Deformation: When a force is acting on a member, it will have a tendency to change its size and shape. Temperature can deform a member. Deformation will not be uniform throughout the volume of the member.
Normal Strain(ε): elongation or contraction of a line segment. Will cause a change in volume.
εavg = (s' - s) / s
- εavg is the average normal strain
- s' is the new length after deformation
- s is the original length
Shear Strain(γ): change in the angle between two line segments and is measured in radians. The original two line segments are perpendicular to each other. Will cause a change in the shape.
- If the angle is larger than the original angle, than the shear stain is negative
- If the angle is smaller than the original angle, than the shear strain is positive
State of Strain: describes the deformation of a rectangular volume element characterized by εx, εy, εz, γxy, γxz, and γyz
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