Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can b...Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.展开更多
With the increasing public consciousness on environmental issues, chemical products and process designs require simultaneous satisfaction and compromise of environmental and economical requirements. To fulfill the two...With the increasing public consciousness on environmental issues, chemical products and process designs require simultaneous satisfaction and compromise of environmental and economical requirements. To fulfill the two conflicting while complementary objectives, a systematic approach for life cycle design of a chemical product is proposed in this article. Multiattribute decision-making is adopted in a trade-off consideration of both technical economical evaluation and environmental impacts assessment using the analytic hierarchy process （AHP） approach. On the basis of an evaluation of the relative importance of the criteria multicriteria decision making is performed. In this study, an AHP model is used to derive single a criteria score by analyzing the environmental impact and life cycle cost of a product, respectively. And a fluctuant weight analysis is put forth to calculate the integrated index of the product to enable products to be ranked or selected intuitionally and conveniently. The proposed AHP model has been applied to a case study, a comparative study on chamber cleaning with NF3 and C2F6. The resuits show that the protposed AHP model is Capable of providing a rational and relevant evaluation.展开更多
Hydrodynamic analysis is one of the key steps in safety assessment ot a structure m waves, lvlany optloll~ axe available for answering challenge raised from marine and offshore energy industry, from costly three dimen...Hydrodynamic analysis is one of the key steps in safety assessment ot a structure m waves, lvlany optloll~ axe available for answering challenge raised from marine and offshore energy industry, from costly three dimensional CFD to the efficient but not perfect boundary element models. Focus on the boundary element methods, analysis methods for the interaction of waves and structures are discussed. Those boundary element models cover frequency domain and time domain, linear and non-linear. Special attention is pay to the problems encountered in those models and approaches we adopted for their engineering solution.展开更多
Natural gas is one of the key energy resources for Turkey due to fact that 32% of annual primary energy supply and 45% of annual electricity production is obtained from natural gas with also common usage of residentia...Natural gas is one of the key energy resources for Turkey due to fact that 32% of annual primary energy supply and 45% of annual electricity production is obtained from natural gas with also common usage of residential and industrial zones. In this study, the supply security of natural gas was taken into consideration with strategic criteria of energy policy with the SWOT （strengths, weaknesses, opportunities and threats） analysis and the future projection for Turkey. It has been concluded on geopolitics criteria, domestic production and research for resources must be stimulated as high as possible and participation to abroad resources must be implemented.展开更多
基金Project(2023YFB4302500)supported by the National Key R&D Program of ChinaProject(52078485)supported by the National Natural Science Foundation of ChinaProjects(2021-Major-16,2021-Special-08)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited。
文摘Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.
基金Supported by the National Natural Science Foundation of China (No.20376025, No.20536020) the China Excellent YoungScientist Fund (No.20225620).
文摘With the increasing public consciousness on environmental issues, chemical products and process designs require simultaneous satisfaction and compromise of environmental and economical requirements. To fulfill the two conflicting while complementary objectives, a systematic approach for life cycle design of a chemical product is proposed in this article. Multiattribute decision-making is adopted in a trade-off consideration of both technical economical evaluation and environmental impacts assessment using the analytic hierarchy process （AHP） approach. On the basis of an evaluation of the relative importance of the criteria multicriteria decision making is performed. In this study, an AHP model is used to derive single a criteria score by analyzing the environmental impact and life cycle cost of a product, respectively. And a fluctuant weight analysis is put forth to calculate the integrated index of the product to enable products to be ranked or selected intuitionally and conveniently. The proposed AHP model has been applied to a case study, a comparative study on chamber cleaning with NF3 and C2F6. The resuits show that the protposed AHP model is Capable of providing a rational and relevant evaluation.
文摘Hydrodynamic analysis is one of the key steps in safety assessment ot a structure m waves, lvlany optloll~ axe available for answering challenge raised from marine and offshore energy industry, from costly three dimensional CFD to the efficient but not perfect boundary element models. Focus on the boundary element methods, analysis methods for the interaction of waves and structures are discussed. Those boundary element models cover frequency domain and time domain, linear and non-linear. Special attention is pay to the problems encountered in those models and approaches we adopted for their engineering solution.
文摘Natural gas is one of the key energy resources for Turkey due to fact that 32% of annual primary energy supply and 45% of annual electricity production is obtained from natural gas with also common usage of residential and industrial zones. In this study, the supply security of natural gas was taken into consideration with strategic criteria of energy policy with the SWOT （strengths, weaknesses, opportunities and threats） analysis and the future projection for Turkey. It has been concluded on geopolitics criteria, domestic production and research for resources must be stimulated as high as possible and participation to abroad resources must be implemented.
