dimensions pertaining to the spe
cimen were given in
millimetres
.
It was
estimated to be an error of
±0.05
mm. Also, the calculated

weight (newtons) had t
o be converted to mass for measurement. This
uncertainty in conversion

was estimated t
o be 0.5%. The weight of the hook

was to be determined and
subtracted from this

value to find the load for each stress level. The error in calculating the

weight was
assu
med to be 10g, although the
tec
h
nique

used to find it (hanging increasing counter

weights
) was highly subjective and could have resulted in

significantly more error, which
was impossible to
determine.


Other errors did

occur reading the
vernier calipers

wh
en calibrating the specimen in the machine.

Human error and w
ell as the accuracy of the caliper

itself could cause error in loading

and measuring

the
part.

Since the equation to find the applied stress has a set value for the distance between the loaded

en
ds of the specimen
, improperly loaded specimens would be incorrect as well. The

mass applied to the specimen depends on the certainty of the label
l
ed weights. The specimens

varied

in weight and dimensions causing variance in the results.