GMP1dMat

Purpose

uniaxial stress-strain relation for Giuffre-Menegotto-Pinto hysteretic material

Synopsis

MatResp = GMP1dMat (action,MatNo,MatData,MatState)

Description

GMP1DMAT uniaxial stress-strain relation for Giuffre-Menegotto-Pinto hysteretic material    
  MATRESP = GMP1DMAT (ACTION,MATNO,MATDATA,MATSTATE)
  function determines the uniaxial stress-strain relation for Giuffre-Menegotto-Pinto hysteretic material
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  the character variable ACTION should have one of the following values
  ACTION = 'chec' function checks material property data for omissions and returns default values in MATDATA
           'init' function returns the material history variables in MATSTATE
           'forc' function returns the material stress (tensor) in MATSTATE
           'stif' function returns the material tangent modulus and the stress (tensor) in MATSTATE
           'post' function returns data structure MATPOST with post-processing information
  depending on the value of character variable ACTION the function returns information in data structure MATRESP
  for the material with number MAT_NO; data structure MATDATA supplies the material property data
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  data structure MATRESP stands for one of the following data objects depending on value of ACTION 
  MATRESP = MATDATA   for action = 'chec'
  MATRESP = MATSTATE  for action = 'init'
  MATRESP = MATSTATE  for action = 'stif'
  MATRESP = MATSTATE  for action = 'forc'
  MATRESP = MATPOST   for action = 'post'
  MATRESP is empty    for unsupported keywords
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  MATSTATE is a data structure with information about the current material state in fields
         eps    = total strain (tensor for 2d or 3d)
         Deps   = strain increments from last convergence
         DDeps  = strain increments from last iteration
         epsdot = strain rate (tensor for 2d or 3d)
         km     = material tangent modulus; returned under ACTION = 'stif'
         sig    = stress (tensor for 2d or 3d); returned under ACTION = 'stif' or 'forc'
         Past   = material history variables at last converged state
         Pres   = current values of material history variables
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  MATDATA is a data structure with material property information in fields
         E   = initial modulus
         fy  = row vector with positive and negative yield strength (default = equal fy)
         b   = strain hardening ratio (can also specify hardening modulus Eh for b = Eh/E)
         R0  = exp transition elastic-plastic (default value 20)
         cR1 = coefficient for variation of R0 (default value 0.925)
         cR2 = coefficient for variation of R0 (default value 0.15)
         a1  = isotropic hardening (IH) coefficient in compression (default value 0)
         a2  = trigger strain ductility for IH      in compression (default value 0)
         a3  = isotropic hardening (IH) coefficient in tension     (default value 0)
         a4  = trigger strain ductility for IH      in tension     (default value 0)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  MATPOST is a data structure with material response information for post-processing in fields
         eps = total strain
         sig = uniaxial stress

Cross-Reference Information

This function calls: