Solid Mechanics

Solid mechanics is the branch of physics and mathematics that concerns the behavior of solid matter under external actions. Solid mechanics had been boomed up by participating in major inventions such as buildings, ships, automobile, railways, petroleum refineries, engines, airplanes, nuclear reactors, composite materials, medical implants, and computers. This is otherwise called as engineering mechanics. Because it is often used in civil engineering, mechanical engineering, materials science and engineering, aerospace engineering, chemical engineering, electrical engineering, nuclear engineering, structural engineering and bioengineering. Solid mechanics is the broader study known as continuum mechanics.

Continuum Mechanics

Continuum mechanics is the branch of mechanics that deals with the study of kinematics and the mechanical behavior of materials as continuous mass rather than as discrete particles. It deals with the physical properties of solids and fluids; they are not dependent of any particular coordinate system in which they are observed.

Linearly Elastic Region

The material has the rest shape and due to stress, its shape departs away from the rest. The amount of departure from the rest shape is called deformation; the proportion of deformation to original size is called strain. If the applied stress is low, the strain is directly proportional to stress. The coefficient of the proportion is called the modulus of elasticity. This section of deformation is called as the linearly elastic region.

Three Models of Solid Mechanics

Due to ease of computation, it is common for analyst in solid mechanics to use the linear material models. As new materials are used in recent times and old ones are pushed to their limits, nonlinear materials models are becoming more common.  The three models are elastically, viscoelastically, and plastically.

Elastically

According to Hooks law, when an applied stress is removed from the material, the material will tend to come back to its original position. Linearly elastic materials, to the applied load can be described as linear elasticity.

Viscoelastically

These materials will behave elastically, but also have damping. When the stress is applied and removed, work has to done against the damping effects and is converted in heat within the material resulting in a hysteresis loop in the stress strain curve.

Plastically

When the applied stress is less than the yield value, material will  behave elastically. If the stress is greater than the yield stress, then the material will behave plastically and will not return to its previous state. It means, the deformation occurring after yield is permanent.

Questions:

• What is solid mechanics?
• What is continuum mechanics?