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Title: Irreducible variational formulation of a class of one-point quadrature solid-shell finite elements
Author: Edem, Ini Benedict
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2011
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In this thesis, a systematic formulation of a new class of physically stabilised one-point quadrature, low order 8-node solid-shell finite elements is undertaken .. The significance, aim and distinguishing contribution of the present research is to obtain a new class of accurate and locking-free, purely displacement variational solid-shell finite element formulation without recourse to mixed variational formu- lations pervasive in shell finite element literature. Standard displacement-based finite elements in shell analysis are known to exhibit an overly stiff behaviour in in-extensional and near-incompressible deformation known as locking, amplified by a decreasing shell mesh thickness domain. Trends in advanced structural shell simulations however require the inclusion of the shell thickness domain for realistic simulations, intensifying active research in the formulation of low order, so-called solid-shells elements specially formulated to avoid the locking phenomenon in three dimensional finite element shell analysis. To further achieve computational efficiency and coarse mesh accuracy in element computations, recent research effort has been geared towards development of the class of mixed variational and the enhanced assumed strain (EAS) approach in physically stabilised, re- duced integration framework. The alternative class of solid-shell elements intro- duced in this thesis is achieved through a systematic design of a displacement space function which enhances the standard hexahedral element isoparametric displacement field using a minimum number of hierarchical quadratic displace- ment fields. The chosen displacement fields expand the elements strain space con- siderably, significantly improving deformation accuracy and robust performance. In combination with the one-point quadrature and physical stabilisation concept, the assumed natural strain (ANS) and the B-bar method, a new class of effi- cient displacement-based solid-shell elements with kinematics described entirely by displacement degrees of freedom is obtained for three dimensional shell analy- sis. An exhaustive investigation within linear elasticity using a wide selection of numerical benchmark problems and coupled with robust comparison with state of the art shell, solid-shell and 3D solid finite elements demonstrates the suit- ability and validity of the new solid-shell element class. The broad applicability of the formulation to various geometric configurations of beams, plates and shell structures exhibiting coarse mesh accuracy, distortion tolerant characteristics and locking-free behaviour is also demonstrated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available