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[behzad <question255780@xxxxxxxxxxxxxxxxxxxxx>]

New question #255780 on Yade:
https://answers.launchpad.net/yade/+question/255780

Hi there,

It's a while I'm working to derive a new constitutive law which gives the properties of viscoelastic Burger's model. 
I share here the first drafts of the model which is integrated in one header and one implementation file. 
It's a draft and I have not yet tested it. It's shared here to find the possible errors.
Any comments and helps are highly appreciated.

Thanks


HEADER:

 



#pragma once

#include<yade/core/GlobalEngine.hpp>
#include<yade/pkg/common/Dispatching.hpp>
#include<yade/pkg/dem/ScGeom.hpp>
#include<boost/tuple/tuple.hpp>
#include<yade/pkg/dem/CohesiveFrictionalContactLaw.hpp>
#include<yade/pkg/dem/FrictPhys.hpp>



//********************** CohBurgersMat ****************************/

class CohBurgersMat : public CohFrictMat
{
	public :
		virtual ~CohBurgersMat ();

/// Serialization
	YADE_CLASS_BASE_DOC_ATTRS_CTOR(CohBurgersMat,FrictMat,"",
		((Real,Em,1e3,,"Stiffness of Maxwell's spring"))
		((Real,Ek,1e3,,"Stiffness of Kelvin's spring"))
		((Real,Cm,10,,"Viscosity of Maxwell's dashpot"))
	        ((Real,Ck,10,,"Viscosity of Kelvin's dashpot"))
                ((Real,poissonRatio,0.5,,""))
		createIndex();
		);
/// Indexable
	REGISTER_CLASS_INDEX(CohBurgersMat,CohFrictMat);
};

REGISTER_SERIALIZABLE(CohBurgersMat);



//********************** CohBurgersPhys ****************************/

class CohBurgersPhys : public CohFrictPhys
{
	public :
		virtual ~CohBurgerPhys() {};
		void SetBreakingState() {cohesionBroken = true; normalAdhesion = 0; shearAdhesion = 0;};

	YADE_CLASS_BASE_DOC_ATTRS_CTOR(CohBurgerPhys,CohFrictPhys,"",
		((bool,cohesionDisablesFriction,false,,"is shear strength the sum of friction and adhesion or only adhesion?"))
		((bool,cohesionBroken,true,,"is cohesion active? Set to false at the creation of a cohesive contact, and set to true when a fragile contact is broken"))
		((bool,fragile,true,,"do cohesion disapear when contact strength is exceeded?"))
		((Real,BurEmn,NaN,,"Stiffness of Maxwell's spring(normal)"))
		((Real,BurEkn,NaN,,"Stiffness of Kelvin's spring(normal)"))
		((Real,BurCmn,NaN,,"Viscosity of Maxwell's dashpot(normal)"))
	        ((Real,BurCkn,NaN,,"Viscosity of Kelvin's dashpot(normal)"))
		((Real,BurEms,NaN,,"Stiffness of Maxwell's spring(shear)"))
		((Real,BurEks,NaN,,"Stiffness of Kelvin's spring(shear)"))
		((Real,BurCms,NaN,,"Viscosity of Maxwell's dashpot(shear)"))
	        ((Real,BurCks,NaN,,"Viscosity of Kelvin's dashpot(shear)"))
                ((Real,poissonRatio,NaN,,""))
		((Real,normalAdhesion,0,,"tensile strength"))
		((Real,shearAdhesion,0,,"cohesive part of the shear strength (a frictional term might be added depending on :yref:`CohFrictPhys::cohesionDisablesFriction`)"))
		,
		createIndex();
	);
/// Indexable
	REGISTER_CLASS_INDEX(CohBurgerPhys,CohFrictPhys);
};

REGISTER_SERIALIZABLE(CohBurgerPhys);




//********************** Ip2_CohBurgersMat_CohBurgersMat_CohBurgersPhys ****************************/

class Ip2_CohBurgersMat_CohBurgersMat_CohBurgersPhys : public IPhysFunctor
{
	public :
		virtual void go(	const shared_ptr<Material>& b1,
					const shared_ptr<Material>& b2,
					const shared_ptr<Interaction>& interaction);
		int cohesionDefinitionIteration;

		YADE_CLASS_BASE_DOC_ATTRS_CTOR(Ip2_CohBurgersMat_CohBurgersMat_CohBurgersPhys,IPhysFunctor,
		
