Creating MPM Materials - Revision history

Nairnj: /* Prepare for Updates */

2021-09-27T19:55:38Z

Prepare for Updates

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	; <tt>void GetCopyOfMechanicalProps(MPMBase mptr,int np,void matBuffer,void altBuffer) const</tt>		; <tt>void GetCopyOfMechanicalProps(MPMBase mptr,int np,void matBuffer,void altBuffer) const</tt>
	: This method is called just before the constitutive law on each time step. You can set any parameters for the material that depend on the current state of the particle. Things that never change (''i.e.'', properties that are independent of particle state) should be calculated in <tt>VerifyAndLoadProperties()<tt> instead. Some materials also used in FEA make use of <tt>LoadMechProps()</tt> in this task, but that method is limited to 2D because it only inputs a single rotation about the z axis.		: This method is called just before the constitutive law on each time step. You can set any parameters for the material that depend on the current state of the particle. Things that never change (''i.e.'', properties that are independent of particle state) should be calculated in <tt>VerifyAndLoadProperties()</tt> instead. Some materials also used in FEA make use of <tt>LoadMechProps()</tt> in this task, but that method is limited to 2D because it only inputs a single rotation about the z axis.

	; <tt>void GetTransportProps(MPMBase ,int,TransportProperties )</tt> const (optional)		; <tt>void GetTransportProps(MPMBase ,int,TransportProperties )</tt> const (optional)

Nairnj: /* History Dependent Properties */

2018-08-07T20:09:46Z

History Dependent Properties

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	; <tt>double GetHistory(int num,char *ptr)</tt>		; <tt>double GetHistory(int num,char *ptr)</tt>
	: This method should extract history variable number num from the allocated data pointer in <tt>ptr</tt>. The <tt>MaterialBase<tt> class assumes history is an array of doubles of length equal to <tt>NumberOfHistoryDoubles()</tt>.		: This method should extract history variable number num from the allocated data pointer in <tt>ptr</tt>. The <tt>MaterialBase</tt> class assumes history is an array of doubles of length equal to <tt>NumberOfHistoryDoubles()</tt>.

	; <tt>int NumberOfHistoryDoubles(void) const</tt>		; <tt>int NumberOfHistoryDoubles(void) const</tt>

Nairnj: /* Optional Initialization Methods */

2018-08-07T20:09:09Z

Optional Initialization Methods

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	; <tt>void SetInitialParticleState(MPMBase *mptr,int np,int offset) const</tt>		; <tt>void SetInitialParticleState(MPMBase *mptr,int np,int offset) const</tt>
	; This method is called in preliminary calculations before a simulation states. It can be used, if needed, to set and material properties for each material point (in the <tt>mptr</tt> pointer).		: This method is called in preliminary calculations before a simulation states. It can be used, if needed, to set and material properties for each material point (in the <tt>mptr</tt> pointer).

	=== Basic Class Accessors ===		=== Basic Class Accessors ===

Nairnj: /* History Dependent Properties */

2017-12-25T00:14:54Z

History Dependent Properties

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	=== History Dependent Properties ===		=== History Dependent Properties ===

	~~This section needs editing and include set initial properties method.~~

	For some materials, the constitutive law will depend on the state of the particle in the form of history-dependent data (e.g. cumulative plastic strain for plasticity or strain history for viscoelasticity). Such properties are implemented in a material by using history data. The methods in the material class are as follows:		For some materials, the constitutive law will depend on the state of the particle in the form of history-dependent data (e.g. cumulative plastic strain for plasticity or strain history for viscoelasticity). Such properties are implemented in a material by using history data. The methods in the material class are as follows:

	; <tt>char *~~MaterialData~~(~~void~~)</tt>		; <tt>char InitHistoryData(char pchr,MPMBase *mptr)</tt>
	: Tthis method is called once for each material point using this material at the start of the calculations. It should allocate memory to store history data on the particle, ~~initialize the values,~~ and return a pointer to the ~~structure~~. It can be as simple as a single variable or a pointer to an array of any number of variables~~. If a class overrides this method in a super class, the material will need to make sure all history data is correctly allocated and accessible~~.		: Tthis method is called once for each material point using this material at the start of the calculations. If <tt>pchr==NULL</tt>, It should allocate memory to store history data on the particle, otherwise assume <tt>pchr</tt> points to enough memory for history data. Fill history data and return pointer to the data. It can be as simple as a single variable or a pointer to an array of any number of variables.

