International Journal of Mechanical Sciences最新文献_第2页

Snap-through behaviors of bistable composite panel in centrifugal environments

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-02 DOI: 10.1016/j.ijmecsci.2025.110036

Pengpeng Liu, Jie Tang, Yang Guo, Yinghui Li

In this paper, a cross-well dynamics model of bistable composite panels in centrifugal environments is proposed. The external excitation applied at the four corners is assumed to be a uniformly distributed harmonic acceleration. Nonlinear equations are derived by combining geometric nonlinearity, thermal stresses, and centrifugal effects with the first-order shear deformation theory, and are expressed in terms of curvature. Additionally, the maximum Lyapunov exponent is used to classify vibration types. Observations of periodic and chaotic snap-throughs are categorized into vibration type domains. To facilitate understanding, bifurcation diagrams, phase portraits, time histories, and Poincaré maps are presented for representative operating conditions. The effects of centrifugal environments, external excitation amplitude, and frequency on snap-through behavior are thoroughly investigated. The results show that there exists a critical static angular velocity, beyond which the panel cannot maintain bistability, and indicate that snap-through behavior in bistable panels is caused by negative stiffness due to residual thermal stresses. Bistable composite panels exhibit both forward and backward bouncing. Furthermore, three types of frequencies are identified: upper Stable I frequency, lower Stable II frequency, and snap-through frequency. It is also noted that the impact of angular velocity on these frequencies is not uniform. When the external excitation frequency approaches one stable state frequency, it can destabilize the configuration, causing vibrations to occur in the other configuration.

{"title":"Snap-through behaviors of bistable composite panel in centrifugal environments","authors":"Pengpeng Liu, Jie Tang, Yang Guo, Yinghui Li","doi":"10.1016/j.ijmecsci.2025.110036","DOIUrl":"10.1016/j.ijmecsci.2025.110036","url":null,"abstract":"<div><div>In this paper, a cross-well dynamics model of bistable composite panels in centrifugal environments is proposed. The external excitation applied at the four corners is assumed to be a uniformly distributed harmonic acceleration. Nonlinear equations are derived by combining geometric nonlinearity, thermal stresses, and centrifugal effects with the first-order shear deformation theory, and are expressed in terms of curvature. Additionally, the maximum Lyapunov exponent is used to classify vibration types. Observations of periodic and chaotic snap-throughs are categorized into vibration type domains. To facilitate understanding, bifurcation diagrams, phase portraits, time histories, and Poincaré maps are presented for representative operating conditions. The effects of centrifugal environments, external excitation amplitude, and frequency on snap-through behavior are thoroughly investigated. The results show that there exists a critical static angular velocity, beyond which the panel cannot maintain bistability, and indicate that snap-through behavior in bistable panels is caused by negative stiffness due to residual thermal stresses. Bistable composite panels exhibit both forward and backward bouncing. Furthermore, three types of frequencies are identified: upper Stable I frequency, lower Stable II frequency, and snap-through frequency. It is also noted that the impact of angular velocity on these frequencies is not uniform. When the external excitation frequency approaches one stable state frequency, it can destabilize the configuration, causing vibrations to occur in the other configuration.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110036"},"PeriodicalIF":7.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143295505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Analytical modelling of parallel multidirectional cutting of slender shafts

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-02 DOI: 10.1016/j.ijmecsci.2025.110024

