Pub Date : 2024-11-24DOI: 10.1016/j.ijmecsci.2024.109855
Xiangwei Guo , Shibo Guo , Yanqi Li , Ming Li , Fuhong Dai
FML (Fiber metal laminate) is widely used in aerospace as an advanced composite material. Metal hybrid bistable composites are one type of FML structure. The hybrid bistable composite is not only deformable but also conductive. In this paper, based on a bistable metamaterial tube, it is proposed to control its shape through metal-composite layups. A theoretical prediction model with a metal slip effect is developed. The energy equation of the theoretical model was solved using the principle of minimum potential energy. The curvature variation rules of two configurations of composite tube with different metal layups and different initial curvatures are discussed. Moreover, the finite element model of the metal hybrid composite is established. Finally, the accuracy of the theoretical and finite element models was verified by experiments. The proposed metal slip model is accurate than the classical model. The effect of metal on the bistable tube was determined. The configuration of the bistable tube is controlled by layups without adding any weight. This plays an important role in deformable metamaterials and multi-functional morphing structure applications.
{"title":"Mechanical adjustment and prediction of metal-composite reconfigurable tubes","authors":"Xiangwei Guo , Shibo Guo , Yanqi Li , Ming Li , Fuhong Dai","doi":"10.1016/j.ijmecsci.2024.109855","DOIUrl":"10.1016/j.ijmecsci.2024.109855","url":null,"abstract":"<div><div>FML (Fiber metal laminate) is widely used in aerospace as an advanced composite material. Metal hybrid bistable composites are one type of FML structure. The hybrid bistable composite is not only deformable but also conductive. In this paper, based on a bistable metamaterial tube, it is proposed to control its shape through metal-composite layups. A theoretical prediction model with a metal slip effect is developed. The energy equation of the theoretical model was solved using the principle of minimum potential energy. The curvature variation rules of two configurations of composite tube with different metal layups and different initial curvatures are discussed. Moreover, the finite element model of the metal hybrid composite is established. Finally, the accuracy of the theoretical and finite element models was verified by experiments. The proposed metal slip model is accurate than the classical model. The effect of metal on the bistable tube was determined. The configuration of the bistable tube is controlled by layups without adding any weight. This plays an important role in deformable metamaterials and multi-functional morphing structure applications.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109855"},"PeriodicalIF":7.1,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748332","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}
Pub Date : 2024-11-23DOI: 10.1016/j.ijmecsci.2024.109853
Saman Ghoddousi, Mohammadreza Mohammadnejad, Majid Safarabadi, Mojtaba Haghighi-Yazdi
In this study, we present a novel nature-inspired metamaterial with a Poisson's ratio sign-switching capability, offering progressive stiffness and enhanced tunability through symmetrical configurations, with potential applications in adaptive materials and impact damping. The metamaterial's architecture is based on the Fibonacci spiral, a pattern frequently observed in biological species and natural formations, derived from the Fibonacci sequence. To develop the metamaterial, the Fibonacci spiral is first thickened to form a 2D structure and then arranged in a circular pattern to create a novel unit cell. This unit cell is then patterned linearly in two directions to form the initial metamaterial structure. To enhance symmetry and stability, the metamaterial is horizontally and vertically cut, mirrored, and augmented with additional material extensions to prevent slipping during compression loading. The final metamaterial design is fabricated using additive manufacturing techniques and examined through finite element analysis (FEA) and experimental testing. Results demonstrate that the metamaterial exhibits an exponential increase in stiffness under compression and displays semi-auxetic behavior, initially shrinking and subsequently expanding when compressed. The proposed metamaterial also shows high specific energy absorption (SEA), particularly in bilateral symmetric configurations. A parametric study reveals that the metamaterial's geometrical parameters, including extrusion thickness, longitudinal cell count, and transverse cell count, significantly influence its stiffness under compression. The unique properties of this nature-inspired mechanical metamaterial, such as its substantial stiffness increase and Poisson's ratio sign-switching behavior, make it promising for applications requiring controlled deformation and high energy absorption. Potential uses include impact absorption systems, biomedical devices, and adaptive structures, particularly in protective gear and automotive components.
