How Do Engineers Choose Part Sizes? | Mechanics of Materials 01: Stress and Strength

What is stress, and how do engineers decide how big a part should be? Learn the foundation of mechanics of materials (strength of materials), normal stress and shear stress, through an animated garden swing problem. In this lesson we build the idea of stress step by step: what mechanics of materials is for, the three requirements of a good design (strength, economy, functionality), the method of sections, and internal forces. We define normal and shear stress, explain stress subscripts, and prove visually why shear stresses on perpendicular faces are equal (τxy = τyx). 🔑 Key concepts: • Stress • Normal stress (σ) • Shear stress (τ) • Method of sections • Internal force and moment • Equality of shear stresses ⏱️ Chapters: 00:00 Intro 00:22 Motivation 00:42 Example: The Garden Swing 02:16 3 Requirements of Design 03:38 Where It Fits 04:14 Small-Deformation Assumption 04:35 Units 04:55 Stress, in Life and in Steel 06:00 Method of Sections 07:17 The Concept of Stress 08:23 Example: The Human Body 09:23 Normal and Shear Stress 10:26 Stress Subscripts 11:13 Equality of Shear Stresses 12:29 Summary ━━━━━━━━━━━━━━━━━━━━ ⚙️ Animated Engineering: Don't memorize engineering. See it. Animated lessons in statics, dynamics, mechanics of materials, fluid mechanics and thermodynamics. 🔔 Subscribe so you don't miss the next lesson:    / @animationengineering   📚 Watch every series in order in our playlists. 💬 Questions? Leave a comment and we'll answer. #mechanicsofmaterials #stress #engineering #strengthofmaterials