Acta Mechanica Sinica最新文献

{"title":"Three-dimensional fluid-structure-acoustic method for aeroelastic flutter analysis of coupled composite panel and cavity system in supersonic flow","authors":"Hao Liu \u0000 (,&nbsp;),&nbsp;Yegao Qu \u0000 (,&nbsp;),&nbsp;Guang Meng \u0000 (,&nbsp;)","doi":"10.1007/s10409-025-24667-x","DOIUrl":"10.1007/s10409-025-24667-x","url":null,"abstract":"<div><p>The paper develops a partitioned three-dimensional fluid-structure-acoustic method to predict the flutter behaviors of a composite panel with a cavity beneath it in supersonic airflow. A higher-order shear deformation theory is employed for laminated panel modeling, considering zigzag effect, and panel’s large deformation is accounted for by incorporating nonlinear von Kármán strains. The supersonic airflow is formulated by the unsteady Navier-Stokes equations within the arbitrary Lagrangian-Eulerian framework, which are solved by a finite volume method. Additionally, the sound waves considering finite-amplitude effects, are calculated using a nonlinear finite element method. An implicit partitioned coupling method is used to establish the strong coupling between the unsteady supersonic airflow, composite panel with large deformation, and nonlinear sound waves, which is confirmed through a monolithic fluid-structure-acoustic coupling method. It is revealed that the composite panel-cavity aeroelastic system exhibits a special flutter induced by acoustic resonance, underscoring the crucial role of acoustic-elastic coupling in nonlinear aeroelastic responses. The impact of instability coefficients on flutter dynamics, as derived from linear modal analysis, is discussed, emphasizing that long-time scales are required for the establishment of acoustic resonance within the cavity. The findings suggest that flutter induced by acoustic resonance leads to an acoustic environment with high sound pressure levels in the cavity, particularly in shallow cavities, which could potentially cause detrimental acoustic fatigue of the structure.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 5","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918630","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}

{"title":"A comparison between artificial neural network and random forest on predicting ferrofluids viscosity under magnetic field application","authors":"Walaeddine Maaoui,&nbsp;Zouhaier Mehrez,&nbsp;Mustapha Najjari","doi":"10.1007/s10409-025-24944-x","DOIUrl":"10.1007/s10409-025-24944-x","url":null,"abstract":"<div><p>This research study focuses on predicting ferrofluids’ viscosity using machine learning models, artificial neural networks (ANNs), and random forests (RFs) incorporating key parameters; ferrofluid type, concentration of magnetic nanoparticles, temperature, and magnetic field intensity as inputs. A comprehensive database of 333 datasets sourced from various literatures was utilized for training and validating models. The ANN model demonstrated high accuracy, with root mean square error (RMSE) values below 0.033 and mean absolute percentage error (MAPE) not exceeding 3.01%, while the RF model achieved similar accuracy with RMSE under 0.052 and MAPE below 4.82%. Maximum deviations observed were 9.14% for ANN and 16.48% for RF, confirming that both models accurately learned the underlying patterns without overestimating viscosity. Additionally, the ANN model successfully captured intricate physical relationships between input parameters and viscosity when it was used to predict viscosity for random input data, confirming its ability to generalize beyond the training dataset. The RF model, however, showed limitations in extrapolating beyond the range of the training data. This research study demonstrates machine learning models’ effectiveness in capturing intricate relationships governing the viscosity of ferrofluid for different types, paving the way for an improved understanding of ferrofluid’s viscosity behavior.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"41 6","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169288","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}

{"title":"An improved nonlinear vibration absorber with adjustable stiffness and rotating mass","authors":"Ke-Fan Xu \u0000 (,&nbsp;),&nbsp;Zhuo-Da Zhou \u0000 (,&nbsp;),&nbsp;Ye-Wei Zhang \u0000 (,&nbsp;),&nbsp;Li-Qun Chen \u0000 (,&nbsp;)","doi":"10.1007/s10409-025-24515-x","DOIUrl":"10.1007/s10409-025-24515-x","url":null,"abstract":"<div><p>A novel approach for vibration reduction is proposed by improving an adjustable stiffness nonlinear vibration absorber (NVA) with a rotating mass system. The adjustable stiffness is realized by a buckling Euler beam and an active control system. The rotating mass is consisted of a primary mass block and two rotating mass blocks. The dynamic responses are analyzed based on nonlinear output frequency response functions. The results indicate that, in comparison to the adjustable stiffness NVA, the enhanced NVA can efficiently suppress the resonance in steady state response. Moreover, the new vibration absorber can improve the robustness of the adjustable stiffness NVA. The mass ratio and the angular velocity are two key parameters of the new vibration absorber with optimal values for effective vibration reduction. The new vibration absorber introduces new possibilities for incorporating the adjustable stiffness and the rotating mass system in the design of NVA.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 3","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169245","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}

