Loading

The application of a force to an object is known as loading. Materials can be subjected to many different loading scenarios and a material’s performance is dependant on the loading conditions. There are five fundamental loading conditions; tension, compression, bending, shear, and torsion. Tension is the type of loading in which the two sections of material on either side of a plane tend to be pulled apart or elongated. Compression is the reverse of tensile loading and involves pressing the material together.  Loading by bending involves applying a load in a manner that causes a material to curve and results in compressing the material on one side and stretching it on the other.  Shear involves applying a load parallel to a plane which caused the material on one side of the plane to want to slide across the material on the other side of the plane. Torsion is the application of a force that causes twisting in a material.

There are generally five types of loading: tesion (when you pull something apart), compression (when you squeeze something together), bending (also known as mode one), shear (also known as mode two), and torsion (also known as mode 3). While tension and compression can take place independently, bending, shear, and torsion are combinations of tensions and compressions.

If a material is subjected to a constant force, it is called static loading. If the loading of the material is not constant but instead fluctuates, it is called dynamic or cyclic loading. The way a material is loaded greatly affects its mechanical properties and largely determines how, or if, a component will fail; and whether it will show warning signs before failure actually occurs.