The user subroutine ``creep.f'' is made available to allow the user to incorporate his own creep law by selecting the keyword sequence *CREEP,LAW=USER in the input deck. The creep routine must return the creep rate and its derivative with respect to the Von Mises stress for a given Von Mises stress. The header and a description of the input and output variables is as follows:
subroutine creep(decra,deswa,statev,serd,ec,esw,p,qtild, & temp,dtemp,predef,dpred,time,dtime,cmname,leximp,lend, & coords,nstatv,noel,npt,layer,kspt,kstep,kinc) ! ! user creep routine ! ! INPUT: ! ! decra(1) material name ! statev(1..nstatv) internal variables ! serd not used ! ec(1) equivalent creep at the start of the increment ! ec(2) not used ! esw(1..2) not used ! p not used ! qtild von Mises stress ! temp temperature at the end of the increment ! dtemp not used ! predef not used ! dpred not used ! time(1) value of the step time at the end of the increment ! time(2) value of the total time at the end of the increment ! dtime time increment ! cmname material name ! leximp not used ! lend not used ! coords(1..3) coordinates of the current integration point ! nstatv number of internal variables ! noel element number ! npt integration point number ! layer not used ! kspt not used ! kstep not used ! kinc not used ! ! ! OUTPUT: ! ! decra(1) equivalent deviatoric creep strain increment ! decra(2..4) not used ! decra(5) derivative of the equivalent deviatoric ! creep strain increment w.r.t. the von Mises ! stress ! deswa(1..5) not used