	; <tt>double GetHistory(int num,char *ptr)</tt>		; <tt>double GetHistory(int num,char *ptr)</tt>
	: This method should extract history variable number num from the allocated data pointer in ptr. ~~This method is only used when archiving results and num will only be 1 through 4 (currently only the first four~~ history ~~variables can be archived). If num~~ is ~~out~~ of ~~range for the current material, this method should return zero.~~		: This method should extract history variable number num from the allocated data pointer in <tt>ptr</tt>. The <tt>MaterialBase<tt> class assumes history is an array of doubles of length equal to <tt>NumberOfHistoryDoubles()</tt>.
	~~To access values~~ of ~~history variables during constitutive law calculations, you can fetch them from the material point methods GetHistoryPtr~~()~~, GetHistoryDble(), and SetHistoryDble~~().
			; <tt>int NumberOfHistoryDoubles(void) const</tt>
			: Return number of doubles used in a simple array of doubles.

	== MPM Step Calculations ==		== MPM Step Calculations ==

Nairnj: /* History Dependent Properties */

2017-12-24T23:59:14Z

History Dependent Properties

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	For some materials, the constitutive law will depend on the state of the particle in the form of history-dependent data (e.g. cumulative plastic strain for plasticity or strain history for viscoelasticity). Such properties are implemented in a material by using history data. The methods in the material class are as follows:		For some materials, the constitutive law will depend on the state of the particle in the form of history-dependent data (e.g. cumulative plastic strain for plasticity or strain history for viscoelasticity). Such properties are implemented in a material by using history data. The methods in the material class are as follows:

	char *MaterialData(void) ~~(optional) - this~~ method is called once for each material point using this material at the start of the calculations. It should allocate memory to store history data on the particle, initialize the values, and return a pointer to the structure. It can be as simple as a single variable or a pointer to an array of any number of variables. If a class overrides this method in a super class, the material will need to make sure all history data is correctly allocated and accessible.		; <tt>char *MaterialData(void)</tt>
	double GetHistory(int num,char *ptr) ~~- this~~ method should extract history variable number num from the allocated data pointer in ptr. This method is only used when archiving results and num will only be 1 through 4 (currently only the first four history variables can be archived). If num is out of range for the current material, this method should return zero.		: Tthis method is called once for each material point using this material at the start of the calculations. It should allocate memory to store history data on the particle, initialize the values, and return a pointer to the structure. It can be as simple as a single variable or a pointer to an array of any number of variables. If a class overrides this method in a super class, the material will need to make sure all history data is correctly allocated and accessible.

			; <tt>double GetHistory(int num,char *ptr)</tt>
			: This method should extract history variable number num from the allocated data pointer in ptr. This method is only used when archiving results and num will only be 1 through 4 (currently only the first four history variables can be archived). If num is out of range for the current material, this method should return zero.
	To access values of history variables during constitutive law calculations, you can fetch them from the material point methods GetHistoryPtr(), GetHistoryDble(), and SetHistoryDble().		To access values of history variables during constitutive law calculations, you can fetch them from the material point methods GetHistoryPtr(), GetHistoryDble(), and SetHistoryDble().

Nairnj: /* Optional Accessors */

2017-12-24T23:56:49Z

Optional Accessors

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	; <tt>bool SupportsDiffusion(void) const</tt>		; <tt>bool SupportsDiffusion(void) const</tt>
	: if a material does not support diffusion or poroelasticity, override and return false only called when diffusion is active. The <tt>MaterialBase</tt> class returns true.		: if a material does not support diffusion or poroelasticity, override and return false only called when diffusion is active. The <tt>MaterialBase</tt> class returns true.

			; <tt>double GetMaterialConcentrationSaturation(MPMBase *mptr) const</tt>
			: Return the saturation concentration for the material. Only needed if the value depends on state of the material point. The <tt>MaterialBase</tt> returns the saturation concentration property.

			; <tt>double GetRho(MPMBase *) const</tt>
			: Return the density for the material. Only needed if the value depends on state of the material point. The <tt>MaterialBase</tt> returns the density property.

	=== Alternate Particle Strain ===		=== Alternate Particle Strain ===

Nairnj: /* Optional Accessors */

2017-12-24T23:37:38Z

Optional Accessors

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	; <tt>bool SupportsArtificialViscosity(void)</tt>		; <tt>bool SupportsArtificialViscosity(void)</tt>
	: Materials that implement [[Common Material Properties#Artificial Viscosity\|artificial viscosity]] must override this method to return <tt>TRUE</tt> and then implement the calculations in the constitutive law methods.		: Materials that implement [[Common Material Properties#Artificial Viscosity\|artificial viscosity]] must override this method to return <tt>TRUE</tt> and then implement the calculations in the constitutive law methods.

