Strain Energy

JoVE Core
Mechanical Engineering
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JoVE Core Mechanical Engineering
Strain Energy

Vidéo suivante27.2: Strain-Energy Density

Consider a rod fixed at one end and subjected to an axial force at the free end, which induces stress and leads to elongation in the rod.

As the axial force is increased, the elongation increases. The plot of axial force versus elongation results in a characteristic load-deformation plot.

The work done by the axial force, as the rod elongates by a small amount, is the product of the axial force and the corresponding elongation.

This work equals the area under the deformation plot, the width of which equals the small deformation.

The total work done can be calculated by integrating the equation within the elongation limits and is equal to the area under the load-deformation curve within the same elongation limits.

The total work done on the rod represents the energy input to the system, known as the strain energy.

Within the elastic limit, the axial force is proportional to the amount of elongation. So, the strain energy is proportional to the square of the elongation.

Strain Energy

Strain energy is a fundamental concept in the field of materials science and structural engineering, describing the energy absorbed by a material or structure when it is deformed under load.

Consider a rod that is fixed at one end and subjected to an axial force at the free end. This axial force induces stress within the rod, leading to its elongation. As the axial force increases, so does the elongation of the rod, illustrating a direct relationship between the force applied and the resulting deformation. This behavior can be graphically represented by a load-deformation plot.

The work done by the axial force to elongate the rod by a small amount is equal to the product of the force and the corresponding elongation. Graphically, this work corresponds to the area under the load-deformation curve for a given elongation. To calculate the total work done on the rod for any given elongation, one must integrate the force-elongation equation over the elongation limits. This total work represents the energy input to the system, which is stored as strain energy. Within the elastic limit of the material, the strain energy U stored in the material due to elastic deformation is proportional to the square of the elongation.

The concept of strain energy allows engineers to quantify the energy absorption capacity of a material or component, which is essential for assessing its ability to withstand loads without undergoing permanent deformation or failure. Strain energy also plays a pivotal role in various engineering applications, such as the design of shock absorbers, energy storage devices, and in the analysis of impact forces.