This document provides guidelines for compression testing of metallic materials at room temperature based on ASTM E-09 standards. It describes the scope, apparatus, specimens, procedure, calculations, and factors that affect precision for compression testing. The key points are: - Compression testing determines properties like yield strength, stress-strain curve, and compressive strength. - Specimens are cylindrical or rectangular metallic samples tested in a universal testing machine with alignment devices to apply axial load. - The procedure involves measuring specimen dimensions, cleaning surfaces, applying strain measurements, and testing within a specified load-strain range while preventing buckling. - Calculations are used to determine material properties from load-strain data and the 0.

1. ASTM E-09
COMPRESSION TESTING OF
METALLIC MATERIAL AT ROOM
TEMPERAUTRE
PRESENTED BY : DARSHIT DESAI
(19MMM003)

2. 1.SCOPE
• These test methods cover the apparatus, specimens, and procedure
for axial-load compression testing of metallic materials at room
temperature.
• The values stated in inch-pound units.

3. 2.REFERENCED DOCUMENTS
ASTM Standards
1. B557 - Methods of Tension Testing Wrought and Cast
Aluminum- and Magnesium-Alloy Product
2. E04 - Practices for Load Verification of Testing Machines
3. E06 - Terminology Relating to Methods of Mechanical Testing
4. E83 - Practice for Verification and Classification of Extensometer
Systems
5. E111 - Test Method for Young’s Modulus, Tangent Modulus and
Chord Modulus
6. E171 - Specification for Standard Atmospheres for Conditoning
and Testing Materials
7. E251 - Test Methods for Performance Characteristics of Bonded
Resistance Strain Gages2
8. E209 - Practice for Compression Tests of Metallic Materials at
Elevated Temperatures with Conventional or Rapid Heating
Rates and Strain Rates

4. 3.TERMINOLOGY
• BUCKLING:- Buckling is a mode of failure
characterized by an unstable lateral
material deflection caused by compressive
stresses.
• Compressive failure may occur by
1) Elastic instability over the length of a column specimen due
to non-axial of loading
2) In elastic instability over the length of a column specimen
3) a twisting or torsional failure in which cross sections rotate
over each other about the longitudinal specimen axis
• These types of failures are all termed buckling.

5. • COLUMN :- A compression member that is axially
loaded and that may fail by buckling.
• RADIUS OF GYRATION :- The square root of the ratio
of the moment of inertia of the cross section about the
centroidal axis to the cross-sectional area.
P=(I/A)^1/2
where,
P = radius of gyration,
I = moment of inertia of the cross section about centroidal
axis
A = cross-sectional area

6. • CRITICAL STRESS:- Axial uniform stress that
causes a column to be on the verge of buckling.
The critical load is calculated by multiplying the
critical stress by the cross-section area.

7. • If the buckling stress is less than or equal to the proportional limit
of the material its value may be calculated using the Euler equation
Scritical = C pie^2 E/(L/p)^2
• If the buckling stress is greater than the proportional limit of the
material its value may be calculated from the modified Euler
equation
Scritical = C pie^2 Er/(L/p)^2
Where,
Scr =critical buckling stress.
E =young's modulus
Er =tangent modulus at the buckling stress
L =column length
c =end-fixity coefficient

8. • Freely rotating ends (pinned or hinged) C = 1 (a)
• One end fixed, the other free to rotate C = 2 (b)
• Both ends fixed C = 4 (c)

9. • BARRELING:-Barreling is the generation of a convex surface
on the exterior of a cylinder that is deformed in compression.

10. 4. SIGNIFICANCE AND USE
SIGNIFICANCE:-
• The data obtained from a compression test may
include the yield strength, the yield point
Young’s modulus, the stress-strain curve, and the
compressive strength.
• In the case of a material that does not fail in
compression by a shattering fracture,
compressive strength is a value that is
dependent on total strain and specimen
geometry.

11. Use:-
• For brittle metals that fracture in tension at
stresses below the yield strength.
Compression tests offer the possibility of
extending the strain range of the stress-
strain data. While the compression test is not
complicated by necking as is the tension test
for certain metallic materials, buckling and
barreling can complicate results and should
be minimized.

12. 5. APPARATUS
• Testing Machine : Universal Testing Machine
• Specimen must be designed so that the ram
does not jam or tilt the device or the frame of
the machine as a result of loading.
• The primary requirements of all alignment
devices are that the load is applied axially,
uniformly, and with negligible friction.

