What do you mean by Solids?

There are three types of matter- solid, liquid and gas. Out of them, solids have a rigid shaped and size. The intermolecular forces of attractions in solids are greatest. Mechanical properties are the physical properties of a material which it shows, when it is provided with certain amount of force or load. These properties are to be kept in mind for various purposes. When a force is applied to an object, the object may or may not get deformed depending upon its elastic property. But every time the object develops a restoring force against the force applied. This is commonly known as stress. If the object changes its dimensions due to the force applied it develops strain ( which is the ratio of change in dimension to the original dimension).

This is the diagram for the stress strain curve.

What are the Mechanical properties of Solids?

The mechanical properties of solids include strength, toughness, hardness, elasticity, plasticity, tensile strength, shear strength, brittleness, malleability, ductility, creep, resilience and fatigue.

Strength

It is that property of a material which resists any kind of deformation or from breaking it down, when some kind of external force is applied to the material. This is the property which is checked while to make some product or to make some part or structure so that the material can stand and work while in different mechanical conditions.

Toughness

 It is that property of a material which causes it to absorb various amount of energies and which helps in deforming plastically without getting fractured or in other words we can say that it is that amount of energy per unit volume that a material can withstand without getting ruptured.

Hardness

 It is that ability of a material which helps it in resisting any kind of deformation. These are generally checked by the help of a standard test where the resistance of surface is checked with respect to the indentation. Types of indent or shape, size or the amount of load are used to find the hardness of material.

Elasticity

 It is that ability of any kind of body which resists the deformation of its shape, when certain amount of load is applied to the body. In this condition, when the load is applied to the system, it deflects with some amount from its location, and when this load is removed from the body, it comes to its original or the initial position without getting any change in its shape. In metals, this generally happens when the force is applied to it, then the lattice moves from its place causing the change in shape and when the load is removed from the body, the lattice moves to its original or the initial place.

Plasticity

 It is defined as that property of any material which makes it to deform permanently when it is subjected to certain amount of load and when the load is removed, it does not return to its original condition. This causes the complete shape change of the body when load is applied. Yielding is known as the change in behaviour of the body from the elastic to the plastic.

Tensile Strength

 It is defined as the property of any material which tells that the maximum stress of the material upto which it can stand when the load is applied to it, when it is stretched and pulled without getting broken. In case of brittle materials, the tensile strength is supposed to be close to the yield point while in ductile materials; it is supposed to be much higher than the brittle materials.

Shear Strength

It is defined as that strength of material which occurs when the body or any component fails against the shearing. A sliding failure occurs on the material which is along the plane which is in the direction which is parallel to the force of shear. One of the classic examples of that is when the paper is cut with the help of scissors, the paper fails in shearing. This type of strength is generally very much used for the manufacturing or while preparing new type of component. And this is very much important for designing the proper dimensions. This can also be seen in the concrete beam in which they are provided with rebar, which is done so that the shear strength will increase.

Brittleness

 This is that property of the material in which, it gets fractured without getting deformed too much elastically and without getting the proper plastic deformation, when a certain amount of stress is provided to it. When the material breaks, it produces a sharp sound. This can generally be seen in the glasses easily. When a very little amount is applied or is produced on the glass, it causes the glass to brake without getting deformed plastically. This property is different in different materials; it can be different for polymers, metals and for ceramics as well.

Malleability

It is that property of any material which helps in drawing any material into the form of thin sheets when the continuous compressive force is applied to it or when the material is beaten up. In this, the material shape is changed or the material is made to bend by hammering it or by applying repeated force. This can be seen in the example of hot iron which is beaten with the help of hammer.

Ductility

 It is that property of the material which helps in drawing the material into the form of wire when the metal is provided with the help of tensile force. The main difference between ductility and malleability is, in case of malleability, the force which is used is compressive force for changing the shape while in case of ductility, the force which is used is tensile force.

Creep

 It is defined as that property of any material, which causes it to change its shape when the continuous amount of stress is applied to it for a long period of time and the stresses which are less than the yield strength of the material which is under deformation. The deformation rate depends upon the property of material, time of exposure and the applied load.

Resilience

 It is defined as the property of any material which causes it to absorb the energy, when it is given the load to deform elastically and to release that energy during the unloading while the proof resilience is the energy which can be absorbed by any material up to elastic limit without causing distortion which is permanent in nature.

Fatigue

It is defined as the failure of material which starts to arise or occur in the form of crack when the load is provided to it in a cyclic way, with each cycle of load, crack size increases.

Context and Applications

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for      

• Bachelors in Science Physics
• Masters in Science Physics