{"title":"Bicycle dynamic modeling and stability analysis with a toroidal-shaped tire geometry","authors":"Ruihan Yu \u0000 (,&nbsp;),&nbsp;Jiaming Xiong \u0000 (,&nbsp;),&nbsp;Xuefeng Wang \u0000 (,&nbsp;),&nbsp;Caishan Liu \u0000 (,&nbsp;)","doi":"10.1007/s10409-024-24695-x","DOIUrl":"10.1007/s10409-024-24695-x","url":null,"abstract":"<div><p>Traditional bicycle modeling often uses line contacts to simplify wheel-ground constraints. However, the geometric shape of the tire can greatly alter the constraint nature, thereby affecting relative equilibria and their stability in dynamics. This work develops a nonlinear dynamic model of the bicycle system with a toroidal-shaped tire geometry to establish a realistic wheel-ground constraint. Such tire geometry significantly increases the complexity of the dynamic equations. Therefore, calculation of the nontrivial equilibria that involves a set of strongly nonlinear algebraic equations is more difficult. To solve the issue, we establish the balance equation in a non-inertial frame to decouple the complex coupling terms of the high-dimensional nonlinear system, which simplifies the calculation of the equilibria. Furthermore, this work proposes a method to facilitate stability analysis of the relative equilibria, where linearization of the multi-dimensional dynamic equations is performed first, and then explicit dimensionality reduction is followed. Finally, we investigate the effects of tire geometric parameters on the equilibrium stability and find that the solution of the equilibria and their stability properties change significantly with the tire geometric shape.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144990383","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}

{"title":"Mechanical behavior and axial load optimization of Bi2212 superconducting CICC with elastic modulus","authors":"Hang Zhao \u0000 (,&nbsp;),&nbsp;Jinggang Qin \u0000 (,&nbsp;),&nbsp;Lei Yu \u0000 (,&nbsp;),&nbsp;Qingbin Hao \u0000 (,&nbsp;),&nbsp;Xiangyang Hu \u0000 (,&nbsp;),&nbsp;Xiaoyan Xu \u0000 (,&nbsp;),&nbsp;Chao Wang \u0000 (,&nbsp;),&nbsp;Yongchao Guo \u0000 (,&nbsp;),&nbsp;Zhaofei Jiang \u0000 (,&nbsp;),&nbsp;Pengcheng Huang \u0000 (,&nbsp;),&nbsp;Wenge Chen \u0000 (,&nbsp;)","doi":"10.1007/s10409-024-24522-x","DOIUrl":"10.1007/s10409-024-24522-x","url":null,"abstract":"<div><p>The Bi2212 high-temperature superconductor is considered one of the solutions for manufacturing large high-field magnets due to its excellent current-carrying performance. The key issue is to improve the mechanical properties of Bi2212 cable-in-conduit-conductor (CICC), as they are sensitive to stress and strain. Therefore, This paper utilized the equivalent elasticity modulus (EEM) method and superconducting wire properties to characterize the CICCs at 300 K and 4.2 K. Then, the EEM of the CICC at various cable stages was analyzed at both short twist pitches (STPs) and long twist pitches (LTPs), and the variation in EEM with void fraction, heat treatment (HT), cryogenic shrinkage, and cable patterns was examined to achieve optimal axial tensile strength. Research results show that the LTPs have higher EEM and axial tensile strength than the STPs, while STPs have better elongation to protect internal wires. Improving cable strength in the earlier stages contributes more to improving the overall performance than the twist pitch of current stages. The Bi2212 CICC maintains better mechanical strength when the porosity is between 28% and 30%, considering HT and low-temperature shrinkage. While the cable temperature drops to 4.2 K, some factors will have little impact on the EEM and can be simplified in multi-level analysis, such as wire reduction in HT, cooling shrinkage, and cable patterns. This study systematically investigated the axial mechanical behavior and work conditions of Bi2212 CICC at 300 K and 4.2 K, offering valuable insights for design applications.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168829","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}

