Constitutive equations

Constitutive equations are mathematical relationships that describe how materials respond to external forces or conditions, like stress and strain. They connect physical properties, such as stiffness or viscosity, to how materials deform or flow under different circumstances. For instance, in engineering, these equations help predict how a bridge will bend under weight or how a fluid will behave when pushed through a pipe. Essentially, they are crucial for understanding and designing materials and structures in various fields like physics, engineering, and material science.