Users:General FEM Analysis/Elements Reference/Membrane NURBS
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Methods in AppliedMechanics and Engineering 303 (May 2016), | Methods in AppliedMechanics and Engineering 303 (May 2016), | ||
pp. 312–340. DOI: 10.1016/j.cma.2016.02.003.</ref> | pp. 312–340. DOI: 10.1016/j.cma.2016.02.003.</ref> | ||
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| + | == Input Parameters == | ||
| + | |||
| + | === Parameter Description === | ||
| + | |||
| + | {| border="1" cellpadding="3" cellspacing="0" | ||
| + | |colspan="3" style="background:#efefef;"| Compulsory Parameters | ||
| + | |- | ||
| + | !Parameter | ||
| + | !Values, Default(*) | ||
| + | !Description | ||
| + | |- | ||
| + | !MAT | ||
| + | |EL-MAT ''int'' | ||
| + | |Number for the used Material | ||
| + | e.g. MAT=EL-MAT 1 | ||
| + | |- | ||
| + | !THICKNESS | ||
| + | | | ||
| + | |Thickness of the membrane | ||
| + | |- | ||
| + | !A_X, A_Y, A_Z | ||
| + | B_X, B_Y, B_Z | ||
| + | | | ||
| + | |Definition of the principal directions of the surface to define the prestress directions. (see description below) | ||
| + | |- | ||
| + | !SIG11 | ||
| + | SIG22 | ||
| + | SIG12 | ||
| + | | | ||
| + | |Prestress state of the membrane. (see description below) | ||
| + | |- | ||
| + | |colspan="3" style="background:#efefef;"| Optional Parameters | ||
| + | |- | ||
| + | !Parameter | ||
| + | !Values, Default(*) | ||
| + | !Description | ||
| + | |- | ||
| + | !LAGRANGE | ||
| + | |''TOTAL, UPDATED'' | ||
| + | |Definition of lagrange type. UPDATED for form finding and TOTAL for statics or dynamics. (e.g. LAGRANGE=UPDATED) | ||
| + | |- | ||
| + | |} | ||
| + | |||
=== Example of a Complete Input Block === | === Example of a Complete Input Block === | ||
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The possibility for oriented anisotropic prestress fields is foreseen, yet no distortion control as for the classical FEM Membrane1-element is implemented. | The possibility for oriented anisotropic prestress fields is foreseen, yet no distortion control as for the classical FEM Membrane1-element is implemented. | ||
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| − | |||
| − | |||
== Tests and Benchmarks == | == Tests and Benchmarks == | ||
Revision as of 08:49, 13 January 2017
Contents |
General Description
Element Type
- This membrane element is an isotropic plane stress element accounting for prestress
- The membrane element neglects bending stiffness
- The ratio of the thickness and the lengths in the other two directions is much smaller than one ( t/Lx << 1 and t/Ly << 1), the membrane is reduced to its mid-surface
- The thickness is constant over the element
An extensive description of the element can be found in [1]
Input Parameters
Parameter Description
| Compulsory Parameters | ||
| Parameter | Values, Default(*) | Description |
|---|---|---|
| MAT | EL-MAT int | Number for the used Material
e.g. MAT=EL-MAT 1 |
| THICKNESS | Thickness of the membrane | |
| A_X, A_Y, A_Z
B_X, B_Y, B_Z |
Definition of the principal directions of the surface to define the prestress directions. (see description below) | |
| SIG11
SIG22 SIG12 |
Prestress state of the membrane. (see description below) | |
| Optional Parameters | ||
| Parameter | Values, Default(*) | Description |
| LAGRANGE | TOTAL, UPDATED | Definition of lagrange type. UPDATED for form finding and TOTAL for statics or dynamics. (e.g. LAGRANGE=UPDATED) |
Example of a Complete Input Block
EL-PROP 1 : MEMBRANE_NURBS MAT= EL-MAT 1 THICKNESS= 1.0 INT_TYPE_MEMBRANE_NURBS = FULL !or USER PROJECTED_PRESTRESS=1 SIG11=400.0 SIG22=400.0 SIG12=0.0 A_X=1.0 A_Y=0.0 A_Z=0.0 !AREA FOR THE DEFINITION OF THE PRESTRESS B_X=0.0 B_Y=1.0 B_Z=0.0 !VECTOR A AND VECTOR B DEFINE THE AREA
The possibility for oriented anisotropic prestress fields is foreseen, yet no distortion control as for the classical FEM Membrane1-element is implemented.
Tests and Benchmarks
The element Membrane_NURBS has successfully been applied in 3D in various geometrically non-linear static applications, as well as in form-finding.
Benchmark examples
- form-finding of a four-point sail with with B-Rep edge cables and elastic columns as supports: ..\examples\benchmark_examples\isogeometric\iga_formfinding_4point_with_trusses\cbm_4PointSailwTrusses.txt
- static geometrically non-linear analysis of a prestressed single-patch membrane with fixed boundaries: ..\examples\benchmark_examples\isogeometric\iga_membrane_nln_1\cbm_iga_membrane_nln_1.txt
References
- ↑ B. Philipp, M. Breitenberger, I. D’Auria, R.Wüchner, and K.-U. Bletzinger. "Integrated design and analysis of structural membranes using the Isogeometric B-Rep Analysis." In: Computer Methods in AppliedMechanics and Engineering 303 (May 2016), pp. 312–340. DOI: 10.1016/j.cma.2016.02.003.
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