{"title":"A higher-order beam theory for analyzing the static and dynamic behaviors of box and tubular beam-columns with the higher-order effect of axial force","authors":"Weili Ma \u0000 (,&nbsp;),&nbsp;Xianfang Li \u0000 (,&nbsp;)","doi":"10.1007/s10409-025-24391-x","DOIUrl":"10.1007/s10409-025-24391-x","url":null,"abstract":"<div><p>Cross-sectional warping of box and tubular beam-columns is often neglected in previous studies and this treatment leads to significant errors for short beam-columns. This article develops a higher-order beam model for exactly analyzing the static and dynamic behaviors of box/tubular beams and columns by taking into account the cross-sectional warping and the higher-order effect (HOE) of axial force. Appropriate warping shapes are constructed for the box and annular cross-section, respectively. Shear deformation and rotary inertia of the corss-section are considered simultaneously, but no shear correction factor is needed. The bending, buckling, wave, and vibration are analyzed. In particular, the HOE of the axial force on the static behaviors including the deflection and critical load, and the dynamic behaviors including the phase velocity and natural frequency are analyzed for hollow-core structures or box/tubular beam-columns. The classical Euler buckling loads and natural frequencies are affected by the HOE of the axial force. The transverse waves are dispersive when the axial force is present. The presented model is also suitable for axially loaded shear deformation beams with rectangular and circular cross-sections only if the hollow-core cross-section reduces to a rectangle and a circle, respectively.</p></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 3","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168830","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}

{"title":"Study on dynamic similarity of elastic shell during water entry","authors":"Haisu Liu \u0000 (,&nbsp;),&nbsp;Fei Xu \u0000 (,&nbsp;),&nbsp;Xinzhe Chang \u0000 (,&nbsp;),&nbsp;Yang Yang \u0000 (,&nbsp;),&nbsp;Xiaocheng Li \u0000 (,&nbsp;),&nbsp;Xiaochuan Liu \u0000 (,&nbsp;),&nbsp;Wei Feng \u0000 (,&nbsp;)","doi":"10.1007/s10409-025-23604-x","DOIUrl":"10.1007/s10409-025-23604-x","url":null,"abstract":"<div><p>In the study of thin-walled wedge shells subjected to lateral water entry impact loads, similarity theory is employed to predict the behavior of the prototype by analyzing the dynamic response of the model. However, the traditional similarity law for structural impact fails to accurately describe the relationship between the dynamic responses of the model and the prototype, mainly due to the ignoring of the fluid-structure coupling effect and geometric distortion in the thickness direction. To address this limitation, this study employs dimensional analysis to derive the scaling factors for achieving structural similarity during water entry while considering the effects of fluid-structure coupling. Based on the analysis of the governing equations for thin-walled wedge shells under water entry impact loads, the scaling factor accounting for geometric distortion for water entry of wedge shells is determined. Numerical models are established to verify the applicability of the geometric distortion similarity model with different materials. The results demonstrate the effectiveness of the proposed similarity model, which significantly reduces the disparities in displacement peaks and energy between the scaled model and the prototype. In addition, experimental platforms are constructed to further verify the proposed similarity model by performing vertical water entry tests on thickness-distorted and material-distorted specimens.</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167345","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}

