In two previous papers a uniaxial-stress model was used to investigate the plastic and creep strain behaviour in the hoop direction of a pressurized tube as the temperature gradient across the tube wall is cycled. The results obtained were concerned with determining the loading conditions under which ratchetting, alternating plasticity and shakedown occur and are readily depicted in terms of the load diagram now frequently referred to as the Bree diagram. The present work is concerned with the development of a biaxial-stress model for the same problem which takes into account the effect of the stress in the axial direction of the tube. Consideration is confined to time independent plastic deformation, the tube is assumed to be constructed of ideal elastic-plastic material and plastic deformation is assumed to occur in accordance with the Tresca yield criterion and associated flow rule. The results are obtained in closed analytic form and lead to a load diagram depicting the loading conditions under which the various types of behaviour occur for the biaxial-stress system. For simplicity Poisson's ratio is assumed to be zero but it is felt that this gives results that will be of assistance in dealing with the problem when Poisson's ratio is non-zero. © 1990.
|Number of pages||28|
|Journal||International Journal of Mechanical Sciences|
|Publication status||Published - 1989|