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悬索桥索鞍位置的分离计算法 被引量:28
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作者 李传习 王雷 +2 位作者 刘光栋 陈明宪 肖勇刚 《中国公路学报》 EI CAS CSCD 北大核心 2005年第1期63-68,共6页
关于索鞍位置计算,已有的计算方法较为繁琐或仅适用于单圆曲线索鞍,针对这种情况,将单圆曲线索鞍位置计算的分离计算法推广到复合圆曲线索鞍位置的计算中,从力学关系和几何关系出发推导得到了复合圆曲线索鞍位置计算的解析公式和由解析... 关于索鞍位置计算,已有的计算方法较为繁琐或仅适用于单圆曲线索鞍,针对这种情况,将单圆曲线索鞍位置计算的分离计算法推广到复合圆曲线索鞍位置的计算中,从力学关系和几何关系出发推导得到了复合圆曲线索鞍位置计算的解析公式和由解析公式求解的牛顿-拉斐森迭代算法。改进约束条件,给出合理的迭代初值计算公式,确保了索鞍位置迭代计算快速收敛于真实解。归纳提出了理论顶点的顺延悬链线交点定义法和切线交点定义法的概念,探讨了两种定义法所得的索鞍位置计算公式或计算结果之间的必然联系。算例表明:该精确方法正确可行,近似方法也具有较高的精度,可供悬索桥施工、设计人员参考。 展开更多
关键词 桥梁工程 悬索桥 分离计算法 索鞍位置 复合圆曲线 约束条件
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自由活塞斯特林机动子运动阻尼特性研究 被引量:1
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作者 罗靖 陈燕燕 +1 位作者 胡剑英 罗二仓 《太阳能学报》 EI CAS CSCD 北大核心 2022年第8期230-235,共6页
为准确描述自由活塞斯特林机动子的动力学特性,将黏性阻尼与库伦阻尼的分离计算法引入动子的运动阻尼分析中。通过理论分析和实验验证,并与等效黏性阻尼计算法进行对比,证明了分离计算法的正确性和实用性。研究结果表明:动子在往复运动... 为准确描述自由活塞斯特林机动子的动力学特性,将黏性阻尼与库伦阻尼的分离计算法引入动子的运动阻尼分析中。通过理论分析和实验验证,并与等效黏性阻尼计算法进行对比,证明了分离计算法的正确性和实用性。研究结果表明:动子在往复运动中的接触摩擦与常规接触摩擦不同,其阻尼力既不只是一个定常摩擦力,也不只是速度的线性函数,而是由于往复运动,动子的局部接触情况随位移发生变化,表现为与位置相关的摩擦力。因此,动子往复运动中的阻尼特性应采用一个黏性阻尼系数与一个定常摩擦力共同描述。 展开更多
关键词 自由活塞 斯特林机 动力学特性 黏性阻尼 库伦阻尼 分离计算法
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Discrete Differential Evolution for Mixed Discrete Non-Linear Problems 被引量:1
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作者 Satoshi Kitayama Masao Arakawa Koetsu Yamazaki 《Journal of Civil Engineering and Architecture》 2012年第5期594-605,共12页
Differential evolution (DE) is a global optimizer for continuous design variables. To enhance DE, it is necessary to handle discrete design variables. In this paper, a discrete differential evolution (DDE) algorit... Differential evolution (DE) is a global optimizer for continuous design variables. To enhance DE, it is necessary to handle discrete design variables. In this paper, a discrete differential evolution (DDE) algorithm is proposed to handle discrete design variables The proposed DDE is based on the DE/l/rand/bin method. In the proposed DDE, the mutation ratio is regarded as the exchange probability, and thus, no modifications of DE/l/rand/bin are required. In addition, in order to maintain diversity through the search process, we initialize all search points. By introducing the initialization of all search points, global or quasi-optimum solution can be found. We validate the proposed DDE by applying it to several benchmark problems. 展开更多
关键词 Global optimization differential evolution mixed-discrete nonlinear problems.
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Separation Processes of Granular Materials by Sizes at the Sieve Classifiers
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作者 Fail Gabdulbarovich Akhmadiev R.F. Gizzjatov 《Journal of Chemistry and Chemical Engineering》 2013年第1期56-63,共8页
A mathematical model of the kinetics of thin-layer separation of granular materials by size stacked sieve classifiers based on the theory of Markov processes is constructed. The probability of screening in a cell in t... A mathematical model of the kinetics of thin-layer separation of granular materials by size stacked sieve classifiers based on the theory of Markov processes is constructed. The probability of screening in a cell in the shape and size of the holes and particle sieve material shared with the influence of the relative speed of their movement was determined. Residues on whole meal with sieves were identified by a kinetic model and numerical calculations, the efficacy of separation. 展开更多
关键词 Multilevel classifier sieve separation process probability sieving the density distribution Fokker-Planck equation.
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Calculation on model of weakening hydrogen bond of thick oil of petroleum
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作者 MiN Xin-min WANG Xu-chao +1 位作者 CHEN Feng CHEN Yan-ling 《Journal of Energy and Power Engineering》 2009年第12期53-59,共7页
The process of use catalyst or functional material that contains iron ion to weaken -O-H-O- hydrogen bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge. covalent bond order, total energy ... The process of use catalyst or functional material that contains iron ion to weaken -O-H-O- hydrogen bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge. covalent bond order, total energy and the average distance of Fe-O. is studied with density function theory and discrete variational method (DFT-DVM), one of the first principle methods. With the decrease of the distance of Fe-O. the charge of Fe ion increases, the charge of hydrogen ion decreases, and hydrogen bond is weakened. There are obvious and more stable effects to use the catalyst that contains multiple metal ions or increase the catalyst amount in weakening hydrogen bond of the thick oil. This theoretic work is helpful to exploit and process the thick oil of petroleum and maybe overcome the crisis of petroleum energy is approaching to us. 展开更多
关键词 calculation: hydrogen bond: weaken: thick oil: petroleum
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Improvement of contact calculation in spherical discontinuous deformation analysis 被引量:3
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作者 WANG Long JIAO YuYong +3 位作者 HUANG GangHai ZHENG Fei ZHAO ZhiYe TAN Fei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第5期765-771,共7页
Discontinuous deformation analysis (DDA) method is a newly developed discrete element method which employs the implicit time-integration scheme to solve the governing equations and the open-close iteration (OCI) m... Discontinuous deformation analysis (DDA) method is a newly developed discrete element method which employs the implicit time-integration scheme to solve the governing equations and the open-close iteration (OCI) method to deal with contact prob- lem, its computational efficiency is relatively low. However, spherical element based discontinuous deformation analysis (SDDA), which uses very simple contact type like point-to-point contact, has higher calculation speed. In the framework of SDDA, this paper presents a very simple contact calculation approach by removing the OCI scheme and by adopting the maximal displacement increment (MDI). Through some verification examples, it is proved that the proposed method is correct and effective, and a higher computational efficiency is obtained. 展开更多
关键词 3D-DDA spherical element open-close iteration calculation efficiency
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