Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included…
Abstract
Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included at the end of the paper presents a bibliography on the subjects retrospectively to 1985 and approximately 1,100 references are listed.
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Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
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In this paper, a superconvergent patch recovery method is proposed for superconvergent solutions of modes in the finite element post-processing stage of variable geometrical…
Abstract
Purpose
In this paper, a superconvergent patch recovery method is proposed for superconvergent solutions of modes in the finite element post-processing stage of variable geometrical Timoshenko beams. The proposed superconvergent patch recovery method improves the solution speed and accuracy of the finite element analysis of a curved beam. The free vibration and natural frequency of the beam were considered for studying forced vibrations and structural resonance. Beam vibration mode analysis was performed for high-precision vibration mode solutions and frequency values. The proposed method can be used to compute beam vibration modes of beams with different shapes and boundary conditions as well as variable cross sections and curvatures. The purpose of this paper is to address these issues.
Design/methodology/approach
An adaptive method was proposed to analyse the in-plane and out-of-plane free vibrations of the variable geometrical Timoshenko beams. In the post-processing stage of the displacement-based finite element method, the superconvergent patch recovery method and high-order shape function interpolation technique were used to obtain the superconvergent solution of mode (displacement). The superconvergent solution of mode was used to estimate the error of the finite element solution of mode in the energy form under the current mesh. Furthermore, an adaptive mesh refinement was proposed by mesh subdivision to derive an optimised mesh and accurate finite element solution to meet the preset error tolerance.
Findings
The results computed using the proposed algorithm were in good agreement with those computed using other high-precision algorithms, thus validating the accuracy of the proposed algorithm for beam analysis. The numerical analysis of parabolic curved beams, beams with variable cross sections and curvatures, elliptically curved beams and circularly curved beams helped verify that the solutions of frequencies were consistent with the results obtained using other specially developed methods. The proposed method is well suited for the mesh refinement analysis of a curved beam structure for analysing the changes in high-order vibration mode. The parts where the vibration mode changed significantly were locally densified; a relatively fine mesh division was adopted that validated the reliability of the mesh optimisation processing of the proposed algorithm.
Originality/value
The proposed algorithm can obtain high-precision vibration solutions of variable geometrical Timoshenko beams based on more optimized and reasonable meshes than the conventional finite element method. Furthermore, it can be used for vibration problems of parabolic curved beams, beams with variable cross sections and curvatures, elliptically curved beams and circularly curved beams. The proposed algorithm can be extended for application in superconvergent computation and adaptive analysis of finite element solutions of general structures and solid deformation fields and used for adaptive analysis of more complex plates, shells and three-dimensional structures. Additionally, this method can analyse the vibration and stability of curved members with crack damage to obtain high-precision vibration modes and instability modes under damage defects.
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Z.C. Zhang, J.H. Lin, Y.H. Zhang, W.P. Howson and F.W. Williams
Purpose — The purpose of this paper is to present a new nonstationary, random vibration method for the analysis of coupled vehicle‐bridge systems with vertical track irregularity…
Abstract
Purpose — The purpose of this paper is to present a new nonstationary, random vibration method for the analysis of coupled vehicle‐bridge systems with vertical track irregularity. Design/methodology/approach — The vehicle is modeled using a two‐layer suspension system and hence possesses ten degrees of freedom. The bridge is simulated using a Bernoulli‐Euler beam and the longitudinal track irregularity is taken as a uniformly modulated, evolutionary random process that includes phase lags between successive wheels. The pseudo‐excitation method (PEM) is extended to include time‐dependent systems for the first time, thus making it possible to compute the nonstationary random vibration of coupled vehicle‐bridge systems. Additionally, the precise integration method (PIM) is adapted to simulate continuous vehicle force variations in both time and space. Findings — The accuracy and effectiveness of the proposed PEM‐PIM method are confirmed by comparisons with Monte Carlo simulations. The influence of vehicle speed and track irregularity on system random responses are evaluated, and it is shown that the first and second derivatives of the track irregularity should not be arbitrarily ignored, as is usually the case. Originality/value — PEM and PIM are relatively new tools for the numerical solution of complicated random vibration problems and direct dynamic analyses. Until now, they have only been applied to time‐independent systems. However, it is shown herein that the proposed PEM‐PIM method performs nonstationary random vibration analysis of time‐dependent coupled vehicle‐bridge systems efficiently and accurately.