{"title":"Compression response of nature-inspired metamaterials based on Fibonacci spiral","authors":"Saman Ghoddousi, Mohammadreza Mohammadnejad, Majid Safarabadi, Mojtaba Haghighi-Yazdi","doi":"10.1016/j.ijmecsci.2024.109853","DOIUrl":"10.1016/j.ijmecsci.2024.109853","url":null,"abstract":"<div><div>In this study, we present a novel nature-inspired metamaterial with a Poisson's ratio sign-switching capability, offering progressive stiffness and enhanced tunability through symmetrical configurations, with potential applications in adaptive materials and impact damping. The metamaterial's architecture is based on the Fibonacci spiral, a pattern frequently observed in biological species and natural formations, derived from the Fibonacci sequence. To develop the metamaterial, the Fibonacci spiral is first thickened to form a 2D structure and then arranged in a circular pattern to create a novel unit cell. This unit cell is then patterned linearly in two directions to form the initial metamaterial structure. To enhance symmetry and stability, the metamaterial is horizontally and vertically cut, mirrored, and augmented with additional material extensions to prevent slipping during compression loading. The final metamaterial design is fabricated using additive manufacturing techniques and examined through finite element analysis (FEA) and experimental testing. Results demonstrate that the metamaterial exhibits an exponential increase in stiffness under compression and displays semi-auxetic behavior, initially shrinking and subsequently expanding when compressed. The proposed metamaterial also shows high specific energy absorption (SEA), particularly in bilateral symmetric configurations. A parametric study reveals that the metamaterial's geometrical parameters, including extrusion thickness, longitudinal cell count, and transverse cell count, significantly influence its stiffness under compression. The unique properties of this nature-inspired mechanical metamaterial, such as its substantial stiffness increase and Poisson's ratio sign-switching behavior, make it promising for applications requiring controlled deformation and high energy absorption. Potential uses include impact absorption systems, biomedical devices, and adaptive structures, particularly in protective gear and automotive components.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109853"},"PeriodicalIF":7.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722791","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}
Pub Date : 2024-11-23DOI: 10.1016/j.ijmecsci.2024.109852
Jun Li , Kun Luo , Qi An
The transition from Hall-Petch to inverse Hall-Petch behaviors in nanocrystalline semiconductors is complex and remains poorly understood, despite its importance to the mechanical performance of these materials. In this study, we used molecular dynamics simulations with a machine-learning force field (ML-FF MD) to examine the shear deformation and failure mechanisms of nanocrystalline cadmium telluride (n-CdTe) across grain sizes ranging from 4.62 nm to 18.47 nm. Our results reveal a transition from Hall-Petch to inverse Hall-Petch behavior in n-CdTe at a critical grain size of ∼9.79 nm, where the material's maximum shear strength reaches about 1.23 GPa. This transition is driven by varying probabilities of phase transitions from the zinc-blende to the β-Sn-like CdTe phase, due to the competition between shear localization and the availability of nucleation sites. Importantly, regardless of grain sizes, this phase transition often starts near grain boundaries (GBs), causing volume shrinkage and tensile stresses at GBs, further leading to fractures between grains. These findings offer valuable insights into the underlying mechanisms driving the transition from Hall-Petch to inverse Hall-Petch behavior as grain size decreases, as well as the failure behaviors observed in n-CdTe and other semiconductor materials.
