Applied Mathematical Modelling最新文献_第6页

A thermal flexible rotor dynamic modelling for rapid prediction of thermo-elastic coupling vibration characteristics in non-uniform temperature fields 用于快速预测非均匀温度场中热弹性耦合振动特性的热弹性转子动态模型

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-16 DOI: 10.1016/j.apm.2024.115751

Yazheng Zhao, Jin Zhou, Mingjie Guo, Yuanping Xu

{"title":"A thermal flexible rotor dynamic modelling for rapid prediction of thermo-elastic coupling vibration characteristics in non-uniform temperature fields","authors":"Yazheng Zhao, Jin Zhou, Mingjie Guo, Yuanping Xu","doi":"10.1016/j.apm.2024.115751","DOIUrl":"10.1016/j.apm.2024.115751","url":null,"abstract":"<div><div>The flexible rotors within aero-engines operate in complex thermal environments, where temperature influences both the vibration frequency and amplitude. This study establishes a simple thermal flexible rotor dynamics model to rapidly and precisely predict thermo-elastic coupling vibration characteristics within a non-uniform temperature field. The thermal potential energy of the thermal rotor element is derived for any temperature field, and the motion equation is obtained using the Euler-Lagrange equation. Specifically, the generalized vector of an arbitrary point and cross-sectional non-uniform thermal stress of the thermal rotor element are considered in the thermal potential energy. The model's frequency error is <1 % under identical boundary conditions. Numerical findings indicate that thermal stress, temperature-dependent material properties, and the coupling effect collectively reduce the natural frequency (NF), with thermal stress having a more pronounced impact under axial constraint. Additionally, thermal stress and material decrease the amplitude across a broad range of rotation speeds, contrasting with thermal bending. This model will play a key role in the iterative calculation of thermo-elastic coupling vibration control due to its accuracy and simplicity.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115751"},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fault diagnosis based on incomplete sensor variables with a hierarchical semi-supervised Gaussian mixture classifier 利用分层半监督高斯混合分类器，基于不完整传感器变量进行故障诊断

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-15 DOI: 10.1016/j.apm.2024.115764

Xingchen Liu , Carman K.M. Lee , Hanxiao Zhang , Piao Chen , Jingyuan Huang , Chak Nam Wong

{"title":"Fault diagnosis based on incomplete sensor variables with a hierarchical semi-supervised Gaussian mixture classifier","authors":"Xingchen Liu , Carman K.M. Lee , Hanxiao Zhang , Piao Chen , Jingyuan Huang , Chak Nam Wong","doi":"10.1016/j.apm.2024.115764","DOIUrl":"10.1016/j.apm.2024.115764","url":null,"abstract":"<div><div>We propose a hierarchical semi-supervised variational semi-Bayesian Gaussian mixture classifier based on the partially incomplete and unlabeled samples for the fault diagnosis of mechanical and electrical systems. These systems are typically complex in structure and are monitored by multiple sensors simultaneously. Some sensor variables in the collected data may be incomplete due to sensor malfunctions or transmission errors. Additionally, labeling the data can be a time-consuming and labor-intensive task, resulting in many unlabeled samples. To address these challenges, the missing sensor variables and the unavailable labels are treated as hidden values and handled within the framework of the Expectation Maximization algorithm. We employ a semi-Bayesian technique with variational inference to estimate the model parameters. Specifically, we introduce prior distribution to the mean and covariance matrix to address the possible singularity of the empirical covariance matrix. The weighting coefficients are left without putting prior distribution so that their values can decay to zero, effectively removing redundant components of the mixture model. The factorized distribution is utilized to approximate the posterior distribution of the model parameters, as well as the missing labels and other latent variables. Numerical and real case studies are carried out to verify the effectiveness of the proposed technique.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115764"},"PeriodicalIF":4.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Flexural edge waves and customizable local modes of circular plates with metasurface 带元表面的圆板的挠性边缘波和可定制的局部模式

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-12 DOI: 10.1016/j.apm.2024.115749

