In mechanical engineering, stress is defined as the measure of an external force acting over the cross-sectional area of an object. It is a fundamental physical quantity that describes forces present during deformation). Stress has units of force per area, such as N/m2 (SI) or lb/in2 (US) . Engineers use stress to aid in the design of structures, and each material has an ultimate stress, which is a measure of how much stress the material can withstand before failing. Stress analysis is a branch of applied physics that covers the determination of the internal distribution of internal forces in solid objects). Stress analysis is an essential tool in engineering for the study and design of structures such as tunnels, dams, mechanical parts, and structural frames, under prescribed or expected loads). Stress analysis is a way to evaluate the effect that different loading conditions have on materials and structures, and it plays a crucial role in every part that is under significant service stress. There are different types of stress in engineering, including compression, tension, shear, bending, torsion, and fatigue.