Pub Date : 2026-01-03DOI: 10.1016/j.apm.2025.116738
Jinghua Zhang , Cheng Zeng , Shikun Wang
Elastoplastic buckling of circular functionally graded material (FGM) plates is analyzed using symplectic technique within the Hamiltonian framework. Firstly, elastoplastic properties of the FGM are estimated using the TTO model and plastic constitutive equations are derived from J2 deformation theory. Here, Mises’s yield condition and linear strengthening material behavior are considered. Then, introducing the symplectic technique, governing equations for the elastoplastic buckling of the circular FGM plate are transformed to canonical equations in the Hamiltonian system. Critical buckling parameter and mode are equivalent to the symplectic eigenvalue and eigenfunction, which are expressed as special functions through the exact analytical solution of the canonical equations under the given boundary conditions. Next, buckling loads and elastoplastic deformation interface at the critical state are calculated by solving the bifurcation condition and yield condition simultaneously. Finally, influences of gradient characteristic, elastoplastic deformation, geometric parameters of the structures together with boundary conditions on the critical buckling loads, elastoplastic interface and failure modes are discussed via parameters research. The variations of failure mode thresholds with geometric and material parameters are also presented.
{"title":"Symplectic technique for analyzing elastoplastic buckling of circular FGM plates","authors":"Jinghua Zhang , Cheng Zeng , Shikun Wang","doi":"10.1016/j.apm.2025.116738","DOIUrl":"10.1016/j.apm.2025.116738","url":null,"abstract":"<div><div>Elastoplastic buckling of circular functionally graded material (FGM) plates is analyzed using symplectic technique within the Hamiltonian framework. Firstly, elastoplastic properties of the FGM are estimated using the TTO model and plastic constitutive equations are derived from J<sub>2</sub> deformation theory. Here, Mises’s yield condition and linear strengthening material behavior are considered. Then, introducing the symplectic technique, governing equations for the elastoplastic buckling of the circular FGM plate are transformed to canonical equations in the Hamiltonian system. Critical buckling parameter and mode are equivalent to the symplectic eigenvalue and eigenfunction, which are expressed as special functions through the exact analytical solution of the canonical equations under the given boundary conditions. Next, buckling loads and elastoplastic deformation interface at the critical state are calculated by solving the bifurcation condition and yield condition simultaneously. Finally, influences of gradient characteristic, elastoplastic deformation, geometric parameters of the structures together with boundary conditions on the critical buckling loads, elastoplastic interface and failure modes are discussed via parameters research. The variations of failure mode thresholds with geometric and material parameters are also presented.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116738"},"PeriodicalIF":4.4,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894395","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}
Pub Date : 2026-01-02DOI: 10.1016/j.apm.2025.116736
Haorui Yang , Mingyang Yu , Jiaqi Zhang , Yafei Xiong , Donglin Wang , Jing Xu
Unmanned Aerial Vehicles (UAVs) path planning is a high-dimensional, nonlinear, and constraint-intensive optimization problem. Conventional metaheuristics often converge slowly and become trapped in local optima. This paper presents a reinforced variant of the Aquila Optimizer that couples four complementary mechanisms to improve convergence stability and solution quality. First, a good-point-set initialization strategy increases early population diversity. Second, an adaptive strategy-selection module dynamically balances global exploration and local exploitation. Third, a moth-flame search operator augmented with quantum rotation gates strengthens global exploration. Fourth, a Q-learning-driven neighborhood perturbation selects disturbance actions from real-time feedback. This work makes three main contributions: a unified reinforcement-driven optimization framework that integrates adaptive learning with hybrid search dynamics; a quantum-enhanced exploration mechanism that accelerates convergence while mitigating premature stagnation; and a comprehensive evaluation protocol spanning CEC2017 and CEC2022 benchmarks and 3D multi-UAVs path planning in cluttered environments. Extensive experiments show consistent gains over thirteen state-of-the-art algorithms in convergence speed, solution accuracy, and robustness. In UAVs applications, the proposed optimizer yields smooth, obstacle-avoiding trajectories with favorable computational efficiency, and extensive experiments show substantial accuracy gains over existing algorithms, including 30% and 47% improvements over AO in different scenarios. These results demonstrate strong generalization capability and practical value for real-world optimization tasks that are dynamic, high-dimensional, and constraint-intensive.
