Resilience vs Toughness: Difference and Comparison

Key Takeaways

1. Material Response to Stress: In materials science, both resilience and toughness refer to a material’s ability to absorb energy. Resilience is the capacity of a material to absorb energy when it’s deformed elastically (i.e., non-permanently), and to release that energy upon unloading. Toughness, on the other hand, is the total amount of energy a material can absorb before rupturing, including both elastic and plastic (i.e., permanent) deformation.
2. Area Under the Stress-Strain Curve: Resilience is represented by the area under the elastic portion (up to the yield point) of a material’s stress-strain curve, quantifying the energy per unit volume that the material can absorb and recover from. Toughness is represented by the total area under the stress-strain curve, up to the point of fracture, signifying the material’s ability to absorb energy before failure.
3. Applications and Material Characteristics: In designing structures or products, a material with high resilience is chosen when the goal is to minimize deformation under stress and to ensure the material returns to its original shape (like springs). A material with high toughness is chosen when the aim is to prevent a sudden failure due to a crack or notch (like in automobile bodies or ship hulls).

What is Resilience?

Resilience is defined as the property shown by the material to store or absorb energy without permanent deformation. When tension or compression is subjected, it is among the materials’ mechanical properties. 

The materials exhibiting high resilience power undergo deformation within the elastic limit and again exhibit their original shape. Examples of materials that show resilience properties are – rubber and certain alloys.

What is Toughness?

Toughness is defined as the ability shown by any material to absorb energy without fracturing. It is also one of the mechanical properties shown by the materials. It is measured by the total area coming under the stress-strain curve. 

The material behaviour in toughness is associated with the materials having the capability to undergo plastic deformation before failure. The formula for toughness is as follows –
Toughness=Area under the stress-Strain curve

Difference Between Resilience and Toughness

1. The term Resilience is defined as the property shown by the material to store or absorb energy without permanent deformation. While at the same time, the term Toughness is defined as the ability shown by any material to absorb energy without fracturing.
2. The behaviour shown by the resilient material is the elastic deformation in which the material regains its original shape. While in contrast, the toughness shown by the materials resembles plastic deformation in which the material undergoes permanent deformation.
3. The resilience is measured by the complete area covering the elastic region of the stress-strain curve. While, in contrast, on the other hand, the toughness of a material is measured by the complete area under the stress-strain curve.
4. The significance of the resilience of a material is the ability to absorb energy and recover after small deformation. Comparatively, on the other hand, the significance of the toughness of a material is the ability to thwart large deformation or impact. 
5. The triangular area of the stress-strain curve under the elastic region represents resilience. At the same time, toughness is represented by the total area under the stress-strain curve.
6. The material behaviour in the case of resilience is that it is associated with materials showing high elastic moduli (stiffness). Comparatively, on the other hand, the material behaviour in toughness is associated with the materials having the capability to undergo plastic deformation before failure. 

Comparison Between Resilience and Toughness

Parameter of Comparison	Resilience	Toughness
Definition	It is the property shown by the material to store or absorb energy without permanent deformation	It is the ability shown by any material to absorb energy without fracturing
Behaviour	Elastic deformation	Plastic deformation
Measure	It is the complete area under the elastic region of the stress-strain curve	It is the complete area under the stress-strain curve
Significance	It is the ability to absorb energy and recover after small deformation	It is the ability to thwart large deformation or impact
Representation	A triangular area of stress-strain curve under the elastic region	Total area coming under the stress-strain curve
Material behaviour	Associated with materials showing high elastic moduli (stiffness)	Associated with the materials having the capability to undergo plastic deformation before failure
Formula	Resilience=0.5×Strain at Yield×Stress at Yield	Toughness=Area under the stress-Strain curve
Units	J/m3 or J/g	J/m2 or J/m3
Critical Use	For shock absorption and load-bearing capacity with elastic limit	Materials that may show significant impacts or plastic deformation

References

1. https://www.sciencedirect.com/science/article/abs/pii/S0022391318303585