Wei Cai , Jingyang Xiang , Guojun Dong , Kee-hung Lai , Marian Wiercigroch

Slender shafts have wide application on the aerospace, automotive and medical devices. However, they are prone to bending deformation during cutting process due to their low rigidity, resulting in poor machining accuracy and efficiency. A parallel multidirectional cutting (PMC) method is proposed using two tools to simultaneously cut the workpiece in forward or reverse directions contributing to overcome the problem of large deflections of these shafts. The main concept and PMC shared and unshared cutting modes are elucidated. An analytical model for PMC is established including chip geometry model, cutting force model and workpiece deflection feedback model. Given tool geometry, feed and depth of cut, chip load is accurately calculated using cutting edge discretization. The Johnson-Cook constitutive model is used to determine shear stress and shear force on the primary shear plane, and therefore the three-dimensional cutting force is obtained. The force condition of the workpiece is analysed under two clamping methods and the deformation of the workpiece is calculated and feed back into the model. On this basis, the influencing mechanism of cutting force, cutting power, cutting temperature and machining error of PMC is explored under different cutting modes, machined shaft geometry, tool parameters and cutting parameters. The smaller-the-better characteristic of Taguchi's method and signal-to-noise ratio are used to analyse the effect of cutting parameters on the PMC performance. Furthermore, an experimental validation is conducted to verify the cutting power, temperature, and diameter errors obtained by the proposed model, and the result shows a strong correlation with simulation predictions. The proposed method significantly improves machining precision and efficiency, with promising applications in high-precision manufacturing industries such as aerospace and medical device production.

{"title":"Analytical modelling of parallel multidirectional cutting of slender shafts","authors":"Wei Cai , Jingyang Xiang , Guojun Dong , Kee-hung Lai , Marian Wiercigroch","doi":"10.1016/j.ijmecsci.2025.110024","DOIUrl":"10.1016/j.ijmecsci.2025.110024","url":null,"abstract":"<div><div>Slender shafts have wide application on the aerospace, automotive and medical devices. However, they are prone to bending deformation during cutting process due to their low rigidity, resulting in poor machining accuracy and efficiency. A parallel multidirectional cutting (PMC) method is proposed using two tools to simultaneously cut the workpiece in forward or reverse directions contributing to overcome the problem of large deflections of these shafts. The main concept and PMC shared and unshared cutting modes are elucidated. An analytical model for PMC is established including chip geometry model, cutting force model and workpiece deflection feedback model. Given tool geometry, feed and depth of cut, chip load is accurately calculated using cutting edge discretization. The Johnson-Cook constitutive model is used to determine shear stress and shear force on the primary shear plane, and therefore the three-dimensional cutting force is obtained. The force condition of the workpiece is analysed under two clamping methods and the deformation of the workpiece is calculated and feed back into the model. On this basis, the influencing mechanism of cutting force, cutting power, cutting temperature and machining error of PMC is explored under different cutting modes, machined shaft geometry, tool parameters and cutting parameters. The smaller-the-better characteristic of Taguchi's method and signal-to-noise ratio are used to analyse the effect of cutting parameters on the PMC performance. Furthermore, an experimental validation is conducted to verify the cutting power, temperature, and diameter errors obtained by the proposed model, and the result shows a strong correlation with simulation predictions. The proposed method significantly improves machining precision and efficiency, with promising applications in high-precision manufacturing industries such as aerospace and medical device production.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110024"},"PeriodicalIF":7.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vibro-acoustic behaviors of a plate-cavity symmetrically embedded with suppressed acoustic spots

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109965

Gang Wang , Weilong Liu , Ziyuan Zhu , Yijie He , Menglong Dong , Jiajun Wu , Chuanyang Wang

Control of structural vibration and noise is crucial in the engineering field, and research on related technologies has significant engineering applications. This paper presents a semi-analytical analysis method to evaluate the vibro-acoustic properties of plate-cavity coupled systems with single or multiple symmetrically embedded suppressed acoustic spots (SAS). The numerical element division method (NEDM) combined with a power-law function to discretely approximate the SAS domain is used to solve the complex boundary integration problem. The spectral-geometry method (SGM) is adopted to express the plate displacement and the sound pressure in the cavity as continuous modified Fourier series to ensure boundary smoothness. Based on the Lagrange energy principle, the coupled theoretical model is constructed and the modal parameters are solved by the generalized Rayleigh-Ritz method, the accuracy of which is verified by comparison with the finite element method (FEM). The study discusses the vibro-acoustic attenuation mechanism of the SAS plate-cavity coupled system under the sound source excitation in the cavity, and the SAS plate parameters are analyzed in depth. The results reveal that when SAS with damping layers (SAS+DL) plates are used for noise reduction, an optimal match between SAS and damping layers needs to be sought rather than simply increasing SAS or damping, which provides a potential theoretical research basis for the design of damped structures applying the SAS principle.