Yizhou Shen , Pengfei Jiang , Feng Liu , Yanlong Xu , Zhichun Yang

{"title":"Flexural edge waves and customizable local modes of circular plates with metasurface","authors":"Yizhou Shen , Pengfei Jiang , Feng Liu , Yanlong Xu , Zhichun Yang","doi":"10.1016/j.apm.2024.115749","DOIUrl":"10.1016/j.apm.2024.115749","url":null,"abstract":"<div><div>In this research, we study the propagation of flexural edge waves of circular plates (also known as circular-edge waves), present design strategies of metasurfaces for manipulating these waves, and realize customizable edge modes on the basis of edge wave manipulations. Theoretical frameworks are presented to solve the dispersion relationship of circular-edge waves propagating along different boundaries, including a free edge, a strip with a weakness stiffness, and a metasurface with a slot array. On the basis of these frameworks, the propagation characteristics of circular-edge waves are revealed, and the rainbow reflection and topological interface state are realized by constructing metasurfaces. Furthermore, the modal frequency prediction, the robustness to structural parameters, and the effective excitation position for circular-edge modes are explored. Finally, based on the above analysis, the customizable local modes are presented, which means that the position of high energy regions in mode shapes can be designed without changing the corresponding modal frequency. Our work provides a new idea for the manipulation of flexural waves in circular plates and find a potential correlation between flexural waves and vibrations, which may exhibit wide applications in vibration control and acoustic device development.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115749"},"PeriodicalIF":4.4,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An adaptive time-step energy-preserving variational integrator for flexible multibody system dynamics 用于柔性多体系统动力学的自适应时间步长能量保护变分积分器

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-12 DOI: 10.1016/j.apm.2024.115759

Shuaizhen Gu, Ju Chen, Qiang Tian

{"title":"An adaptive time-step energy-preserving variational integrator for flexible multibody system dynamics","authors":"Shuaizhen Gu, Ju Chen, Qiang Tian","doi":"10.1016/j.apm.2024.115759","DOIUrl":"10.1016/j.apm.2024.115759","url":null,"abstract":"<div><div>An adaptive time-step variational integrator for simulating flexible multibody system dynamics is proposed. The integrator can adapt the time-step based on the variation of the system's energy. The flexible components in the system can undergo large overall motions and large deformations and are modelled by elements of absolute nodal coordinate formulations. In addition, a three-stage Newton-Raphson iteration method is developed to accurately solve the nonlinear discrete Euler-Lagrange equations in each time-step. Finally, three dynamic examples are presented to validate performance of the proposed integrator. Numerical results indicate that the proposed three-stage method has fast convergence rate. For the nonlinear flexible double pendulum system and the slider-crank mechanism, compared with constant time-step integrators, the proposed integrator can preserve the system's total energy more accurately and lead to more accurate dynamic responses. For the contact problem, the proposed integrator can quickly change the time-step size based on the sudden changes of energy to precisely compute the contact force and dynamic responses. Moreover, the proposed integrator can exactly preserve the displacement constraints and the velocity constraints simultaneously. In addition, it is noted that the computation efficiency of the proposed integrator needs to be further improved.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115759"},"PeriodicalIF":4.4,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Semiparametric model averaging prediction for case K informatively interval-censored data 针对 K 例信息区间删失数据的半参数模型平均预测

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-11 DOI: 10.1016/j.apm.2024.115758

Yunfei Cheng, Shuying Wang, Chunjie Wang

引用次数: 0

Enabling accurate simulations of the nonlinear magnetic hysteresis behavior in ferromagnetic materials 实现铁磁材料非线性磁滞行为的精确模拟

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-11 DOI: 10.1016/j.apm.2024.115739

Jingyu Zheng , Xin Hu , Guangze Tang , Zhenhui Liu , She Li , Hanghang Yan , Xiangyang Cui

引用次数: 0

Optimal scheduling of battery energy storage system operations under load uncertainty 负载不确定情况下电池储能系统运行的优化调度

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-11 DOI: 10.1016/j.apm.2024.115756

Syed Mahbub Rafayal, Aliaa Alnaggar

{"title":"Optimal scheduling of battery energy storage system operations under load uncertainty","authors":"Syed Mahbub Rafayal, Aliaa Alnaggar","doi":"10.1016/j.apm.2024.115756","DOIUrl":"10.1016/j.apm.2024.115756","url":null,"abstract":"<div><div>This paper investigates the optimal scheduling of battery energy storage system operations considering energy load uncertainty. We develop a novel two-stage distributionally robust optimization model to determine an optimal battery usage schedule that minimizes the worst-case energy costs considering peak load costs. The model leverages deep-learning-based probabilistic forecasting in the construction of the ambiguity set. Specifically, we develop a Deep Autoregressive Recurrent Networks model to generate a probabilistic forecast of energy loads over a time horizon. The output of the forecasting model is then used to construct a marginal-moment ambiguity set for the distributionally robust optimization model. To solve the proposed model, we establish a closed-form characterization of the optimal second-stage objective function value. Leveraging this closed-form expression and using second-order conic duality, we derive an exact single-level mixed integer second-order conic reformulation of the problem. Extensive computational experiments, conducted on a real dataset, demonstrate the value of our proposed model and the effectiveness of the resulting battery schedule. The results show that the proposed model outperforms several benchmarks, including two-stage stochastic programming. Furthermore, the accuracy of the load forecast significantly impacts the effectiveness of the optimal battery schedule in eliminating peak loads by achieving up to 18% reduction in the maximum energy load.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115756"},"PeriodicalIF":4.4,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonlinear characteristics in the cylindrical roller bearing with raceway defects 有滚道缺陷的圆柱滚子轴承的非线性特性

