The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and wei...The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and weighted curve fitting method were presented to make the calculation more simple and accurate. The vertical scales of fluctuation of typical layers of Tianjin Port were calculated based on a number of engineering geotechnical investigation data, which can be guidance to other projects in this area. Meanwhile, the influences of sample interval and type of soil index on the scale of fluctuation were analyzed, according to which, the principle of determining the scale of fluctuation when the sample interval changes was defined. It can be obtained that the scale of fluctuation is the basic attribute reflecting spatial variability of soil, therefore, the scales of fluctuation calculated according to different soil indexes should be basically the same. The non-correlation distance method was improved, and the principle of determining the variance reduction function was also discussed.展开更多
in geotechnical engineering, numerical simulation of problems is of great importance. This work proposes a new formulation of coupled finite-infinite elements which can be used in numerical simulation ofgeotechnical p...in geotechnical engineering, numerical simulation of problems is of great importance. This work proposes a new formulation of coupled finite-infinite elements which can be used in numerical simulation ofgeotechnical problems in both static and dynamic conditions. Formulation and various implementation aspects of the proposed coupled finite-infinite elements are carefully discussed. To the authors＇ knowledge, this approach that considers coupled finite-infinite elements is more efficient in the sense that appropriate and accurate results are obtained by using less elements. The accuracy and efficiency of the proposed approach is considered by comparing the obtained results with analytical and numerical results. In a static case, the problem of circular domain ol infinite length is considered. In a dynamic case, one dimensional wave propagation problems arising from the Heaviside step fimction and impulse functions are considered. In order to get a more complete picture, two dimensional wave propagation in a circular qtmrter space is considered and the results are presented. Finally, a soil-structure interaction system subjected to seismic excitation is analyzed. In the analysis of soil-structure interaction phenomenon, frames with different number of storeys and soil media with various stiffness characteristics have been taken into consideration. In the analysis, the finite element software ANSYS has been used. For the newly developed infinite element, the programming has been done by the help of the User Programmable Features of the ANSYS software, which enable creating new elements in the ANSYS software.展开更多
A good cooling circle should ensure that the system can work at an appropriate temperature in the requirements of power increase,engine compartment constraint and working demands for modern engineering machinery,which...A good cooling circle should ensure that the system can work at an appropriate temperature in the requirements of power increase,engine compartment constraint and working demands for modern engineering machinery,which asks for a thorough understanding of system thermal loads before practical production.However,traditional experiment method spends a long time,costs a huge resource but lacks efficiency,whereas virtual design can avoid the shortcomings of traditional method and can analyze operating states adequately with variable loads on engine,generator,drives,battery pack and HVAC systems.Therefore,this paper focuses on a new virtual design method based on multi-dimension coupled simulation adopting Flowmaster software for initial prediction and CFX tool for further optimization.The simulation results in different operating conditions are compared and validated with experiments.Orthogonal experiment and range analysis are used to explore key parameters of cooling system.The research will be helpful in guiding future design and optimization of engineering machinery.展开更多
基金Supported by the National Natural Science Foundation of China(No.41272323)Tianjin Natural Science Foundation(No.13JCZDJC 35300)
文摘The scale of fluctuation is one of the vital parameters for the application of random field theory to the reliability analysis of geotechnical engineering. In the present study, the fluctuation function method and weighted curve fitting method were presented to make the calculation more simple and accurate. The vertical scales of fluctuation of typical layers of Tianjin Port were calculated based on a number of engineering geotechnical investigation data, which can be guidance to other projects in this area. Meanwhile, the influences of sample interval and type of soil index on the scale of fluctuation were analyzed, according to which, the principle of determining the scale of fluctuation when the sample interval changes was defined. It can be obtained that the scale of fluctuation is the basic attribute reflecting spatial variability of soil, therefore, the scales of fluctuation calculated according to different soil indexes should be basically the same. The non-correlation distance method was improved, and the principle of determining the variance reduction function was also discussed.
文摘in geotechnical engineering, numerical simulation of problems is of great importance. This work proposes a new formulation of coupled finite-infinite elements which can be used in numerical simulation ofgeotechnical problems in both static and dynamic conditions. Formulation and various implementation aspects of the proposed coupled finite-infinite elements are carefully discussed. To the authors＇ knowledge, this approach that considers coupled finite-infinite elements is more efficient in the sense that appropriate and accurate results are obtained by using less elements. The accuracy and efficiency of the proposed approach is considered by comparing the obtained results with analytical and numerical results. In a static case, the problem of circular domain ol infinite length is considered. In a dynamic case, one dimensional wave propagation problems arising from the Heaviside step fimction and impulse functions are considered. In order to get a more complete picture, two dimensional wave propagation in a circular qtmrter space is considered and the results are presented. Finally, a soil-structure interaction system subjected to seismic excitation is analyzed. In the analysis of soil-structure interaction phenomenon, frames with different number of storeys and soil media with various stiffness characteristics have been taken into consideration. In the analysis, the finite element software ANSYS has been used. For the newly developed infinite element, the programming has been done by the help of the User Programmable Features of the ANSYS software, which enable creating new elements in the ANSYS software.
基金supported by the Natural Science Foundation of Fujian Province of China(Grant No.2014J01210)Knowledge Innovation of Shenzhen City of China(Grant No.JCYJ20140417162429675)National Key Technology R&D Program of China(Grant No.2013BAF07B04)
文摘A good cooling circle should ensure that the system can work at an appropriate temperature in the requirements of power increase,engine compartment constraint and working demands for modern engineering machinery,which asks for a thorough understanding of system thermal loads before practical production.However,traditional experiment method spends a long time,costs a huge resource but lacks efficiency,whereas virtual design can avoid the shortcomings of traditional method and can analyze operating states adequately with variable loads on engine,generator,drives,battery pack and HVAC systems.Therefore,this paper focuses on a new virtual design method based on multi-dimension coupled simulation adopting Flowmaster software for initial prediction and CFX tool for further optimization.The simulation results in different operating conditions are compared and validated with experiments.Orthogonal experiment and range analysis are used to explore key parameters of cooling system.The research will be helpful in guiding future design and optimization of engineering machinery.
