Users:General FEM Analysis/Elements Reference/Shell NURBS KL
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* FULL: p+1 and q+1 quadrature points are used (p and q are the polynomial degrees of the NURBS patch) | * FULL: p+1 and q+1 quadrature points are used (p and q are the polynomial degrees of the NURBS patch) | ||
* USER: the optional parameters GAUSS_U and GAUSS_V define the number of quadrature points | * USER: the optional parameters GAUSS_U and GAUSS_V define the number of quadrature points | ||
| − | * | + | * OPTIMAL: uses in the interior of the patch less quadrature points (some tests required for higher polynomial degrees >3 |
|- | |- | ||
| − | !rowspan="3" | | + | !rowspan="3" | THICKNESS = ''float'' |
| − | + | |thickness of the shell | |
| − | | | + | |
|- | |- | ||
|HEIGHT = ''float'' <br> WIDTH = ''float'' | |HEIGHT = ''float'' <br> WIDTH = ''float'' | ||
Revision as of 06:29, 9 December 2016
Contents |
General Description
This element is based on the Phd Thesis of J.Kiendl.
Example of a Complete Input Block
EL-PROP 1 : SHELL_NURBS_KL MAT= EL-MAT 1 !material property THICKNESS = 1.0 COUPLING = EL-PROP 6 !BRep coupling element to handle C^0 continuity inside the patch ! STABILIZATION = EL-PROP 7 !Stabilization element for improving condition number NEJA = NURBS !DIP or FULL !Method for handling the integration for trimmed elements(use NURBS) INT_TYPE_SHELL_NURBS_KL = USER !or FULL or OPTIMAL !FULL means p+1 and q+1;OPTIML uses in the interior of the patch less quadrature points (some tests required for higher polynomial degrees >3 ! GAUSS_U = 4 !# of quadratur points in u-dir in case of INT_TYPE = USER ! GAUSS_V = 4 !# of quadratur points in u-dir in case of INT_TYPE = USER
Element Type
- The element formulation is well tested for static and dynamic linear and nonlinear analysis.
- Stresses for nonlinear case need to be corrected.
- Can be used for thin shell structures
Degrees of Freedom
The element uses three translatoric degrees of freedom (Disp_X, Disp_Y, Disp_Z) at each control point.
Parameter Description
| Compulsory Parameters | ||
| Parameter | Values, Default(*) | Description |
|---|---|---|
| MAT | EL-MAT int | Linking to a material input block |
| INT_TYPE_SHELL_NURBS_KL | FULL, USER, OPTIMAL | Control of integration type.
|
| THICKNESS = float | thickness of the shell | |
| HEIGHT = float WIDTH = float |
rectangular cross section defined by height and width. A = h*w, Iy = h^3*w/12 Iz = h*w^3/12 It= min(h,w)^3*max(h,w)/3 | |
| AREA = float IY = float IZ = float IT = float |
cross section defined directly | |
| AXIS | AXIS float1 float2 float3 float4 | Definition of the cross sectional principal axis. Second axis is perpendicual to first and tangent of the curve. float1 is the position on the curve and float - float4 the direction (x,y,z). Base vectors are normalized and linearly interpolated for postions inbetween the defined ones. Axes for start and end knot of the NURBS curve are mandatory. |
| 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_BEAM_3D_NURBS_KLRod = USER |
Element Loading
The KL shell element is able to handle the following loads:
- dead load
- snow load
- pressure load
Benchmarks
The main benchmark file in the Carat++-repository is
- '../examples/benchmark_examples/isogeometric/KL_shell_trim_plate_hole/cbm_plate_with_hole.txt'.
It is further used in:
- '../examples/benchmark_examples/isogeometric/isogeometric_trim_non_linear/cbm_PlateHoleLineSupHighAcc.txt.txt'
References
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