The Hierarchical Quadrature Element Method for 3D Solids

2000 ◽  
Author(s):  
Chang-New Chen

Abstract The differential quadrature element method (DQEM) and the extended differential quadrature (EDQ) have been proposed by the author. The EDQ is used to the DQEM vibration analysis frame structures. The element can be a nonprismatic beam considering the warping due to torsion. The EDQ technique is used to discretize the element-based differential eigenvalue equations, the transition conditions at joints and the boundary conditions on domain boundaries. An overall discrete eigenvalue system can be obtained by assembling all of the discretized equations. A numerically rigorous solution can be obtained by solving the overall discrete eigenvalue system. Mathematical formulations for the EDQ-based DQEM vibration analysis of nonprismatic structures considering the effect of warping torsion are carried out. By using this DQEM model, accurate results of frame problems can efficiently be obtained.


2019 ◽  
Vol 821 ◽  
pp. 459-464
Author(s):  
Qi Gao Hu ◽  
Xu Dong Hu ◽  
Zhi Qiang Shen ◽  
Liang Yun Tao ◽  
Ze Tan

The buried pipelines or vessels and other similar structures made of homogeneous or advanced composite materials are commonly used in civil engineering and biotechnology. The radial stability problem of these structures was widely studied using the cylindrical shell model over the past years. In this paper, the linear stability of cylindrical shells resting on Winkler elastic foundation under uniformly distributed external pressure was analyzed with semi-analytical quadrature element method (QEM). As for the longitudinal direction, the radial deflection of shell was approximated by the quadrature element formulation. While the analytic trigonometric function was adopted for description of radial deflection in circumferential direction. The Numerical results of critical buckling load were compared with the semi-analytical FEM. It is found that the semi-analytical QEM possesses higher computational efficiency and applicability than semi-analytical FEM. Then, the effects of the shell length, radius, and thickness on the critical buckling pressures are systematically investigated through the parametric studies.


1999 ◽  
Vol 121 (2) ◽  
pp. 204-208 ◽  
Author(s):  
F.-L. Liu ◽  
K. M. Liew

A new numerical technique, the differential quadrature element method (DQEM), has been developed for solving the free vibration of the discontinuous Mindlin plate in this paper. By the DQEM, the complex plate domain is decomposed into small simple continuous subdomains (elements) and the differential quadrature method (DQM) is applied to each continuous subdomain to solve the problems. The detailed formulations for the DQEM and the connection conditions between each element are presented. Several numerical examples are analyzed to demonstrate the accuracy and applicability of this new method to the free vibration analysis of the Mindlin plate with various discontinuities which are not solvable directly using the differential quadrature method.


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