This document summarizes a lecture on compression testing. It discusses how compression tests are used to determine material properties like compressive strength and modulus of elasticity. The test involves placing a sample in a universal testing machine and applying a compressive load until failure. Common applications include the aerospace, automotive, and construction industries. While easier than tension tests, compression tests can be impacted by friction, eccentric loading, and buckling of the sample. The document outlines best practices for sample geometry and preparation to minimize these issues and get accurate results.

1. Engineering Tests
Lecture No. (2)
Faculty of Engineering
Prod. & Mech. Design Engineering Department
Dr. Rania Mostafa
Compression Test

2. Outline
• compression test
• test purpose
• Applications
• Limitations
• test specimen
• Test procedures
• Types of fractures

4. Electromechanical Universal testing machine
▪ Consists of frame , engine, gear, screws , crosshead , grips (gripping jaws) ,
extensometer , specimen, hardware and software control
Capacities for range from low-load forces of 2kN (448 lbf) up to high-capacity 1000 kN (225,000 lbf) test frames.

5. Compression test
1 2

6. Compression test

7. ➢ The goal of a compression test is to determine the behavior
or response of a material while it experiences a compressive
load by measuring fundamental variables.
➢ Mechanical properties such as compressive strength, yield
strength, yield point, elastic modulus, and stress–strain
curve may also be determined from compressive tests.
➢ With the understanding of these different parameters and the
values associated with a specific material it may be
determined whether or not the material is suited for specific
applications or if it will fail under the specified stresses.
➢ This test procedure offers the possibility to test brittle and
nonductile metals that fracture at low strains and avoids the
complications arising out of necking.
Compression test purpose
1
2
3

8. Applications
➢Aerospace and Automotive Industry
➢Construction Industry
➢Cosmetics Industry
➢Electrical and Electronic Industry
➢Medical Device Industry
➢Packaging Industry
➢Paper and Board Industry
➢Plastics, Rubber and Elastomers Industry
➢Safety, Health, Fitness Industry
➢ Compression testing is usually easier to conduct than tension test and is used more
commonly at elevated temperature in plasticity or formability studies since it simulates
compressive stress as is expected under rolling, forging or extrusion operation.

9. Compression test Limitations
➢ Friction between the machine head and the sample
affects the results causing stresses to have small
inclination.
➢ Eccentricity may cause instability (Fig.1).
➢ for certain metallic materials, buckling (Fig.2a) and
barreling (Fig.2b) complicate testing and can be
minimized by designing the samples as per
specifications and using proper lubricants.
➢ Long samples are prone to buckling therefore the
length of the specimen must be limited
➢ Using small samples results in inaccuracies in results
and using large samples requires testing machines
with large capacities
Fig.1
Fig.2

10. Tests Specimen (Concrete)

12. ➢ Bearing blocks are used to ensure the load is applied to the
specimen.
➢ Spherical loading heads are used to avoid applying the load at a
single point if the loading surfaces are at a small angle
➢ Cylindrical specimens are preferred to ensure uniform distribution
of stresses, three types of specimens are used (L ≤ 10 d to avoid
buckling)
 Long specimens (L=8-10 d) to install deformation measurement
devices for obtaining the stress strain curves and other mechanical
properties like the Modulus of Elasticity, Resilience, Toughness, etc.
 Medium specimens (L= 3 d) to obtain compression strength of metals
 Short specimens (L= 0.9 d) to test metals used as bearings since the
friction induced in testing will resemble bearing conditions
Compression Test Procedure

13. Break and fracture

14. Break and Fracture

15. Break and fracture
Semi-ductile and Brittle material

17. Concrete Failure Shapes