Damage plasticity model

doc/content/bib/blackbear.bib

@@ -244,3 +244,50 @@ @article{poyet2009temperature
 	  year={2009},
 	  publisher={Elsevier}
 	}
+
+	@article{lee1998plastic,
+  title={Plastic-damage model for cyclic loading of concrete structures},
+  author={Lee, Jeeho and Fenves, Gregory L},
+  journal={Journal of engineering mechanics},
+  volume={124},
+  number={8},
+  pages={892--900},
+  year={1998},
+  publisher={American Society of Civil Engineers}
+}
+
+@phdthesis{lee1996theory,
+  title={Theory and implementation of plastic-damage model for concrete structures under cyclic and dynamic loading},
+  author={Lee, Jeeho},
+  year={1996},
+  school={University of California, Berkeley}
+}
+
+@article{wilkins2020method,
+  title = {A method for smoothing multiple yield functions},
+ author = {Andy Wilkins and Benjamin W. Spencer and Amit Jain and Bora Gencturk},
+   year = {2020},
+journal = {International Journal for Numerical Methods in Engineering},
+ volume = {121},
+ number = {3},
+  pages = {434--449},
+    doi = {10.1002/nme.6215}
+}
+
+@article{lubliner1989plastic,
+  title={A plastic-damage model for concrete},
+  author={Lubliner, Jacob and Oliver, Javier and Oller, Sand and Onate, EJIJos},
+  journal={International Journal of solids and structures},
+  volume={25},
+  number={3},
+  pages={299--326},
+  year={1989},
+  publisher={Elsevier}
+}
+
+@article{krabbenhoft2002basic,
+  title={Basic computational plasticity},
+  author={Krabbenh{\o}ft, KRISTIAN},
+  journal={University of Denmark},
+  year={2002}
+}

doc/content/source/materials/ComputeMultipleInelasticDamageStress.md

@@ -0,0 +1,27 @@
+# Compute Multiple Inelastic Damage Stress
+
+!syntax description /Materials/ComputeMultipleInelasticDamageStress
+
+## Description
+
+`ComputeMultipleInelasticDamageStress` is a class based on `ComputeMultipleInelasticStress`
+that is designed specifically to be used with [DamagePlasticityStressUpdate](DamagePlasticityStressUpdate.md).
+The main difference between this class and the standard `ComputeMultipleInelasticStress` class is that
+it makes some modifications to both the current and old stress to account for the damage in a way that
+is appropriate for the damaged plasticity model. It divides the old stress passed to the plasticity model
+by $(1-D)$, and multiplies the new stress by $(1-D)$, where $D$ is the damage index.
+
+This ComputeMultipleInelasticStress is to be used with (/DamagePlasticityStressUpdate.md).
+## Example Input Files
+
+The input settings for the inelastic material model is as follows
+
+!listing test/tests/damage_plasticity_model/uniaxial_test.i block=Materials/stress
+
+!syntax parameters /Materials/ComputeMultipleInelasticDamageStress
+
+!syntax inputs /Materials/ComputeMultipleInelasticDamageStress
+
+!syntax children /Materials/ComputeMultipleInelasticDamageStress
+
+!bibtex bibliography

include/materials/ComputeMultipleInelasticDamageStress.h

@@ -0,0 +1,45 @@
+/****************************************************************/
+/*               DO NOT MODIFY THIS HEADER                      */
+/*                       BlackBear                              */
+/*                                                              */
+/*           (c) 2017 Battelle Energy Alliance, LLC             */
+/*                   ALL RIGHTS RESERVED                        */
+/*                                                              */
+/*          Prepared by Battelle Energy Alliance, LLC           */
+/*            Under Contract No. DE-AC07-05ID14517              */
+/*            With the U. S. Department of Energy               */
+/*                                                              */
+/*            See COPYRIGHT for full restrictions               */
+/****************************************************************/
+
+#pragma once
+
+#include "ComputeMultipleInelasticStress.h"
+
+/**
+ * This ComputeMultipleInelasticStress is to be used with DamagePlasticityStressUpdate
+ */
+class ComputeMultipleInelasticDamageStress : public ComputeMultipleInelasticStress
+{
+public:
+  static InputParameters validParams();
+  ComputeMultipleInelasticDamageStress(const InputParameters & parameters);
+  virtual void initialSetup() override;
+
+protected:
+  /// damage parameter for DamagePlasticityStressUpdate model
+  const MaterialProperty<Real> & _D;
+  const MaterialProperty<Real> & _D_old;
+
+  virtual void computeQpJacobianMult() override;
+
+  virtual void computeAdmissibleState(unsigned model_number,
+                                      RankTwoTensor & elastic_strain_increment,
+                                      RankTwoTensor & inelastic_strain_increment,
+                                      RankFourTensor & consistent_tangent_operator) override;
+
+  virtual void
+  updateQpStateSingleModel(unsigned model_number,
+                           RankTwoTensor & elastic_strain_increment,
+                           RankTwoTensor & combined_inelastic_strain_increment) override;
+};