Stress-strain behavior describes how materials respond to applied forces. When a force is applied to a material, it experiences stress, which is the force per unit area. The material deforms, and this deformation is measured as strain, which is the change in length divided by the original length. The relationship between stress and strain helps engineers understand how materials will behave under different loads. Different materials exhibit unique stress-strain curves, which illustrate their mechanical properties. For example, metals typically show a linear relationship up to a certain point, known as the yield strength, after which they may deform permanently. In contrast, rubbers can stretch significantly before breaking, demonstrating high elasticity.