纳米晶体半导体中从Hall-Petch行为到逆Hall-Petch行为的转变是复杂的，尽管它对这些材料的机械性能很重要，但仍然知之甚少。在这项研究中，我们使用带有机器学习力场（ML-FF MD）的分子动力学模拟来研究纳米结晶碲化镉（n-CdTe）在4.62 nm至18.47 nm晶粒尺寸范围内的剪切变形和破坏机制。我们的研究结果揭示了n-CdTe在临界晶粒尺寸为~ 9.79 nm时从Hall-Petch行为转变为逆Hall-Petch行为，此时材料的最大剪切强度达到约1.23 GPa。这种转变是由从锌-闪锌矿到β- sn -类CdTe相的不同相变概率驱动的，这是由于剪切定位和成核位点的可用性之间的竞争。重要的是，无论晶粒大小如何，这种相变通常在晶界附近开始，导致晶界处的体积收缩和拉伸应力，进一步导致晶粒之间的断裂。这些发现为从霍尔-佩奇行为向反向霍尔-佩奇行为转变的潜在机制，以及在n-CdTe和其他半导体材料中观察到的失效行为提供了有价值的见解。
{"title":"Unraveling the Hall-Petch to inverse Hall-Petch transition in nanocrystalline CdTe","authors":"Jun Li , Kun Luo , Qi An","doi":"10.1016/j.ijmecsci.2024.109852","DOIUrl":"10.1016/j.ijmecsci.2024.109852","url":null,"abstract":"<div><div>The transition from Hall-Petch to inverse Hall-Petch behaviors in nanocrystalline semiconductors is complex and remains poorly understood, despite its importance to the mechanical performance of these materials. In this study, we used molecular dynamics simulations with a machine-learning force field (ML-FF MD) to examine the shear deformation and failure mechanisms of nanocrystalline cadmium telluride (<em>n</em>-CdTe) across grain sizes ranging from 4.62 nm to 18.47 nm. Our results reveal a transition from Hall-Petch to inverse Hall-Petch behavior in <em>n</em>-CdTe at a critical grain size of ∼9.79 nm, where the material's maximum shear strength reaches about 1.23 GPa. This transition is driven by varying probabilities of phase transitions from the zinc-blende to the <em>β</em>-Sn-like CdTe phase, due to the competition between shear localization and the availability of nucleation sites. Importantly, regardless of grain sizes, this phase transition often starts near grain boundaries (GBs), causing volume shrinkage and tensile stresses at GBs, further leading to fractures between grains. These findings offer valuable insights into the underlying mechanisms driving the transition from Hall-Petch to inverse Hall-Petch behavior as grain size decreases, as well as the failure behaviors observed in <em>n</em>-CdTe and other semiconductor materials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109852"},"PeriodicalIF":7.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748423","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}
Pub Date : 2024-11-23DOI: 10.1016/j.ijmecsci.2024.109840
Xiaoyuan Ying, Dilum Fernando, Marcelo A. Dias
Shape-morphing structures have the ability to transform from one state to another, making them highly valuable in engineering applications. This study proposes a two-stage shape-morphing framework, inspired by kirigami structures, to design structures that can deploy from a compacted state to a prescribed state under certain mechanical stimuli — although the framework can also be extended to accommodate various physical fields, such as magnetic, thermal and electric fields. The framework establishes a connection between the geometry and mechanics of kirigami structures. The proposed approach combines finite element analysis (FEA), genetic algorithm (GA), and an analytical energy-based model to obtain kirigami designs with robustness and efficiency. We expect that this approach to the design of kirigami structures will open up new avenues of research and application in shape-morphing structure design.
