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Complete solutions for elastic fields induced by point load vector in functionally graded material model with transverse isotropy 被引量:2
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作者 Sha XIAO Zhongqi YUE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第3期411-430,共20页
The paper develops and examines the complete solutions for the elastic field induced by the point load vector in a general functionally graded material(FGM)model with transverse isotropy.The FGMs are approximated with... The paper develops and examines the complete solutions for the elastic field induced by the point load vector in a general functionally graded material(FGM)model with transverse isotropy.The FGMs are approximated with n-layered materials.Each of the n-layered materials is homogeneous and transversely isotropic.The complete solutions of the displacement and stress fields are explicitly expressed in the forms of fifteen classical Hankel transform integrals with ten kernel functions.The ten kernel functions are explicitly expressed in the forms of backward transfer matrices and have clear mathematical properties.The singular terms of the complete solutions are analytically isolated and expressed in exact closed forms in terms of elementary harmonic functions.Numerical results show that the computation of the complete solutions can be achieved with high accuracy and efficiency. 展开更多
关键词 functionally graded material(FGM) transverse isotropy ELASTICITY closedform singular solution Green's function point load vector
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Long Term Load Forecasting and Recommendations for China Based on Support Vector Regression
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作者 Shijie Ye Guangfu Zhu Zhi Xiao 《Energy and Power Engineering》 2012年第5期380-385,共6页
Long-term load forecasting (LTLF) is a challenging task because of the complex relationships between load and factors affecting load. However, it is crucial for the economic growth of fast developing countries like Ch... Long-term load forecasting (LTLF) is a challenging task because of the complex relationships between load and factors affecting load. However, it is crucial for the economic growth of fast developing countries like China as the growth rate of gross domestic product (GDP) is expected to be 7.5%, according to China’s 11th Five-Year Plan (2006-2010). In this paper, LTLF with an economic factor, GDP, is implemented. A support vector regression (SVR) is applied as the training algorithm to obtain the nonlinear relationship between load and the economic factor GDP to improve the accuracy of forecasting. 展开更多
关键词 LONG TERM load Forecasting Support vector Regression China
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Heating load interval forecasting approach based on support vector regression and error estimation
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作者 张永明 于德亮 齐维贵 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第4期94-98,共5页
As the existing heating load forecasting methods are almostly point forecasting,an interval forecasting approach based on Support Vector Regression (SVR) and interval estimation of relative error is proposed in this p... As the existing heating load forecasting methods are almostly point forecasting,an interval forecasting approach based on Support Vector Regression (SVR) and interval estimation of relative error is proposed in this paper.The forecasting output can be defined as energy saving control setting value of heating supply substation;meanwhile,it can also provide a practical basis for heating dispatching and peak load regulating operation.By means of the proposed approach,SVR model is used to point forecasting and the error interval can be gained by using nonparametric kernel estimation to the forecast error,which avoid the distributional assumptions.Combining the point forecasting results and error interval,the forecast confidence interval is obtained.Finally,the proposed model is performed through simulations by applying it to the data from a heating supply network in Harbin,and the results show that the method can meet the demands of energy saving control and heating dispatching. 展开更多
