Testing Methods for
Composites
Yiping Qiu
Properties of Composites
Mechanical properties
Tensile
Compression
Bending
Shear
Impact
Properties of Composites
Physical Properties
Thermal
Electric
Environmental
Dimensional Stability
Mechanical Testing
Tensile test
Purpose of tensile test
To determine the strength, moduli and Poison’s ratio
of a composite
• For a unidirectional composite, Ex, Ey, Es and nxy
To determine the energy absorption of a composite
It can also be used to assess fatigue properties by
cyclic loading of a specimen
Tensile testing
Single fiber tensile test
Fiber tow or yarn test
Composite tensile test
Single fiber tensile test
Purpose
Sample preparation
Testing condition
Sample size or number of specimens
Analysis of results
Yarn tensile test
Purpose
Sample preparation
Yarn as is
Resin impregnated
Testing conditions
Sample size
Analysis of results
Composite Test
Sample size
Specimen shape
Protection of specimen ends
Testing devices:
Machine
Load cell
Strain gauge
Testing condition
Shear test
Interlaminar shear: interlaminar bonding
strength
In-plane shear: shear stiffness and
strength
Interlaminar shear test
Testing method
Testing device
Bending test
Three point bending
Four point bending