Strain describes a deformation of a material, which is loaded mechanically by an external force or StressStress is defined as a level of force applied on a sample with a well-defined cross section. (Stress = force/area). Samples having a circular or rectangular cross section can be compressed or stretched. Elastic materials like rubber can be stretched up to 5 to 10 times their original length.stress. Rubber compounds show creep properties, if a static load is applied.