Permanent Elongation of a Bar Using Stress–Strain Diagram | Axial Load Problem (100 kN → 360 kN)

In this Mechanics of Materials example, we determine the elongation of a square hollow bar subjected to an axial load of 100 kN. The load is then increased to 360 kN and released, and we calculate the permanent elongation using the stress–strain diagram. This problem demonstrates the difference between elastic deformation and plastic deformation, and how to determine permanent strain after unloading. Topics covered in this video: • Axial loading of bars • Stress–strain diagram interpretation • Elastic vs plastic deformation • Permanent elongation after unloading • Hooke’s Law and modulus of elasticity • Mechanics of materials problem solving This type of problem commonly appears in engineering mechanics, strength of materials, mechanical engineering, and civil engineering courses. If you're preparing for FE exam, engineering exams, or mechanics homework, this step-by-step solution will help you understand the concept clearly. 👍 Subscribe for more Engineering Mechanics and Mechanics of Materials tutorials. 👉 Support the channel: Become a member to help me create more high-quality tutorials:    / @mathphysicsengage