Users:General FEM Analysis/Elements Reference/NURBS BRep Edge coupling

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== General Description ==
 
== General Description ==
  
=== Example of a Complete Input Block ===
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=== Element Type ===
<pre>
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EL-PROP 1 : NURBS_BREP_EDGE_COUPLING 
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  BREP_TYPE = COUPLING_DISP ! or: COUPLING_ROT, COUPLING_DISP_ROT
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  !NITSCHE=AUTO
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  BL_FACTOR_DISP = 10000
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  BL_FACTOR_DISP = 10000
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  INT_TYPE_NURBS_EDGE_COUPLING = USER or FULL
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  GAUSS_U = 4
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</pre>
+
  
=== Element Type ===
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The formulation is based on Breitenberger et al. <ref>Breitenberger, M.; Apostolatos, A.; Philipp, B.; Wüchner, R.; Bletzinger, K.-U.: Analysis in computer aided design: Nonlinear isogeometric B-Rep analysis of shell structures. Computer Methods in Applied Mechanics and Engineering 284, 2015, 401--457</ref>. The element allows to
 +
 
 +
* coupling trimmed NURBS surfaces for geometrically linear and nonlinear analysis.
  
* This element provides a geometrically nonlinear, isogeometric spatial cable.
 
* Mass computation is implemented.
 
  
The formulation is stabilized by an additional bending stiffness based on Raknes et al.<ref>S.B. Raknes, X. Deng, Y. Bazilevs, D.J. Benson, K.M. Mathisen, T. Kvamsdal: „Isogeometric rotation-free bending-stabilized cables: Statics, dynamics, bending strips and coupling with shells“, in „Computer methods in applied mechanics and engineering“, Vol. 263, 2013, Seiten 127-143 http://dx.doi.org/10.1016/j.cma.2013.05.005</ref>. The bending stiffness is computed out of the area with the assumption of a circular cross section.
 
  
 
=== Degrees of Freedom ===
 
=== Degrees of Freedom ===
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!Description
 
!Description
 
|-
 
|-
!MAT
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!INT_TYPE_NURBS_EDGE_COUPLING
|EL-MAT ''int''
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|Linking to a material input block
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|-
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!INT_TYPE_CORD_3D_NURBS
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|FULL, USER
 
|FULL, USER
 
|Control of integration type.  
 
|Control of integration type.  
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* USER: the optional Parameter GAUSS_U defines the number of Gauss points
 
* USER: the optional Parameter GAUSS_U defines the number of Gauss points
 
|-
 
|-
!CROSS SECTION
 
|AREA = ''float''
 
|area of the cross section
 
 
|-
 
|-
!PRESTRESS
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!BREP_TYPE
|PRESTRESS = ''float''
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|COUPLING_DISP, COUPLING_ROT, COUPLING_DISP_ROT
|prestress of the cable element
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|Type of coupling.
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* COUPLING_DISP: only displacements are coupled
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* COUPLING_ROT: only rotations are coupled
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* COUPLING_DISP_ROT: displacements and rotations are coupled
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|-
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!BL_FACTOR_DISP
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|BL_FACTOR_DISP= ''float''
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|penalty factor for the displacement
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|-
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!BL_FACTOR_ROT
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|BL_FACTOR_ROT= ''float''
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|penalty factor for the rotation
 
|-
 
|-
 
|colspan="3" style="background:#efefef;"| Optional Parameters
 
|colspan="3" style="background:#efefef;"| Optional Parameters
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=== Example of a Complete Input Block ===
 
=== Example of a Complete Input Block ===
 
<pre>
 
<pre>
EL-PROP 1 : NURBS_BREP_CHORD  
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EL-PROP 1 : NURBS_BREP_EDGE_COUPLING  
   MAT= EL-MAT 1
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   BREP_TYPE = COUPLING_DISP ! or: COUPLING_ROT, COUPLING_DISP_ROT
   AREA = 1
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   !NITSCHE=AUTO
   PRESTRESS = 4000
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   BL_FACTOR_DISP = 10000
   INT_TYPE_NURBS_BREP_CHORD = USER or FULL
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   BL_FACTOR_DISP = 10000
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  INT_TYPE_NURBS_EDGE_COUPLING = USER or FULL
 
   GAUSS_U = 4
 
   GAUSS_U = 4
 
</pre>
 
</pre>
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== Benchmarks ==
 
== Benchmarks ==
  
The main benchmark file in the ''Carat++''-repository is  
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The main benchmark file in the ''Carat++''-repository (cmake option ''extensive benchmarks'' is  
* '../examples/benchmark_examples/isogeometric/iga_formfinding_4point_with_trusses/cbm_4PointSailwTrusses.txt'.
+
* '../examples/benchmark_examples/isogeometric/x_ibra_oilsump_8mm/xcbm_oilsump_8mm.txt'.
  
 
== References ==
 
== References ==
  
 
<references/>
 
<references/>

Latest revision as of 09:12, 9 December 2016

Contents

General Description

Element Type

The formulation is based on Breitenberger et al. [1]. The element allows to

  • coupling trimmed NURBS surfaces for geometrically linear and nonlinear analysis.


Degrees of Freedom

The element uses the translatoric degrees of freedom (Disp_X, Disp_Y, Disp_Z) at each control point.

Parameter Description

Compulsory Parameters
Parameter Values, Default(*) Description
INT_TYPE_NURBS_EDGE_COUPLING FULL, USER Control of integration type.
  • FULL: p+1 Gauss points are used (p = polynomial degree of the NURBS patch)
  • USER: the optional Parameter GAUSS_U defines the number of Gauss points
BREP_TYPE COUPLING_DISP, COUPLING_ROT, COUPLING_DISP_ROT Type of coupling.
  • COUPLING_DISP: only displacements are coupled
  • COUPLING_ROT: only rotations are coupled
  • COUPLING_DISP_ROT: displacements and rotations are coupled
BL_FACTOR_DISP BL_FACTOR_DISP= float penalty factor for the displacement
BL_FACTOR_ROT BL_FACTOR_ROT= float penalty factor for the rotation
Optional Parameters
Parameter Values, Default(*) Description
GAUSS_U GAUSS_U = int Number of Gauss point per element. Must only to be defined when INT_TYPE_CORD_3D_NURBS = USER

Example of a Complete Input Block

EL-PROP 1 : NURBS_BREP_EDGE_COUPLING  
  BREP_TYPE = COUPLING_DISP ! or: COUPLING_ROT, COUPLING_DISP_ROT
  !NITSCHE=AUTO
  BL_FACTOR_DISP = 10000
  BL_FACTOR_DISP = 10000
  INT_TYPE_NURBS_EDGE_COUPLING = USER or FULL
  GAUSS_U = 4

Element Loading

The NURBS_BRep_Edge_Cord element is able to carry the following loads:

  • dead load
  • snow load
  • pressure load
  • temperature load (not tested)

Benchmarks

The main benchmark file in the Carat++-repository (cmake option extensive benchmarks is

  • '../examples/benchmark_examples/isogeometric/x_ibra_oilsump_8mm/xcbm_oilsump_8mm.txt'.

References

  1. Breitenberger, M.; Apostolatos, A.; Philipp, B.; Wüchner, R.; Bletzinger, K.-U.: Analysis in computer aided design: Nonlinear isogeometric B-Rep analysis of shell structures. Computer Methods in Applied Mechanics and Engineering 284, 2015, 401--457




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