Dynamics of Machines Lecture Note

Description

Name of Notes : – Dynamics of Machines Lecture Note

Introduction

Relation between motion and forces causing is a fascinating subject. This study is a generally referred as dynamic. Modern Engineering aims at analyzing and predicting dynamics behavior of physical systems

Theory of Mechanisms & Machines is used to understand the relationships between the geometry and motions of the parts of a machine or mechanism and forces which produce motion.

TOM (M&M theory) is divided into two parts:-

1. Kinematics of Machinery: Study of motion of the components and basic geometry of the mechanism and is not concerned with the forces which cause or affect motion. Study includes the determination of velocity and acceleration of the machine members
2. Dynamics of Machinery: Analyses the forces and couples on the members of the machine due to external forces (static force analysis) also analyses the forces and couples due to accelerations of machine members ( Dynamic force analysis)

Deflections of the machine members are neglected in general by treating machine members as rigid bodies (also called rigid body dynamics). In other words the link must be properly designed to withstand the forces without undue deformation to facilitate proper functioning of the system.
In order to design the parts of a machine or mechanism for strength, it is necessary to determine the forces and torques acting on individual links. Each component however small, should be carefully analyzed for its role in transmitting force.

The forces associated with the principal function of the machine are usually known or assumed.
Ex:
a) Piston type of engine: gas force on the piston is known or assumed
b) QRM – Resistance of the cutting tool is assumed.
a & b are called static forces.

• Module-1 Dynamics of Rigid Bodies in Plane Motion; Dynamic Force Analysis of Machines
• Module-2 Dynamics of Rotating Bodies; Unbalance Effects and Balancing of Inertia Forces; …
• Module-3 Dynamics of Reciprocating machines with single slider; …
• Module-4 Unbalance in Multicylinder Engines; – In-line, V twin and Radial Engines; …
• Module-5 Turning Moment Diagram for Engines and Speed Fluctuations; …
• Module-6 Vibration of Mechanical Systems; Types of Vibration; …
• Module-7 Free Undamped Vibration of Single Degree of freedom system; …
• Module-8 Free Vibration with Viscous Damping; Critical Damping and Aperiodic motion; …
• Module-9 Forced Vibration with Harmonic Excitation; Undamped system and resonance; …
• Module-10 Vibration of Two and Multidegree of Freedom systems; Concept of Normal mode; …
• Module-11 Free Vibration of Elastic Bodies; Longitudinal vibration of Bars; …
• Module-12 Instruments for Dynamic Measurements