{"title":"A reinforced quantum Aquila Optimizer for multi-threat 3D UAVs path planning in complex environments","authors":"Haorui Yang , Mingyang Yu , Jiaqi Zhang , Yafei Xiong , Donglin Wang , Jing Xu","doi":"10.1016/j.apm.2025.116736","DOIUrl":"10.1016/j.apm.2025.116736","url":null,"abstract":"<div><div>Unmanned Aerial Vehicles (UAVs) path planning is a high-dimensional, nonlinear, and constraint-intensive optimization problem. Conventional metaheuristics often converge slowly and become trapped in local optima. This paper presents a reinforced variant of the Aquila Optimizer that couples four complementary mechanisms to improve convergence stability and solution quality. First, a good-point-set initialization strategy increases early population diversity. Second, an adaptive strategy-selection module dynamically balances global exploration and local exploitation. Third, a moth-flame search operator augmented with quantum rotation gates strengthens global exploration. Fourth, a Q-learning-driven neighborhood perturbation selects disturbance actions from real-time feedback. This work makes three main contributions: a unified reinforcement-driven optimization framework that integrates adaptive learning with hybrid search dynamics; a quantum-enhanced exploration mechanism that accelerates convergence while mitigating premature stagnation; and a comprehensive evaluation protocol spanning CEC2017 and CEC2022 benchmarks and 3D multi-UAVs path planning in cluttered environments. Extensive experiments show consistent gains over thirteen state-of-the-art algorithms in convergence speed, solution accuracy, and robustness. In UAVs applications, the proposed optimizer yields smooth, obstacle-avoiding trajectories with favorable computational efficiency, and extensive experiments show substantial accuracy gains over existing algorithms, including 30% and 47% improvements over AO in different scenarios. These results demonstrate strong generalization capability and practical value for real-world optimization tasks that are dynamic, high-dimensional, and constraint-intensive.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116736"},"PeriodicalIF":4.4,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894397","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}
Pub Date : 2026-01-01DOI: 10.1016/j.apm.2025.116733
Xinfa Zhuang , Tao Wang , Jing Zhang , Junfang Tian , Jianjun Wu
Platoon control enhances traffic efficiency, safety, and energy savings through coordinated vehicle movement and reduced human intervention. However, external disturbances and communication interruptions pose critical challenges to the reliability of platoon control. While control strategies based on disturbance observers are effective in mitigating disturbances, high-gain observers often suffer from the “peaking phenomenon” at the initial estimation time. Moreover, can disrupt controller failure, and substituting state information of the vehicle with sensor measurements introduces perception uncertainty. To address these issues, this paper proposes a disturbance dynamic compensation-based consensus control strategy that leverages a modified extended state observer to suppress external disturbances. By incorporating the initial state information of the vehicles into the extended state observer design, the peaking phenomenon associated with high-gain observers is effectively eliminated, thereby enhancing disturbance estimation accuracy at the initial moment. In addition, a communication topology compensator is developed to connect sensor-measured information flow, enabling uninterrupted controller operation despite the occurrence of communication interruptions. To mitigate perception uncertainty induced by sensor measurements, a hierarchical state information filtering and estimation algorithm is introduced to provide accurate acceleration estimates and process position and velocity information. Simulation results demonstrate that the proposed control strategy effectively maintains tracking performance in the presence of disturbances and significantly reduces the adverse impact of on platoon stability.
