UNIT 5

UNIT 5

1. Force,stresses and strength

   • Force
     • Is an influence that can deform a body or change its movement
   • Stresses
     • Are the physical demands that a body or object must withstand
   • Strength
     • Is its ability to withstand external forces without breaking

2. STRUCTURE

   • Is a collection of elements arranged in a way to support a body or an object
   • Structure of an object
     • Is a orderly distribution of its essential parts

3. Types of stress

   • Compression
   • Torsion
   • Bending
   • Tension
   • Shear

4. Condition for strong structures

   • Rigidity
   • Stability
   • Equilibrium

5. Strengthening elements

   • The strength of a structure depends on
     • The types
     • The shape
   • Elements that increase stability
     • Widening the base
     • By locating the centre of gravity of the structure
     • By making a good foundation for the structure
     • By supporting the structure with stay cables

6. Elements that increase rigidity

   • Sections
   • Stay cables
   • Trussing
   • Brace

7. Components of the machines

   • Driver element
   • Driven elements
   • Converting and transmitting elements

8. Pulleys

   • Are used to lift heavy loads they are wheels with a grooved rim

9. Rotary transmission mechanism

   • Belt and pulley system
     • The system is made up of two pulley wheels
   • Gears
     • Is a mechanism consisting of two wheels with teeth
   • Friction wheels
     • Are a set of two wheels located one next to other