Lecture 17 part 2

Question 1

Ascertaining the best available experimental technique should be done only after considering ______ ________ ____________

Answer 1

Stress analysis requirements

Question 2

What are the 2 most sensitive techniques? One of these has a limitation with regard to information. what is it?

Answer 2

Moire interferometry and Strain guages - which only give point by point data, depending on the gauge length.

Question 3

Name the 3 easiest and the most difficult technique

Answer 3

2D photoelasticity, TSA and DIC

Moire Interferometry

Question 4

One technique does not inform about full field strain difference and direction. Which is this, and name 4 that give excellent information.

Answer 4

Strain gauge.

2Dphotoelasticity, 3D photoelasticity, TSA and DIC

Question 5

Most methods allow use of real components under high temperature conditions. name the exceptions

Answer 5

2D and reflection photoelasticity must be performed at room temperature and DIC has no such high temperature capability.

3D photoelasticity requires a model and reflection requires a coating on the part

Question 6

3 methods only give surface information, one other method requires a very flat surface, and only one of all the methods deals with a curved surface positively.

Name em.

Answer 6

You know my name?!
William!

Hes coming for me.
youll see.

Reflection photoelasticity, Strain Gauge and TSA

Moire

DIC

Question 7

Moire methods require the application of a pattern in the form of a grating. Name another method that requires application of a pattern, and mention some advantages despite this.

Answer 7

DIC
Large range of specimen sizes
Relatively fast data processing

Question 8

Name a unique advantage and a unique limitation of TSA

Answer 8

Non -contact :)
Requires cyclic loading :(

Question 9

Comment on the observable loading from 2D and 3D photoelasticity methods

Answer 9

2D observes mainly static loading
3D requires models which can only ovserve one mode of loading each.

Question 10

Here is a summary of key points of the methods. Arent I nice.

Answer 10

Question 11

So for the glass case study, why is reflection photoelasticity suitable to observe the working stress?

Answer 11

The glass is birefringent.
The processing causes compressive stresses on the surface which this method is suited to observe. A stress distribution through its thickness is also caused, which can be observed at the edge of the glass. Consistency can then be assessed and a measure of control of the processing obained.