关键词 heating supply energy-saving load forecasting support vector regression nonparametric kernel estimation confidence interval
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Slope stability analysis under seismic load by vector sum analysis method 被引量:15
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作者 Mingwei Guo Xiurun Ge Shuilin Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第3期282-288,共7页
The vibration characteristics and dynamic responses of rock and soil under seismic load can be estimated with dynamic finite element method (DFEM). Combining with the DFEM, the vector sum analysis method (VSAM) is... The vibration characteristics and dynamic responses of rock and soil under seismic load can be estimated with dynamic finite element method (DFEM). Combining with the DFEM, the vector sum analysis method (VSAM) is employed in seismic stability analysis of a slope in this paper. Different from other conventional methods, the VSAM is proposed based on the vector characteristic of force and current stress state of the slope. The dynamic stress state of the slope at any moment under seismic load can he obtained by the DFEM, thus the factor of safety of the slope at any moment during earthquake can be easily obtained with the VSAM in consideration of the DFEM. Then, the global stability of the slope can be estimated on the basis of time-history curve of factor of safety and reliability theory. The VSAM is applied to a homogeneous slope under seismic load. The factor of safety of the slope is 1.30 under gravity only and the dynamic factor of safety under seismic load is 1.21. The calculating results show that the dynamic characteristics and stability state of the slope with input ground motion can be actually analyzed. It is believed that the VSAM is a feasible and practical approach to estimate the dynamic stability of slopes under seismic load. 展开更多
关键词 slope stability vector sum analysis method (VSAM) seismic load dynamic finite element method (DFEM)
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基于矢量编码技术研究负重时楼梯行走时协调性和变异性
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作者 方玉铃 高原 +2 位作者 焦培豪 孙阳 张星辰 《湖北体育科技》 2026年第1期113-118,共6页
目的利用矢量编码技术量化分析负重楼梯行走时下肢协调性及变异性。方法通过三维动作捕捉系统与测力台,采集16名男性在正常与负重状态下楼梯行走的下肢运动学数据,运用矢量编码方法计算关节间耦合角及耦合角标准差。结果与对照组相比,... 目的利用矢量编码技术量化分析负重楼梯行走时下肢协调性及变异性。方法通过三维动作捕捉系统与测力台,采集16名男性在正常与负重状态下楼梯行走的下肢运动学数据,运用矢量编码方法计算关节间耦合角及耦合角标准差。结果与对照组相比,负重组在冠状面呈现不同协调模式:摆动后期髋—膝耦合中,手提负重呈远端协调,对照组为反相;膝—踝耦合中,手/肩扛负重以反相为主,拥持负重呈近端协调;负重反应期髋—膝耦合中,肩扛负重为近端协调,对照组为同相。负重组在摆动前期矢状面内髋—膝耦合变异性更高,在摆动前期和负重反应期冠状面内髋—膝、膝—踝耦合变异性亦显著增大。结论矢量编码技术可有效识别负重下楼行走的下肢协调变化。不同负重方式诱发特定协调模式,可能增加膝关节损伤风险;协调变异性的普遍提高反映运动控制适应性改变,或影响步态稳定性。 展开更多
关键词 楼梯行走 负重 矢量编码 协调性 变异性
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Determination of influential parameters for prediction of total sediment loads in mountain rivers using kernel-based approaches
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作者 Kiyoumars ROUSHANGAR Saman SHAHNAZI 《Journal of Mountain Science》 SCIE CSCD 2020年第2期480-491,共12页
It is important to have a reasonable estimation of sediment transport rate with respect to its significant role in the planning and management of water resources projects. The complicate nature of sediment transport i... It is important to have a reasonable estimation of sediment transport rate with respect to its significant role in the planning and management of water resources projects. The complicate nature of sediment transport in gravel-bed rivers causes inaccuracies of empirical formulas in the prediction of this phenomenon. Artificial intelligences as alternative approaches can provide solutions to such complex problems. The present study aimed at investigating the capability of kernel-based approaches in predicting total sediment loads and identification of influential parameters of total sediment transport. For this