Question

Which of the following strain mainly represents the change of shape?

• A. Lateral strain
• B. Longitudinal strain
• C. Shear strain
• D. Volumetric strain

Hint:

Shear strain is often used to describe the deformation in materials where forces cause a change in shape without altering the object's overall size or volume. To identify shear strain, look for situations where an object’s angles change but its volume stays constant.

Answer 1

The Correct Option is C

We are asked to determine which strain mainly represents the change in shape of an object. Let's go through the four types of strain and analyze their effects on the shape of the material.

Step 1: Understanding different types of strain. There are four types of strain mentioned in the options:
Lateral strain: This refers to the strain that occurs in directions perpendicular to the applied force. Lateral strain usually causes changes in the dimensions (like the radius or cross-sectional area) but doesn't typically affect the overall shape in a drastic manner. 
Longitudinal strain: This strain occurs along the direction of the applied force and changes the length of an object. It does not affect the shape as much as it affects the size (the length) of the object. 
Shear strain: This strain results from forces that cause the object to deform by changing its shape without changing its volume. It involves a shift in angles between parts of the object, typically affecting the shape but not the overall size. 
Volumetric strain: This strain affects the volume of an object, such as when a material is compressed or expanded, changing its size. This does not directly affect the shape unless the volume change is very significant.

Step 2: Identifying the strain responsible for shape change. Out of these four types of strain, shear strain is the one that primarily leads to a change in the shape of the object. In shear strain, an object experiences a deformation where the internal angles change. This leads to a change in shape (like the object becoming slanted), while the object's volume might remain constant. This is exactly what we are looking for: a strain that mainly represents a change in shape without necessarily affecting the volume.