{"title":"Inverse design of programmable shape-morphing kirigami structures","authors":"Xiaoyuan Ying, Dilum Fernando, Marcelo A. Dias","doi":"10.1016/j.ijmecsci.2024.109840","DOIUrl":"10.1016/j.ijmecsci.2024.109840","url":null,"abstract":"<div><div>Shape-morphing structures have the ability to transform from one state to another, making them highly valuable in engineering applications. This study proposes a two-stage shape-morphing framework, inspired by kirigami structures, to design structures that can deploy from a compacted state to a prescribed state under certain mechanical stimuli — although the framework can also be extended to accommodate various physical fields, such as magnetic, thermal and electric fields. The framework establishes a connection between the geometry and mechanics of kirigami structures. The proposed approach combines finite element analysis (FEA), genetic algorithm (GA), and an analytical energy-based model to obtain kirigami designs with robustness and efficiency. We expect that this approach to the design of kirigami structures will open up new avenues of research and application in shape-morphing structure design.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109840"},"PeriodicalIF":7.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748424","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}
Pub Date : 2024-11-23DOI: 10.1016/j.ijmecsci.2024.109854
Zaiwei Liu , Bin Lin , Yi He , Zhongqing Su
Lamb wave has been widely used as a non-destructive testing tool for inspecting the defects or damage in the plate system. A comprehensive understanding and correct prediction of the modal characteristics of Lamb waves are of high importance for ensuring successful practical applications. In this paper, a new method called the semi-analytical peridynamic (SAPD) method for analyzing wave propagation is developed. This method, within the framework of the general acoustoelasticity theory, uses the peridynamic differential operator to transform the equations of motion for guided waves in prestressed anisotropic media and the boundary conditions from local differential forms to nonlocal integral forms. By introducing meshfree discretization and Lagrange multipliers, these governing equations can be reorganized into a standard generalized eigenvalue formalism and solved. The effectiveness and accuracy of the SAPD method are first verified through comparison with the exact solutions. Phase and group velocity dispersion curves and displacement distributions of Lamb waves in three typical cases are then calculated to study the effects of material heterogeneity, applied stress and residual stress on the propagation of Lamb waves. Since complex grid generation algorithms are avoided, the SAPD method exhibits the advantages in terms of simplicity and implementation.
{"title":"Semi-analytical peridynamic method for modal analysis of acoustoelastic Lamb waves","authors":"Zaiwei Liu , Bin Lin , Yi He , Zhongqing Su","doi":"10.1016/j.ijmecsci.2024.109854","DOIUrl":"10.1016/j.ijmecsci.2024.109854","url":null,"abstract":"<div><div>Lamb wave has been widely used as a non-destructive testing tool for inspecting the defects or damage in the plate system. A comprehensive understanding and correct prediction of the modal characteristics of Lamb waves are of high importance for ensuring successful practical applications. In this paper, a new method called the semi-analytical peridynamic (SAPD) method for analyzing wave propagation is developed. This method, within the framework of the general acoustoelasticity theory, uses the peridynamic differential operator to transform the equations of motion for guided waves in prestressed anisotropic media and the boundary conditions from local differential forms to nonlocal integral forms. By introducing meshfree discretization and Lagrange multipliers, these governing equations can be reorganized into a standard generalized eigenvalue formalism and solved. The effectiveness and accuracy of the SAPD method are first verified through comparison with the exact solutions. Phase and group velocity dispersion curves and displacement distributions of Lamb waves in three typical cases are then calculated to study the effects of material heterogeneity, applied stress and residual stress on the propagation of Lamb waves. Since complex grid generation algorithms are avoided, the SAPD method exhibits the advantages in terms of simplicity and implementation.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109854"},"PeriodicalIF":7.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746568","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}
Pub Date : 2024-11-22DOI: 10.1016/j.ijmecsci.2024.109839
Yaode Yin, Hongjun Yu, Hongru Yan, Shuai Zhu
In phase field fracture (PFF) method, the sharp crack is approximated by a phase field crack zone whose size is characterized by a diffusive length scale. Recently, the diffusive length scale is usually regarded as a constant material parameter determined by the fracture toughness, material strength, and young's modulus. As a result, the application of the PFF method poses challenges when dealing with structures whose sizes are much too large or small compared to the constant diffusive length scale. In details, for a large-scale structure, a significant computational burden is inevitable due to the limitation imposed by the constant diffusive crack length scale on the element size (i.e. the element size is generally at least smaller than half of the diffusive crack length scale to achieve the sufficient precision for the phase field process zone). For a small-scale structure, the crack patterns tend to be unclear and unrealistic due to the excessively large diffusive crack zone. To address these limitations, we propose a novel PFF method to make the relation between the diffusive length scale and the material parameters adjustable via modifying the energetic degradation functions. It is found that with the increase of the diffusive crack length scale, a transition from quasi-brittleness to brittleness is observed in the constitutive relationship curves, which coincides with the classical size effect on structural strength. Further, the Bažant's size effect in classical fracture mechanics can be reproduced by the present PFF method through scaling the size of a geometrically similar structure, i.e. a large-scale structure exhibits toughness-dominated fracture while a small-scale structure behavior strength-dominated fracture. The present PFF method efficiently addresses the mismatch of diffusive length scales for various material constituents by examining phase field crack growth in particle-reinforced composite plates. By adjusting the diffusive crack length scale based on structure size, it avoids high computational costs from large structures and unrealistic crack patterns from small ones. Moreover, it outperforms traditional PFF methods using a constant diffusive length scale in handling composite materials.