{"title":"Connected vehicle platoon consensus control with disturbance rejection under communication interruption and perception uncertainty","authors":"Xinfa Zhuang , Tao Wang , Jing Zhang , Junfang Tian , Jianjun Wu","doi":"10.1016/j.apm.2025.116733","DOIUrl":"10.1016/j.apm.2025.116733","url":null,"abstract":"<div><div>Platoon control enhances traffic efficiency, safety, and energy savings through coordinated vehicle movement and reduced human intervention. However, external disturbances and communication interruptions pose critical challenges to the reliability of platoon control. While control strategies based on disturbance observers are effective in mitigating disturbances, high-gain observers often suffer from the “peaking phenomenon” at the initial estimation time. Moreover, can disrupt controller failure, and substituting state information of the vehicle with sensor measurements introduces perception uncertainty. To address these issues, this paper proposes a disturbance dynamic compensation-based consensus control strategy that leverages a modified extended state observer to suppress external disturbances. By incorporating the initial state information of the vehicles into the extended state observer design, the peaking phenomenon associated with high-gain observers is effectively eliminated, thereby enhancing disturbance estimation accuracy at the initial moment. In addition, a communication topology compensator is developed to connect sensor-measured information flow, enabling uninterrupted controller operation despite the occurrence of communication interruptions. To mitigate perception uncertainty induced by sensor measurements, a hierarchical state information filtering and estimation algorithm is introduced to provide accurate acceleration estimates and process position and velocity information. Simulation results demonstrate that the proposed control strategy effectively maintains tracking performance in the presence of disturbances and significantly reduces the adverse impact of on platoon stability.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116733"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894399","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}
Pub Date : 2026-01-01DOI: 10.1016/j.apm.2025.116735
Hua Liu , Chunya Liu , Yumei Wei , Qibin Zhang , Jingyan Ma
In August 2020, the World Health Assembly approved the Global Strategy to eliminate cervical cancer, marking the first time that numerous countries committed to eliminating a form of cancer. China introduced the HPV vaccine in 2016 and has made significant advancements in both prevention and treatment strategies. However, due to the relatively late introduction of the vaccine, the burden of cervical cancer in China continues to rise. In light of this, we develop a compartmental model to assess the impact of the WHO's 90–70–90 strategy, along with adult catch-up vaccination, on the control of HPV-induced cervical cancer in China. We analyze the basic properties of the model and provide proofs of the local and global asymptotic stability of the equilibrium points. Additionally, a sensitivity analysis is performed, and we use the MCMC algorithm to fit the number of new cervical cancer cases and cumulative deaths in China from 1990 to 2021. The estimated basic reproduction number before and after the introduction of the HPV vaccine in China is 1.2133 (95% CI: 1.1593–1.2673) and 0.8317 (95% CI: 0.8042–0.8592), respectively. The sensitivity analysis reveals that screening, as a non-pharmaceutical intervention, plays a crucial role in controlling the spread of the disease. We apply the 90–70–90 strategy to predict the future number of new cervical cancer cases in China. The results indicate that prioritizing the 70–90 target combination is the most cost-effective approach and can achieve the goal of zero new cervical cancer cases by 2063 (within the range of 2052–2066). Finally, an optimal control model is developed to explore the best implementation strategies for HPV vaccination and screening under various plausible scenarios.
