Download to read offline
dynamics-machines2.ppt
- 1. DYNAMICS OF MACHINES •To know the purpose for which the m/c is needed. • To develop concept design. • To analyze the motion involved - Kinematics • To calculate & analyze the forces and torques required for producing the motion - Kinetics • To give physical shape to the components. - Machine Design
- 2. STATIC FORCE ANALYSISIN MACHINES • To evaluate the forces acting on the machine members at a particular configuration. • Each configuration is considered as system of rigid bodies in static equilibrium under the action of external forces. • Helps in finding load carried by each part of the machine during cycle of its operation
- 3. TYPES OF FORCES •Applied forces : Gas, hydraulic & pneumatic forces etc.. Electrical, magnetic & gravity forces • Constraint forces : Reaction forces. • Friction forces. • Inertia forces. Due to mass of accelerating parts
- 4. Condition for staticequilibrium • ∑ F i = 0 • ∑ Mi = 0 F1 F4 F2 F3 F5 CG M/c part
- 5. Fi = 0 Mi = 0 EQUATIONS FOR STATIC EQUILIBRIUM
- 6. EQUILIBRIUM OF TWOFORCE AND THREE FORCE MEMBERS Two force member in equilibrium F1 F2
- 7. THREE FORCE MEMBERIN EQUILIBRIUM F1 F2 F3 O F1 F2 F3 O
- 8. P O2 A B P 3 2 4 1 F14 F34 A B 3 F32 F12 2 4 STATICFORCE ANALYSIS IN SLIDER-CRANK MACHANISM C12 F43 F23 P F14 F34 FBDof Link 4 FBDof Link 3 FBDof Link 2
- 9. A B P 2 4 O4 O2 3 P F34 F14 O P F14 F34 F23 F43 F32 F12 C12 STATIC FORCEANALYSIS IN 4-BAR MECHANISM 3 4 h C12 = F32 X h O2 C
- 10.
- 11.
- 12. Inertia force -m a -Inertia torque - I α
- 13. D’ Alemberts principle Inorder to find the effect of inertia of the actual link on the forces transmitted to the adjacent links of a mechanism, the actual link may be replaced by a rigid mass-less link to which inertia force F i = -ma is applied. The mass-less link is then under equilibrium under systems of forces along with inertia force.