Classification of deformation
1. Longitudinal deformation: When both ends of the rod are under pressure or tension, the length changes;
2. Volume deformation: change in the volume of the object;
3. Shear: When two opposing surfaces of an object are affected by a (tangential) force couple in the surface, the two surfaces undergo relative displacement, which is called shear
4. Twisting: a cylindrical object, both ends of which are twisted by the torque in opposite directions, which is called torsional deformation;
5. Bending: The steel bars fixed at both ends are bent due to load, which is called bending deformation.
It also includes the strain of elastic materials, the permanent deformation of plastic materials and the flow of liquids. No matter what deformation occurs, it can be attributed to long change and shear.
6. Micro-deformation refers to deformation that cannot be seen by the naked eye. If a force does not change the motion state of the object and the above deformation does not occur, it must be a small deformation of the object. Elastic deformation
7. Shear deformation