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Applied Mathematics and Mechanics(English Edition) 1997年第7期18卷 663-665,667-670页

作者：钱仍勣 Shanghai Jiaotong University 200030 Shanghai P. R. China

The variational functional of the Hellinger-Reissner variational principle for the large displacement problem of a thin shallow shell with an arbitrary shape is first established. Then the functional of the modified principle suitable for the finite element method is derived. In the functional only two independent variables, the deflection w and the stress function F are included. The displacement expressions in the middle surface on the boundary of the shell is also derived by means of the previous two variables.

关键词： variational principle shallow shell large displacement finite element method

NEURO FUZZY MODEL FOR PREDICTING THE DYNAMIC CHARACTERISTICS OF BEAMS

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Acta Mechanica Solida Sinica 2014年第1期27卷 85-96页

作者： Imad O.Bachi Nabeel Abdulrazzaq Zeng He Department of Mechanical Engineering Basrah University Department of Mechanics Engineering Huazhong University of Science and Technology Department of Civil Engineering Basrah University

An adaptive neuro-fuzzy inference system （ANFIS） is introduced to predict the dynamic behavior of beams. The effects of axial forces and large displacements are considered in the analysis. A database of tests for the dynamic characteristics of beams is developed from the experimental tests. The responses of nonlinear vibration force for the single and multiple-stepped beams are calculated from the finite element method （FEM）, experimental tests and neuro-fuzzy model for comparison. The neuro-fuzzy model provides a general framework for the combination of neural networks and fuzzy logic. It is more flexible with more options of incorporating the fuzzy nature of the real-world system and is an useful estimation tool for the dynamic characteristics of beams. Therefore, ANFIS can be a useful tool for dynamic behaviour analysis of multiple-stepped beams subjected to axial loads and large displacement.

关键词： dynamic analysis large displacement neuro-fuzzy finite element beam

Multi-catenary isogeometric discretization with the sliding constraint

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Acta Mechanica Sinica 2021年第1期37卷 80-91,I0003页

作者： Damir Sedlar Zeljan Lozina Andela Bartulovic Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture University of Split21000SplitCroatia

The purpose of this paper is to present the formulation of isogeometric dynamic analysis with frictionless sliding constraint between two *** sliding condition at the constraint point is defined employing the augmented Lagrangian method,that specifies unique degree of freedom along sliding *** governing equations for the coupled system are derived in terms of Hamilton’s principle together with sliding constraint form differential algebraic equations of multi-catenary *** developed isogeometric approach is employed to discretize the catenaries what enables us to define the unique degree of freedom of sliding constraint along the whole catenary and thus avoid the process of searching for the sliding point as required in some other discretization techniques,*** element *** numerical examples are provided to validate the proposed method and the results are assessed against the results in the literature.

关键词： Isogeometric analysis Multi-catenary dynamics large displacement Sliding constraint

Dual reciprocity boundary element based block model for discontinuous deformation analysis

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Science China(Technological Sciences) 2015年第9期58卷 1575-1586页

作者： FU GuoYang MA GuoWei QU XiaoLei School of Civil Environmental and Mining Engineering University of Western Australia School of Civil Environmental and Chemical Engineering RMIT University College of Architecture and Civil Engineering Beijing University of Technology

This paper presents a further development of the dual reciprocity boundary element method(DRBEM) with stepwise updating to pave the way for the introduction of boundary element mesh into the discontinuous deformation analysis(DDA). The advantage of the proposed method lies in its adoption of static fundamental solutions and reduction in the size of the governing equations by transforming the inertial term domain integrals to boundary integrals in the dynamic large displacement analysis. The unconditionally stable Newmark-β time integration method involving numerical damping to enhance the numerical stability is implemented for the dynamic analysis. In order to be coupled with the DDA to improve the deformability of the DDA block domains, a stepwise updating algorithm of the system variables is introduced. The stress updating in the analysis involved in the calculation of a domain integral and internal cells are used for the integration of the initial stress term. Several examples are used to verify the geometry-updated DRBEM model and satisfactory results have been obtained.

关键词： boundary element method stepwise updating initial stress large displacement

FUNDAMENTAL EQUATIONS OF large SPATIAL DEFLECTION PROBLEMS OF RODS AND ITS APPLICATION TO DRILLING ENGINEERING

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Applied Mathematics and Mechanics(English Edition) 1993年第12期14卷 1103-1111页

作者：蔡宗熙 Tianjin University Tianjin

The fundamental equations for analysis of a straight slender rod which deform at large deflections of order of several times of the dimension of the cross section of the rod are derived by using convecled coordinate system. In accordance with the practice of oil drilling, an effective method of three dimensional static analysis of bottom-hole assemblies is simply described. Errors in reference [8 ] are pointed out.

关键词： bottom-hole assemblies large displacement analytic solution