Relative deformation, ΔL/L; dimensionless.
Normal strain ε=ΔL/L and shear strain γ equals the change of a right angle in radians. Strain is dimensionless, often quoted in microstrain. Strain gauges measure it via change in electrical resistance.
A 2 m bar that stretches 1 mm has ε=500 µε.
Strain measures how much a material deforms, so it links the load to the change in shape and is used with strain gauges.
Relative deformation, ΔL/L; dimensionless.
Strain measures how much a material deforms, so it links the load to the change in shape and is used with strain gauges.
It is a ratio of change in length to original length, so the units cancel. Strains are often quoted in microstrain for small values.
Engineering strain uses the original length, while true strain uses the instantaneous length. They differ at large deformations.
Typical applications include calculating the elongation of a steel rod under load, checking the change in length of a pipe from thermal expansion and interpreting readings from a strain gauge on a bracket.
Study "Stress" first (topic 43 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
Engineering vs true strain. Elastic strains are small. Volumetric strain sums normal strains.
A 2 m bar that stretches 1 mm has ε=500 µε.
The next topic is "Stress-strain curve", which builds directly on this one.
It is classed as Intermediate in Engineering Mechanics (topic 44 of 106). It is an intermediate topic. Work through the beginner topics in Engineering Mechanics first.
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