IMKBilin fix

A fix for an observed zigzag bug in the response during high frequency un/reloading.
zhuminjie · Jul 2, 2021 · 727beff · 727beff
1 parent 60b8945
commit 727beff
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/SRC/material/uniaxial/IMKBilin.cpp b/SRC/material/uniaxial/IMKBilin.cpp
@@ -41,7 +41,7 @@ OPS_IMKBilin(void)
 {
 	if (numIMKBilinMaterials == 0) {
 		numIMKBilinMaterials++;
-		OPS_Error("Mod. IMK Model with Bilinear Hysteretic Response - Code by A. ELKADY\n", 1);
+		OPS_Error("Mod. IMK Model with Bilinear Hysteretic Response - Code by A.ELKADY-21\n", 1);
 	}
 
 	// Pointer to a uniaxial material that will be returned
@@ -337,7 +337,8 @@ int IMKBilin::setTrialStrain(double strain, double strainRate)
 	}
 
 	//  Simple and unified notation for current bacbone parameters
-	if (Di >= 0.0) {
+	Mi_temp = Mi_1 + K_j * (Ri - Ri_1);
+	if (Mi_temp >= 0.0) {
 		Ki = K_j;
 		slope_pi = slope_p_pos_j;
 		slope_pci = slope_pc_pos_j;

diff --git a/SRC/material/uniaxial/IMKBilin.h b/SRC/material/uniaxial/IMKBilin.h
@@ -178,6 +178,7 @@ class IMKBilin : public UniaxialMaterial
 	double Theta_y_x, cTheta_y_x;
 	double MpeProject_x, cMpeProject_x;
 
+	double Mi_temp;
 };