Mechanical Properties of Solids Flashcards
what is elasticity
The
property of a body, by virtue of which it tends to regain its
original size and shape when the applied force is removed, is
known as elasticity
what is an elastic body
what is a plastic body
The property on account of which a body regains its original size and shape on removal of external deforming force is called as elastic body
A body that has no tendency to regain its intial shape or size after removing deformign force ie it is permanently deformed is called as a plastic body.
what is the deforming force
the external force applied on a body that brings about a change in the configuration of the body
what is stress
it is the restoring force per unit area
why are bodies elastic
We know that in a solid, each atom or molecule
is surrounded by neighbouring atoms or
molecules. These are bonded together by
interatomic or intermolecular forces and stay
in a stable equilibrium position. When a solid is
deformed, the atoms or molecules are displaced
from their equilibrium positions causing a
change in the interatomic (or intermolecular)
distances. When the deforming force is removed,
the interatomic forces tend to drive them back
to their original positions. Thus the body regains
its original shape and size.
state hooke’s law
elongation (change in the length)
produced in a body is proportional to the applied
force or load.
what is strain
d strain is the fractional change in dimension
what is the reason behind the elastic behaviour of solids
in a solid, each atom or molecule
is surrounded by neighbouring atoms or
molecules. These are bonded together by
interatomic or intermolecular forces and stay
in a stable equilibrium position. When a solid is
deformed, the atoms or molecules are displaced
from their equilibrium positions causing a
change in the interatomic (or intermolecular)
distances. When the deforming force is removed,
the interatomic forces tend to drive them back
to their original positions. Thus the body regains
its original shape and size.
what is linear or longitudinal stress
Restoring force per unit area perpendicular surface of the body
(I) Tensile stress : when 2 equal and opp forces are applied on the body causes an increase in the length of the body
(II) Compressive stress: when 2 equal and opposite forces are applied on the body causes a decerase in the length of the body
The change in the length
ΔL to the original length L of the body (cylinder
in this case) is known as longitudinal strain.
l/L
what is bulk stress/ volume stress/ hydraulic stress
when body immersed in liquid/gas
the force acts uniformly and normally all over the body and the stress is called bulk stress.
The strain produced by a hydraulic pressure
is called volume strain and is defined as the
ratio of change in volume (ΔV) to the original
volume (V).
