STRENGTH OF MATERIALS

1. STRENGTH OF MATERIALS Young’s Modules of Elasticity Y= Y = = A tensile or longitudinal force is a force which stretches or increases the length of a material Fig 1: The graph of extension against weight or Force. Key of the graphs A = Proportionality limit B = Elastic limit C = Yield point D = The material becomes thin and breaks breaking point
2. 2. é = Permanent extension Fig 2: The graph of stress against strain S = Permanent strain. 0A = Hooke’s law obeyed. 0B = Elastic deformation region. 0C = Region of plastic deformation. Features of the graphs · The proportionality limit is the maximum stress beyond which Hooke’s law is not obeyed or the ratio of stress/strain is no longer constant · 0A: Hooke’s law is obeyed i.e. F = KX. Stress α Strain i.e. stress/strain = constant. · Elastic limit is the maximum stress 

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