APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SECOND SEMESTER M-TECH DEGREE EXAMINATION, MAY 2016
Mechanical Engineering

(Machine Design)
0 | ME6106 EXPERIMENTAL STRESS ANALYSIS

Max marks : 60 Duration : 3 houKS

Answer any two full questions from each PART

PART A

1.(a) Derive the equations ofcompatibility. (3)

(b) The Cartesian components of stress at a point in a steel (E—- 207 GPa, v = 0.30) machine
part are
2௦: 220 MPa, = 77 MPa, = 154 MPa, = 1 10 MPa,
= 55 MPa,Txz = 66 MPa.
Deten-nine the principal strains at that point, (5) (€) Explain cubical dilatation. (1)

2. (9) Describe about any one mechanical strain gauge. (3)

(0) A three element rectangular rosette is mounted on a steel component with E= 200 GPa and v
= 0.3. The manufacturer's gauge factor F and the cross sensitivity ICt ofthis type of gauge is
known to be 2.8 and 0.06 respectively. The readings correspond to three gauges as indicated
on astrain meter are (6) €4= 850 strain, = -50 .11 strain, -850 g Strain,

i. Find the actual strains त, 6B, cc.
ii. Find the magnitude of corrected principal stresses.

iii, What is the error, if indicated strains iA, and are used to calculate the principal strains.

3. (a) Explain the in-plane displacement Moire fringe analysis of strain measurement. (4)
(b) What is residual stress? Brief about the residual stress measurement? (5)
PART B

4. (a) Explain the use ofcircular polariscope in photoelasticity. Derive the equations for light passing
through a stressed model in a circular polariscope. (6)

(b) Discuss about isochromatic and isoclinic fringe patterns. (3)