{"title":"Vibro-acoustic behaviors of a plate-cavity symmetrically embedded with suppressed acoustic spots","authors":"Gang Wang , Weilong Liu , Ziyuan Zhu , Yijie He , Menglong Dong , Jiajun Wu , Chuanyang Wang","doi":"10.1016/j.ijmecsci.2025.109965","DOIUrl":"10.1016/j.ijmecsci.2025.109965","url":null,"abstract":"<div><div>Control of structural vibration and noise is crucial in the engineering field, and research on related technologies has significant engineering applications. This paper presents a semi-analytical analysis method to evaluate the vibro-acoustic properties of plate-cavity coupled systems with single or multiple symmetrically embedded suppressed acoustic spots (SAS). The numerical element division method (NEDM) combined with a power-law function to discretely approximate the SAS domain is used to solve the complex boundary integration problem. The spectral-geometry method (SGM) is adopted to express the plate displacement and the sound pressure in the cavity as continuous modified Fourier series to ensure boundary smoothness. Based on the Lagrange energy principle, the coupled theoretical model is constructed and the modal parameters are solved by the generalized Rayleigh-Ritz method, the accuracy of which is verified by comparison with the finite element method (FEM). The study discusses the vibro-acoustic attenuation mechanism of the SAS plate-cavity coupled system under the sound source excitation in the cavity, and the SAS plate parameters are analyzed in depth. The results reveal that when SAS with damping layers (SAS+DL) plates are used for noise reduction, an optimal match between SAS and damping layers needs to be sought rather than simply increasing SAS or damping, which provides a potential theoretical research basis for the design of damped structures applying the SAS principle.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109965"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Structural galloping suppression with high-frequency flutter

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109928

Liwei Dong , Chaoyang Zhao , Shuai Qu , Wei Ding , Guobiao Hu , Chengjia Han , Yaowen Yang

Galloping presents a significant challenge in engineering, often causing large-amplitude vibrations in structures such as suspended electrical cables, bridges and towers, posing substantial risks and property damage. While injecting high-frequency excitations can mitigate structural galloping, current active suppression methods, which apply excitations after galloping has developed, are suboptimal, limiting their widespread adoption. In this study, a low-cost and easy-to-implement passive galloping suppression approach utilizing flutter-induced vibrations is proposed, exhibiting robust anti-galloping effects under natural wind conditions. By strategically placing flags, high-frequency fluttering forces generated by wind flow are exploited to impose surface loads on the structure rapidly. This preemptively suppresses low-frequency galloping, mitigating its onset effectively without necessitating substantial force. A distributed aerodynamic model is developed to simulate the suppression phenomenon, accompanied by a comprehensive analysis considering factors such as flutter characteristics, wind speed, and flag position and geometric parameters. The analysis also explores distinct suppression mechanisms that arise when the fluttering frequency approaches the second and third modal frequencies of the structure. The proposed galloping suppression approach has been successfully simulated and validated through theoretical calculations and experimental tests, and test results showcase a significant reduction in vibration amplitudes, with suppression ratios ranging from 85% to 95% across wind speeds of 3 m/s to 10 m/s. Additionally, this approach demonstrates effective suppression capabilities under variable wind speed conditions, indicating its reliability and practicality for mitigating detrimental galloping in real-world scenarios.

