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基于多项式位移分布模式的空间圆弧曲梁单元有限元分析
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作者 李整 李奥利 +2 位作者 陈代海 许世展 杨朝旭 《力学与实践》 2024年第6期1212-1220,共9页
为满足曲线梁桥有限元分析的需要,根据有限元分析理论,通过引入多项式位移分布模式构造曲梁单元的位移形函数,利用虚功原理推导局部坐标系下曲梁单元的刚度矩阵和一致质量矩阵表达式,并由曲梁单元空间坐标建立局部坐标系与整体坐标系之... 为满足曲线梁桥有限元分析的需要,根据有限元分析理论,通过引入多项式位移分布模式构造曲梁单元的位移形函数,利用虚功原理推导局部坐标系下曲梁单元的刚度矩阵和一致质量矩阵表达式,并由曲梁单元空间坐标建立局部坐标系与整体坐标系之间的坐标转换矩阵,运用Fortran语言编制相应的有限元计算程序,对比分析3种模型的静动力性能和自振特性进行验证。研究结果表明,曲梁单元模型与实体模型的计算结果吻合较好,验证了曲梁单元刚度矩阵、质量矩阵的准确性。研究结果为后续曲线梁桥的力学性能分析提供了理论参考,可以为工程实践中的设计和评估提供有力支持。 展开更多
关键词 曲梁单元 多项式位移分布模式 单元刚度矩阵 单元质量矩阵 有限元分析
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用多项式模拟烤烟赤星病病指趋势值的研究
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作者 陈惠明 王明 +3 位作者 顾本文 杨硕媛 胡坚 杨璧愫 《云南农业大学学报》 CAS CSCD 2003年第1期35-38,共4页
用多项式模式模拟预测了2001年玉溪红塔区烤烟赤星病病指的趋势值,并与实测值进行了误差分析;同时已模拟预测了2002年烤烟赤星病病指的发生趋势值,为烤烟生产的综合防治工作服务。
关键词 烤烟 赤星病 趋势值 模拟 多项式模式 病情指数
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SVM with Quadratic Polynomial Kernel Function Based Nonlinear Model One-step-ahead Predictive Control 被引量:12
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作者 钟伟民 何国龙 +1 位作者 皮道映 孙优贤 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第3期373-379,共7页
A support vector machine (SVM) with quadratic polynomial kernel function based nonlinear model one-step-ahead predictive controller is presented. The SVM based predictive model is established with black-box identifica... A support vector machine (SVM) with quadratic polynomial kernel function based nonlinear model one-step-ahead predictive controller is presented. The SVM based predictive model is established with black-box identification method. By solving a cubic equation in the feature space, an explicit predictive control law is obtained through the predictive control mechanism. The effect of controller is demonstrated on a recognized benchmark problem and on the control of continuous-stirred tank reactor (CSTR). Simulation results show that SVM with quadratic polynomial kernel function based predictive controller can be well applied to nonlinear systems, with good performance in following reference trajectory as well as in disturbance-rejection. 展开更多
关键词 nonlinear model predictive control support vector machine nonlinear system identification kernel function
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A Unified Model of All Generalizations from the Jones Polynomial
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作者 QIANShang-Wu GUZhi-Yu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第4期431-434,共4页
From the basic properties of skein systems, we build a generalized tangle algebra (GTA). The elements of GTA are four basic tangles. There are three operations, which are connection, splicing and scalar multiplication... From the basic properties of skein systems, we build a generalized tangle algebra (GTA). The elements of GTA are four basic tangles. There are three operations, which are connection, splicing and scalar multiplication. From GTA we derive two generalized recursion formulae (GRF) and prove the existence of a generalized skein relation which satisfies GRF. The obtained generalized skein relation epitomizes all generalizations from the Jones polynomial and thus forms a unified model. Two important topological parameters, twisting measure and loop values, appear explicitly in the expressions of the unified model, and this fact greatly simplifies the operations. 展开更多
关键词 Jones polynomial skein relation tangle algebra recursion formula
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基于模态分析的二维绝对节点坐标剪切梁单元力学特性研究
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作者 周川 赵春花 +2 位作者 独亚平 郭嘉辉 张立强 《机械强度》 CAS CSCD 北大核心 2022年第6期1419-1425,共7页
借助理论分析和数值仿真,研究了二维绝对节点坐标低阶梁单元和高阶梁单元模态参数。推导了考虑泊松效应的低阶和高阶梁单元1阶厚度固有频率解析解。基于广义特征方程获得了绝对节点坐标剪切梁单元的弯曲、轴向、剪切和厚度四种固有频率... 借助理论分析和数值仿真,研究了二维绝对节点坐标低阶梁单元和高阶梁单元模态参数。推导了考虑泊松效应的低阶和高阶梁单元1阶厚度固有频率解析解。基于广义特征方程获得了绝对节点坐标剪切梁单元的弯曲、轴向、剪切和厚度四种固有频率和固有振型。以简支梁结构为实例,分析了剪切梁单元多项式位移模式对弯曲、轴向、剪切和厚度四种固有频率和固有振型的作用规律。研究结果表明:绝对节点坐标剪切梁单元高阶多项式位移模式需要同时引入横向和纵向高阶项x2和y2,它们主要影响的是弯曲和轴向模态参数,对剪切和厚度模态参数影响较小,且低阶和高阶单元1阶厚度固有频率和它们的解析解均比较接近。 展开更多
关键词 绝对节点坐标法 多项式位移模式 固有频率 固有振型 剪切梁单元
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Motion Estimation of an Omnidirectional Mobile Robot
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作者 Mkhinini Maher Knani Jilani 《Journal of Mechanics Engineering and Automation》 2011年第5期357-364,共8页
The motion's generation consists in finding an analytic expression of a motion according to time. A Map road type planner or Cell decomposition provide to the motion generator some possible free crossing points of co... The motion's generation consists in finding an analytic expression of a motion according to time. A Map road type planner or Cell decomposition provide to the motion generator some possible free crossing points of collision. The global trajectory's interpolation by a polynomial is generally not possible, because the degree of the polynomial increases with the number of crossing points which can generate vibrations or loops of the. trajectory. The solution consists in using polynomials in an inferior degree and to build the motion in pieces. The theoretical developments concern the motion's generation, the modeling of the vehicle, then the management of its redundancy steam-power. All these methods contribute to improve the robot precision (accuracy). The authors are presenting the motion's generator which constructs into lines a continuous trajectory C2 while enabling the transformation of the crossing points into lines. The generator presented here as part of omnidirectional robot is adaptable to any kind of vehicle. 展开更多
关键词 ROBOTICS generation control MOTION omnidirectionnal mobile robot.
