Stress is defined as the force per unit area that acts on a material. It is the force applied to a material, divided by the material’s cross-sectional area. Stress can be caused by externally applied forces, uneven heating, or permanent deformation. Stress can be normal, shear, or a mixture, and can also be uniaxial, biaxial, or multiaxial, and can change with time.
Strain is the amount of deformation experienced by a body in the direction of the force applied, divided by the initial dimensions of the body. Strain is the deformation or displacement of material that results from an applied stress. The form of deformation can be compression, stretching, torsion, rotation, and so on.
The relationship between stress and strain is described by the stress-strain curve, which gives the relationship between stress and strain for a material. It is obtained by gradually applying load to a test coupon and measuring the deformation. The stress-strain curve can be used to predict the performance and failure of materials and structures.
In summary, stress is the force applied to a material, while strain is the resulting deformation of the material due to the stress.
