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--- doc:user:elements:volumes:isohard [2017/10/03 08:37] – [KrupkowskyIsotropicHardening] boman
+++ doc:user:elements:volumes:isohard [2020/07/08 10:16] (current) – [Python] papeleux
@@ Line 21: / Line 21: @@
 |Initial yield stress $\sigma^{el}$  |  ''IH_SIGEL''  |  ''TM/TO''         |
 |Plastic Modulus $h $                |    ''IH_H''    |  ''TM/TO''         |
+**NB**: the plastic modulus is defined as $h = \frac{E E_T}{E - E_T} $, where $E$ is the Young's modulus and $E_T$ the tangent modulus.
 ===== SaturatedIsotropicHardening =====
@@ Line 97: / Line 99: @@
 $$
-\sigma_{vm} = K \left(\bar{\varepsilon}^{vp}_ {0} + \bar{\varepsilon}^{vp}\right)^{n}
+\sigma_{vm} = K \left(\bar{\varepsilon}^{vp}_{0} + \bar{\varepsilon}^{vp}\right)^{n}
 $$
 === Parameters ===
-^          Name                                        ^  Metafor Code  ^ Dependency         ^
+^          Name                                                   ^  Metafor Code  ^ Dependency         ^
-|Initial equivalent plastic strain |  ''IH_EVPL0''  |  ''TM/TO''         |
+| Initial equivalent plastic strain $\bar{\varepsilon}^{vp}_{0}$  |  ''IH_EVPL0''  |  ''TM/TO''         |
-|$K $                                      |    ''IH_K''    |  ''TM/TO''         |
+| strength coefficient  $K$                                       |    ''IH_K''    |  ''TM/TO''         |
-|$n $                                      |    ''IH_N''    |  ''TM/TO''         |
+| strain hardening exponent $n$                                   |    ''IH_N''    |  ''TM/TO''         |
 ===== Nl8pIsotropicHardening =====
@@ Line 248: / Line 250: @@
 |$\Theta_{0}$  |   ''KM_THETA0''     |  ''TM/TO''           |
 |$\Theta_{IV}$ |   ''KM_THETA4''     |  ''TM/TO''           |
+===== Python =====
+User defined Isotropic Hardening by a pythonDirector :
+Python Director allows user to define their own Isotropic Hardening law. Five functions has to be defined in the Python Class :
+  * a constructor (<code>__init__</code>),
+  * a destructor (<code>__del__</code>) that must never be called,
+  * computeSvm  (epl, pLaw)
+  * computeH (epl, pLaw)
+  * computePotential (epl, pLaw) for hyperElastics models
+See the example below of a Linear Isotropic Hardening :
+<code>
+class MyIsoH(PythonIsotropicHardening):
+    def __init__(self, _no, _svm0, _h):
+        print("MyIsoH : __init__")
+        PythonIsotropicHardening.__init__(self,_no)
+        self.svm0 = _svm0
+        self.h    = _h
+        print("no = ", _no)
+        print("self.svm0 = ", self.svm0)
+        print("self.h = ", self.h)
+        print("MyIsoH : __init__ finished")
+        print("computeSvm(0.0) = " , self.computeSvm(0.0, None))
+    def __del__(self):
+        print("MyIsoH : __del__")
+        print("callToDestructor of MyIsoH not allowed. Add MyIsoH.__disown__()")
+        input('')
+        exit(1)
+    def computeSvm(self, epl, pLaw) :
+        #print "MyIsoH compute SVM"
+        return self.svm0+epl*self.h
+    def computeH(self, epl, pLaw) :
+        #print "MyIsoH compute H"
+        return self.h
+    def computePotential(self, epl, pLaw) :
+        #print "MyIsoH compute Potential"
+        return (self.svm0+self.h*epl*0.5)*epl
+</code>