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基于黏土颗粒含量的泥石流容重计算 被引量:58
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作者 陈宁生 崔鹏 +1 位作者 刘中港 韦方强 《中国科学(E辑)》 CSCD 北大核心 2003年第B12期164-174,共11页
泥石流的粘粒含量对泥石流容重(γc)有很大的影响.通过对我国西南地区45条典型的沟道泥石流容重与粘粒含量关系的统计分析,基于粘粒含量,使用多项式对泥石流容重进行计算,取得良好的结果,所建立的广义多项式模式和针对粘性泥石流的对数... 泥石流的粘粒含量对泥石流容重(γc)有很大的影响.通过对我国西南地区45条典型的沟道泥石流容重与粘粒含量关系的统计分析,基于粘粒含量,使用多项式对泥石流容重进行计算,取得良好的结果,所建立的广义多项式模式和针对粘性泥石流的对数模式可应用于无法观测的泥石流沟的泥石流容重计算.计算结果与实际观测分析的误差较小,这说明该模式具有很强的针对性.通过分析确定泥石流粘粒含量与容重的关系是粘粒含量影响泥石流的形成、运动和悬浮颗粒粒径的结果,其机理清楚可靠.通过泥石流粘粒含量与容重的关系趋势线分析发现粘粒含量很少(3%以下)时,形成的泥石流通常为稀性泥石流,泥石流体的容重随粘粒含量的减少而减小,这种泥石流随着粘粒含量的降低向水石流或者夹沙水流的状态发展,粘粒含量在3%~18%之间时,容易形成粘性泥石流,粘粒含量在5%~10%时泥石流的容重随粘粒含量的增加而增加,粘粒含量在10%~18%时泥石流的容重随粘粒含量的增加而减小,粘粒含量超过18%时,容易形成泥流,这时候形成的泥流的容重与低粘粒含量时形成的稀性泥石流随粘粒含量的变化趋势相反,性质方面也有很大差别,粘粒含量在7%~11%之间时候形成的泥石流的容重平均值最大.特别地,对于粘性泥石流,模拟出的对数容重计算公式,适用于粘粒含量3%~18%的泥石流体,该方程容重计算值最大可达2.32(t/m^3).这与目前泥石流容重的最大观测值相符. 展开更多
关键词 泥石流容量 黏土颗粒含量 中国 对数模式 广义多项式模式 稀性泥石流 容重计算值 最大观测值
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The RCH Method for Computing Minimal Polynomials of Polynomial Matrices 被引量:1
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作者 YU Bo ZHANG Jintao XU Yanyan 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第1期190-209,共20页
In this paper,a randomized Cayley-Hamilton theorem based method(abbreviated by RCH method) for computing the minimal polynomial of a polynomial matrix is presented.It determines the coefficient polynomials term by ter... In this paper,a randomized Cayley-Hamilton theorem based method(abbreviated by RCH method) for computing the minimal polynomial of a polynomial matrix is presented.It determines the coefficient polynomials term by term from lower to higher degree.By using a random vector and randomly shifting,it requires no condition on the input matrix and works with probability one.In the case that coefficients of entries of the given polynomial matrix are all integers and that the algorithm is performed in exact computation,by using the modular technique,a parallelized version of the RCH method is also given.Comparisons with other algorithms in both theoretical complexity analysis and computational tests are given to show its effectiveness. 展开更多
关键词 Characteristic polynomial minimal polynomial polynomial matrix.
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Nonlinear identification of electro-magnetic force model 被引量:1
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作者 R. SHABANI S. TARIVERDILO H. SALARIEH 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2010年第3期165-174,共10页
Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of el... Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of electromagnetic losses,flux leakage or saturation of iron.In this paper,based on results from an experimental set-up designed to study magnetic force,a novel parametric model is presented in the form of a nonlinear polynomial with unknown coefficients.The parameters of the proposed model are identified using the weighted residual method.Validations of the model identified were performed by comparing the results in time and frequency domains.The results show a good correlation between experiments and numerical simulations. 展开更多
关键词 Identification Nonlinear vibration Magnetic bearing Weighted residual method
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SOME STUDIES ON GROBNER BASES FOR MODULES AND APPLICATIONS
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作者 WANG Mingsheng +1 位作者 LIU Zhuojun 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2002年第4期396-406,共11页
Hong's theorem for Grobner bases under polynomial composition is generalized to module case with more general cosideration. Similar generalization is also considered when the coefficient field is replaced by a Ded... Hong's theorem for Grobner bases under polynomial composition is generalized to module case with more general cosideration. Similar generalization is also considered when the coefficient field is replaced by a Dedekind domain. 展开更多
关键词 COMPOSITION Grobner basis for module universal Grobner basis.
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