From a1c3a6483debddc8720cd450f8fc59fff2c1a9af Mon Sep 17 00:00:00 2001
From: Romain Boman <romain.boman@gmail.com>
Date: Thu, 13 Mar 2025 11:49:24 +0100
Subject: [PATCH] add principal strain extraction script
---
min_max_strain.py | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 min_max_strain.py
diff --git a/min_max_strain.py b/min_max_strain.py
new file mode 100644
index 0000000..41d461f
--- /dev/null
+++ b/min_max_strain.py
@@ -0,0 +1,38 @@
+#! /usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# extract principal strains from results
+# (run this script in the workspace folder)
+
+import gmsh
+import numpy as np
+
+gmsh.initialize()
+gmsh.merge('mesh.msh')
+gmsh.merge('smooth_strain_tensor.msh')
+
+dataType, tags, data, time, numComp = gmsh.view.getModelData(1, 0)
+
+# compute the 3 principal strains from nodal strain tensor
+
+e1s = []
+e2s = []
+e3s = []
+
+for epl in data:
+ [xx, xy, xz, yx, yy, yz, zx, zy, zz] = epl
+ # compute the 3 principal strains
+ epl = np.array([[xx, xy, xz], [yx, yy, yz], [zx, zy, zz]])
+ eigvals = np.linalg.eigvals(epl)
+ eigvals = np.sort(eigvals)
+ e1s.append(eigvals[0])
+ e2s.append(eigvals[1])
+ e3s.append(eigvals[2])
+
+e1s = np.array(e1s)
+e2s = np.array(e2s)
+e3s = np.array(e3s)
+
+# display min of lowest principal strain and max of highest principal strain
+print(f'e1_min = {np.min(e1s)}')
+print(f'e3_max = {np.max(e3s)}')
--
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