# Stress and stain Essays and Papers

This essay has a total of 1470 words and 6 pages.

Stress and stain

Simple Stress and Strain

The strength of materials are expressed from the point of view of machine designer. A
machine designer needs to know the properties of different materials so that he can select
the most suitable material for each part of a machine. A machine designer uses his
information of stress to make sure that the stress is reasonable and that each part of the
machine is sufficiently strong. Strength of materials is the scientific area of applied
mechanics for the study of the strength of engineering materials and their mechanical
behavior in general (such as stress, deformation, strain and stress-strain relations).
Strength is considered in terms of compressive strength, tensile strength, and shear
strength, namely the limit states of compressive stress, tensile stress and shear stress
respectively.

One can see the importance of stress and strain. They are an indication of how severely
the part in machine is loaded and how it is a factor that determines whether the forces
applied are reasonable. Stress and strain always occur together. When a material is
subjected to stress, it deforms, and when a material is deformed there must be strain. If
the stress and strain are not the same for all materials, then it is found by experiments
There is a relation between the stress and the strain for any given material. It said,
when the relationship between the two are given, the stress and the strain can be found in
one another. All materials deform when subjected to stress and it is necessary to be able
to calculate the deformation of a body under load, because in most cases the deformation
is more momentous than the stress.

Stress is in all probability the most imperative word in the subject matter of strength of
materials. Stress is defined as force per unit area. It has the same units as pressure,
and in fact pressure is one special variety of stress. However, stress is a much more
complex quantity than pressure because it varies both with direction and with the surface
it acts on. The simple stress are: compression (stress that acts to shorten an object),
tension (stress that acts to lengthen an object), and shear (stress that acts parallel to
a surface). Shear can cause one object to slide over another. It also tends to deform
originally rectangular objects into parallelograms. The most general definition is that
shear acts to change the angles in an object.

Strain is defined as the amount of deformation an object experiences compared to its
original size and shape. For example, if a block 10 cm on a side is deformed so that it
becomes 9 cm long, the strain is (10-9)/10 or 0.1 (sometimes expressed in percent, in this
case 10 percent.) Note that strain is dimensionless. Strain in addition can be express
further in these familiar terms: compression (longitudinal strain that shortens an
object), tension (longitudinal strain that lengthens an object) and shear (strain that
changes the angles of an object). Shear can also causes lines to rotate in strain. These
stresses can further be said to be a member of a machine or structure that indicates how
severely it is loaded; a stress is said to be a failure if the machine part is loaded to
heavy.

Tensile stress is the stress that can be applied to an object by pulling on it, or
attempting to stretch it. Further, it is a loading that tends to produce stretching on a
material by the application of axially directed pulling forces. Materials can withstand
some tensile loading, but if enough force is applied, they will eventually break into two
parts. Steel is an example of a material with high tensile strength. Its opposite is
compressive stress and compression stress. Compressive is the stress applied to materials
resulting to their compaction (decrease of volume). When a material is subjected to
compressive stress then this material is under compression. Usually compressive stress
applied to bars, and columns. In architecture and structural engineering, a column is that
part of a structure whose purpose is to transmit through compression the weight of the
structure. Other compression members are often termed columns because of the similar
stress conditions. Columns can be either compounded of parts or made as a single piece. In
addition, a material is compression stress when the forces acting on it tend to shorten
it. The forces have a propensity to squeeze the material together and this predisposition
is resisted by interior forces or stresses.

Stress is plotted vertically and strain is plotted horizontally. After it is plotted, the
line then is drawn trough the plotted points to give the stress-strain curve. It is
understood that it is not always a straight line but straight enough for practical

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