{"title":"Impact of the WHO's 90-70-90 Strategy on HPV-related cervical cancer control: A mathematical model evaluation in China","authors":"Hua Liu , Chunya Liu , Yumei Wei , Qibin Zhang , Jingyan Ma","doi":"10.1016/j.apm.2025.116735","DOIUrl":"10.1016/j.apm.2025.116735","url":null,"abstract":"<div><div>In August 2020, the World Health Assembly approved the Global Strategy to eliminate cervical cancer, marking the first time that numerous countries committed to eliminating a form of cancer. China introduced the HPV vaccine in 2016 and has made significant advancements in both prevention and treatment strategies. However, due to the relatively late introduction of the vaccine, the burden of cervical cancer in China continues to rise. In light of this, we develop a compartmental model to assess the impact of the WHO's 90–70–90 strategy, along with adult catch-up vaccination, on the control of HPV-induced cervical cancer in China. We analyze the basic properties of the model and provide proofs of the local and global asymptotic stability of the equilibrium points. Additionally, a sensitivity analysis is performed, and we use the MCMC algorithm to fit the number of new cervical cancer cases and cumulative deaths in China from 1990 to 2021. The estimated basic reproduction number before and after the introduction of the HPV vaccine in China is 1.2133 (95% CI: 1.1593–1.2673) and 0.8317 (95% CI: 0.8042–0.8592), respectively. The sensitivity analysis reveals that screening, as a non-pharmaceutical intervention, plays a crucial role in controlling the spread of the disease. We apply the 90–70–90 strategy to predict the future number of new cervical cancer cases in China. The results indicate that prioritizing the 70–90 target combination is the most cost-effective approach and can achieve the goal of zero new cervical cancer cases by 2063 (within the range of 2052–2066). Finally, an optimal control model is developed to explore the best implementation strategies for HPV vaccination and screening under various plausible scenarios.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116735"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894398","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}
Pub Date : 2025-12-31DOI: 10.1016/j.apm.2025.116729
Jiachang Tang , Yong Lei , Taolin Zhang , Chengji Mi , Qishui Yao , Lixiong Cao
A double-level dimension-reduction alternating interval inverse method incorporating parameter correlation is proposed to solve the uncertain nonlinear inverse problem. This method is employed to address the issue of concurrent output uncertainty and model uncertainty, as well as correlation among model parameters. First, an uncertain inverse problem is modeled where both the output and the model exhibit uncertainty, and the model parameters are correlated. Second, a multidimensional parallel interval model is utilized to characterize the domain of uncertainty in correlation parameters, and an affine coordinate transformation is introduced to transform the uncertainty domain of correlated parameters into a standardized parameter domain. Third, a double-level dimension-reduction alternating interval inverse method is proposed, where the first level of dimension-reduction converts the uncertain function response into the sum of the input uncertain function response and the model's uncertain function response, and the second level dimension-reduction utilizes interval dimension-reduction analysis to construct a deterministic optimization model. By employing outer optimization and inner interval computation, the alternating solution for the interval midpoint and radius is achieved. Finally, the effectiveness and efficiency of this method are demonstrated through three examples.
{"title":"A double-level dimension-reduction alternating interval inverse method incorporating parameter correlation","authors":"Jiachang Tang , Yong Lei , Taolin Zhang , Chengji Mi , Qishui Yao , Lixiong Cao","doi":"10.1016/j.apm.2025.116729","DOIUrl":"10.1016/j.apm.2025.116729","url":null,"abstract":"<div><div>A double-level dimension-reduction alternating interval inverse method incorporating parameter correlation is proposed to solve the uncertain nonlinear inverse problem. This method is employed to address the issue of concurrent output uncertainty and model uncertainty, as well as correlation among model parameters. First, an uncertain inverse problem is modeled where both the output and the model exhibit uncertainty, and the model parameters are correlated. Second, a multidimensional parallel interval model is utilized to characterize the domain of uncertainty in correlation parameters, and an affine coordinate transformation is introduced to transform the uncertainty domain of correlated parameters into a standardized parameter domain. Third, a double-level dimension-reduction alternating interval inverse method is proposed, where the first level of dimension-reduction converts the uncertain function response into the sum of the input uncertain function response and the model's uncertain function response, and the second level dimension-reduction utilizes interval dimension-reduction analysis to construct a deterministic optimization model. By employing outer optimization and inner interval computation, the alternating solution for the interval midpoint and radius is achieved. Finally, the effectiveness and efficiency of this method are demonstrated through three examples.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116729"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894400","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}
To address the limitations of conventional piezoelectric energy harvesting, such as narrow operational bandwidth, uncontrollable band distribution, and poor material durability, this paper develops an efficient energy harvester based on a motional bi-directional piezoelectric pipe. The sandwich square pipe spins around its longitudinal axis, and a steady fluid flows inside. Two groups of piezoelectric bimorph are symmetrically arranged on the orthogonal exterior surfaces of the pipe, each connected to a resistive load circuit. The simply supported and cantilevered configurations are both considered. Numerical results demonstrate superior performance of the proposed energy harvester as follows: i) the spinning motion transforms voltage response from a unimodal to bimodal pattern, greatly improving the electricity output bandwidth; ii) the energy harvesting band can be manipulated by tuning the spinning speed; iii) the gyroscopic effect simultaneously activates voltages in both transverse directions, achieving synchronous multi-source energy output. It is also found that the voltage response to the fluid–structure interaction (FSI) effect is highly sensitive to the support condition. Additionally, the impacts of pipe length, fiber orientation angle in the face layers, and core layer property on the energy harvesting performance are investigated, clarifying comprehensive parametric regulation mechanisms.