13. Universal Testing Machine

14. Compression Testing Jigs
• Testing of the thin specimens, such as sheet material ,some means
should be adopted to prevent the specimen from buckling .
• The jig must afford a suitable combination of lateral-support
pressure and spring constant to prevent buckling ,but with out
interfering with axial deformation of the specimen, Although
suitable combination vary some what with variation in specimen
material and thickness.
• The blocks shall be made hard material. like, tungsten carbide when
testing steel and hardened steel blocks .
• when testing nonferrous materials such as aluminium,copper, etc.
The specimen must be carefully centered with respect to the testing
machine.

15. • There are two types of bearing blocks
(1) spherical seated bearing block
(2) adjustable bearing block

17. STRAIN MEASUREMENT
• Mechanical or electromechanical devices used for measuring
strain that occur during compression test.

18. QUALIFICATION OF TEST
APPARATUS
• Compression-test consists of the alignment
device, the jig and the strain-measurement
system.
• Specimens shall be machined from sheet or bar
specified in Test Methods B 557.
• When the qualification specimens each provide a
modulus value of 10.7*10^6 psi +-5%

19. 6. TEST SPECIMENS
1. Specimens in solid cylindrical form:-

20. 2. Rectangular or Sheet type specimens:-
• Where lateral support is necessary, the width and
length are dependent upon the dimensions of the jig
used to support the specimen

21. Preparation of specimen:-
• Lateral surfaces in the gage length shall not vary in
diameter, width, or thickness by more than 1%.
Surface finish:-
• Machined surfaces of specimens shall have a surface
finish of 1.6 micrometre or better.
• Machined lateral surfaces to which lateral support is
to be applied shall be finished to at least 40 micro
inches average.

22. Flatness and Parallelism:-
• The ends of a specimen shall be flat and parallel within
0.0005 in./in. and perpendicular to the lateral surfaces to
within 3’ of the arc. The machining or grinding of the ends
of the specimen.
Edges of Rectangular Specimen:-
• A width of material equal to at least the thickness of the
specimen shall be machined from all sheared.
• Specimens shall be finished so that the surfaces are free of
nicks, grooves, and burrs.

23. 7. PROCEDURE
Specimen Measurement:-
• Measure the width, thickness or diameter of the
specimen with the help of micrometer.
• Specimen dimensions greater than 0.10 in should be
measure to the nearest 0.001 in. and those less than
0.10 in. should be determine to the nearest 1% of
the dimension being measured.
• Calculate the average cross sectional area of the
specimen gauge section.

24. Cleaning:-
• Clean the ends of the specimen and fixture bearing
blocks with acetone or other solvent to remove all
traces of grease and oil.
Lubrication:
• Bearing surface friction can affect test result.
• Friction can be successfully reduced by fluorocarbon
sheet, molybdenum disulfide or other materials.

25. Load-Strain Range Selection:-
• Set the load range of the testing machine so the maximum
expected load is at least one third of the range selected.
Strain Measurements:-
• Devices used for measuring strain shall comply with the
requirements for the applicable class of extensometer.

26. Precautions:-
• Buckling: In compression tests of relatively long,
slender specimens that are not laterally supported, the
specimens may buckle elastically and fly from the test
setup. A protective device should be in place to prevent
injury.
• Shattering Fracture: Some materials may fail in a
shattering manner which will cause pieces to be expelled
as shrapnel. A protective device should be in place to
prevent injury

27. 8. CALCULATIONS
• Determine the properties of the material from the dimensions of
the specimen and the stress-strain diagram.
• For testing machines that record load units instead of stress,
convert the load-versus-strain diagram to units of stress by dividing
the load by the original cross-sectional area of the specimen gage
section
• Yield Strength: To determine Yield Strength of the offset method .
• Yield Point: The yield point can be determined by noting the load at
which the load dial indicator needle suddenly drops with the testing
machine running at a steady rate.
• Compressive Strength: It is the maximum stress at or before
fracture, as determined by dividing the maximum load by the cross-
sectional area.

28. Determine Yield Strengthof by .2% offset
method

29. 9. PRECISION AND BIAS
Precision:
Parameters that affect precision of the test methods:-
• specimen buckling
• loading surface friction
• specimen barreling
• specimen size.
Bias:-
• There are no available reference standards for
destructive type tests such as compression.
Therefore, the bias of this method is an unknown.

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