Why values of stresses and strains are different between experimental and theoretical?

The differences in values of stresses and strains between experimental and theoretical results can arise from several factors. Experimental conditions may include imperfections, material inhomogeneities, and environmental influences not accounted for in theoretical models. Additionally, assumptions made in theoretical calculations, such as idealized material behavior or simplified boundary conditions, can lead to discrepancies. Furthermore, measurement errors and limitations in experimental techniques can also contribute to the observed differences.