Analysis of Stress and Strain
                     ANALYSIS OF STRESS 
AND STRAIN
Introduction
Stress–strain analysis (or stress analysis) is an engineering 
discipline that uses many methods to determine the stresses 
and strains in materials and structures subjected to forces. In 
continuum mechanics, stress is a physical quantity that 
expresses the internal forces that neighboring particles of a 
continuous material exert on each other, while strain is the 
measure of the deformation of the material.
20XX 2
Source: en.wikipedia.org
Mathematical 
Formulae
In simple terms we can define stress as the force of 
resistance per unit per unit area, offered by a body against 
deformation. 
Stress is the ratio of force over area (S =R/A, where S is the 
stress, R is the internal resisting force and A is the cross-
sectional area). 
Strain is the ratio of change in length to the original length, 
when a given body is subjected to some external force 
(Strain= change in length÷the original length).
20XX 3
Source: en.wikipedia.org
Stress Analysis
Stress analysis is a primary task for civil, mechanical and 
aerospace engineers involved in the design of structures of 
all sizes, such as tunnels, bridges and dams, aircraft and 
rocket bodies, mechanical parts, and even plastic cutlery and 
staples. 
Stress analysis is also used in the maintenance of such 
structures, and to investigate the causes of structural 
failures.
20XX 4
Source: en.wikipedia.org
Geometrical 
description
Typically, the starting point for stress analysis are a 
geometrical description of the structure, the properties of 
the materials used for its parts, how the parts are joined, and 
the maximum or typical forces that are expected to be 
applied to the structure. 
The output data is typically a quantitative description of how 
the applied forces spread throughout the structure, resulting 
in stresses, strains and the deflections of the entire structure 
and each component of that structure.
20XX 5
Source: en.wikipedia.org
In Engineering
In engineering, stress analysis is often a tool rather than a 
goal in itself; the ultimate goal being the design of structures 
and artifacts that can withstand a specified load, using the 
minimum amount of material or that satisfies some other 
optimality criterion.
20XX 6
Source: en.wikipedia.org
General principles
Stress analysis is specifically concerned with solid objects. 
The study of stresses in liquids and gases is the subject of 
fluid mechanics.
Stress analysis adopts the macroscopic view of materials 
characteristic of continuum mechanics, namely that all 
properties of materials are homogeneous at small enough 
scales.
20XX 7
Source: en.wikipedia.org
Fundamental 
problem
The fundamental problem in stress analysis is to determine 
the distribution of internal stresses throughout the system, 
given the external forces that are acting on it. In principle, 
that means determining, implicitly or explicitly, the Cauchy 
stress tensor at every point.
20XX 8
Source: en.wikipedia.org
 Analysis of strain
Strain differs in this respect from stress. It is a complete 
quantity that can be seen and generally measured directly 
as a relative change of length or shape. In generally, stress 
is the ratio of change in original dimension and the original 
dimension. It is the dimensionless constant quantity.
20XX 9
Source: www.intechopen.com
Stress-strain relation
The state of stress at a point was characterized by six 
components of stress, and the internal stresses and the 
applied forces are accompanied with the three equilibrium 
equation. These equations are applicable to all types of 
materials as the relationships are independent of the 
deformations (strains) and the material behavior.
20XX 10
Source: www.intechopen.com
THANK YOU