DG shell interactions

Once shell interactions are defined, they must be completed with (Discontinuous Galerkin) interface interactions, following the well-known material-element-interaction pattern.

Materials

First, the material is defined as:

materialno = materialset.define (number, type)
materialno = materialset(number)
materialno.put(param, value)
materialno.depend(param, fct, Key(Lock)))
...

`number`	material number (must be unique with respect to all elements in `materialset`, not to shells)
`type`	shell type (for example `DgShellMaterial`)
`param`	name of the shell parameter (for example `STABILIZATION_PARAMETER`)
`value`	value of the corresponding parameter `param`
`fct`	function which characterizes the dependency of the property (optional: no fct if no dependency)
`Lock`	Lock which defines the dependency variable of the property (compulsory if there is a dependency)

DgShellMaterial

Description

DG law for shell interface elements.

Parameters

Name	Metafor Code	Dependency
Stabilization parameter (>1)	`STABILIZATION_PARAMETER`

Elements

After defining the material, it must be associated to an ElementProperties:

prp = ElementProperties(typeEl)
prp.put(param1, value1)
prp.depend(param1, fct1, Lock1)) #facultatif
...

where

`type`	desired type of element (for example `DgShellFirstDegreeElement`)
`param1`	name of the property associated to the element (for example `MATERIAL` to associate the desired material)
`value1`	value of the corresponding property
`fct1`	function which characterizes the dependency of the property (optional: no fct if no dependency)
`Lock1`	Lock which defines the dependency variable of the property (compulsory if there is a dependency)

DgShellFirstDegreeElement

DG interface element to insert between shells. These are 2-nodes linear lines, but they are interfering over all neighboring dofs.

By default, stresses are integrated over dim*2 integration points. The material used is dgShellMaterial.

DgShellSecondDegreeElement

Same as DgShellFirstDegreeElement, but 8-nodes second order shell element.

DgShellNineNodeSecondDegreeElement

Same as DgShellSecondDegreeElement, but 9-nodes second order shell element.

DgShellSixteenNodeThirdDegreeElement

Same as DgShellNineNodeSecondDegreeElement, but 16-nodes third order shell element.

Parameters of shell DG interface elements

Name	Metafor Code	Dependency
`MATERIAL`	Number of the material to consider	-
`STIFFMETHOD`	Method used to compute the stiffness matrix = `STIFF_ANALYTIC` : analytic matrix (default) = `STIFF_NUMERIC` : numerical matrix	-
`BENDING_NPG`	Number of integration points along one direction for bending solving = 2 classical solving (second order) = 3 EAS solving with 22 or 7 added modes (8 or 9-nodes second order) = 4 solving without EAS (16-nodes third order)	-

Interactions

DG shell interface elements are generated at the start of the simulation by a DgShellInteraction Interaction, defined over desired entities.

dg = DgShellInteraction(number)
dg.push(gObject1)
dg.push(gObject2)
...
dg.addProperty(prp)
interactionset.add(dg)                 # the interaction is added in InteractionSet

or

dg = interactionset.add( DgShellInteraction(number) )
dg.push(gObject1)
dg.push(gObject2)
...
dg.addProperty(prp)

`number`	User number of the interaction
`gObject1`, `gObject2`	mesh geometric entities where the finite elements are applied
`prp`	Properties ofDG interface elements to generate

Careful, for now if two entities have common nodes, to many elements will be generated.

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