Editing Elastic modulus (section)

== Elastic constants and moduli ==
Elastic constants are specific parameters that quantify the [[stiffness]] of a material in response to applied [[Stress–strain curve|stresses]] and are fundamental in defining the elastic properties of materials. These constants form the elements of the stiffness matrix in tensor notation, which relates [[Stress–strain curve|stress to strain]] through linear equations in [[Anisotropy|anisotropic]] materials. Commonly denoted as ''C<sub>ijkl</sub>'', where ''i'',''j'',''k'', and ''l'' are the coordinate directions, these constants are essential for understanding how materials deform under various loads.<ref>{{Cite book |last1=Schreiber |first1=Edward |title=Elastic constants and their measurement |last2=Anderson |first2=O. L. |last3=Soga |first3=Naohiro |date=1974 |publisher=McGraw-Hill |isbn=978-0-07-055603-4 |location=New York}}</ref>