Stress analysis very near to the point of application of load \( P \). Saint-Venant's principle: the stress and strain produced at points in a body sufficiently removed* from the region of external load application will be the same as the stress and strain produced by any other applied external loading that has the same statically equivalent resultant and is applied to the body within the same region.
*farther than the widest dimension of the cross section\( \delta_T \) , \( \varepsilon_T \) present in addition to elastic \( \delta_E \) , \( \varepsilon_E \) (from internal forces). Superposition (small strains):
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Stress concentration factors build on this content in engineering materials and mechanical design.
The stress concentration factor is the highest at lowest cross-sectional area.