{"title":"Structural galloping suppression with high-frequency flutter","authors":"Liwei Dong , Chaoyang Zhao , Shuai Qu , Wei Ding , Guobiao Hu , Chengjia Han , Yaowen Yang","doi":"10.1016/j.ijmecsci.2025.109928","DOIUrl":"10.1016/j.ijmecsci.2025.109928","url":null,"abstract":"<div><div>Galloping presents a significant challenge in engineering, often causing large-amplitude vibrations in structures such as suspended electrical cables, bridges and towers, posing substantial risks and property damage. While injecting high-frequency excitations can mitigate structural galloping, current active suppression methods, which apply excitations after galloping has developed, are suboptimal, limiting their widespread adoption. In this study, a low-cost and easy-to-implement passive galloping suppression approach utilizing flutter-induced vibrations is proposed, exhibiting robust anti-galloping effects under natural wind conditions. By strategically placing flags, high-frequency fluttering forces generated by wind flow are exploited to impose surface loads on the structure rapidly. This preemptively suppresses low-frequency galloping, mitigating its onset effectively without necessitating substantial force. A distributed aerodynamic model is developed to simulate the suppression phenomenon, accompanied by a comprehensive analysis considering factors such as flutter characteristics, wind speed, and flag position and geometric parameters. The analysis also explores distinct suppression mechanisms that arise when the fluttering frequency approaches the second and third modal frequencies of the structure. The proposed galloping suppression approach has been successfully simulated and validated through theoretical calculations and experimental tests, and test results showcase a significant reduction in vibration amplitudes, with suppression ratios ranging from 85% to 95% across wind speeds of 3 m/s to 10 m/s. Additionally, this approach demonstrates effective suppression capabilities under variable wind speed conditions, indicating its reliability and practicality for mitigating detrimental galloping in real-world scenarios.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109928"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Free and random-vibration characteristics of sandwich panels featuring orthogonal accordion cores 正交手风琴芯夹层板的自由和随机振动特性

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109941

Liu Rong , Zhong Yifeng , Zhu Yilin , Cao Haiwen , Chen Minfang

The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.

由两个二维手风琴蜂窝结构正交组合而成的三维正交手风琴芯，具有多向零泊松比效应和优异的抗变形能力。为了有效分析夹层板的随机振动特性，采用变分渐近方法建立了二维等效Reissner-Mindlin模型（2D- erm）。通过3D打印试件的自由模态振动试验，验证了2D-ERM在自由振动分析中的精度。通过与三维有限元（FE）仿真（包括PSD/RMS响应）的比较，验证了该方法在随机振动分析中的精度。模态分析表明，2D-ERM预测前6个特征频率的相对误差保持在2%以下，模态云具有较高的可靠性。在基础加速度激励下，位移- psd曲线、速度- psd曲线和加速度- psd曲线及其均方根值在各种边界条件下均与3D-FEM曲线吻合较好，最大误差小于5%。伸出杆的长厚比对等效刚度的影响显著，而倾斜杆的再入角和长厚比对特征频率和位移- psd峰值的影响最大。与SP-3D-XYAS相比，SP-3D-OAC的等效密度降低了20%，同时仍然实现了较低的驱位- psd峰值。这种平衡，再加上没有耦合效应，使SP-3D-OAC特别适合于精密设备支架和隔振材料的应用。

{"title":"Free and random-vibration characteristics of sandwich panels featuring orthogonal accordion cores","authors":"Liu Rong , Zhong Yifeng , Zhu Yilin , Cao Haiwen , Chen Minfang","doi":"10.1016/j.ijmecsci.2025.109941","DOIUrl":"10.1016/j.ijmecsci.2025.109941","url":null,"abstract":"<div><div>The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109941"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Investigation on the vortex dynamics in the wake of a rotating propeller 旋转螺旋桨尾迹涡动力学研究

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109918

Lianzhou Wang , Hao Huang , Chenyu Huang , Xinyu Liu

Improved Delayed Detached Eddy Simulation (IDDES) method on a 48 million grid is utilized to numerically simulate the E779A propeller wake, with a focus on comparing the evolution mechanisms and dynamics of wake topology instability under varying loading conditions. A tip vortex identification method is employed to extract and analyze the evolution trajectories along with the core positions of the tip vortices. Based on this, a Lumley map is established to visualize the development of the turbulence anisotropy at the tip and hub vortex cores. Detailed discussions of the turbulent energy spectra across various regions of the wake are also conducted. In addition, mode structures are analyzed using a reduced order strategy, emphasizing variations under different loading conditions. As tip vortices evolve downstream, the distorted and deformed trailing edge vortices undergo mutual induction with adjacent downstream tip vortices, signaling the onset of elliptical instability and the beginning of vortex system destabilization. Eventually, turbulence anisotropy gradually takes up in the vortex core. Similarity in the turbulence energy spectra can be observed under all loading conditions, in terms of both the energy injection scale and the inertial subrange. Additionally, mode decomposition results of reduced order modeling are examined, focusing on spatial flow patterns and characteristic temporal frequencies. The results show that the circumferential and radial deformation significantly contributes to vortex instability. The present paper aims to provide an insightful perspective and valuable reference for understanding the key mechanisms of propeller wake dynamics.