{"title":"Enhanced energy harvesting of a spinning bi-directional piezoelectric pipe conveying fluid","authors":"An-Xiang Zhao , Xiao-Tian Guo , Feng Liang , Yao Chen","doi":"10.1016/j.apm.2025.116730","DOIUrl":"10.1016/j.apm.2025.116730","url":null,"abstract":"<div><div>To address the limitations of conventional piezoelectric energy harvesting, such as narrow operational bandwidth, uncontrollable band distribution, and poor material durability, this paper develops an efficient energy harvester based on a motional bi-directional piezoelectric pipe. The sandwich square pipe spins around its longitudinal axis, and a steady fluid flows inside. Two groups of piezoelectric bimorph are symmetrically arranged on the orthogonal exterior surfaces of the pipe, each connected to a resistive load circuit. The simply supported and cantilevered configurations are both considered. Numerical results demonstrate superior performance of the proposed energy harvester as follows: i) the spinning motion transforms voltage response from a unimodal to bimodal pattern, greatly improving the electricity output bandwidth; ii) the energy harvesting band can be manipulated by tuning the spinning speed; iii) the gyroscopic effect simultaneously activates voltages in both transverse directions, achieving synchronous multi-source energy output. It is also found that the voltage response to the fluid–structure interaction (FSI) effect is highly sensitive to the support condition. Additionally, the impacts of pipe length, fiber orientation angle in the face layers, and core layer property on the energy harvesting performance are investigated, clarifying comprehensive parametric regulation mechanisms.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116730"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894402","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}
Pub Date : 2025-12-31DOI: 10.1016/j.apm.2025.116734
Xiaoxiao Huang, Gang Zhang, Lianbing Xu, Lin He, Jiachen Hou
Stochastic resonance (SR) is a nonlinear phenomenon in which noise and periodic forcing interact within an excitable system, facilitating the transfer of energy from noise to a useful signal. Consequently, SR serves as an effective method for extracting weak signals from noisy backgrounds. The Fitz Hugh-Nagumo (FHN) model describes excitable stochastic dynamics. In this article, we construct a coupled FHNSR array (CFHNSRA) model, investigate the enhancement of SR in such coupled neurons, and apply the model to diagnosing composite faults in rolling bearings. First, we derive the equivalent potential function from the Langevin equation governing the system and analyze its steady state points and structural characteristic. Second, we derive the corresponding Fokker-Planck equation (FPE) and compute the steady state probability (SPD) to analyze the model’s dynamical behavior under parameter variations. We measure the impact of coupling factors and system parameters on the output signal-to-noise ratio (SNR). The results show that, under specific conditions, the response end not only replicates the SR phenomenon at the driver end, but also amplifies it, with the coupling factor playing a significant role in enhancing this effect. Next, to facilitate engineering applications, we develop an index, WMKC, to characterize fault impacts and propose an adaptive coupled FHN stochastic resonance method based on QGA-WMKC. We simulate periodic impact signals and validate the method's effectiveness using the fourth-order Runge-Kutta algorithm. Finally, to demonstrate the practicality and superiority of the CFHNSRA system, we utilized the dataset from the University of Paderborn, Germany, to detect three distinct fault signals. By comparing the coupled bistable SR, FHNSR, and coupled FHNSR systems, we show that the CFHNSRA effectively extracts weak signal features, accurately identifies fault frequencies, and performs well in detecting multi-interference and composite bearing faults.
