Users:General FEM Analysis/Elements Reference/Shell NURBS KL
From Carat++ Public Wiki
< Users:General FEM Analysis | Elements Reference(Difference between revisions)
(→Parameter Description) |
|||
(21 intermediate revisions by one user not shown) | |||
Line 1: | Line 1: | ||
− | This element is based on | + | == General Description == |
+ | This element is based on Kiendl et al. 2009 <ref>J. Kiendl, K.-U. Bletzinger, J. Linhard, and R.Wüchner. “Isogeometric shell analysis with Kirchhoff–Love elements.” In: ComputerMethods in AppliedMechanics and Engineering 198.49-52 (2009), pp. 3902–3914. DOI: 10.1016/j.cma.2009.08.013 </ref> and [https://mediatum.ub.tum.de/node?id=1002634 Phd Thesis of J.Kiendl]. | ||
=== Example of a Complete Input Block === | === Example of a Complete Input Block === | ||
<pre> | <pre> | ||
EL-PROP 1 : SHELL_NURBS_KL | EL-PROP 1 : SHELL_NURBS_KL | ||
− | MAT= EL-MAT 1 | + | MAT= EL-MAT 1 !material property |
THICKNESS = 1.0 | THICKNESS = 1.0 | ||
− | INT_TYPE_SHELL_NURBS_KL = USER !or FULL | + | COUPLING = EL-PROP 6 !BRep coupling element to handle C^0 continuity inside the patch |
− | GAUSS_U = 4 | + | ! STABILIZATION = EL-PROP 7 !Stabilization element for improving condition number (requires some tests, no optimal solution) |
− | + | 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 | ||
</pre> | </pre> | ||
+ | |||
+ | |||
+ | === 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 === | ||
+ | |||
+ | {| border="1" cellpadding="3" cellspacing="0" | ||
+ | |colspan="3" style="background:#efefef;"| 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. | ||
+ | * 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 | ||
+ | * OPTIMAL: uses in the interior of the patch less quadrature points (some tests required for higher polynomial degrees >3 | ||
+ | |- | ||
+ | !THICKNESS | ||
+ | | ''float'' | ||
+ | | Thickness of the shell | ||
+ | |- | ||
+ | |- | ||
+ | !NEJA | ||
+ | | NURBS, DIP, FULL | ||
+ | | Integration technique for trimmed elements | ||
+ | *NURBS: trimmed elements are parametrized with untrimmed NURBS within the parameter space | ||
+ | * DIP: ''Discrete Integration procedure'' does not work properly, requires improvement (quadrature points must fullfill the moment fitting equations) | ||
+ | * FULL: Full integration of trimmed elements (not recommended) | ||
+ | |- | ||
+ | |colspan="3" style="background:#efefef;"| Optional Parameters | ||
+ | |- | ||
+ | !Parameter | ||
+ | !Values, Default(*) | ||
+ | !Description | ||
+ | |- | ||
+ | !GAUSS_U | ||
+ | |GAUSS_U = ''int'' | ||
+ | |Number of quadrature points in u-direction. Requires INT_TYPE_SHELL_NURBS_KL= USER | ||
+ | |- | ||
+ | |- | ||
+ | !GAUSS_V | ||
+ | |GAUSS_V = ''int'' | ||
+ | ||Number of quadrature points in v-direction. Requires INT_TYPE_SHELL_NURBS_KL= USER | ||
+ | |- | ||
+ | |- | ||
+ | !COUPLING | ||
+ | | EL-PROP= ''int'' | ||
+ | ||BRep coupling element to handle C^0 continuity inside the patch | ||
+ | |- | ||
+ | |- | ||
+ | !STABILIZATION | ||
+ | | EL-PROP= ''int'' | ||
+ | ||Stabilization element for improving condition number (requires some tests, no optimal solution) | ||
+ | |- | ||
+ | !PRESTRESS_CRV | ||
+ | | PRESTRESS_CRV = AUTO | ||
+ | ||All curvature terms (b_ref) are set to zero in stiff_mat_el_nln(). This is equal to having a flat patch as reference patch | ||
+ | |- | ||
+ | !PRESTRESS_CL_A1 | ||
+ | | PRESTRESS_CL_A1 = AUTO | ||
+ | ||covariant metric for reference configuration (gab_ref[0] and gab_ref[2]) is set to the one of the center line (v_mid=const) in stiff_mat_el_nln(). This is only valid for special case of pre-bent lamellas. | ||
+ | |- | ||
+ | !PRESTRESS_CL_A2 | ||
+ | | PRESTRESS_CL_A2 = AUTO | ||
+ | ||covariant metric for reference configuration (gab_ref[1] and gab_ref[2]) is set to the one of the center line (u_mid=const) in stiff_mat_el_nln(). This is only valid for special case of pre-bent lamellas. | ||
+ | |- | ||
+ | |} | ||
+ | |||
+ | == 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 == | ||
+ | |||
+ | <references/> |
Latest revision as of 09:56, 19 December 2018
Contents |
General Description
This element is based on Kiendl et al. 2009 [1] and 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 (requires some tests, no optimal solution) 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 |
NEJA | NURBS, DIP, FULL | Integration technique for trimmed elements
|
Optional Parameters | ||
Parameter | Values, Default(*) | Description |
GAUSS_U | GAUSS_U = int | Number of quadrature points in u-direction. Requires INT_TYPE_SHELL_NURBS_KL= USER |
GAUSS_V | GAUSS_V = int | Number of quadrature points in v-direction. Requires INT_TYPE_SHELL_NURBS_KL= USER |
COUPLING | EL-PROP= int | BRep coupling element to handle C^0 continuity inside the patch |
STABILIZATION | EL-PROP= int | Stabilization element for improving condition number (requires some tests, no optimal solution) |
PRESTRESS_CRV | PRESTRESS_CRV = AUTO | All curvature terms (b_ref) are set to zero in stiff_mat_el_nln(). This is equal to having a flat patch as reference patch |
PRESTRESS_CL_A1 | PRESTRESS_CL_A1 = AUTO | covariant metric for reference configuration (gab_ref[0] and gab_ref[2]) is set to the one of the center line (v_mid=const) in stiff_mat_el_nln(). This is only valid for special case of pre-bent lamellas. |
PRESTRESS_CL_A2 | PRESTRESS_CL_A2 = AUTO | covariant metric for reference configuration (gab_ref[1] and gab_ref[2]) is set to the one of the center line (u_mid=const) in stiff_mat_el_nln(). This is only valid for special case of pre-bent lamellas. |
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
- ↑ J. Kiendl, K.-U. Bletzinger, J. Linhard, and R.Wüchner. “Isogeometric shell analysis with Kirchhoff–Love elements.” In: ComputerMethods in AppliedMechanics and Engineering 198.49-52 (2009), pp. 3902–3914. DOI: 10.1016/j.cma.2009.08.013
Whos here now: Members 0 Guests 0 Bots & Crawlers 1 |