{"title":"Diffusive-length-scale adjustable phase field fracture model for large/small structures","authors":"Yaode Yin, Hongjun Yu, Hongru Yan, Shuai Zhu","doi":"10.1016/j.ijmecsci.2024.109839","DOIUrl":"10.1016/j.ijmecsci.2024.109839","url":null,"abstract":"<div><div>In phase field fracture (PFF) method, the sharp crack is approximated by a phase field crack zone whose size is characterized by a diffusive length scale. Recently, the diffusive length scale is usually regarded as a constant material parameter determined by the fracture toughness, material strength, and young's modulus. As a result, the application of the PFF method poses challenges when dealing with structures whose sizes are much too large or small compared to the constant diffusive length scale. In details, for a large-scale structure, a significant computational burden is inevitable due to the limitation imposed by the constant diffusive crack length scale on the element size (i.e. the element size is generally at least smaller than half of the diffusive crack length scale to achieve the sufficient precision for the phase field process zone). For a small-scale structure, the crack patterns tend to be unclear and unrealistic due to the excessively large diffusive crack zone. To address these limitations, we propose a novel PFF method to make the relation between the diffusive length scale and the material parameters adjustable via modifying the energetic degradation functions. It is found that with the increase of the diffusive crack length scale, a transition from quasi-brittleness to brittleness is observed in the constitutive relationship curves, which coincides with the classical size effect on structural strength. Further, the Bažant's size effect in classical fracture mechanics can be reproduced by the present PFF method through scaling the size of a geometrically similar structure, i.e. a large-scale structure exhibits toughness-dominated fracture while a small-scale structure behavior strength-dominated fracture. The present PFF method efficiently addresses the mismatch of diffusive length scales for various material constituents by examining phase field crack growth in particle-reinforced composite plates. By adjusting the diffusive crack length scale based on structure size, it avoids high computational costs from large structures and unrealistic crack patterns from small ones. Moreover, it outperforms traditional PFF methods using a constant diffusive length scale in handling composite materials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109839"},"PeriodicalIF":7.1,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746570","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}
Pub Date : 2024-11-20DOI: 10.1016/j.ijmecsci.2024.109826
Quan Zhang, Stephan Rudykh
In this work, an approach for engineering translational-rotational coupling (TRC) metamaterials with magnetically tunable topological states is proposed. The metamaterial exhibits diverse nonlinear mechanical behaviors, remotely controlled and activated by an external magnetic field. The design is realized through a multi-material microstructure with highly deformable hinge configurations, targeting desirable strain-softening/stiffening characteristics. This 3D-printable hinge design eliminates the complex manual assembly processes typically required in current TRC metamaterials that are based on triangulated cylindrical origami. The stiffness transition property of the TRC metamaterials can be exploited to break the space-inversion symmetry and thus achieve tunable topological phase transition. Specifically, hard-magnetic active material is incorporated to enable untethered shape- and property-actuation in these metamaterials. The TRC metamaterial design is supported by a simplified analytical model whose stiffness parameters are directly linked to the hinge microstructure, offering a significant improvement over previous empirical model. The accuracy of the analytical model is demonstrated through the comparison with the finite element and experimental results. Through these methods, the deformations induced by a magnetic field and the dynamics of superimposed waves in the TRC metamaterial system are studied. Thanks to the magneto-mechanical coupling effect, the proposed TRC metamaterial design enables remote tunability of wave dispersions and topological invariants (including the Zak phase and winding number), in contrast to existing designs that require direct mechanical loading to achieve similar effects. This tunability extends to the control of topologically protected edge and interface states within the finite system. Our findings can potentially open new ways for designing remotely reconfigurable and switchable soft mechanical metamaterials with robust wave guiding and energy harvesting capabilities.
