Mechanics of materials, aka Strength of materials, is a subject which deals with the behavior of solid objects subject to stresses and strains.
The study of strength of materials often refers to various methods of calculating the stresses and strains in structural members, such as beams, columns, and shafts. The methods employed to predict the response of a structure under loading and its susceptibility to various failure modes takes into account the properties of the materials such as its yield strength, ultimate strength, Young's modulus, and Poisson's ratio; in addition the mechanical element's macroscopic properties (geometric properties), such as it length, width, thickness, boundary constraints and abrupt changes in geometry such as holes are considered.
vCalc's Mechanics of Materials contains formulas that help in determining the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties.