囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立...囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立了基于关键设计参量的囊式空气弹簧统一结构参数预测模型。搭建了结构参数测试装置,试验验证了统一结构参数模型的正确性。揭示了CAS有效容积及其变化率、有效面积与关键设计参量均正相关,但有效面积变化率与曲囊弧长正相关、与有效法兰半径呈负线性相关特性,为设计刚度更低的CAS提供指导;进一步指出有效法兰半径对CAS结构参数的影响比曲囊弧长更为显著,增大有效法兰半径能够明显增大有效面积而显著提升CAS的承载特性,为保证工作气压不变前提下提升CAS承载能力提供了设计指引。研究结果为设计阶段准确计算囊式空气弹簧的结构参数、力学特性奠定基础,也为其结构参数设计与优化提供理论支撑。展开更多
AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir...AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.展开更多
A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method f...A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method for different graphic modelon based on variable constraint. At the same time, with the aim of engineering application in the collaboration design, the autonmous constraint in modelon and relative constraint between two modelons are given. Finally, with the tool of variable and relation dbase, the solving method of variable relating and variable-driven among different graphic modelon in a part, and double-acting variable relating parametric method among different parts for collaboration are given.展开更多
It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the mi...It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters.展开更多
Parametric design of typical parts holds a very important position during process of product designs. In order to develop a parametric design system of typical parts compatible with heterogeneous CAD systems, this pap...Parametric design of typical parts holds a very important position during process of product designs. In order to develop a parametric design system of typical parts compatible with heterogeneous CAD systems, this paper presents a framework of a network-oriented design system of typical parts, enabled by eXtensible Markup Language (XML), capable of providing parametric design. Firstly, an overview of the framework is presented. In order to map the part feature hierarchy tree of 3D model into an XML tree, an XML-based part template is introduced. The methods of XML-based parametric design and parametric design navigation are described. Finally, an application example of prototype system under the Pro/Engineer platform is given. The application indicates that the proposed framework is valid for parametric design of typical parts/components in heterogeneous CAD systems.展开更多
Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this ...Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm.展开更多
An equation of state （EOS） for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· （2V/2p）T·.Based on the equation, a generalized EOS for high pressu...An equation of state （EOS） for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· （2V/2p）T·.Based on the equation, a generalized EOS for high pressure-liquids is established by using the reduced state principle and introducing a characteristic parameter-configuration factor ξ. Reasonably satisfactory P-V-T data for many organic compounds, including some polar components, were calculated by using the equation.展开更多
The inverse design method of a dynamic system with linear parameters has been studied. For some specified eigenvalues and eigenvectors, the design parameter vector which is often composed of whole or part of coefficie...The inverse design method of a dynamic system with linear parameters has been studied. For some specified eigenvalues and eigenvectors, the design parameter vector which is often composed of whole or part of coefficients of spring and mass of the system can be obtained and the rigidity and mass matrices of an initially designed structure can be reconstructed through solving linear algebra equations. By using implicit function theorem, the conditions of existence and uniqueness of the solution are also deduced. The theory and method can be used for inverse vibration design of complex structure system.展开更多
文摘囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立了基于关键设计参量的囊式空气弹簧统一结构参数预测模型。搭建了结构参数测试装置,试验验证了统一结构参数模型的正确性。揭示了CAS有效容积及其变化率、有效面积与关键设计参量均正相关,但有效面积变化率与曲囊弧长正相关、与有效法兰半径呈负线性相关特性,为设计刚度更低的CAS提供指导;进一步指出有效法兰半径对CAS结构参数的影响比曲囊弧长更为显著,增大有效法兰半径能够明显增大有效面积而显著提升CAS的承载特性,为保证工作气压不变前提下提升CAS承载能力提供了设计指引。研究结果为设计阶段准确计算囊式空气弹簧的结构参数、力学特性奠定基础,也为其结构参数设计与优化提供理论支撑。
文摘AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.
基金Natural Science Foundation of Anhui Province (No. 01042209)
文摘A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method for different graphic modelon based on variable constraint. At the same time, with the aim of engineering application in the collaboration design, the autonmous constraint in modelon and relative constraint between two modelons are given. Finally, with the tool of variable and relation dbase, the solving method of variable relating and variable-driven among different graphic modelon in a part, and double-acting variable relating parametric method among different parts for collaboration are given.
基金Projects(51474251,51874351)supported by the National Natural Science Foundation,China。
文摘It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters.
基金Project supported by the National Key Lab . of Flexible Manufacturing System Technology ( Grant No.51458060104J W0316) the National High-Tech. R & D Programfor CI MS , China (Grant No.2003AA414033) .
文摘Parametric design of typical parts holds a very important position during process of product designs. In order to develop a parametric design system of typical parts compatible with heterogeneous CAD systems, this paper presents a framework of a network-oriented design system of typical parts, enabled by eXtensible Markup Language (XML), capable of providing parametric design. Firstly, an overview of the framework is presented. In order to map the part feature hierarchy tree of 3D model into an XML tree, an XML-based part template is introduced. The methods of XML-based parametric design and parametric design navigation are described. Finally, an application example of prototype system under the Pro/Engineer platform is given. The application indicates that the proposed framework is valid for parametric design of typical parts/components in heterogeneous CAD systems.
基金Sponsored by the Program for New Excellent Talents in University(Grant No.NZCT2004-0332)
文摘Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm.
文摘An equation of state （EOS） for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· （2V/2p）T·.Based on the equation, a generalized EOS for high pressure-liquids is established by using the reduced state principle and introducing a characteristic parameter-configuration factor ξ. Reasonably satisfactory P-V-T data for many organic compounds, including some polar components, were calculated by using the equation.
基金Science Developing Plan of Beijing Educational Committee, Beijing Natural Science Fund (No. 3022003), and NationalNatural Science Fund of China(No.50375002)
文摘The inverse design method of a dynamic system with linear parameters has been studied. For some specified eigenvalues and eigenvectors, the design parameter vector which is often composed of whole or part of coefficients of spring and mass of the system can be obtained and the rigidity and mass matrices of an initially designed structure can be reconstructed through solving linear algebra equations. By using implicit function theorem, the conditions of existence and uniqueness of the solution are also deduced. The theory and method can be used for inverse vibration design of complex structure system.
