By means of bidirectional combined coordinate system, three kinds of calculation methods are proposed with respect to the damage-evolvlng rate and the life of elastic-plastic material, which include the single-paramet...By means of bidirectional combined coordinate system, three kinds of calculation methods are proposed with respect to the damage-evolvlng rate and the life of elastic-plastic material, which include the single-parameter method, the ratio-method and the multiplication-method. In this work a lot of new calculation equations are given; a new concept on the all-around material constant is provided, which has functional relations with each of the typical material parameters： the fatigue strength coefficient σ′f, the fatigue strength exponent b′t, the fatigue ductility coefficient ε′f, the fatigue ductility exponent c′1, the average stress, the average strain, critical loading time and so on. In addition, an example of a car part is given, and some comparisons of calculation results are made. The calculation methods will have practical significance in avoiding the unnecessary fatigue tests, saving time, manpower and capital, as well as providing the convenience for engineering applications in a certain degree.展开更多
Parameter calculation and result storage, as two necessary steps in phase-field simulation play an important role in ensuring the accuracy of simulation results. A strategy of parameter calculation and result storage ...Parameter calculation and result storage, as two necessary steps in phase-field simulation play an important role in ensuring the accuracy of simulation results. A strategy of parameter calculation and result storage is presented for phase-field simulation in α-Mg dendrite growth of Mg-5-wt% Zn alloy under isothermal solidification. Based on the phase diagram and empirical formulas, key parameters of the phase-field model, such as equilibrium partition coefficient k, liquidus slope m, solutal diffusion coefficient in liquid Dl, and solutal diffusion coefficient in solid Ds, can be obtained.Both structured grid method and structured point method can be used to store simulation results, but using the latter method will reduce about 60% storage space and 37.5% storage time compared with the former. Finally, convergent simulation results of α-Mg dendrite growth are obtained and they are in good agreement with the experimental results about optical micrograph, which verify the accuracy of parameters and stability of storage method.展开更多
To accurately control the full-span erection of continuous steel box girder bridges with complex cross-sections and long cantilevers, both the augmented finite element method(A-FEM) and the degenerated plate elements ...To accurately control the full-span erection of continuous steel box girder bridges with complex cross-sections and long cantilevers, both the augmented finite element method(A-FEM) and the degenerated plate elements are adopted in this paper. The entire construction process is simulated by the A-FEM with the mesh-separation-based approximation technique, while the degenerated plate elements are constructed based on 3D isoparametric elements, making it suitable for analysis of a thin-walled structure. This method significantly improves computational efficiency by avoiding numerous degrees of freedom(DoFs) when analyzing complex structures. With characteristics of the full-span erection technology, the end-face angle of adjacent girder segments, the preset distance of girder segments from the design position, and the temperature difference are selected as control parameters, and they are calculated through the structural response of each construction stage. Engineering practice shows that the calculation accuracy of A-FEM is verified by field-measured results. It can be applied rapidly and effectively to evaluate the matching state of girder segments and the stress state of bearings as well as the thermal effect during full-span erection.展开更多
The ocean is a crucial area for future economic development.The marine environment has high energy-efficient and ecological requirements for building construction.Meteorological parameters are the key basis for the an...The ocean is a crucial area for future economic development.The marine environment has high energy-efficient and ecological requirements for building construction.Meteorological parameters are the key basis for the analysis and design of building energy efficiency.The lack of meteorological parameters for energy efficiency,particularly hourly data,under oceanic climatic conditions is a universal problem.The appropriate calculation methods of hourly meteorological parameters under oceanic climatic conditions are explored in this study.The impact of the calculation errors of the hourly meteorological parameters on building energy consumption is also analyzed.Three key meteorological parameters are selected:temperature,humidity,and wind speed.Five hourly calculations methods,including linear interpolation,cubic spline interpolation,pieceated three-Hermite interpolation,Akima interpolation,and radial basis function interpolation,are selected to calculate the error of the difference method,with Xiamen,Haikou,and Sanya as the locations of meteorological research.Appropriate interpolation methods are selected for the three parameters,and the seasonal and regional characteristics of the errors of each parameter are compared.Different interpolation methods should be selected for different meteorological parameters in different seasons.The error data of the three parameters of different magnitudes are constructed.A quantitative relationship between the sum of squares due to error of the three meteorological parameters and the rate of change of cooling energy consumption is established.The hourly calculation errors of meteorological parameters have an important impact on the calculation of dynamic energy consumption.The energy consumption differences caused by the errors of different parameters are significant.Obvious regional and seasonal differences also exist.This research strengthens the research foundation of building energy consumption calculation under oceanic climate conditions.展开更多