{"title":"Magnetically tunable topological states in translational-rotational coupling metamaterials","authors":"Quan Zhang, Stephan Rudykh","doi":"10.1016/j.ijmecsci.2024.109826","DOIUrl":"10.1016/j.ijmecsci.2024.109826","url":null,"abstract":"<div><div>In this work, an approach for engineering translational-rotational coupling (TRC) metamaterials with magnetically tunable topological states is proposed. The metamaterial exhibits diverse nonlinear mechanical behaviors, remotely controlled and activated by an external magnetic field. The design is realized through a multi-material microstructure with highly deformable hinge configurations, targeting desirable strain-softening/stiffening characteristics. This 3D-printable hinge design eliminates the complex manual assembly processes typically required in current TRC metamaterials that are based on triangulated cylindrical origami. The stiffness transition property of the TRC metamaterials can be exploited to break the space-inversion symmetry and thus achieve tunable topological phase transition. Specifically, hard-magnetic active material is incorporated to enable untethered shape- and property-actuation in these metamaterials. The TRC metamaterial design is supported by a simplified analytical model whose stiffness parameters are directly linked to the hinge microstructure, offering a significant improvement over previous empirical model. The accuracy of the analytical model is demonstrated through the comparison with the finite element and experimental results. Through these methods, the deformations induced by a magnetic field and the dynamics of superimposed waves in the TRC metamaterial system are studied. Thanks to the magneto-mechanical coupling effect, the proposed TRC metamaterial design enables remote tunability of wave dispersions and topological invariants (including the Zak phase and winding number), in contrast to existing designs that require direct mechanical loading to achieve similar effects. This tunability extends to the control of topologically protected edge and interface states within the finite system. Our findings can potentially open new ways for designing remotely reconfigurable and switchable soft mechanical metamaterials with robust wave guiding and energy harvesting capabilities.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109826"},"PeriodicalIF":7.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696893","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}
Pub Date : 2024-11-20DOI: 10.1016/j.ijmecsci.2024.109842
Han Zhu , Ning Qiu , Pei Xu , Wenjie Zhou , Yifu Gong , Bangxiang Che
The scale effect of vortex generators, as microstructures, influences cavitation erosion remains unclear, posing a key challenge to applying vortex generators in large-scale hydraulic machinery. In this study, the vortex generators (VGs) with heights of 0.25 mm (micro-VG) and 2.5 mm (large-VG), installed at the leading edge of a smooth NACA0015 hydrofoil, were investigated through experimental and simulation methods. The results demonstrate that the vortex generators can induce tubular vortexes that enhance near-wall flow stability. After installing the VGs, the large-scale cloud cavitation is effectively controlled. On the hydrofoil with micro-VGs, this control manifests as localized, small-scale cavitation shedding and collapse, while on the hydrofoil with large-VGs, the cavitation shedding is entirely absent, which shows that larger VGs further mitigate cavitation effects. Pressure signal analysis reveals that the VGs alter the pressure fluctuation period and reduce the main frequency amplitude compared to that on the smooth hydrofoil, with larger VGs providing superior suppression of pressure fluctuations. Additionally, an improved strength function method is proposed and applied, highlighting that the reduction in large-scale cloud cavitation by the VGs contributes to decreased erosion risk on the hydrofoil, with larger VGs showing enhanced effectiveness in preventing cavitation erosion.
