Users:Structural Optimization/Design Variables/Nodal Thickness

Contents 1 General Description 1.1 Short Info 1.2 Parameters in the Input File 1.3 Example of a Complete Input Block 2 A complete test example 2.1 Model description 2.2 Input File 2.3 Documented Results 3 Theory and Details 4 References

General Description

Short Info

With this design variable, the nodal thickness can be optimized. This is especially usefull in combination with SHELL elements, which are able to take variable thicknesses into account.

The thickness at each node can be initialized by . Alternatively, the initial thickness is computed as the mean thickness of the surrounding elements.

Parameters in the Input File

Compulsory Parameters
Parameter	Values, Default(*)	Description
MATERIAL	EL-MAT int	Linking to a material input block
INT_TYPE_HEXA	FULL, REDUCED	Control of integration type 20-noded elements are able to perform a uniform reduced integration (2x2x2 instead of 3x3x3) without hourglassing stabilisation
Optional Parameters
Parameter	Values, Default(*)	Description
EAS	int	Flag Enhances Assumed Strains (EAS) method Possible values are: 0* = EAS off 9 = full and locking free linear strains can be described (recommended for one axial bending) 15 = ellimination of parasitic bi-linear strains 24 = full and locking free bi-linear strains can be described (recommended for two axial bending) 30 = full tri-linear strains can be described

Example of a Complete Input Block

This design variable can be defined for one node of for a nodal set. Since the thickness has generally an obvious limit, it is good practice to add a bound. Since this is a scalar design variable, only SCALAR_BOUND is appropriate.

OPT-VAR 1
 TYPE=NODE 100 SUBTYPE=THICKNESS BOUND=OPT-BOUND 1
 TYPE=ND-SET 2 SUBTYPE=THICKNESS BOUND=OPT-BOUND 1

A complete test example

Model description

blabla mit bildern

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  HEXA8

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  HEXA8EAS9

Input File

bla

Documented Results

bla

Theory and Details

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References

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