{"title":"A data-driven integrated optimization method of macroscopic topology and microscopic configuration for the graded functional cellular structures","authors":"Yu Guo \u0000 (,&nbsp;),&nbsp;Yijie Lu \u0000 (,&nbsp;),&nbsp;Zhengwei Zhang \u0000 (,&nbsp;),&nbsp;Yanguo Zhou \u0000 (,&nbsp;),&nbsp;Hui Liu \u0000 (,&nbsp;)","doi":"10.1007/s10409-024-24535-x","DOIUrl":"10.1007/s10409-024-24535-x","url":null,"abstract":"<div><p>In the topology optimization of the multiscale structure, how to ensure the connectivity between adjacent microstructures, how to control the design space of microstructures, and how to reduce the amount of calculation and improve calculation efficiency are three basic challenging issues currently faced. To this end, this paper proposes a data-driven approach to achieve the integrated optimization of macroscopic topology and microscopic configuration of the graded functional cellular structures. At the macro level, a topological description function is introduced to realize the topological control of the macrostructure. At the micro level, several cutting functions are used to realize the control of the configuration and size of the microstructure. The integrated optimization design of macro and micro cellular structures can be realized. Based on the computational homogenization method and numerical integration technology, an optimization problem independent offline microstructure database is established at the microscopic scale, where the relationship between the equivalent elastic parameters, relative pseudo-density, and design variables of the microstructure is stored. Based on this offline database, the entire topology optimization process is completed only on a macro scale, which greatly reduces the amount of calculation and improves calculation efficiency. In addition, implicit geometric modeling of full-scale cellular structures can be achieved using the reconstruction technique introduced in this work, which ensures smooth connection between adjacent microstructures. Finally, numerical examples are used to verify the effectiveness of the algorithm and the superiority of gradient cellular structures compared with single-scale structures.</p></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 2","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909813","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}

{"title":"Extraction of residual stresses by instrumented indentation based on force-contact area (F-S) measurement","authors":"Ji Fu \u0000 (,&nbsp;),&nbsp;Yuhao Sun \u0000 (,&nbsp;),&nbsp;Faxin Li \u0000 (,&nbsp;)","doi":"10.1007/s10409-025-24759-x","DOIUrl":"10.1007/s10409-025-24759-x","url":null,"abstract":"<div><p>In the past decades, residual stresses have attracted wide attention due to their significant influences on material’s strength, fatigue life, and dimensional stability. Various residual stress measurement methods have been developed such as X-ray diffraction, neutron diffraction, crack compliance, and hole drilling. These methods may suffer from different disadvantages including radiation, high cost, destructive, unportable, etc. In this work, an <i>in situ</i> residual stress measurement method was proposed based on instrumented indentation using a piezoelectric bimorph cantilever. A Vickers’ indenter was fabricated onto the free end of the cantilever for pressing into the sample and a strain gauge was bonded on the cantilever to monitor the indentation load. During testing, the contact area was extracted by tracking the cantilever’s contact resonance frequency based on the electromechanical impendence method. Different from traditional indentation-based methods that use a single hardness value to compute the residual stress, here the indentation force-contact area (<i>F-S</i>) curves with and without residual stresses were measured to derive the residual stress based on an empirical model. Experiments were then conducted on a specially designed CrMnCu specimen with different applied stresses. Results show that the measured residual stress values agreed well with the applied stresses monitored by a strain gauge. The proposed residual stress measurement method holds great promise for <i>in situ</i> residual stress estimation due to its portable apparatus, simple operation procedure and insensitiveness to testing environment.\u0000</p><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"41 8","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143563","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}

{"title":"Mathisson–Papapetrou force on wedge disclinations","authors":"Cheng Yuan \u0000 (,&nbsp;),&nbsp;Xiao-Wen Lei \u0000 (,&nbsp;),&nbsp;Toshiyuki Fujii \u0000 (,&nbsp;),&nbsp;Kazuyuki Shizawa \u0000 (,&nbsp;)","doi":"10.1007/s10409-024-24637-x","DOIUrl":"10.1007/s10409-024-24637-x","url":null,"abstract":"<div><p>In this study, we derive a more generalized form of the Mathisson–Papapetrou force equation and perform an in-depth analysis of the variation in the Mathisson–Papapetrou force between two wedge disclinations across different calculation models in a two-dimensional plane. The results demonstrate that the stress field magnitude along the <i>x</i>₁ and <i>x</i>₂ axes consistently remains zero, facilitating the wedge disclination dipole in achieving equilibrium state along these two directions within the plane. Furthermore, the stress field enables the Mathisson–Papapetrou force acting on one wedge disclination in semicircular motion to be approximated by the force in linear motion within the same two-dimensional plane. This study contributes a more comprehensive understanding of wedge disclination by deriving a generalized Mathisson–Papapetrou force equation applicable to disclinations.</p></div>","PeriodicalId":7109,"journal":{"name":"Acta Mechanica Sinica","volume":"42 4","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165692","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}