purpose, Gaussian process regression(GPR), Support vector machine(SVM) and kernel extreme learning machine(KELM) are applied to enhance the prediction level of total sediment loads in 19 mountain gravel-bed streams and rivers located in the United States. Several parameters based on two scenarios are investigated and consecutive predicted results are compared with some well-known formulas. Scenario 1 considers only hydraulic characteristics and on the other side, the second scenario was formed using hydraulic and sediment properties. The obtained results reveal that using the parameters of hydraulic conditions asinputs gives a good estimation of total sediment loads. Furthermore, it was revealed that KELM method with input parameters of Froude number(Fr), ratio of average velocity(V) to shear velocity(U*) and shields number(θ) yields a correlation coefficient(R) of 0.951, a Nash-Sutcliffe efficiency(NSE) of 0.903 and root mean squared error(RMSE) of 0.021 and indicates superior results compared with other methods. Performing sensitivity analysis showed that the ratio of average velocity to shear flow velocity and the Froude number are the most effective parameters in predicting total sediment loads of gravel-bed rivers. 展开更多
关键词 Total sediment loads Support vector machine Gaussian process regression Kernel extreme learning machine Mountain Rivers
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Static response of a layered magneto-electro-elastic half-space structure under circular surface loading
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作者 Jiangyi Chen Junhong Guo 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2017年第2期145-153,共9页
A cylindrical system of vector functions, the stiffness matrix method and the corresponding recursive algorithm are proposed to investigate the static response of transversely isotropic,layered magneto-electro-elastic... A cylindrical system of vector functions, the stiffness matrix method and the corresponding recursive algorithm are proposed to investigate the static response of transversely isotropic,layered magneto-electro-elastic(MEE) structures over a homogeneous half-space substrate subjected to circular surface loading. In terms of the system of vector functions, we expand the extended displacements and stresses, and deduce two sets of ordinary differential equations, which are related to the expansion coeficients. The solution to one of the two sets of these ordinary differential equations can be evaluated by using the stiffness matrix method and the corresponding recursive algorithm. These expansion coeficients are then integrated by adaptive Gaussian quadrature to obtain the displacements and stresses in the physical domain. Two types of surface loads, mechanical pressure and electric loading,are considered in the numerical examples. The calculated results show that the proposed technique is stable and effective in analyzing the layered half-space MEE structures under surface loading. 展开更多
关键词 Magneto-electro-elastic material Layered and half-space structure Stiffness matrix method System of vector functions Surface loading
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Forecasting the Demand of Short-Term Electric Power Load with Large-Scale LP-SVR 被引量:1
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作者 Pablo Rivas-Perea Juan Cota-Ruiz +3 位作者 David Garcia Chaparro Abel Quezada Carreón Francisco J. Enríquez Aguilera Jose-Gerardo Rosiles 《Smart Grid and Renewable Energy》 2013年第6期449-457,共9页
