From 74a48ab859c87f1ea0d5192c7b93e0e5b49e4e40 Mon Sep 17 00:00:00 2001
From: Juan Camilo Velasquez <75626235+jucavel09@users.noreply.github.com>
Date: Mon, 19 Aug 2024 15:50:25 -0600
Subject: [PATCH] Modification of the nemlumat.f file
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A change was implemented in the nemlumat.f file. The multipliers for shear stress and strain, which convert them to Mandel notation, were incorrectly defined. The stress multipliers have been adjusted from 1.0/√2.0 to √2.0. Additionally, the shear strain components were reduced by half to align with Abaqus's interpretation of shear strains as engineering strains, not tensorial strains.
---
 util/abaqus/nemlumat.f | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/util/abaqus/nemlumat.f b/util/abaqus/nemlumat.f
index 8fff8781..1db38463 100644
--- a/util/abaqus/nemlumat.f
+++ b/util/abaqus/nemlumat.f
@@ -113,18 +113,18 @@ SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD,
       smult(1) = 1.0
       smult(2) = 1.0
       smult(3) = 1.0
-      smult(4) = 1.0 / sqrt(2.0)
-      smult(5) = 1.0 / sqrt(2.0)
-      smult(6) = 1.0 / sqrt(2.0)
+      smult(4) = sqrt(2.0)
+      smult(5) = sqrt(2.0)
+      smult(6) = sqrt(2.0)
 c
 c           Strain
 c
       emult(1) = 1.0
       emult(2) = 1.0
       emult(3) = 1.0
-      emult(4) = sqrt(2.0)
-      emult(5) = sqrt(2.0)
-      emult(6) = sqrt(2.0)
+      emult(4) = sqrt(2.0) / 2.0
+      emult(5) = sqrt(2.0) / 2.0
+      emult(6) = sqrt(2.0) / 2.0
 c
 c           Load the model
 c