{"title":"Enhanced stochastic resonance in the coupled FitzHugh-Nagumo neuron model with applications in rolling bearing composite fault diagnosis","authors":"Xiaoxiao Huang, Gang Zhang, Lianbing Xu, Lin He, Jiachen Hou","doi":"10.1016/j.apm.2025.116734","DOIUrl":"10.1016/j.apm.2025.116734","url":null,"abstract":"<div><div>Stochastic resonance (SR) is a nonlinear phenomenon in which noise and periodic forcing interact within an excitable system, facilitating the transfer of energy from noise to a useful signal. Consequently, SR serves as an effective method for extracting weak signals from noisy backgrounds. The Fitz Hugh-Nagumo (FHN) model describes excitable stochastic dynamics. In this article, we construct a coupled FHNSR array (CFHNSRA) model, investigate the enhancement of SR in such coupled neurons, and apply the model to diagnosing composite faults in rolling bearings. First, we derive the equivalent potential function from the Langevin equation governing the system and analyze its steady state points and structural characteristic. Second, we derive the corresponding Fokker-Planck equation (FPE) and compute the steady state probability (SPD) to analyze the model’s dynamical behavior under parameter variations. We measure the impact of coupling factors and system parameters on the output signal-to-noise ratio (SNR). The results show that, under specific conditions, the response end not only replicates the SR phenomenon at the driver end, but also amplifies it, with the coupling factor playing a significant role in enhancing this effect. Next, to facilitate engineering applications, we develop an index, WMKC, to characterize fault impacts and propose an adaptive coupled FHN stochastic resonance method based on QGA-WMKC. We simulate periodic impact signals and validate the method's effectiveness using the fourth-order Runge-Kutta algorithm. Finally, to demonstrate the practicality and superiority of the CFHNSRA system, we utilized the dataset from the University of Paderborn, Germany, to detect three distinct fault signals. By comparing the coupled bistable SR, FHNSR, and coupled FHNSR systems, we show that the CFHNSRA effectively extracts weak signal features, accurately identifies fault frequencies, and performs well in detecting multi-interference and composite bearing faults.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116734"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894401","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}
Pub Date : 2025-12-31DOI: 10.1016/j.apm.2025.116731
Penghao Zhao , Jianhua Liu , Hao Gong , Zhengyue Tan , Zhongtian Lu
The intense vibration of rotor system assembled with bolted joints in high rotational speed brings a potential harm to aero-engine. However, the microscopic contact between disks, coupled with nonuniform preloads, introduces complex nonlinear properties to the rotor system, complicating vibration analysis. This study develops a novel dynamic model of rotor system with bolted joints, considering microscopic contact and nonuniform preloads. Specifically, sub-regions are divided based on pressure distribution under nonuniform preloads, and a multi-scale contact model is deduced based on the fractal theory and semi-analytical method. Subsequently, the lateral and bending stiffness models of bolted-joint disk are refined to incorporate nonuniform preload effects. After solving the motion equations, time/frequency-domain analyses are conducted to reveal the influence of nonuniform preloads and surface roughness on the vibration responses. Through numerical simulation, a comparative analysis is conducted with the traditional dynamic model without microscopic contact and nonuniform preloads. Finally, a bolted-joint rotor test rig is designed to verify the simulation results, and the vibration characteristics under rub-impact faults are analyzed numerically and experimentally.