			; <tt>bool SupportsDiffusion(void) const</tt>
			: if a material does not support diffusion or poroelasticity, override and return false only called when diffusion is active. The <tt>MaterialBase</tt> class returns true.

	=== Alternate Particle Strain ===		=== Alternate Particle Strain ===

Nairnj: /* Basic Class Accessors */

2017-12-24T23:27:36Z

Basic Class Accessors

Nairnj: /* Creating Material Properties */

2017-12-24T23:25:27Z

Creating Material Properties

← Older revision		Revision as of 23:25, 24 December 2017
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	</ol>		</ol>

			Once a property variable and name are defined, you set that variable, check it setting, and use it with the following methods:

	==== Required Initialization Methods ====		==== Required Initialization Methods ====

	~~Once a property variable and name are defined, you set that variable, check it setting, and use it with the following methods:~~

	; <tt>char InputMaterialProperty(char xName,int &input,double &gScaling)</tt>		; <tt>char InputMaterialProperty(char xName,int &input,double &gScaling)</tt>

Nairnj: /* Required Initialization Methods */

2017-12-24T23:24:22Z

Required Initialization Methods

← Older revision		Revision as of 23:24, 24 December 2017
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	: This method should print all mechanical properties or call a super class and thenprint just the new mechanical properties. Use a style similar to other materials. To help in formatting, you can use the <tt>MaterialBase</tt> class method <tt>PrintProperty(label,prop,units)</tt> to print a label, a property numeric value, and units within one column. You can use several calls in sequence to get several properties on the same line. You can also call <tt>PrintProperty(text,right)</tt> to print text in a column and right or left justified if <tt>right</tt> is true or false. This method need not pass on to <tt>MaterialBase</tt> because it does not print any mechanical properties. This method is called after <tt>VerifyAndLoadProperties()</tt> is done.		: This method should print all mechanical properties or call a super class and thenprint just the new mechanical properties. Use a style similar to other materials. To help in formatting, you can use the <tt>MaterialBase</tt> class method <tt>PrintProperty(label,prop,units)</tt> to print a label, a property numeric value, and units within one column. You can use several calls in sequence to get several properties on the same line. You can also call <tt>PrintProperty(text,right)</tt> to print text in a column and right or left justified if <tt>right</tt> is true or false. This method need not pass on to <tt>MaterialBase</tt> because it does not print any mechanical properties. This method is called after <tt>VerifyAndLoadProperties()</tt> is done.

	~~; <tt>void ValidateForUse(int np)</tt> (optional)~~		==== Optional Initialization Methods ====
	: This method is called just before the first MPM time step and only for materials used by one or more materials. Throw a <tt>CommonException</tt> if this material cannot by used in current MPM mode (type specified in <tt>np</tt> which will be <tt>PLANE_STRAIN_MPM</tt>, <tt>PLANE_STRESS_MPM</tt>, <tt>AXISYMMETRIC_MPM</tt>, or <tt>THREED_MPM</tt>). If no exceptions, must call the same method in the parent class. Basic material properties and usually checked in <tt>VerifyAndLoadProperties()</tt> instead; this method is for materials that may have valid properties, but may be contingent on other MPM settings.

	; <tt>~~FillTransportProperties~~(TransportProperties *)</tt> ~~(optional)~~		; <tt>void ValidateForUse(int np)</tt>
	: This method is called by <tt>~~MaterialBase::VerifyAndLoadProperties~~()</tt> ~~and can~~ be ~~used calculate transport properties that are independent of the particle state and thus will remain constant throughout the calculation. The~~ <tt>~~MaterialBase~~</tt> ~~class automatically finds diffusion and conductivity tensors for isotropic materials by using material properties~~ <tt>D</tt> ~~(in~~ <tt>~~diffusionCon~~</tt>~~) for diffusion constant and~~ <tt>~~kCond~~</tt> (in <tt>~~kCond~~</tt>) for ~~thermal conductivity. It~~ only ~~needs to be overridden is something more is needed~~.		: This method is called just before the first MPM time step and only for materials used by one or more materials. Throw a <tt>CommonException</tt> if this material cannot by used in current MPM mode (type specified in <tt>np</tt> which will be <tt>PLANE_STRAIN_MPM</tt>, <tt>PLANE_STRESS_MPM</tt>, <tt>AXISYMMETRIC_MPM</tt>, or <tt>THREED_MPM</tt>). If no exceptions, must call the same method in the parent class. Basic material properties are usually checked in <tt>VerifyAndLoadProperties()</tt> instead; this method is for materials that may have valid properties, but may be contingent on other MPM settings or for materials only implement for certain styles of simulations.

