The subject of Engineering and particularly Mechanical Engineering has as a basic components the study and design of Materials, Strength and design of Structures and Machine elements. All these require a study of the topic known as SOM or Stregth of Materials. Together with this come that of Mechanics of Solids, which is a closer analysis of the materials and their strengths, without which structures would not be able to stand for appreciable amounts of time.
Relaible design requires an analysis of the suitability and durability of component materials, and their subsequent behaviour under prolonged loadings. Social responsibility is one of the main goals of engineers and hence, strucutres and their components must be built to last several decades, and not as a use and throw product.