A MULTI-DIMENSIONAL COMPOSITE MODEL FOR PLASTIC CONTINUA UNDER POLYAXIAL LOADING CONDITION

By replacing a medium with reinforcing components oriented and distributed uniformly in a mul-ti-dimensional space,a constitutive model is constructed.The components are extended/compressed compatiblywith the strain and the resultant of load exerted on them to balance the stress.Their load-elongation relation canbe determined from a conventional material test.Each component undergoes different elongation history dependingon its own orientation during deformation,so that the model can simulate elasto-plastic behavior of materials un-der polyaxial loading conditions.The incremental constitutive matrix bas been derived for application in numeri-cal analysis and a yield criterion is also introduced.A few subsequent yield surfaces have been predicted and com-pared with experiments.