Q1: The maximum value, which the residual stress in a material can reach is the __________ of the material.

ANS:A - elastic limit

The elastic limit, also known as the proportional limit, is a property of materials that describes the maximum stress that a material can withstand without undergoing permanent deformation. Here's an explanation of the elastic limit:

1. Definition: The elastic limit is defined as the maximum stress at which a material remains elastic, meaning that it can return to its original shape and size after the applied stress is removed, without any permanent deformation.
2. Elastic Deformation: When a material is subjected to stress below its elastic limit, it deforms elastically. In this region, the material follows Hooke's Law, which states that the stress applied is directly proportional to the strain produced. This means that when the stress is removed, the material returns to its original dimensions without any permanent change.
3. Plastic Deformation: Beyond the elastic limit, if the stress applied to the material exceeds the elastic limit, the material undergoes plastic deformation. Plastic deformation involves permanent changes in the material's shape or size, even after the applied stress is removed. At this point, the material does not return to its original dimensions, indicating that it has exceeded its elastic limit.
4. Determination: The elastic limit is determined experimentally through tensile testing or other mechanical tests. In a tensile test, the stress-strain curve of the material is plotted, and the elastic limit is identified as the point at which the curve deviates from linearity and begins to exhibit plastic behavior.
5. Importance: The elastic limit is a critical property of materials, especially in engineering applications where the ability to withstand repeated loading without permanent deformation is essential. Materials used in structural components, machinery parts, and other critical applications are often selected based on their elastic limit to ensure that they can withstand the expected loads without failure or deformation.