It is the mechanical design engineer’s responsibility to do the material selection right the first time. In fact, the competitiveness of a design depends largely on material selection. Moreover, end users never specify the material of the product. Following are five important parameters that largely influence the engineering material selection process.
Young’s modulus, yield strength, and the Poisson ratio are some of the mechanical properties that lead you to select a suitable material for a particular application. Most of the time you can obtain the required mechanical property values from mechanical design calculations or from the FEA packages.
The properties like density, boiling point, melting point, and freezing points are called the physical properties of material. But, unlike mechanical properties, the physical properties values of a material are not obtained from the design calculation, but need to be decided based upon atmospheric conditions.
For designing electromechanical or electrical systems, various electrical properties like resistivity, permeability, conductivity, etc. will influence your engineering material selection process. For example, for the windings of a motor, copper or aluminum would need to be selected.
The raw material you have selected for your design needs to shape up as per your design requirements, and here manufacturability comes into picture. Rather than a material selection factor, the manufacturability can be termed a bottleneck. For example, you need a part to be made by casting and you then select stainless steel, which is probably not the best selection.
Cost is the most important factor for every part of any business and nothing different in the case of material selection. For example, you can afford to use costly lightweight composites for aerospace applications, but not for automotive applications.
Engineering material selection process is one of the most important steps for a competitive mechanical design. And much of the selection process involves trade-offs among the different parameters. Various charts are available for comparing different parameters with respect to others. These charts are helpful for doing the trade-off optimally.