Mechanical cantilever springs action has been put to use by humans since the invention of crossbow. Although theoretical knowledge of yield strength was quite rudimentary, importance of its practicality was understood. Yield strength of a spring is defined as the stress at which the spring starts deforming plastically, i.e. stress beyond which the spring stops returning to initial position. It is also known as elastic limit or yield point. This article discusses the methods of calculating the yi
