Materials: Elastic Strain Energy

Elastic Strain Energy: Basic Understanding

Elastic strain energy is the energy stored in a material when it is deformed elastically.
It is the work done on the material to cause deformation, which can later be recovered if the deformation is within the elastic limit.
The elastic strain energy per unit volume is equivalent to the area under the stress-strain graph.

The elastic strain energy is dependent on two key parameters: the amount of stress and the degree of strain experienced by the material.
Stress is defined as the force per unit area applied to an object, which leads to deformation.
Strain is the degree of deformation experienced by the object, typically calculated as the change in dimension over the original dimension.
The elastic strain energy (U) can be calculated using the formula: U = 0.5 x Stress (σ) x Strain (ε).

The elastic strain energy stored in a material is influenced by its elastic modulus, with stiffer materials storing more energy.
The shape and dimensions of the material also affect the amount of energy stored.
Higher deformation (within the elastic limit) leads to more energy being stored, evidenced by a greater area under the stress-strain curve.

Within the limit of proportionality, the relationship between stress and strain is linear, as stated by Hooke’s Law. In this region, the elastic strain energy can be represented by the area of a triangle on the stress-strain graph.
Hooke’s law can be used to calculate the elastic strain energy. This energy is equivalent to the work done stretching the material, and within the elastic limit, can be regained when the material is unloaded.

Understanding elastic strain energy is crucial in engineering applications such as designing springs and buffer systems, where the storage and release of energy is a key function.
In structures such as buildings and bridges, predicting and mitigating elastic strain energy helps in ensuring structural stability and preventing catastrophic failures.
Elastic strain energy concepts are also key in the field of biomechanics, understanding muscle and tendon function, and designing prosthetics.
In the aerospace sector, materials are often chosen and workflow designed based on how best to manage and utilise elastic strain energy.