fix of giveInternalForceVector in lattice2d

Author: githubgrasp

src/sm/Elements/LatticeElements/lattice2d.C

@@ -192,7 +192,59 @@ Lattice2d :: computeStiffnessMatrix(FloatMatrix &answer, MatResponseMode rMode,
     answer.plusProductUnsym(bj, dbj, dV);
 }
 
+void
+Lattice2d :: giveInternalForcesVector(FloatArray &answer,
+				      TimeStep *tStep, int useUpdatedGpRecord)
+{
+    FloatMatrix b;
+    FloatArray u, stress(3), strain;
+
+    this->computeVectorOf(VM_Total, tStep, u);
+    // subtract initial displacements, if defined
+    if ( initialDisplacements ) {
+        u.subtract(* initialDisplacements);
+    }
 
+    answer.clear();
+
+    for ( GaussPoint *gp : * this->giveDefaultIntegrationRulePtr() ) {
+        this->computeBmatrixAt(gp, b);
+
+        if ( useUpdatedGpRecord == 1 ) {
+            auto status = gp->giveMaterialStatus();            
+	    LatticeMaterialStatus *lmatStat = dynamic_cast< LatticeMaterialStatus * >( status );
+	    FloatArray stressTemp;
+	    if ( lmatStat ) {
+	      stressTemp = lmatStat->giveLatticeStress();
+	    }
+	    stress.at(1) = stressTemp.at(1);
+            stress.at(2) = stressTemp.at(2);
+            stress.at(3) = stressTemp.at(6);
+        } else {
+            if ( !this->isActivated(tStep) ) {
+	      strain.zero();
+            }
+            strain.beProductOf(b, u);
+            this->computeStressVector(stress, strain, gp, tStep);
+        }
+
+        if ( stress.giveSize() == 0 ) {
+            break;
+        }
+
+        // compute nodal representation of internal forces using f = B^T*Sigma dV
+        double dV = this->computeVolumeAround(gp);
+        answer.plusProduct(b, stress, dV);
+
+    }
+
+    // if inactive update state, but no contribution to global system
+    if ( !this->isActivated(tStep) ) {
+        answer.zero();
+        return;
+    }
+}
+ 
 void Lattice2d :: computeGaussPoints()
 // Sets up the array of Gauss Points of the receiver.
 {

src/sm/Elements/LatticeElements/lattice2d.h

@@ -131,7 +131,8 @@ class Lattice2d : public LatticeStructuralElement
     void computeStressVector(FloatArray &answer, const FloatArray &strain, GaussPoint *gp, TimeStep *tStep) override;
     void computeConstitutiveMatrixAt(FloatMatrix &answer, MatResponseMode rMode, GaussPoint *gp, TimeStep *tStep) override;
     void computeStiffnessMatrix(FloatMatrix &answer, MatResponseMode rMode, TimeStep *tStep) override;
-
+    void giveInternalForcesVector(FloatArray &answer, TimeStep *tStep, int useUpdatedGpRecord) override;
+  
     int giveNumberOfCrossSectionNodes() override { return 2; }
     double givePitch();
     void computeGaussPoints() override;