2. M Waqas Mushtaq MME-12-11
Muhammad Zubair MME-12-29
M. Faisal Maqsood MME-12-20
Muhammad Ahmad MME-12-14
Gulfam Hussain MME-12-30
Arif Ali MME-12-01
Group No 1
3. Mechanics Of materials:
Mechanics of materials is a branch of mechanics that
develops relationships between the external loads
applied to a deformable body and the intensity of
internal forces acting within the body as well as the
deformations of the body.
Stress
Strain
Introduction
6. Universal Testing Machine
The results from the test are
commonly used to select a material
for an application, for quality control,
and to predict how a material will
react under other types of forces.
Properties that are directly measured
via a tensile test are ultimate tensile
strength, maximum elongation and
reduction in area. From these
measurements the following
properties can also be determined:
Young's modulus, yield strength, and
strain-hardening characteristics.
9. TYPES
Mechanical
The electromechanical machine uses an
electric motor, gear reduction system
and one, two or four screws to move the
crosshead up or down
. A range of crosshead speeds can be
achieved by changing the speed of the
motor.
A microprocessor based closed-loop
servo system can be Implemented to
accurately control the speed of the
crosshead.
Hydraulic
A hydraulic testing machine uses either a
single- or dual-acting piston to move the
crosshead up or down.
In a manually operated machine, the
operator adjusts a needle valve to control
the rate of loading. In a closed-loop
hydraulic servo system, the needle valve is
replaced by an electrically operated servo-
valve for precise control.
In general, the electromechanical machine
is capable of a wide range of test speeds
and long crosshead displacements, whereas
the hydraulic machine is a cost-effective
solution for generating high forces.
11. It works on the principle of elongation and
deformation.
In UTM Tensile, Compressive and Shear Forces are
acting.
Working Principle
12. Working Procedure
Compression Test
In compression test the
specimen is gripped in
machine jaws and load is
applied through a screw
gear mechanism by a
movable crosshead jaw
when we apply load our
specimen is compressed
under load and its
compressive strength
shows on screen by graph.
13. In tensile test the specimen is gripped in machine
jaws and load is applied through a screw gear
mechanism by a movable crosshead jaw when we
apply load our specimen is elongated under load and
stress strain graph is shown on screen.
Tensile Test
14. TENSILE TEST
Step 1: Original shape and size
of the specimen with no load.
Step 2: Specimen undergoing
uniform elongation.
Step 3: Point of maximum load
and ultimate tensile strength.
Step 4: The onset of necking
(plastic instability).
Step 5: Specimen fractures.
Step 6: Final length.