This research studies short-term electricity load prediction with a large-scalelinear programming support vector regression (LP-SVR) model. The LP-SVR is compared with other three non-linear regression models: Collob... This research studies short-term electricity load prediction with a large-scalelinear programming support vector regression (LP-SVR) model. The LP-SVR is compared with other three non-linear regression models: Collobert’s SVR, Feed-Forward Neural Networks (FFNN), and Bagged Regression Trees (BRT). The four models are trained to predict hourly day-ahead loads given temperature predictions, holiday information and historical loads. The models are trained on-hourly data from the New England Power Pool (NEPOOL) region from 2004 to 2007 and tested on out-of-sample data from 2008. Experimental results indicate that the proposed LP-SVR method gives the smallest error when compared against the other approaches. The LP-SVR shows a mean absolute percent error of 1.58% while the FFNN approach has a 1.61%. Similarly, the FFNN method shows a 330 MWh (Megawatts-hour) mean absolute error, whereas the LP-SVR approach gives a 238 MWh mean absolute error. This is a significant difference in terms of the extra power that would need to be produced if FFNN was used. The proposed LP-SVR model can be utilized for predicting power loads to a very low error, and it is comparable to FFNN and over-performs other state of the art methods such as: Bagged Regression Trees, and Large-Scale SVRs. 展开更多
关键词 Power load Prediction Linear PROGRAMMING Support vector Regression NEURAL Networks for Regression Bagged Regression Trees
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Local vs. cross station simulation of suspended sediment load in successive hydrometric stations: heuristic modeling approach 被引量:1
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作者 Kiyoumars ROUSHANGAR Shabnam HOSSEINZADEH Jalal SHIRI 《Journal of Mountain Science》 SCIE CSCD 2016年第10期1773-1788,共16页
The present paper aims at modeling suspended sediment load(SSL) using heuristic data driven methodologies, e.g. Gene Expression Programming(GEP) and Support Vector Machine(SVM) in three successive hydrometric stations... The present paper aims at modeling suspended sediment load(SSL) using heuristic data driven methodologies, e.g. Gene Expression Programming(GEP) and Support Vector Machine(SVM) in three successive hydrometric stations of Housatonic River in U.S. The simulations were carried out through local and cross-station data management scenarios to investigate the interrelations between the SSL values of upstream/downstream stations. The available scenarios were applied to predict SSL values using GEP to obtain the best models. Then, the best models were predicted by SVM approach and the obtained results were compared with those of GEP. The comparison of the results revealed that the SVM technique is more capable than the GEP for modeling the SSL through the both local and cross-station data management strategies. Besides, local application seems to be better than cross-station application for modeling SSL. Nevertheless, the cross-station application demonstrated to be a valid methodology for simulating SSL, which would be of interest for the stations with lack of observational data. Also, the prediction capability of conventional Sediment Rating Curve(SRC) method was compared with those of GEPand SVM techniques. The obtained results revealed the superiority of GEP and SVM-based models over the traditional SRC technique in the studied stations. 展开更多
关键词 Suspended sediment load Successive hydrometric stations Gene expression programming Support vector machine
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Short Term Electric Load Prediction by Incorporation of Kernel into Features Extraction Regression Technique
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作者 Ruaa Mohamed-Rashad Ghandour Jun Li 《Smart Grid and Renewable Energy》 2017年第1期31-45,共15页
Accurate load prediction plays an important role in smart power management system, either for planning, facing the increasing of load demand, maintenance issues, or power distribution system. In order to achieve a rea... Accurate load prediction plays an important role in smart power management system, either for planning, facing the increasing of load demand, maintenance issues, or power distribution system. In order to achieve a reasonable prediction, authors have applied and compared two features extraction technique presented by kernel partial least square regression and kernel principal component