利用改进的延迟分离涡模拟（IDDES）方法对E779A螺旋桨尾流进行了4800万网格的数值模拟，重点比较了不同载荷条件下尾流拓扑不稳定性的演化机制和动力学。采用叶尖涡识别方法提取并分析了叶尖涡核心位置及其演化轨迹。在此基础上，建立了Lumley图，直观地反映了涡顶和轮毂涡核湍流各向异性的发展。对尾迹不同区域的湍流能谱进行了详细的讨论。此外，采用降阶策略分析了模态结构，强调了不同载荷条件下的变化。在叶尖涡向下游演化的过程中，变形后的尾缘涡与邻近的下游叶尖涡相互诱导，标志着椭圆不稳定的开始，旋涡系统开始失稳。最终，湍流各向异性在涡旋核心逐渐显现。在所有加载条件下，无论是能量注入规模还是惯性子范围，都可以观察到湍流能谱的相似性。此外，研究了降阶模型的模态分解结果，重点研究了空间流模式和特征时间频率。结果表明，涡旋的周向和径向变形对涡旋失稳有重要影响。本文旨在为理解螺旋桨尾流动力学的关键机理提供有价值的参考。

{"title":"Investigation on the vortex dynamics in the wake of a rotating propeller","authors":"Lianzhou Wang , Hao Huang , Chenyu Huang , Xinyu Liu","doi":"10.1016/j.ijmecsci.2025.109918","DOIUrl":"10.1016/j.ijmecsci.2025.109918","url":null,"abstract":"<div><div>Improved Delayed Detached Eddy Simulation (IDDES) method on a 48 million grid is utilized to numerically simulate the E779A propeller wake, with a focus on comparing the evolution mechanisms and dynamics of wake topology instability under varying loading conditions. A tip vortex identification method is employed to extract and analyze the evolution trajectories along with the core positions of the tip vortices. Based on this, a Lumley map is established to visualize the development of the turbulence anisotropy at the tip and hub vortex cores. Detailed discussions of the turbulent energy spectra across various regions of the wake are also conducted. In addition, mode structures are analyzed using a reduced order strategy, emphasizing variations under different loading conditions. As tip vortices evolve downstream, the distorted and deformed trailing edge vortices undergo mutual induction with adjacent downstream tip vortices, signaling the onset of elliptical instability and the beginning of vortex system destabilization. Eventually, turbulence anisotropy gradually takes up in the vortex core. Similarity in the turbulence energy spectra can be observed under all loading conditions, in terms of both the energy injection scale and the inertial subrange. Additionally, mode decomposition results of reduced order modeling are examined, focusing on spatial flow patterns and characteristic temporal frequencies. The results show that the circumferential and radial deformation significantly contributes to vortex instability. The present paper aims to provide an insightful perspective and valuable reference for understanding the key mechanisms of propeller wake dynamics.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109918"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

3D dynamic analysis of elastically restrained multi-directional FGMs rectangular parallelepiped 弹性约束多向fgm矩形平行六面体的三维动力学分析

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109950

Xiaochao Chen, Runbin Li, Chengcheng Chang, Lin Cheng

In this research, the dynamic features of three-directional functionally graded materials (3DFGMs) rectangular parallelepiped with classic/elastic restraints are investigated based on 3D elastic theory. The general boundary conditions are implemented by introducing artificial displacement springs on the chosen surfaces of rectangular solid. The gradient materials are distributed along the two in-plane and thickness directions of parallelepiped. By setting boundary constraints and geometric parameters, the 3DFGMs rectangular parallelepiped can be evolved into slender beam, thick or thin plate, or even a cuboidal solid. Lagrangian energy functions are formulated for parallelepiped-spring system. The free vibration characters of 3DFGMs rectangular parallelepiped are solved employing the Ritz method in conjunction with the Jacobi polynomials. For transient analysis, the analytical expressions of impulse responses are derived for different types of pulsed excitation. The presented modeling and solution methods are validated by comparing with the results from open literature, finite element analysis and experimental results. Numerical simulations are performed to reveal the effect mechanisms of material gradients, geometrical configuration and boundary restraints on the vibration characters of 3DFGMs parallelepiped. The results demonstrate that dynamic performance of rectangular parallelepiped depends critically on material gradient which may be regarded as regulatory factor to regulate the modal displacement distribution or modal sequence.

