add elastic_constants

pyiron_continuum/reference/elastic_constants.py

@@ -0,0 +1,28 @@
+# coding: utf-8
+# Copyright (c) Max-Planck-Institut für Eisenforschung GmbH - Computational Materials Design (CM) Department
+# Distributed under the terms of "New BSD License", see the LICENSE file.
+
+
+import numpy as np
+from atomistics.referencedata.wikipedia import get_elastic_properties
+
+
+def get_elastic_constants(chemical_symbol):
+    """
+    Get the elastic tensor of a material from the wikipedia database.
+
+    Args:
+        chemical_symbol (str): Chemical symbol of the element.
+
+    Returns:
+        dict: Dictionary with the elastic tensor of the material (isotropic).
+    """
+    d = get_elastic_properties(chemical_symbol)
+    G = d["shear_modulus"]
+    v = d["poissons_ratio"]
+    E = d["youngs_modulus"]
+    C_11 = E * (1 - v) / (1 + v) / (1 - 2 * v)
+    C_12 = E * v / (1 + v) / (1 - 2 * v)
+    C_44 = G
+    d.update({"C_11": C_11, "C_12": C_12, "C_44": C_44})
+    return d

tests/unit/reference/test_elastic_constants.py

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+# coding: utf-8
+# Copyright (c) Max-Planck-Institut für Eisenforschung GmbH - Computational Materials Design (CM) Department
+# Distributed under the terms of "New BSD License", see the LICENSE file.
+
+import unittest
+from pyiron_continuum.reference.elastic_constants import get_elastic_constants
+import numpy as np
+
+
+class TestDecorators(unittest.TestCase):
+    def test_elastic_constants(self):
+        d = get_elastic_constants("Fe")
+        self.assertTrue(all(key in d for key in ["C_11", "C_12", "C_44"]))
+        for value in d.values():
+            self.assertTrue(np.isscalar(value))
+            self.assertGreater(value, 0)
+
+
+if __name__ == "__main__":
+    unittest.main()