regression, and both of them are carried out by polynomial and Gaussian kernels to map the original features’ to high dimension features’ space, and then draw new predictor variables known as scores and loadings, while kernel principal component regression draws the predictor features to construct new predictor variables without any consideration to response vector. In contrast, kernel partial least square regression does take the response vector into consideration. Models are simulated by three different cities’ electric load data, which used historical load data in addition to weekends and holidays as common predictor features for all models. On the other hand temperature has been used for only one data as a comparative study to measure its effect. Models’ results evaluated by three statistic measurements, show that Gaussian Kernel Partial Least Square Regression offers the more powerful features and significantly can improve the load prediction performance than other presented models. 展开更多
关键词 Short TERM load PREDICTION Support vector Regression (SVR) KERNEL Principal Component Regression (KPCR) KERNEL PARTIAL Least SQUARE Regression (KPLSR)
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Loading Localization by Small-Diameter Optical Fiber Sensors 被引量:1
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作者 Liu Rongmei Zhu Lujia +1 位作者 Lu Jiyun Liang Dakai 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2018年第2期275-281,共7页
Structural health monitoring(SHM)in service has attracted increasing attention for years.Load localization on a structure is studied hereby.Two algorithms,i.e.,support vector machine(SVM)method and back propagation ne... Structural health monitoring(SHM)in service has attracted increasing attention for years.Load localization on a structure is studied hereby.Two algorithms,i.e.,support vector machine(SVM)method and back propagation neural network(BPNN)algorithm,are proposed to identify the loading positions individually.The feasibility of the suggested methods is evaluated through an experimental program on a carbon fiber reinforced plastic laminate.The experimental tests involve in application of four optical fiber-based sensors for strain measurement at discrete points.The sensors are specially designed fiber Bragg grating(FBG)in small diameter.The small-diameter FBG sensors are arrayed in 2-D on the laminate surface.The testing results indicate that the loading position could be detected by the proposed method.Using SVM method,the 2-D FBG sensors can approximate the loading location with maximum error less than 14 mm.However,the maximum localization error could be limited to about 1 mm by applying the BPNN algorithm.It is mainly because the convergence conditions(mean square error)can be set in advance,while SVM cannot. 展开更多
关键词 SMALL DIAMETER optical fiber sensor structural health monitoring loadING LOCALIZATION BACK propagation neural network support vector machine
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Adaptive load balancing scheme in ad hoc networks
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作者 袁玉华 陈惠民 贾旻 《Journal of Shanghai University(English Edition)》 CAS 2007年第3期296-299,共4页
An adaptive load balancing scheme is proposed to balance the load in ad hoc networks. The new scheme can be applied in most on-demand routing protocols resulting in significant performance improvement. The proposed sc... An adaptive load balancing scheme is proposed to balance the load in ad hoc networks. The new scheme can be applied in most on-demand routing protocols resulting in significant performance improvement. The proposed scheme is applied to the ad hoc on-demand distance vector (AODV) routing protocol. Simulation results show that the network load is balanced on the whole, and performance in packet loss rate, routing overhead and average end-to-end delay is also improved. 展开更多
关键词 ad hoc network load balancing ad hoc on-demand distance vector (AODV)