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A. Shanmugam and T. Paul Robert
The purpose of this paper is to present a literature review on human factors in aircraft maintenance and to analyze and synthesize the findings in the literature on human factors…
Abstract
Purpose
The purpose of this paper is to present a literature review on human factors in aircraft maintenance and to analyze and synthesize the findings in the literature on human factors engineering in aircraft maintenance.
Design/methodology/approach
The review adopts a threefold approach: searching and collecting the scientific literature; sorting them on the basis of relevance and applications; and review of the scientific evidences. Broad areas of aircraft maintenance regulations are identified and each area was explored to study the level of scientific growth and publications. Notable theories, models and concepts are being summarized.
Findings
Application of human factor principles in aviation spread beyond the technical arena of man-machine interface. The discipline has created a great impact on aircraft design, operations and maintenance. Its applications have percolated into design of aircraft maintenance facilities, task cards and equipment. Human factor concepts are being used for maintenance resource management. The principles are applied to shape the safety behavior and culture in aviation maintenance workplace. Nevertheless, the review unfolds immense potential for future research.
Research limitations/implications
Research outcomes of non-aviation studies are also reviewed and consolidated to extend the applications to the aviation industry.
Practical implications
This review would be a consolidated source of information confining to the physical aspect of human factors engineering in aircraft maintenance. It is intended to serve as a quick reference guide to the researchers and maintenance practitioners.
Social implications
It brought out the benefits of adopting the principles of human factor engineering in aircraft maintenance. Application of human factor philosophy ensures enhanced safety in air transport, personal safety and well-being of maintenance personnel.
Originality/value
This is a unique review based on aircraft maintenance regulations that are baseline performance standards made mandatory by regulatory authorities. Therefore, the review has been considered to be made on aircraft maintenance regulatory requirements that surpass corporate or competitive strategies in aviation maintenance organization.
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A bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical…
Abstract
A bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view is given. The bibliography at the end of the paper contains 1,726 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1996‐1999.
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Xiu‐hui Hou, Zi‐chen Deng and Jia‐xi Zhou
The purpose of this paper is to analyze the frequency and response of hexagonal cell honeycomb structures under Hamilton system.
Abstract
Purpose
The purpose of this paper is to analyze the frequency and response of hexagonal cell honeycomb structures under Hamilton system.
Design/methodology/approach
Taking orthotropic sandwich cylinder as the analytical model, the basic equilibrium equations are transformed into Hamilton system, where the canonical transformation, the extended Wittrick‐Williams algorithm and the precise integration method can be applied to calculate the frequency and the responses of the honeycomb sandwich structures.
Findings
For the cellular structures, the basic frequency is the most important which can be affected greatly by the wave number. It is also found that the displacement mode shape is dominated by the radial displacement and the axial principal stress is much higher than that of the radial or the circumferential principal stress for the sandwich cylinders.
Originality/value
A new solution procedure is proposed for the cellular structures by constructing the Hamilton matrix in the cylindrical coordinates. The analysis system is thus transformed from Lagrange to Hamilton.
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This study aims to obtain earthquake responses of linear-elastic multi-span arch-frames by using exact curved beam formulations. For this purpose, the dynamic stiffness method…
Abstract
Purpose
This study aims to obtain earthquake responses of linear-elastic multi-span arch-frames by using exact curved beam formulations. For this purpose, the dynamic stiffness method (DSM) which uses exact mode shapes is applied to a three-span arch-frame considering axial extensibility, shear deformation and rotational inertia for both columns and curved beams. Using exact free vibration properties obtained from the DSM approach, the arch-frame model is simplified into an equivalent single degree of freedom (SDOF) system to perform earthquake response analysis.
