TABLE OF CONTENTS Many materials are especially brought to use in various mechanical components. The ones which are commonly used are surveyed here with an explanation of why they are used in the given applications.
Efficient, single components such as gears, cams, shafts, pins, and springs are vital for the smooth functioning of a mechanical system. The latter is made up of several single components put together such that a coordinated system results, e.g. a pump. In the following write-up, selected single components are analyzed and their materials requirements specified. Suitable materials for construction of the component, as well as their functional characteristics in the component, are described.
Springs can be in the form of sheets (as in leaf springs) or spirals (helical springs). They are mainly required to undergo repeated stressing in the elastic region, efficiently absorb the energy (i.e., have good resilience), damp any vibration that would be created, and have high enough strength (yield strength) to withstand the required amount of maximum stress that is applied on them.
High resiliency requires that ? 2 /E be high. If the springs were required to be light also, the specific resiliency, ? 2 /E ?, should be high. ( ? is the applied elastic stress, the maximum allowable value of which is the yield strength ? y, E is the young s modulus of elasticity, and p is the density.) These are the Material Engineering Indices for springs (see Chapter 2); with these requirements in mind, several...