文摘By means of bidirectional combined coordinate system, three kinds of calculation methods are proposed with respect to the damage-evolvlng rate and the life of elastic-plastic material, which include the single-parameter method, the ratio-method and the multiplication-method. In this work a lot of new calculation equations are given; a new concept on the all-around material constant is provided, which has functional relations with each of the typical material parameters： the fatigue strength coefficient σ′f, the fatigue strength exponent b′t, the fatigue ductility coefficient ε′f, the fatigue ductility exponent c′1, the average stress, the average strain, critical loading time and so on. In addition, an example of a car part is given, and some comparisons of calculation results are made. The calculation methods will have practical significance in avoiding the unnecessary fatigue tests, saving time, manpower and capital, as well as providing the convenience for engineering applications in a certain degree.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 52074246, 52275390, 52205429, and 52201146)the National Defense Basic Scientific Research Program of China (Grant Nos. JCKY2020408B002 and WDZC2022-12)+1 种基金the Science and Technology Major Project of Shanxi Province, China (Grant Nos. 20191102008 and 20191102007)the Guiding Local Science and Technology Development Projects by the Central Government, China (Grant Nos. YDZJSX2022A025 and YDZJSX2021A027)。
文摘Parameter calculation and result storage, as two necessary steps in phase-field simulation play an important role in ensuring the accuracy of simulation results. A strategy of parameter calculation and result storage is presented for phase-field simulation in α-Mg dendrite growth of Mg-5-wt% Zn alloy under isothermal solidification. Based on the phase diagram and empirical formulas, key parameters of the phase-field model, such as equilibrium partition coefficient k, liquidus slope m, solutal diffusion coefficient in liquid Dl, and solutal diffusion coefficient in solid Ds, can be obtained.Both structured grid method and structured point method can be used to store simulation results, but using the latter method will reduce about 60% storage space and 37.5% storage time compared with the former. Finally, convergent simulation results of α-Mg dendrite growth are obtained and they are in good agreement with the experimental results about optical micrograph, which verify the accuracy of parameters and stability of storage method.
基金Project supported by the National Natural Science Foundation of China(Nos.51578496 and 51878603)the Zhejiang Provincial Natural Science Foundation of China(No.LZ16E080001)。
文摘To accurately control the full-span erection of continuous steel box girder bridges with complex cross-sections and long cantilevers, both the augmented finite element method(A-FEM) and the degenerated plate elements are adopted in this paper. The entire construction process is simulated by the A-FEM with the mesh-separation-based approximation technique, while the degenerated plate elements are constructed based on 3D isoparametric elements, making it suitable for analysis of a thin-walled structure. This method significantly improves computational efficiency by avoiding numerous degrees of freedom(DoFs) when analyzing complex structures. With characteristics of the full-span erection technology, the end-face angle of adjacent girder segments, the preset distance of girder segments from the design position, and the temperature difference are selected as control parameters, and they are calculated through the structural response of each construction stage. Engineering practice shows that the calculation accuracy of A-FEM is verified by field-measured results. It can be applied rapidly and effectively to evaluate the matching state of girder segments and the stress state of bearings as well as the thermal effect during full-span erection.
基金the National Key Research and Development Program of China(Grant No.2018YFC0704505)the General Program of National Natural Science Foundation of China(Grant No.51878536).
文摘The ocean is a crucial area for future economic development.The marine environment has high energy-efficient and ecological requirements for building construction.Meteorological parameters are the key basis for the analysis and design of building energy efficiency.The lack of meteorological parameters for energy efficiency,particularly hourly data,under oceanic climatic conditions is a universal problem.The appropriate calculation methods of hourly meteorological parameters under oceanic climatic conditions are explored in this study.The impact of the calculation errors of the hourly meteorological parameters on building energy consumption is also analyzed.Three key meteorological parameters are selected:temperature,humidity,and wind speed.Five hourly calculations methods,including linear interpolation,cubic spline interpolation,pieceated three-Hermite interpolation,Akima interpolation,and radial basis function interpolation,are selected to calculate the error of the difference method,with Xiamen,Haikou,and Sanya as the locations of meteorological research.Appropriate interpolation methods are selected for the three parameters,and the seasonal and regional characteristics of the errors of each parameter are compared.Different interpolation methods should be selected for different meteorological parameters in different seasons.The error data of the three parameters of different magnitudes are constructed.A quantitative relationship between the sum of squares due to error of the three meteorological parameters and the rate of change of cooling energy consumption is established.The hourly calculation errors of meteorological parameters have an important impact on the calculation of dynamic energy consumption.The energy consumption differences caused by the errors of different parameters are significant.Obvious regional and seasonal differences also exist.This research strengthens the research foundation of building energy consumption calculation under oceanic climate conditions.