Design/methodology/approach
The dynamic stiffness formulations of curved beams for free vibrations are validated by using the experimental data in the literature. The free vibrations of the arch-frame model are investigated for various span lengths, opening angle and column dimensions to observe their effects on the dynamic behaviour. The calculated natural frequencies via the DSM are presented in comparison with the results of the finite element method (FEM). The mode shapes are presented. The earthquake responses are calculated from the modal equation by using Runge-Kutta algorithm.
Findings
The displacement, base shear, acceleration and internal force time-histories that are obtained from the proposed approach are compared to the results of the finite element approach where a very good agreement is observed. For various span length, opening angle and column dimension values, the displacement and base shear time-histories of the arch-frame are presented. The results show that the proposed approach can be used as an effective tool to calculate earthquake responses of frame structures having curved beam elements.
Originality/value
The earthquake response of arch-frames consisting of curved beams and straight columns using exact formulations is obtained for the first time according to the best of the author’s knowledge. The DSM, which uses exact mode shapes and provides accurate free vibration analysis results considering each structural members as one element, is applied. The complicated structural system is simplified into an equivalent SDOF system using exact mode shapes obtained from the DSM and earthquake responses are calculated by solving the modal equation. The proposed approach is an important alternative to classical FEM for earthquake response analysis of frame structures having curved members.
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Kai Zhang, Zichen Deng, Junmiao Meng and Xiaojian Xu
The purpose of this paper is to provide an efficient numerical solution for dynamic properties of sandwich tubes with honeycomb cores and investigate the effects of material…
Abstract
Purpose
The purpose of this paper is to provide an efficient numerical solution for dynamic properties of sandwich tubes with honeycomb cores and investigate the effects of material distribution and relative density on the dynamic properties of the structure.
Design/methodology/approach
By introducing dual variables and applying the variational principle, the canonical equations of Hamiltonian system are constructed. The precise integration algorithm and extended Wittrick-Williams algorithm are adopted to solve the equations and obtain the dispersion relations of sandwich tubes. The effects of the material distribution and the relative density on the non-dimensional frequencies of the sandwich tubes are investigated.
Findings
The validity of the procedure and programs is verified by comparing with other works. Dispersion relations of the typical sandwich tubes are obtained. Dramatic differences are observed as the material distribution and relative density of the sandwich structures vary.
Originality/value
The work gains insight into the role of symplectic analysis in the structural dynamic properties and expects to provide new opportunities for the optimal design of sandwich tubes with honeycomb cores in engineering applications.
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This chapter investigates the nature of the transformation of macroeconomics by focusing on the impact of the Great Depression on economic doctrines. There is no doubt that the…
Abstract
This chapter investigates the nature of the transformation of macroeconomics by focusing on the impact of the Great Depression on economic doctrines. There is no doubt that the Great Depression exerted an enormous influence on economic thought, but the exact nature of its impact should be examined more carefully. In this chapter, I examine the transformation from a perspective which emphasizes the interaction between economic ideas and economic events, and the interaction between theory and policy rather than the development of economic theory. More specifically, I examine the evolution of what became known as macroeconomics after the Depression in terms of an ongoing debate among the “stabilizers” and their critics. I further suggest using four perspectives, or schools of thought, as measures to locate the evolution and transformation; the gold standard mentality, liquidationism, the Treasury view, and the real-bills doctrine. By highlighting these four economic ideas, I argue that what happened during the Great Depression was the retreat of the gold standard mentality, the complete demise of liquidationism and the Treasury view, and the strange survival of the real-bills doctrine. Each of those transformations happened not in response to internal debates in the discipline, but in response to government policies and real-world events.