{"title":"Cavitation erosion characteristics influenced by a microstructure at different scales","authors":"Han Zhu , Ning Qiu , Pei Xu , Wenjie Zhou , Yifu Gong , Bangxiang Che","doi":"10.1016/j.ijmecsci.2024.109842","DOIUrl":"10.1016/j.ijmecsci.2024.109842","url":null,"abstract":"<div><div>The scale effect of vortex generators, as microstructures, influences cavitation erosion remains unclear, posing a key challenge to applying vortex generators in large-scale hydraulic machinery. In this study, the vortex generators (VGs) with heights of 0.25 mm (micro-VG) and 2.5 mm (large-VG), installed at the leading edge of a smooth NACA0015 hydrofoil, were investigated through experimental and simulation methods. The results demonstrate that the vortex generators can induce tubular vortexes that enhance near-wall flow stability. After installing the VGs, the large-scale cloud cavitation is effectively controlled. On the hydrofoil with micro-VGs, this control manifests as localized, small-scale cavitation shedding and collapse, while on the hydrofoil with large-VGs, the cavitation shedding is entirely absent, which shows that larger VGs further mitigate cavitation effects. Pressure signal analysis reveals that the VGs alter the pressure fluctuation period and reduce the main frequency amplitude compared to that on the smooth hydrofoil, with larger VGs providing superior suppression of pressure fluctuations. Additionally, an improved strength function method is proposed and applied, highlighting that the reduction in large-scale cloud cavitation by the VGs contributes to decreased erosion risk on the hydrofoil, with larger VGs showing enhanced effectiveness in preventing cavitation erosion.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109842"},"PeriodicalIF":7.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722689","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}
Pub Date : 2024-11-20DOI: 10.1016/j.ijmecsci.2024.109847
Lili Xie , Kaijin Wu , Xiaozhi Liang , Zhaoqiang Song , Jun Ding , Jianhai Jin , Yu Yao , Linghui He , Yong Ni
Dynamic breaking and reforming of sacrificial bonds in sliding interfaces of biological and bioinspired heterostructures could greatly enhance fracture resistance by providing a self-healing energy dissipation process. Nevertheless, how interfacial self-healing behaviors and nonuniform stress transfer act in concert over multiple length scales and boost fracture toughness remains elusive. Here, a multiscale fracture mechanics model for bioinspired staggered heterostructures was developed by integrating interfacial self-healing behaviors, RVE's deformation responses, and macroscopic crack bridging. We found two critical brick sizes between which the fracture toughness enhanced by interfacial self-healing processes surpasses that by ideal elastic-plastic interface. The simultaneous increased crack-bridging stress and opening displacement induced by interfacial nonuniform deformation modes, including elastic, strengthening and sliding stages between the two critical sizes, are identified to enhance the fracture resistance. Moreover, our model provides parametric guidelines for optimizing bioinspired fracture-resistant structural materials with self-healing interfaces.
