Hookes Law= up to a given load, the extension of a pring is directly proportional to the force applied to the spring. F= KX (k-spring constant)

Limit of proportionality- the point the material stops obeying hooks law. but would still return to its original shape if stress is removed.

elastic limit- at this point the material starts to behave plastically. at this point the material would no longer return to its original shape once the stress was removed.

Yield point- the stress at which a large amont of plastic deformation takes place with a constant or reduced load.

Work done= 1/2 X Max force X extention

Elastic strain energy= the area under the graph.

Stress=Force/Cross sectional area

Strain=Extension/ original length

Young modulus= stress/strain.

Energy density= work done/ volume = 1/2 X stress X strain = the area under a stress stain graph.

the hysteresis loop for a stress starin graph represents the energy per unit volume transferred to internal energy during the cycle.

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