Failures arising from bad material selection are not uncommon in many industries. In an application that demands a high tensile strength, a material with higher tensile strength must be selected. If the product is to be used outdoors, it may be necessary to consider the effect of ultraviolet light. If a proper material selection is not done, the product life tends to be highly unpredictable. Therefore the material selection process is quite important for the long term success of engineering applications.
Facts to Consider in the Material Selection Procedure
In the field of mechanical engineering, the selection of material is a tedious task because there are number of factors that have to carefully evaluated before making the final decision. The main requirement may be the strength of a particular application, but depending on the working environment and behavior, several other factors may have to be considered.
In the selection of materials, a systematic approach is necessary to select the best materials for a particular application. If a proper technique is followed, first it is required to carefully define the application requirements in terms of mechanical, thermal, environmental, electrical, and chemical properties. Then the choices are narrowed down by the method of elimination. Production techniques also have a major importance in selecting the best material. Material property data sheets never should be used for the ultimate selection of materials. The actual performance of a particular material under different conditions may differ from what is expected.
Material Selection Ensures the Integrity at Design
The integrity of a design can be ensured only after a systematic material selection procedure. Otherwise, the result it is highly susceptible for failures. In the selection process, materials will be assessed for tensile strength and modulus, flexural strength and modulus, impact strength, compressive strength, fatigue endurance, creep, and stress-relaxation properties depending on the application. This will ensure that the design will have a better probability of succeeding. It will also assure that the design is technically fit to obtain desired properties.
Structural Integrity for Lifetime of the Field
A great design may fail in the actual working environment. It may be subjected to a higher load than ever expected. It may be damaged by a chemical. In these ageing and transient conditions, only a good design with proper material selection may survive. Therefore the material engineer should have the ability to predict the conditions from clues he may already have about what a certain product may face in its actual working conditions. Then he must carefully select the appropriate materials to suit those possible conditions.
Competitive Advantage and Cost
In extreme applications such as the space shuttle, materials selection plays an invaluable role. A tiny bit of negligence may cause a deadly disaster. This applies not only this type of complex designs, but also to the simple designs, too. Proper selection of materials is always advisable to make sure that the product will perform well in an unpredictable situation.
So there are several areas where selection of material is inevitable, but it is becoming even important in this highly competitive industrial arena.
One of significant importance of material selection is the fact that it provides the designer a greater flexibility to his design process. He may design several alternative designs and processes and the best performing material can be evaluated by proper material selection procedures. In the material selection phase, the minimum and maximum properties are examined. The designer can modify the design and/or process for possible improvements or adjustments because he knows the limits of the materials exactly. Also in case of a failure, he has the ability to redesign it easily.
These are the main reasons why material selection is inevitable in engineering design. It is becoming more and more important because of the complexity and diversity of the design process and engineering materials today. Therefore knowing the importance of material selection is may be a forward step for any person who is involved in the engineering field.