基于三维弹性理论，研究了具有经典/弹性约束的三方向功能梯度材料（3dfgm）矩形平行六面体的动力学特性。通过在选定的矩形实体表面上引入人工位移弹簧，实现了一般边界条件。梯度材料沿平行六面体的面内方向和厚度方向分布。通过设置边界约束和几何参数，可以将三维fgm矩形平行六面体演化为细长梁、厚板或薄板，甚至是立方体实体。导出了平行六面体-弹簧系统的拉格朗日能量函数。采用Ritz法结合Jacobi多项式对三维fgm矩形平行六面体的自由振动特性进行了求解。在瞬态分析中，推导了不同类型脉冲激励下脉冲响应的解析表达式。通过与公开文献、有限元分析和实验结果的比较，验证了所提出的建模和求解方法的正确性。通过数值模拟揭示了材料梯度、几何形态和边界约束对三维fgm平行六面体振动特性的影响机理。结果表明，矩形平行六面体的动力性能主要取决于材料梯度，材料梯度可以作为调节因素来调节模态位移分布或模态序列。

{"title":"3D dynamic analysis of elastically restrained multi-directional FGMs rectangular parallelepiped","authors":"Xiaochao Chen, Runbin Li, Chengcheng Chang, Lin Cheng","doi":"10.1016/j.ijmecsci.2025.109950","DOIUrl":"10.1016/j.ijmecsci.2025.109950","url":null,"abstract":"<div><div>In this research, the dynamic features of three-directional functionally graded materials (3DFGMs) rectangular parallelepiped with classic/elastic restraints are investigated based on 3D elastic theory. The general boundary conditions are implemented by introducing artificial displacement springs on the chosen surfaces of rectangular solid. The gradient materials are distributed along the two in-plane and thickness directions of parallelepiped. By setting boundary constraints and geometric parameters, the 3DFGMs rectangular parallelepiped can be evolved into slender beam, thick or thin plate, or even a cuboidal solid. Lagrangian energy functions are formulated for parallelepiped-spring system. The free vibration characters of 3DFGMs rectangular parallelepiped are solved employing the Ritz method in conjunction with the Jacobi polynomials. For transient analysis, the analytical expressions of impulse responses are derived for different types of pulsed excitation. The presented modeling and solution methods are validated by comparing with the results from open literature, finite element analysis and experimental results. Numerical simulations are performed to reveal the effect mechanisms of material gradients, geometrical configuration and boundary restraints on the vibration characters of 3DFGMs parallelepiped. The results demonstrate that dynamic performance of rectangular parallelepiped depends critically on material gradient which may be regarded as regulatory factor to regulate the modal displacement distribution or modal sequence.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109950"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

High-performance 3D auxetic metamaterials enabled by multiple auxetic mechanisms

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109981

Haoming Yang , Le Yang , Xiangrui Zheng , Shuhan Xu , Yao Zhang

The negative Poisson's ratio (NPR) effect can modify the deformation path and thus enhance the mechanical performance of metamaterials, which have been widely used in biomedical, aerospace, and vibration damping applications. However, designing 3D auxetic structures with NPR over a large strain range remains challenging. This study proposes a novel combined-auxetic-mechanism design method that integrates three distinct auxetic mechanisms — rotational polygonal, chirality, and re-entrant. This approach enables the effective maintenance of the NPR effect across a large strain range (0–0.8), while simultaneously enhancing mechanical properties such as load-bearing capacity, energy absorption, and fracture resistance. The innovative design allows for these mechanisms to be applied both individually or in combination, resulting in four distinct configurations of combined-auxetic-mechanism structures (CAMSs). The mechanical performances and underlying mechanisms of 3D-printed CAMSs using superelastic thermoplastic polyurethane (TPU) and plastic photopolymer were experimentally and numerically investigated. In addition, a new theoretical model capable of predicting their effective elastic modulus was developed based on energy conservation principles and verified by finite element analysis (FEA) and experiments. The experimental and simulation results demonstrate that the CAMSs containing the rotational polygonal, chirality, and re-entrant auxetic mechanisms could exhibit the NPR effect in a large compression strain range of 0–0.8, high load-bearing capacity, large energy absorption, and advantages in mitigating the effects of viscosity and reducing the risk of fracture. This research provides valuable insights for overcoming existing limitations and advancing the multifunctionality of 3D auxetic structures.

