First-order finite element method for elasticity
Received:May 23, 2014  Revised:November 03, 2014
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DOI:10.7511/jslx201504016
KeyWord:finite element  weak form  elasticity  first-order algorithm  stress accuracy
        
AuthorInstitution
卞正宁 湖南大学 土木工程学院, 长沙
杜世森 湖南大学 土木工程学院, 长沙
罗建辉 湖南大学 土木工程学院, 长沙
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Abstract:
      In the conventional displacement finite element methods,the stresses are obtained from a diffe-rential operation after the nodal displacements are determined,which is not accurate.In order to improve the stress accuracy,a first-order multi-variable form is proposed to make sure the order of stresses and displacements are equal,and the weak form is then derived.Using the finite element method,a two-dimensional and a three-dimensional elastic problem is solved by first-order method respectively,and the first-order solutions and the solutions of the conventional displacement finite element method were compared.The numerical results show that the first-order solution effectively improves the accuracy of the stresses while the displacement errors and the stress errors have the same convergence order,which verify the effectiveness of the method and provides a new idea of improving the stress accuracy of the finite element method.