# BASIC DEFINITION

## BASIC DEFINITION

Stress - The strength of a material may be defined as the maximum resistance which a material can offer to the externally applied force .The strength of a material depends upon a number of factors type of loading ,temperature ,internal structure etc.

Stress - When some external force are applied to a body ,then the body offers internal resistance to these forces .The magnitude of the internal resisting force is numerically equal to the applied forces . This internal resisting force per unit area is called 'stress' .

Strain -It is defined as the change in length per unit length .

Poisson's ratio  - When a material is subjected to longitudinal deformation then the lateral dimensions also charge .The ratio of the later strain to longitudinal strain is a constant quantity called the poisson's ratio .

lateral strain
Poisson's ratio =  ------------------------
longitudinal strain

Hooke's law - This law states that within elastic limits, strain is proprotional to stress.

Bulk modulus - It is defined as the ratio of uniform stress intensity to volumetric strain , within the elastic limits and is denoted by K.

Factor of safety - Factor of safety defined as the ratio of the maximum stress to the allowable or working stress .

SOM BOOK