{"title":"High-performance 3D auxetic metamaterials enabled by multiple auxetic mechanisms","authors":"Haoming Yang , Le Yang , Xiangrui Zheng , Shuhan Xu , Yao Zhang","doi":"10.1016/j.ijmecsci.2025.109981","DOIUrl":"10.1016/j.ijmecsci.2025.109981","url":null,"abstract":"<div><div>The negative Poisson's ratio (NPR) effect can modify the deformation path and thus enhance the mechanical performance of metamaterials, which have been widely used in biomedical, aerospace, and vibration damping applications. However, designing 3D auxetic structures with NPR over a large strain range remains challenging. This study proposes a novel combined-auxetic-mechanism design method that integrates three distinct auxetic mechanisms — rotational polygonal, chirality, and re-entrant. This approach enables the effective maintenance of the NPR effect across a large strain range (0–0.8), while simultaneously enhancing mechanical properties such as load-bearing capacity, energy absorption, and fracture resistance. The innovative design allows for these mechanisms to be applied both individually or in combination, resulting in four distinct configurations of combined-auxetic-mechanism structures (CAMSs). The mechanical performances and underlying mechanisms of 3D-printed CAMSs using superelastic thermoplastic polyurethane (TPU) and plastic photopolymer were experimentally and numerically investigated. In addition, a new theoretical model capable of predicting their effective elastic modulus was developed based on energy conservation principles and verified by finite element analysis (FEA) and experiments. The experimental and simulation results demonstrate that the CAMSs containing the rotational polygonal, chirality, and re-entrant auxetic mechanisms could exhibit the NPR effect in a large compression strain range of 0–0.8, high load-bearing capacity, large energy absorption, and advantages in mitigating the effects of viscosity and reducing the risk of fracture. This research provides valuable insights for overcoming existing limitations and advancing the multifunctionality of 3D auxetic structures.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109981"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Prediction on quasi-static compression deformation modes of circular tubes based on machine learning

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109993

Xiaodong Wu , Tianyu Hu , Nima Khodadadi , Antonio Nanni

This paper proposes a methodology that combines finite element simulation and machine learning to predict the deformation pattern and the number of circumferential lobes of circular tubes. It calibrates the deformation modes with finite element simulation to obtain rich data and then classifies them through various machine learning models. In addition, it conducts refined classification and prediction on the number of circumferential lobes. By the performance of both the training and testing sets of the machine learning model, the random forest model delivers the best performance in predicting deformation modes. The classification accuracy, precision, and recall on the test set were 0.990, 0.937, and 0.987, respectively. The decision tree model demonstrates the best performance in predicting several circumferential lobes. The classification accuracy, precision, and recall on the test set were 0.978, 0.971, and 0.985, respectively. The machine learning model constructed in this study ensures precise classification and prediction of deformation modes for thin-walled circular tubes under given working conditions, making up for the insufficient experience in predicting the number of circumferential lobes. It has a guiding significance for the energy absorption evaluation of thin-walled structures and also guides the design and optimization of thin-walled circular tube dimensions.