{"title":"Toughening by interfacial self-healing processes in bioinspired staggered heterostructures","authors":"Lili Xie , Kaijin Wu , Xiaozhi Liang , Zhaoqiang Song , Jun Ding , Jianhai Jin , Yu Yao , Linghui He , Yong Ni","doi":"10.1016/j.ijmecsci.2024.109847","DOIUrl":"10.1016/j.ijmecsci.2024.109847","url":null,"abstract":"<div><div>Dynamic breaking and reforming of sacrificial bonds in sliding interfaces of biological and bioinspired heterostructures could greatly enhance fracture resistance by providing a self-healing energy dissipation process. Nevertheless, how interfacial self-healing behaviors and nonuniform stress transfer act in concert over multiple length scales and boost fracture toughness remains elusive. Here, a multiscale fracture mechanics model for bioinspired staggered heterostructures was developed by integrating interfacial self-healing behaviors, RVE's deformation responses, and macroscopic crack bridging. We found two critical brick sizes between which the fracture toughness enhanced by interfacial self-healing processes surpasses that by ideal elastic-plastic interface. The simultaneous increased crack-bridging stress and opening displacement induced by interfacial nonuniform deformation modes, including elastic, strengthening and sliding stages between the two critical sizes, are identified to enhance the fracture resistance. Moreover, our model provides parametric guidelines for optimizing bioinspired fracture-resistant structural materials with self-healing interfaces.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"285 ","pages":"Article 109847"},"PeriodicalIF":7.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722687","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}
Pub Date : 2024-11-19DOI: 10.1016/j.ijmecsci.2024.109819
Ruifeng Wang , Liang Wang , Botao Jia , Shuchao Deng , Zhenhua Zhao
Sandwich single-phase-driven piezoelectric actuators have attracted increasing interest owing to their simple control circuits, flexible designs, and high output forces. However, there are challenges in constructing a standing-wave driving mode for sandwich single-phase-driven rotary piezoelectric actuators and in achieving bidirectional driving as well as an integrated structural and functional design, which limit their applications. To address these issues and meet the demands of the joint drive, a novel sandwich single-phase-driven rotary piezoelectric actuator is proposed in this study. The actuator stator has a beam-ring configuration, with dual rotors effectively integrated with a preload adjustment mechanism to solve the contact-warping problem of the cantilever joint and achieve an integrated structural and functional design of the joint drive. The standing-wave rotation drive and steering functions are realized through the special design of modes and unique arrangement of the upper and lower driving teeth. To reveal the dynamic characteristics of the stator, a universal electromechanical coupling dynamic model for the torsional-bending composite vibration of sandwich piezoelectric actuators was developed for the first time using the transfer matrix method, and the correctness of the dynamic model was verified using a prototype of the proposed stator. Finally, the structural design feasibility of the proposed piezoelectric actuator was verified through performance evaluation experiments on the actuator prototype. The proposed sandwich single-phase-driven rotary piezoelectric actuator lays the technical and theoretical foundations for achieving simple, fast, efficient, and precise driving and control of robotic joints.
{"title":"Design and modelling of a novel single-phase-driven piezoelectric actuator","authors":"Ruifeng Wang , Liang Wang , Botao Jia , Shuchao Deng , Zhenhua Zhao","doi":"10.1016/j.ijmecsci.2024.109819","DOIUrl":"10.1016/j.ijmecsci.2024.109819","url":null,"abstract":"<div><div>Sandwich single-phase-driven piezoelectric actuators have attracted increasing interest owing to their simple control circuits, flexible designs, and high output forces. However, there are challenges in constructing a standing-wave driving mode for sandwich single-phase-driven rotary piezoelectric actuators and in achieving bidirectional driving as well as an integrated structural and functional design, which limit their applications. To address these issues and meet the demands of the joint drive, a novel sandwich single-phase-driven rotary piezoelectric actuator is proposed in this study. The actuator stator has a beam-ring configuration, with dual rotors effectively integrated with a preload adjustment mechanism to solve the contact-warping problem of the cantilever joint and achieve an integrated structural and functional design of the joint drive. The standing-wave rotation drive and steering functions are realized through the special design of modes and unique arrangement of the upper and lower driving teeth. To reveal the dynamic characteristics of the stator, a universal electromechanical coupling dynamic model for the torsional-bending composite vibration of sandwich piezoelectric actuators was developed for the first time using the transfer matrix method, and the correctness of the dynamic model was verified using a prototype of the proposed stator. Finally, the structural design feasibility of the proposed piezoelectric actuator was verified through performance evaluation experiments on the actuator prototype. The proposed sandwich single-phase-driven rotary piezoelectric actuator lays the technical and theoretical foundations for achieving simple, fast, efficient, and precise driving and control of robotic joints.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"286 ","pages":"Article 109819"},"PeriodicalIF":7.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696894","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}
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