Title Combined Bending and Torsion Lab report 1.1Β MB 14
##### Document Text Contents
Page 1

MMEE22111144 -- 22 CCoommbbiinneedd

by

Lin Shaodun

Student ID: A0066078X

Sub Group: Lab 2B

Date: 5
th

Feb 2010

Page 13

12

Above graphs shows, FEA result match with theoretical calculation very well,

deviation is less than 5% for both bending and shear stress. So the possible

reason of deviation between experimental and theoretical result could be the

strain gauge output drift, hence the strain measurement result needs to be

compensated by a new Gauge Factor (πΊπΉ =
βπ/ππ

π
).

2) From the results of step (b5), deduce the type of stain the stain-meter reading

represent.

ππ is the axial strain from combined bending and torsion, ππ is the lateral

strain from combined bending and torsion . Hence Poissonβs ratio can be

obtained by this equation: π = ππ/ππ

3) Apart from the uniaxial tension method used in the experiment, how can the

elastic constant be determined?

Ultrasonic method can be used to determine the elastic constant:

π = 1 β 2
πΆπ
πΆπΏ

2

2 β 2
πΆπ
πΆπΏ

2

πΈ = 2ππΆπ
2 1 + π

CS --- Speed of sound wave in longitudinal direction

CL --- speed of sound wave in shear direction

A commercial equipment of using this technique can be found in this

webpage: http://www.olympus-ims.com/en/applications-and-solutions/ndt-

theory/elastic-modulus-measurement/

http://www.olympus-ims.com/en/applications-and-solutions/ndt-theory/elastic-modulus-measurement/
http://www.olympus-ims.com/en/applications-and-solutions/ndt-theory/elastic-modulus-measurement/