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fem Analysis on Acoustic Performance of Wall Flow Diesel Particulate Filters

Chinese Journal of Mechanical Engineering 2011年第4期24卷 701-706页

作者： GAO Wenzhi FENG Liming State Key Laboratory of Engines Tianjin University Tianjin 300072 China

Diesel powered vehicles, in compliance with the more strict exhaust emission standards such as Euro V, is likely to require a diesel particulate filter （DPF）. A DPF used on a vehicle will affect the acoustic emission of the diesel engine, so it is important to investigate the sound propagation rule in DPF and further to propose the optimum DPF design. However, due to the geometrical complexity of the DPF, the traditional analysis method, such as analytical method, can not assess the acoustic performance of DPF accurately in medium and high frequency band. In this paper, a combined approach of finite element analysis and viscosity correction is proposed to predict acoustic performance of DPF. A simplified model of the full DPF is established and is used to analyze the sound propagation characteristic of the DPF. The distribution of the sound pressure and velocity, the transmission matrix of the DPF are obtained using the finite element method. In addition, the method of the viscosity correction is used in the transmission matrix of the DPF to evaluate the acoustic performance of DPF. Based on the fem computation and the viscosity correction, the transmission losses under the rated load and idle condition of a diesel engine are calculated. The calculation results show that DPF can effectively attenuate exhaust noise, and sound attenuation increase with the rise of the frequency. Sound attenuation is better under rated condition than idle condition of diesel engine, particularly in frequency above 1 000 Hz.

关键词： diesel particulate filter acoustic performance fem model viscosity correction

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Numerical Simulation and Sensitivity Analysis of Parameters for Multistand Roll Forming of Channel Section With Outer Edge

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Journal of Iron and Steel Research(International) 2009年第1期16卷 32-37页

作者： ZENG Guo LAI Xin-min YU Zhong-qi LIN Zhong-qin School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Mechanical System and Vibration Shanghai 200240 China

Cold roll forming is a high production but complex metal forming process under the conditions of coupled effects with multi-factor. A new booting finite element method （fem） model using the updated Lagrangian （IAL） method for multistand roll forming process is developed and validated. Compared with most of the literatures related to roll forming simulation, the new model can take the roll rotation into account and is well suited for simulating multistand roll forming. Based on the model, the process of a channel section with outer edge formed with twelve passes is simulated and the sensitivity analysis of parameters is conducted with orthogonal design combined fem model. It is found that the multistand roll forming process can be efficiently analyzed by the new booting model, and sensitivity analysis shows that the yield strength plays an important role in controlling the quality of the products.

关键词： cold roll forming multistand roll forming sensitivity fem model

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Active tectonics in Taiwan:insights from a 3-D viscous finite element model

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Earthquake Science 2015年第5期28卷 353-363页

作者： Yujun Sun Mian Liu Shuwen Dong Huai Zhang Yaolin Shi Institute of Geomechanics Chinese Academy of Geological Sciences Key Laboratory of Computational Geodynamics Chinese Academy of Sciences Department of Geological Sciences University of Missouri Chinese Academy of Geological Sciences

Taiwan is a young orogenic belt with complex spatial distributions of deformation and earthquakes. We have constructed a three-dimensional finite element model to explore how the interplays between lithospheric struc- ture and plate boundary processes control the distribution of stress and strain rates in the Taiwan region. The model assumes a liberalized power-law rheology and incorporates main lithospheric structures; the model domain is loaded by the present-day crustal velocity applied at its bound- aries. The model successfully reproduces the main features of the GPS-measured strain rate patterns and the earth- quake-indicated stress states in the Taiwan region. The best fitting model requires the viscosity of the lower crust to be two orders of magnitude lower than that of the upper crust and lithospheric mantle. The calculated deviatoric stress is high in regions of thrust faulting and low in regions of extensional and strike-slip faulting, consistent with the spatial pattern of seismic intensity in Taiwan.

关键词： Taiwan Stress Strain rate fem model Earthquake

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