Final answer:
Elastic deformation is the reversible change in shape or size of a material under stress, reverting back to its original state when the stress is removed. It stops when the stress increases beyond the material's elastic limit, leading to permanent, plastic deformation.
Step-by-step explanation:
Elastic deformation refers to the temporary change in the shape or size of a material under stress, which reverses after the stress is removed, allowing the material to return to its original state. Materials stop exhibiting elastic deformation when the applied stress surpasses the elastic limit, a threshold value beyond which the material deforms permanently, known as plastic deformation. To give an example, when a rubber band is stretched within its capacity, it will return to its initial shape once the force is released; this is elastic deformation. If the rubber band is stretched too far beyond its elastic limit, it might break or remain stretched out, illustrating plastic deformation.
The elastic modulus and elastic limit are crucial parameters that determine the elasticity of a material. Materials like steel, with a high elastic modulus, are hard to deform. In contrast, materials with a low elastic modulus, such as rubber, deform more easily. When stress progresses beyond the elasticity limit, the material no longer snaps back to its original form and instead becomes permanently reshaped or resized. This behavior is evident in stress-strain diagrams where the linear, elastic portion gives way to a plastic, non-linear region as stress increases.
Elasticity is immensely significant in engineering, including bioengineering, because materials that can undergo elastic deformation without permanent change are essential in applications where energy absorption and recovery are necessary, such as in shock absorbers. Understanding the elastic properties helps in designing materials and structures that respond predictably under stress.