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-11 DOI: 10.1016/j.apm.2024.115760

Jinyuan Tian , Xumin Yin , Hongyang Xu , Hui Ma , Pengfei Wang , Xiaoxu Zhang , Songtao Zhao

{"title":"Nonlinear characteristics in the cylindrical roller bearing with raceway defects","authors":"Jinyuan Tian , Xumin Yin , Hongyang Xu , Hui Ma , Pengfei Wang , Xiaoxu Zhang , Songtao Zhao","doi":"10.1016/j.apm.2024.115760","DOIUrl":"10.1016/j.apm.2024.115760","url":null,"abstract":"<div><div>Cylindrical roller bearings (CRBs) are subjected to significant cyclic stress under extreme operating conditions. This leads to the formation of localized wave defects on the raceway surface, such as burn. Thus, a new mathematical model is proposed to consider the local wave defects on the raceway caused by burns in this paper. Further, a dynamic model of CRB incorporating raceway defects is developed based on the contact relationships between components, and the proposed model is verified by measured acceleration responses. The effects of local wave defects on the nonlinear vibration characteristics of the bearings are studied and the results show that an increase in the number of defect waves reduces the additional displacement of rollers passing through the defect area, obscuring signal characteristics induced by the defect. Moreover, the presence of the defect influences the nonlinear interaction between the roller and raceway, which subsequently affects the cage whirling motion. This study of bearing dynamic behavior in this paper can contribute to the condition monitoring of bearings.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115760"},"PeriodicalIF":4.4,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimal resource allocation for rapid convergence to stable healthy state in epidemic spreading models 流行病传播模型中快速趋近稳定健康状态的最优资源分配

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-10 DOI: 10.1016/j.apm.2024.115754

Saber Jafarizadeh

{"title":"Optimal resource allocation for rapid convergence to stable healthy state in epidemic spreading models","authors":"Saber Jafarizadeh","doi":"10.1016/j.apm.2024.115754","DOIUrl":"10.1016/j.apm.2024.115754","url":null,"abstract":"<div><div>The networked Susceptible-Infected-Susceptible (SIS) model has been widely investigated as a model for the spread of epidemics within networked systems. In networks with SIS dynamics and unstable healthy states, a critical question is how to distribute compensatory curing resources (with constrained total cost) among individuals, ensuring that the network converges to a healthy state as fast as possible. This paper introduces a novel approach to this problem by developing an algorithm for the optimal allocation of compensatory curing resources required by agents in a given network. This solution approach has been made possible by reformulating the original convergence rate optimization problem and an additional constraint guaranteeing a minimum convergence rate as a standard semidefinite programming problem. The applicability of the proposed algorithm to arbitrary undirected topologies and other variations of the SIS model, including the one with a weighted cost function, has been demonstrated. In the case of symmetry preserving curing and infection rates, it has been shown that the problem over a given network with a symmetric topology can be reduced to a smaller network with each orbit acting as a node. Additionally, for networks with one or two orbits, the problem has been addressed analytically, and several examples have been included. Based on two different scenarios inspired by the SARS outbreak in Hong Kong and the COVID-19 outbreak in the USA, it is shown that the algorithm's optimal results outperform the uniform distribution of additional curing resources. The paper also explores how optimal performance metrics change with the given upper limit on the total amount of additional curing resources.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"138 ","pages":"Article 115754"},"PeriodicalIF":4.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bias and multiscale correction methods for variational state estimation 变分状态估计的偏差和多尺度校正方法

IF 4.4 2区工程技术

Applied Mathematical Modelling Pub Date : 2024-10-10 DOI: 10.1016/j.apm.2024.115761

F. Galarce , J. Mura , A. Caiazzo

引用次数: 0