		((bool,setCohesionNow,false,,"If true, assign cohesion to all existing contacts in current time-step. The flag is turned false automatically, so that assignment is done in the current timestep only."))
		((bool,setCohesionOnNewContacts,false,,"If true, assign cohesion at all new contacts. If false, only existing contacts can be cohesive (also see :yref:`Ip2_CohFrictMat_CohFrictMat_CohFrictPhys::setCohesionNow`), and new contacts are only frictional."))	
		,
		cohesionDefinitionIteration = -1;
		);
	FUNCTOR2D(CohBurgersMat,CohBurgersMat);
};

REGISTER_SERIALIZABLE(Ip2_CohBurgersMat_CohBurgersMat_CohBurgersPhys);



//********************** Ip2_FrictMat_CohBurgersMat_CohFrictPhys ****************************/


class Ip2_FrictMat_CohBurgersMat_CohFrictPhys : public IPhysFunctor
{
	public :
		virtual void go(	const shared_ptr<Material>& b1,
					const shared_ptr<Material>& b2,
					const shared_ptr<Interaction>& interaction);
		int cohesionDefinitionIteration;

		YADE_CLASS_BASE_DOC_ATTRS_CTOR(Ip2_FrictMat_CohBurgersMat_CohFrictPhys,IPhysFunctor,
		
		((bool,setCohesionNow,false,,"If true, assign cohesion to all existing contacts in current time-step. The flag is turned false automatically, so that assignment is done in the current timestep only."))
		((bool,setCohesionOnNewContacts,false,,"If true, assign cohesion at all new contacts. If false, only existing contacts can be cohesive (also see :yref:`Ip2_CohFrictMat_CohFrictMat_CohFrictPhys::setCohesionNow`), and new contacts are only frictional."))	
		,
		cohesionDefinitionIteration = -1;
		);
	FUNCTOR2D(FrictMat,CohBurgersMat);
};

REGISTER_SERIALIZABLE(Ip2_FrictMat_CohBurgersMat_CohFrictPhys);




//******************** Law2_ScGeom_CohBurgersPhys_CohesiveBurgers *************************/


class Law2_ScGeom_CohBurgersPhys_CohesiveBurgers: public LawFunctor{
	public:
		OpenMPAccumulator<Real> plasticDissipation;
		Real normElastEnergy();
		Real shearElastEnergy();
		Real normalDisplacement();
		Real shearDisplacement();
		Real totalElastEnergy();
		Real ((BurgEmn, 0.0, "Em in normal direction"))
		Real ((BurgEkn, 0.0, "Ek in normal direction"))
		Real ((BurgEms, 0.0, "Em in shear direction"))
		Real ((BurgEks, 0.0, "Ek in shear direction"))
		Real ((BurgCmn, 0.0, "Cm in normal direction"))
		Real ((BurgCkn, 0.0, "Ck in normal direction"))
		Real ((BurgCms, 0.0, "Cm in shear direction"))
		Real ((BurgCks, 0.0, "Ck in shear direction"))
		Real ((BurgPoi,0.0,"Poisson ratio"))

		void initPlasticDissipation(Real initVal=0);
	virtual bool go(shared_ptr<IGeom>& _geom, shared_ptr<IPhys>& _phys, Interaction* I);
	YADE_CLASS_BASE_DOC_ATTRS_CTOR_PY(Law2_ScGeom6D_CohBurgerPhys_CohesiveBurger,
		((bool,neverErase,false,,))
		,,
		.def("normElastEnergy",&Law2_ScGeom6D_CohFrictPhys_CohesionMoment::normElastEnergy,"Compute normal elastic energy.")
		.def("shearElastEnergy",&Law2_ScGeom6D_CohFrictPhys_CohesionMoment::shearElastEnergy,"Compute shear elastic energy.")
		.def("normalDisplacement",&Law2_ScGeom6D_CohFrictPhys_CohesionMoment::normalDisplacement,"Compute normal displacement.")
		.def("shearDisplacement",&Law2_ScGeom6D_CohFrictPhys_CohesionMoment::shearDisplacement,"Compute shear displacement.")
		.def("elasticEnergy",&Law2_ScGeom6D_CohFrictPhys_CohesionMoment::totalElastEnergy,"Compute total elastic energy.")
	);
	FUNCTOR2D(ScGeom,CohBurgersPhys);
	DECLARE_LOGGER;
};
REGISTER_SERIALIZABLE(Law2_ScGeom_CohBurgersPhys_CohesiveBurgers);


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