Question

Toughness is the ability of the material to absorb energy

• A. till ultimate failure
• B. before yielding fatigue
• C. within the elastic limit
• D. up to the proportionality limit

Hint:

Toughness measures energy absorption capacity until failure, not just until yield.

Answer 1

The Correct Option is A

Toughness Explained: 

Toughness is a critical material property in engineering, particularly in fields such as aerospace engineering, where materials are often subjected to various forms of stress. It is defined as the ability of a material to absorb energy and plastically deform without fracturing.

The toughness of a material is represented by the area under the stress-strain curve from zero stress up to the point of fracture. This encompasses all the energy a material can absorb before it ultimately breaks. Therefore, toughness is best described by the option 'till ultimate failure'. This indicates that the material can sustain deformation and absorb energy until it reaches its breaking point, rather than merely yielding or remaining within any elastic or proportional limits.

Stage of Material	Explanation
Within the Elastic Limit	The material returns to its original shape after the removal of stress.
Up to the Proportionality Limit	Stress and strain are directly proportional; material behaves elastically.
Before Yielding	Material undergoes plastic deformation for the first time but can absorb some energy.
If Taken Till Ultimate Failure	This is true toughness, where maximum energy absorption occurs before fracture.

In conclusion, the correct understanding of toughness in materials science and aerospace engineering is its ability to absorb energy till ultimate failure.