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| A three dimensional computational investigation on the influence of essential boundary condition imposition in NURBS isogeometric finite element analysis |
| Received:January 05, 2010 Revised:April 22, 2010 |
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| DOI：10.7511/jslx20121006 |
| KeyWord:NURBS finite element method isogeometric analysis meshfree method penalty method essential boundary condition |
| Author | Institution |
| 王东东 |
厦门大学 土木工程系, 厦门 |
| 轩军厂 |
厦门大学 土木工程系, 厦门 |
| 张灿辉 |
厦门大学 土木工程系, 厦门 |
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| Abstract: |
| The NURBS isogeometric finite element analysis provides a perfect unification of the non-uniform rational B-spline (NURBS) functions used for computer aided geometry design and the finite element methodology. In this method the geometric modeling error is significantly reduced with improved solution accuracy. Nevertheless the NURBS basis functions commonly are not interpolatory functions and consequently the way of direct imposition of essential boundary conditions on the control points may yield noticeable solution errors. In this work the interpolation property of NURBS basis functions is discussed in details and thereafter a penalty formulation with improved solution accuracy and convergence behavior is proposed to enforce the essential boundary conditions in NURBS isogeometric analysis of three dimensional elasticity problems. Numerical results demonstrate that the approach with direct boundary condition enforcement on the control variables produces much larger solution errors as well as lower displacement and strain energy convergence rates,while the proposed method is capable of achieving the optimal convergence rates simultaneously with superior accuracy. |