	; <tt>void PrintTransportProperties(void)</tt> ~~(optional)~~		; <tt>FillTransportProperties(TransportProperties *)</tt>
			: This method is called by <tt>MaterialBase::VerifyAndLoadProperties()</tt> and can be used calculate transport properties that are independent of the particle state and thus will remain constant throughout the calculation. The <tt>MaterialBase</tt> class automatically finds diffusion and conductivity tensors for isotropic materials by using material properties <tt>D</tt> (in <tt>diffusionCon</tt>) for diffusion constant and <tt>kCond</tt> (in <tt>kCond</tt>) for thermal conductivity. It only needs to be overridden if something more is needed.

			; <tt>void PrintTransportProperties(void)</tt>
	: This method should print all transport properties in format similar to other materials (see help <tt>PrintProperty()</tt> methods described above). It should only print them if transport is activated (''i.e.'', <tt>if(DiffusionTask::active)</tt> or <tt>if(ConductionTask::active)</tt>). The <tt>MaterialBase</tt> class prints isotropic properties and the <tt>ORTHO</tt> and <tt>TRANSISO1(2)</tt> classes print anisotropic properties. No additional printing is needed if one of these classes handles the task.		: This method should print all transport properties in format similar to other materials (see help <tt>PrintProperty()</tt> methods described above). It should only print them if transport is activated (''i.e.'', <tt>if(DiffusionTask::active)</tt> or <tt>if(ConductionTask::active)</tt>). The <tt>MaterialBase</tt> class prints isotropic properties and the <tt>ORTHO</tt> and <tt>TRANSISO1(2)</tt> classes print anisotropic properties. No additional printing is needed if one of these classes handles the task.

			; <tt>void SetInitialParticleState(MPMBase *mptr,int np,int offset) const</tt>
			; This method is called in preliminary calculations before a simulation states. It can be used, if needed, to set and material properties for each material point (in the <tt>mptr</tt> pointer).

	=== Basic Class Accessors ===		=== Basic Class Accessors ===

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	These methods (required unless specified as optional) return basic facts about the material:		These methods (required unless specified as optional) return basic facts about the material:

			==== Required Accessors ====

	; <tt>const char *MaterialType(void)</tt>		; <tt>const char *MaterialType(void)</tt>
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	: Return the maximum wave speed for material in [[ConsistentUnits Command#Legacy and Consistent Units\|velocity units]]. This method is called once for each material point at start of calculation and after material properties have been defined. If the wave speed might change during the simulation, be conservative and return the maximum possible save speed. The first parameter is true for 3D calculations or false for 2D. This speed is needed to pick the time step for explicit calculations. The second parameter is pointer to a material point in case the wave speed depends on the initial particle state. This method is also used in some crack propagation methods. If the material supports crack propagation, make sure it gives good results for these uses.		: Return the maximum wave speed for material in [[ConsistentUnits Command#Legacy and Consistent Units\|velocity units]]. This method is called once for each material point at start of calculation and after material properties have been defined. If the wave speed might change during the simulation, be conservative and return the maximum possible save speed. The first parameter is true for 3D calculations or false for 2D. This speed is needed to pick the time step for explicit calculations. The second parameter is pointer to a material point in case the wave speed depends on the initial particle state. This method is also used in some crack propagation methods. If the material supports crack propagation, make sure it gives good results for these uses.

	; <tt>double CurrentWaveSpeed(bool,MPMBase *)</tt> ~~(optiona)~~		==== Optional Accessors ====

			; <tt>double CurrentWaveSpeed(bool,MPMBase *)</tt>
	: Return the current wave speed, which might depend on particle state. This method is only used by the [[AdjustTimeStep Custom Task\|<tt>AdjustTimeStep</tt> task]] to change time step as needed; without this method, the time step will not adjust for this new material.		: Return the current wave speed, which might depend on particle state. This method is only used by the [[AdjustTimeStep Custom Task\|<tt>AdjustTimeStep</tt> task]] to change time step as needed; without this method, the time step will not adjust for this new material.