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Optimal seismic design of reinforced concrete structures under timehistory earthquake loads using an intelligent hybrid algorithm 被引量:1
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作者 Sadjad Gharehbaghi Mohsen Khatibinia 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2015年第1期97-109,共13页
A reliable seismic-resistant design of structures is achieved in accordance with the seismic design codes by designing structures under seven or more pairs of earthquake records. Based on the recommendations of seismi... A reliable seismic-resistant design of structures is achieved in accordance with the seismic design codes by designing structures under seven or more pairs of earthquake records. Based on the recommendations of seismic design codes, the average time-history responses (ATHR) of structure is required. This paper focuses on the optimal seismic design of reinforced concrete (RC) structures against ten earthquake records using a hybrid of particle swarm optimization algorithm and an intelligent regression model (IRM). In order to reduce the computational time of optimization procedure due to the computational efforts of time-history analyses, IRM is proposed to accurately predict ATHR of structures. The proposed IRM consists of the combination of the subtractive algorithm (SA), K-means clustering approach and wavelet weighted least squares support vector machine (WWLS-SVM). To predict ATHR of structures, first, the input-output samples of structures are classified by SA and K-means clustering approach. Then, WWLS-SVM is trained with few samples and high accuracy for each cluster. 9- and 18-storey RC frames are designed optimally to illustrate the effectiveness and practicality of the proposed IRM. The numerical results demonstrate the efficiency and computational advantages of IRM for optimal design of structures subjected to time-history earthquake loads. 展开更多
关键词 optimal seismic design reinforced concrete frames earthquake loads particle swarm optimization intelligent regression model support vector machine
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基于负载观测器的PMSM预测电流控制
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作者 于树友 盛恩聪 +1 位作者 徐明生 孙晓东 《控制工程》 北大核心 2025年第1期1-11,共11页
针对永磁同步电机(permanent magnet synchronous motor,PMSM)预测电流控制系统在线优化计算负担大和抗负载扰动性能不足的问题,提出了一种基于负载转矩观测器的PMSM预测电流控制策略。首先,基于离散空间矢量调制构建虚拟电压矢量,并利... 针对永磁同步电机(permanent magnet synchronous motor,PMSM)预测电流控制系统在线优化计算负担大和抗负载扰动性能不足的问题,提出了一种基于负载转矩观测器的PMSM预测电流控制策略。首先,基于离散空间矢量调制构建虚拟电压矢量,并利用无差拍的思想对备选电压矢量控制集进行优化,降低电压矢量寻优的计算负担。然后,为了提高系统的抗负载扰动能力,设计降阶观测器对负载转矩进行实时观测,并将负载转矩观测值按比例前馈至电流环,补偿由负载转矩变化引起的电流波动。仿真结果表明,所提电压矢量寻优策略在保证控制效果的同时有效降低了计算负担,降阶观测器的引入明显提高了系统的抗负载扰动能力。 展开更多
关键词 永磁同步电机 预测电流控制 离散空间矢量调制 负载扰动 降阶观测器
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矢量推力台架中测力传感器组件的性能仿真与试验
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作者 张军 温晓杰 +3 位作者 李新阳 林山 张巍 任宗金 《航空发动机》 北大核心 2025年第2期137-141,共5页
航空发动机矢量推力的高精度测量对于飞行器的姿态控制至关重要。针对测力传感器组件在矢量推力测试中的变形与其在单向推力测试中的变形存在差异问题,开展了测力传感器组件的性能分析。通过仿真与试验相结合的方法,分析了测力传感器组... 航空发动机矢量推力的高精度测量对于飞行器的姿态控制至关重要。针对测力传感器组件在矢量推力测试中的变形与其在单向推力测试中的变形存在差异问题,开展了测力传感器组件的性能分析。通过仿真与试验相结合的方法,分析了测力传感器组件变形影响规律。从单个挠性件入手,通过力学分析其受力模型,建立了挠性件及测力传感器组件的3维模型;仿真其3向变形,获取了其刚度性能,进行了其变形叠加原理的验证。开展了挠性件及测力组件的变形试验,分析讨论不同测点位置对变形测量结果的影响,提出解决方案以避免在力作用下引起的测力传感器组件翘曲以及微小偏斜导致的误差对变形测量的影响,得到了试验状态下的变形规律和刚度性能。经仿真与试验变形对比,结果表明:挠性件及测力传感器组件各向变形的仿真与试验误差在5%之内,轴向刚度和侧向刚度的仿真与试验误差分别在5%和2%之内。 展开更多
关键词 矢量推力 推力台架 挠性件 测力传感器组件 性能分析 航空发动机
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Two-dimensional interactions due to moving load in generalized thermoelastic solid with diffusion 被引量:2
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作者 Sunita Deswal Suman Choudhary 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第2期207-221,共15页
