The elastic-plastic deformation analysis on cylinder of different modulus in tension and compression

In this paper a theory of cylinder elastic-plastic formation in materials with difficult tension and compression modulus is presented. Based on elastic theory with different modulus in tension and compression and the classic plastic theory, the radius of the plastic zone and the stress field solution of the cylinder have been educed. By analyzing the factor of the development of plastic zone in the finite radius cylinder, the results indicate that the radius of plastic zone, the elastic extreme-pressure, the stress and displacement fields vary remarkable with the modulus coefficient and the ratio of outside radius and inside radius. If the classic theory is still applied to design the engineering structure, big mistake may be resulted, and which may be the real reason of structure instability.