By a News Reporter-Staff News Editor at Journal of Engineering -- Fresh data on Mechanical Engineering are presented in a new report. According to news originating from Wuhan, People's Republic of China, by VerticalNews correspondents, research stated, "The sensitivity problem of dynamic analysis of linear nonviscously damped systems is considered. The assumed nonviscous damping forces depend on the past history of motion via convolution integrals over some kernel functions."
Our news journalists obtained a quote from the research from the Huazhong University of Science and Technology, "The nonviscous damping model can be alternatively chosen from familiar viscoelastically damping structures and is considered as a further generalization of the familiar viscous damping. The computations of dynamic responses are reviewed for the purpose of design sensitivity analysis development. The dynamic response can be easily calculated using direct frequency response method and modal superposition method when the dynamic equation of motion of nonviscously damped systems is transformed into the frequency domain using the Laplace transform. It is shown that the dynamic response of nonviscously damped systems can be obtained using traditional modal analysis in a familiar manner used in undamped or viscously damped systems. The discrete Fourier transform and inverse discrete Fourier transform algorithms are also suggested to obtain the displacement in the time domain. Based on these expressions of dynamic response, the adjoint variable and direct differentiation methods, originally presented to obtain the dynamic response sensitivity of undamped or viscously damped systems, are both developed for efficiently and accurately calculating the sensitivity of dynamic response of nonviscously damped systems. Finally, some case studies are used to show the application, effectiveness and some characters of the derived formulas. The numerical sensitivity results show the sensitivity obtained using the developed methods are in excellent agreement with the finite difference results."
According to the news editors, the research concluded: "However, the finite difference method suffers from computational inefficiency and possible errors."
For more information on this research see: Design sensitivity analysis of dynamic response of nonviscously damped systems. Mechanical Systems and Signal Processing, 2013;41(1-2):613-638. Mechanical Systems and Signal Processing can be contacted at: Academic Press Ltd- Elsevier Science Ltd, 24-28 Oval Rd, London NW1 7DX, England. (Elsevier - www.elsevier.com; Mechanical Systems and Signal Processing - www.elsevier.com/wps/product/cws_home/622912)
The news correspondents report that additional information may be obtained from L. Li, Huazhong University of Science & Technology, Sch Mech Sci & Engn, Wuhan 430074, People's Republic of China. Additional authors for this research include Y.J. Hu and X.L. Wang.
Keywords for this news article include: Asia, Wuhan, Mechanical Engineering, People's Republic of China
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