Longitudinal or Linear Strain Strain that changes the length of a line without changing its direction. Can be either compressional or tensional. Compression Longitudinal strain that shortens an object. Tension Longitudinal strain that lengthens an object. Shear Strain that changes the angles of an object.
Shear causes lines to rotate.
Infinitesimal Strain Strain that is tiny, a few percent or less. Allows a number of useful mathematical simplifications and approximations. Finite Strain Strain larger than a few percent. Requires a more complicated mathematical treatment than infinitesimal strain. Homogeneous Strain Uniform strain.