Definition and Scope of Applied Mechanics
Mechanics is a branch of science which deals with the response of particles and rigid bodies to mechanical disturbances (forces, moments, displacements). The foundation of mechanics was laid by Aristotle and Archimedes; however, it was Newton who first devised a satisfactory formulation of its fundamental principles.
Applied Mechanics is the study of physical principles that can be applied over day-to-day activities.
Mechanics is a branch of science which deals with the response of particles and rigid bodies to mechanical disturbances (forces, moments, displacements). The foundation of mechanics was laid by Aristotle and Archimedes; however, it was Newton who first devised a satisfactory formulation of its fundamental principles.
Applied Mechanics is the study of physical principles that can be applied over day-to-day activities.
- It provides fundamental principles and formulas for the analysis and design of different structures.
- It acts as a bridge between the pure science and the applied science.
Concept of Rigid and Deformed Bodies
Particle:
Rigid Bodies:
Deformable Bodies: They change in shape, size and volume on the application of external forces.
Free Body Diagram (FBD)
It is a simple sketch of the body in such a way that it contains applied forces, reaction forces, external moments without any support and connections.
FBD = Space Diagram - Support and Connections (if any) + External Forces + Reaction + Internal Forces (if any)
Particle:
- Particle is massless and dimension less.
- The distance traveled by a particle is many times greater than its size.
Rigid Bodies:
- A rigid body is a combination of a large number of particles occupying fixed positions with respect to each other.
- They do not change in shape, size and volume on application of external force.
Deformable Bodies: They change in shape, size and volume on the application of external forces.
Free Body Diagram (FBD)
It is a simple sketch of the body in such a way that it contains applied forces, reaction forces, external moments without any support and connections.
FBD = Space Diagram - Support and Connections (if any) + External Forces + Reaction + Internal Forces (if any)
- A clear decision regarding the choice of the free body to be used is made. It is then detached from the ground and separated from any other body. The contour of the body thus isolated is sketched.
- All external forces are then indicated. These forces represent the action exerted on the free body by the ground and the bodies which have been detached. NOTE: The weight of the free body should also be included among the external forces, since it represents the attraction exerted by the earth on the various particles forming the free body.
- Unknown external forces usually consist of the reactions through which the ground and other bodies oppose a possible motion of the free body and thus constrain it to remain in the same position.
- When the free body is made of several parts, the forces the various parts exert on each other comprise the internal forces.