	; <tt>double ShearWaveSpeed(bool)</tt> ~~(optional)~~		; <tt>double ShearWaveSpeed(bool)</tt>
	: Return the shear wave speed for the material. This method is only used by [[Boundary Condition Styles#Silent Boundary Conditions\|silent boundary conditions]] for force. The <tt>MaterialBase</tt> class returns <tt>WaveSpeed()/sqrt(3)</tt>. You only need to override this method if you want a better value. Also note that [[Boundary Condition Styles#Silent Boundary Conditions\|silent boundary conditions]] only work for isotropic materials.		: Return the shear wave speed for the material. This method is only used by [[Boundary Condition Styles#Silent Boundary Conditions\|silent boundary conditions]] for force. The <tt>MaterialBase</tt> class returns <tt>WaveSpeed()/sqrt(3)</tt>. You only need to override this method if you want a better value. Also note that [[Boundary Condition Styles#Silent Boundary Conditions\|silent boundary conditions]] only work for isotropic materials.

	; <tt>double MaximumDiffusion(void)</tt> ~~(optional)~~		; <tt>double MaximumDiffusion(void)</tt>
	: Return maximum diffusion constant in [[ConsistentUnits Command#Legacy and Consistent Units\|diffusion units]]. This method is called once for each material at the start of the calculations and after material properties are defined. The <tt>MaterialBase</tt> class returns the appropriate result for isotropic materials. You only need to override if you need a different result.		: Return maximum diffusion constant in [[ConsistentUnits Command#Legacy and Consistent Units\|diffusion units]]. This method is called once for each material at the start of the calculations and after material properties are defined. The <tt>MaterialBase</tt> class returns the appropriate result for isotropic materials. You only need to override if you need a different result.

	; <tt>double MaximumDiffusivity(void)</tt> ~~(optional)~~		; <tt>double MaximumDiffusivity(void)</tt>
	: Return maximum thermal diffusivity in [[ConsistentUnits Command#Legacy and Consistent Units\|diffusion units]] = k/(100 rho Cp). This method is called once for each material at the start of the calculations and after material properties are defined. The <tt>MaterialBase</tt> class returns the appropriate result for isotropic materials. You only need to override if you need a different result.		: Return maximum thermal diffusivity in [[ConsistentUnits Command#Legacy and Consistent Units\|diffusion units]] = k/(100 rho Cp). This method is called once for each material at the start of the calculations and after material properties are defined. The <tt>MaterialBase</tt> class returns the appropriate result for isotropic materials. You only need to override if you need a different result.

	; <tt>double GetCurrentRelativeVolume(MPMBase *)</tt> ~~(optional)~~		; <tt>double GetCurrentRelativeVolume(MPMBase *)</tt>
	: Return current relative volume to be used to convert tracked stress to true stress. Low strain materials track stress/initial density and they should return 1 (which is what base material class returns). Large deformation materials should be tracking specific Cauchy stress (= Kirchoff stress/initial density) and therefore should return relative volume (''i.e.'', initial density/current density).		: Return current relative volume to be used to convert tracked stress to true stress. Low strain materials track stress/initial density and they should return 1 (which is what base material class returns). Large deformation materials should be tracking specific Cauchy stress (= Kirchoff stress/initial density) and therefore should return relative volume (''i.e.'', initial density/current density).

	; <tt>Tensor GetStress(Tensor *sp,double pressure)</tt> ~~(optional)~~		; <tt>Tensor GetStress(Tensor *sp,double pressure)</tt>
	: Return current stress. Most materials just return the contents of <tt>sp</tt> which is the particle stress. Materials that track pressure and deviatoric stress separately (or use some other stress tracking scheme), should reconstruct and return the full stress in this method.		: Return current stress. Most materials just return the contents of <tt>sp</tt> which is the particle stress. Materials that track pressure and deviatoric stress separately (or use some other stress tracking scheme), should reconstruct and return the full stress in this method.

	; <tt>bool SupportsArtificialViscosity(void)</tt> ~~(optional)~~		; <tt>bool SupportsArtificialViscosity(void)</tt>
	: Materials that implement [[Common Material Properties#Artificial Viscosity\|artificial viscosity]] must override this method to return <tt>TRUE</tt> and then implement the calculations in the constitutive law methods.		: Materials that implement [[Common Material Properties#Artificial Viscosity\|artificial viscosity]] must override this method to return <tt>TRUE</tt> and then implement the calculations in the constitutive law methods.