{"title":"Prediction on quasi-static compression deformation modes of circular tubes based on machine learning","authors":"Xiaodong Wu , Tianyu Hu , Nima Khodadadi , Antonio Nanni","doi":"10.1016/j.ijmecsci.2025.109993","DOIUrl":"10.1016/j.ijmecsci.2025.109993","url":null,"abstract":"<div><div>This paper proposes a methodology that combines finite element simulation and machine learning to predict the deformation pattern and the number of circumferential lobes of circular tubes. It calibrates the deformation modes with finite element simulation to obtain rich data and then classifies them through various machine learning models. In addition, it conducts refined classification and prediction on the number of circumferential lobes. By the performance of both the training and testing sets of the machine learning model, the random forest model delivers the best performance in predicting deformation modes. The classification accuracy, precision, and recall on the test set were 0.990, 0.937, and 0.987, respectively. The decision tree model demonstrates the best performance in predicting several circumferential lobes. The classification accuracy, precision, and recall on the test set were 0.978, 0.971, and 0.985, respectively. The machine learning model constructed in this study ensures precise classification and prediction of deformation modes for thin-walled circular tubes under given working conditions, making up for the insufficient experience in predicting the number of circumferential lobes. It has a guiding significance for the energy absorption evaluation of thin-walled structures and also guides the design and optimization of thin-walled circular tube dimensions.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109993"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Evaluation of fracture parameters for three-dimensional cracks by a hierarchical quadrature element method

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmecsci.2025.109954

Wei Xiang , Ming Chen , Yifeng Tian , Bo Liu

This work integrates the hierarchical quadrature element method (HQEM), which is known to have p-convergence, into the virtual crack closure method (VCCM) to evaluate fracture parameters for three-dimensional (3D) crack configurations. The prerequisite of the VCCM when dealing with 3D crack problems is the orthogonality of mesh arrangement in the vicinity of the crack front, which cannot be strictly met when traditional h-version finite element methods are employed. Compared with the h-version methods, one of the distinguished advantages of the HQEM is its simplicity in pre-processing, which is helpful to solve the difficulty of orthogonal mesh generation.

The technical details regarding the combination of HQEM and VCCM are illustrated in this work. Firstly, the method of generating higher-order mesh which strictly meets the orthogonality requirement is proposed. Then, a universal formula for crack closure integral is proposed for hexahedral hierarchical quadrature element, regardless of node arrangements and the number of nodes per element boundary. In addition, the subdomain integration technique is incorporated to estimate SIFs at a large number of subsegments along the crack front under a coarse mesh consisting of only a few elements. The effectiveness and accuracy of the present method are verified by several typical numerical examples, including through-the-thickness cracks, embedded elliptical cracks and semi-elliptical surface cracks. The results show that with only one or two elements arranged along the crack front, the present method is capable of easily and accurately obtaining the SIF distribution of 3D crack configurations with straight or curved crack fronts.

{"title":"Evaluation of fracture parameters for three-dimensional cracks by a hierarchical quadrature element method","authors":"Wei Xiang , Ming Chen , Yifeng Tian , Bo Liu","doi":"10.1016/j.ijmecsci.2025.109954","DOIUrl":"10.1016/j.ijmecsci.2025.109954","url":null,"abstract":"<div><div>This work integrates the hierarchical quadrature element method (HQEM), which is known to have <em>p</em>-convergence, into the virtual crack closure method (VCCM) to evaluate fracture parameters for three-dimensional (3D) crack configurations. The prerequisite of the VCCM when dealing with 3D crack problems is the orthogonality of mesh arrangement in the vicinity of the crack front, which cannot be strictly met when traditional <em>h</em>-version finite element methods are employed. Compared with the <em>h</em>-version methods, one of the distinguished advantages of the HQEM is its simplicity in pre-processing, which is helpful to solve the difficulty of orthogonal mesh generation.</div><div>The technical details regarding the combination of HQEM and VCCM are illustrated in this work. Firstly, the method of generating higher-order mesh which strictly meets the orthogonality requirement is proposed. Then, a universal formula for crack closure integral is proposed for hexahedral hierarchical quadrature element, regardless of node arrangements and the number of nodes per element boundary. In addition, the subdomain integration technique is incorporated to estimate SIFs at a large number of subsegments along the crack front under a coarse mesh consisting of only a few elements. The effectiveness and accuracy of the present method are verified by several typical numerical examples, including through-the-thickness cracks, embedded elliptical cracks and semi-elliptical surface cracks. The results show that with only one or two elements arranged along the crack front, the present method is capable of easily and accurately obtaining the SIF distribution of 3D crack configurations with straight or curved crack fronts.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109954"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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