{"title":"Dynamic modeling of the rotor system with bolted joints considering microscopic contact and nonuniform preloads","authors":"Penghao Zhao , Jianhua Liu , Hao Gong , Zhengyue Tan , Zhongtian Lu","doi":"10.1016/j.apm.2025.116731","DOIUrl":"10.1016/j.apm.2025.116731","url":null,"abstract":"<div><div>The intense vibration of rotor system assembled with bolted joints in high rotational speed brings a potential harm to aero-engine. However, the microscopic contact between disks, coupled with nonuniform preloads, introduces complex nonlinear properties to the rotor system, complicating vibration analysis. This study develops a novel dynamic model of rotor system with bolted joints, considering microscopic contact and nonuniform preloads. Specifically, sub-regions are divided based on pressure distribution under nonuniform preloads, and a multi-scale contact model is deduced based on the fractal theory and semi-analytical method. Subsequently, the lateral and bending stiffness models of bolted-joint disk are refined to incorporate nonuniform preload effects. After solving the motion equations, time/frequency-domain analyses are conducted to reveal the influence of nonuniform preloads and surface roughness on the vibration responses. Through numerical simulation, a comparative analysis is conducted with the traditional dynamic model without microscopic contact and nonuniform preloads. Finally, a bolted-joint rotor test rig is designed to verify the simulation results, and the vibration characteristics under rub-impact faults are analyzed numerically and experimentally.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116731"},"PeriodicalIF":4.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894405","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}
Pub Date : 2025-12-27DOI: 10.1016/j.apm.2025.116727
Elliot J. Carr
Thermal diffusivity of solid materials is commonly measured using laser flash analysis. This technique involves applying a heat pulse to the front surface of a small sample of the material and calculating the thermal diffusivity from the resulting increase in temperature on the back surface. Current formulas for the thermal diffusivity are based on the assumption that heat is transported within the sample according to the standard heat equation. While this assumption is valid in most practical cases, it admits the non-physical property of infinite propagation speed, that is, the heat pulse applied at the front surface is instantaneously perceived at the back surface. This paper carries out a mathematical analysis to determine the effect of replacing the standard heat equation in laser flash analysis by the Cattaneo heat equation, which exhibits finite propagation speed through the inclusion of a relaxation time in the Fourier law. The main results of the paper include (i) analytical insights into the spatiotemporal behaviour of temperature within the sample and (ii) analytical formulas for determining the thermal diffusivity and relaxation time of the sample. Numerical experiments exploring and verifying the analytical results are presented with supporting MATLAB code made publicly available.
{"title":"Modelling and analysis of laser flash experiments using the Cattaneo heat equation","authors":"Elliot J. Carr","doi":"10.1016/j.apm.2025.116727","DOIUrl":"10.1016/j.apm.2025.116727","url":null,"abstract":"<div><div>Thermal diffusivity of solid materials is commonly measured using laser flash analysis. This technique involves applying a heat pulse to the front surface of a small sample of the material and calculating the thermal diffusivity from the resulting increase in temperature on the back surface. Current formulas for the thermal diffusivity are based on the assumption that heat is transported within the sample according to the standard heat equation. While this assumption is valid in most practical cases, it admits the non-physical property of infinite propagation speed, that is, the heat pulse applied at the front surface is instantaneously perceived at the back surface. This paper carries out a mathematical analysis to determine the effect of replacing the standard heat equation in laser flash analysis by the Cattaneo heat equation, which exhibits finite propagation speed through the inclusion of a relaxation time in the Fourier law. The main results of the paper include (i) analytical insights into the spatiotemporal behaviour of temperature within the sample and (ii) analytical formulas for determining the thermal diffusivity and relaxation time of the sample. Numerical experiments exploring and verifying the analytical results are presented with supporting MATLAB code made publicly available.</div></div>","PeriodicalId":50980,"journal":{"name":"Applied Mathematical Modelling","volume":"155 ","pages":"Article 116727"},"PeriodicalIF":4.4,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845492","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}
Pub Date : 2025-12-26DOI: 10.1016/j.apm.2025.116706
Masaki Tanigawa , Toru Takahashi
This paper introduces a novel physics-informed neural network (PINN) for two-dimensional steady-state acoustic scattering problems, specifically designed to parametrically represent the sound source’s position and wavenumber. A key advancement of this approach is the incorporation of the Burton–Miller-type boundary integral equation into the loss function, which effectively addresses the persistent fictitious eigenvalue problem common in acoustic simulations and improves upon existing boundary integral equation-based PINN methodologies. The model’s numerical framework leverages the isogeometric boundary element method, expressing outputs as expansion coefficients of quadratic B-spline basis functions. This strategy is anticipated to significantly reduce the data requirements and enhance computational efficiency compared to conventional full-domain PINNs. Numerical experiments demonstrate the model’s accuracy in predicting sound pressure fields for varying source positions and wavenumbers, including unseen interior points.
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