The present paper is concerned with the investigation of disturbances in'a homogeneous, isotropic elastic medium with generalized thermoelastic diffusion, when a moving source is acting along one of the co-ordinate a... The present paper is concerned with the investigation of disturbances in'a homogeneous, isotropic elastic medium with generalized thermoelastic diffusion, when a moving source is acting along one of the co-ordinate axis on the boundary of the medium. Eigen value approach is applied to study the disturbance in Laplace-Fourier transform domain for a two dimensional problem. The analytical expressions for displacement components, stresses, temperature field, concentration and chemical potential are obtained in the physical domain by using a numerical technique for the inversion of Laplace transform based on Fourier expansion techniques. These expressions are calculated numerically for a copper like material and depicted graphically. As special cases, the results in generalized thermoelastic and elastic media are obtained. Effect of presence of diffusion is analyzed theoretically and numerically. 展开更多
关键词 Eigen value approach vector matrix differential equation thermoelastic diffusion generalized thermoelasticity moving load Laplace and Fourier transforms
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基于PSO-SVR算法的钢板-混凝土组合连梁承载力预测 被引量:2
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作者 田建勃 闫靖帅 +2 位作者 王晓磊 赵勇 史庆轩 《振动与冲击》 北大核心 2025年第7期155-162,共8页
为准确预测钢板-混凝土组合(steel plate-RC composite,PRC)连梁承载力,本文分别通过支持向量机回归算法(support vector regression,SVR)、极端梯度提升算法(XGBoost)和粒子群优化的支持向量机回归(particle swarm optimization-suppor... 为准确预测钢板-混凝土组合(steel plate-RC composite,PRC)连梁承载力,本文分别通过支持向量机回归算法(support vector regression,SVR)、极端梯度提升算法(XGBoost)和粒子群优化的支持向量机回归(particle swarm optimization-support vector regression,PSO-SVR)算法进行了PRC连梁试验数据的回归训练,此外,通过使用Sobol敏感性分析方法分析了数据特征参数对PRC连梁承载力的影响。结果表明,基于SVR、极端梯度提升算法(extreme gradient boosting,XGBoost)和PSO-SVR的预测模型平均绝对百分比误差分别为5.48%、7.65%和4.80%,其中,基于PSO-SVR算法的承载力预测模型具有最高的预测精度,模型的鲁棒性和泛化能力更强。此外,特征参数钢板率(ρ_(p))、截面高度(h)和连梁跨高比(l_(n)/h)对PRC连梁承载力影响最大,三者全局影响指数总和超过0.75,其中,钢板率(ρ_(p))是对PRC连梁承载力影响最大的单一因素,一阶敏感性指数和全局敏感性指数分别为0.3423和0.3620,以期为PRC连梁在实际工程中的设计及应用提供参考。 展开更多
关键词 钢板-混凝土组合连梁 机器学习 粒子群优化的支持向量机回归(PSO-SVR)算法 承载力 敏感性分析
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耦合上装载荷的多轴车辆动力学建模与仿真
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作者 李文浩 于会龙 +2 位作者 卢玉传 任延飞 席军强 《兵工学报》 北大核心 2025年第8期140-156,共17页
多轴轮式车辆动力学模型是新型车辆快速开发及车辆设计参数优化、控制算法搭建的基础。目前普遍采用商用软件搭建,其动力学方程及模型梯度信息难以获取,无法将其应用于整车全局设计与控制参数的动态优化,且现有商业软件及理论建模研究... 多轴轮式车辆动力学模型是新型车辆快速开发及车辆设计参数优化、控制算法搭建的基础。目前普遍采用商用软件搭建,其动力学方程及模型梯度信息难以获取,无法将其应用于整车全局设计与控制参数的动态优化,且现有商业软件及理论建模研究对上装载荷动力学影响考虑较少。针对上述问题,基于拉格朗日动力学,考虑簧下质量纵横向运动及上装载荷反作用力对整车动力学的影响,应用矢量化建模方法搭建8×8轮式车辆24自由度动力学模型,分别基于C++和M语言进行软件开发。在变加速、阶跃转向、双移线、正弦扫频等多种工况下与商业软件TruckSim进行全面对比。研究结果表明,自主开发的仿真模型其轮胎力、悬架力及空气阻力、纵横垂向运动等与商业软件高度一致,最大误差小于5%,验证了新方法的准确性。 展开更多
关键词 多轴轮式车辆 上装载荷 矢量化建模 动力学建模与仿真
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高温天气板式轨道宽窄接缝变形规律试验研究
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作者 蔡理平 陈松 张斌 《振动.测试与诊断》 北大核心 2025年第4期722-728,844,共8页
针对我国高速铁路CRTSⅡ型板式无砟轨道接缝病害情况开展现场测试,基于实测数据研究了温度荷载作用下轨道板宽窄接缝处变形与破坏规律。首先,通过搭建轨道板温度场和宽窄接缝变形监测系统,实现了对轨道板不同位置温度变化以及接缝处变... 针对我国高速铁路CRTSⅡ型板式无砟轨道接缝病害情况开展现场测试,基于实测数据研究了温度荷载作用下轨道板宽窄接缝处变形与破坏规律。首先,通过搭建轨道板温度场和宽窄接缝变形监测系统,实现了对轨道板不同位置温度变化以及接缝处变形情况的实时获取;其次,基于特征参量选取支持向量机算法,建立宽窄接缝变形预测模型,通过5折交叉验证和网格搜索法对惩罚系数和核参数进行优化;最后,对高温天气作用下轨道板与宽窄接缝处日相对位移进行预测。试验结果表明:夏季高温天气条件下,宽窄接缝变形与层间温度变化量、竖向温度梯度和纵向温差存在较强的相关性;预测模型具有较强的泛化能力,宽窄接缝变形值预测相对误差分别降低至9.565%和4.524%;通过实测数据验证了模型的有效性,预测精度分别达到93.641%和97.669%,可为避免宽窄接缝病害加剧及其他附加病害的产生提供预警,满足工程实践的需要。 展开更多
关键词 板式轨道 接缝病害 温度荷载 相对位移 支持向量机
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矢量推力测试系统中测力组件布局仿真及试验
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作者 张军 李孟曈 +3 位作者 林山 李新阳 周伟 任宗金 《航空发动机》 北大核心 2025年第5期131-135,共5页
航空矢量发动机推力精确测试对飞行器准确控制至关重要,测试装置的性能直接决定了矢量推力的测试准确性和真实性,其中单元测力组件的布局对于测试装置的测试精度影响较大。为了提高推力测试装置的测试性能,依据航空发动机推力测试系统... 航空矢量发动机推力精确测试对飞行器准确控制至关重要,测试装置的性能直接决定了矢量推力的测试准确性和真实性,其中单元测力组件的布局对于测试装置的测试精度影响较大。为了提高推力测试装置的测试性能,依据航空发动机推力测试系统动架结构与单元测力组件形式,以推力测试系统固有频率、输出误差、维间耦合为研究目标对组件布局形式进行分析。基于刚体假设与理论力学理论,分析了测试系统不同组件布局方案下输入与输出之间的关系,通过仿真分析获得了测试系统的固有频率和在矢量力作用下组件的输出。基于输出数据,对比了不同组件布局下测试系统性能,进而得到组件在系统中的输出性能最佳的布局方案。结果表明:系统输出误差小于2%,各向维间耦合均小于0.5%。通过试验验证了该组件布局下系统输出结果的正确性,对矢量发动机测试中测力组件的合理布局有一定的指导意义。 展开更多
关键词 矢量推力 测试系统 六分量试车台 单元测力组件 有限元仿真 组件布局 输出性能
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