Pub Date : 2024-10-10DOI: 10.1016/j.ijsolstr.2024.113097
Yongqiang Li
A thirteen-node octahedral three-dimensional lattice-spring model based on the sapphire crystal structure is established by applying the parameter mapping theory, and the finite element stiffness matrix is mapped into the linear spring stiffness coefficients of the lattice-spring model according to the parameter mapping method, so that the selection of the spring stiffness coefficients has a strict mathematical derivation. The elastic–plastic potential function that unifies the elastic–plastic characteristics of the material and the fracture energy is established. The lattice-spring model is tested by three algorithms, including longitudinal wave velocity, three-dimensional crack extension path under dynamic indentation, and impact compression deformation and lattice size sensitivity test, and the test results show that the established three-dimensional lattice-spring model has a high computational accuracy. The correctness of the calculation of the lattice-spring model is verified by comparing the calculation of the evolution process of spherical impact damage on the edge of sapphire under different crystal directions with the experiment.
{"title":"Three-dimensional elastic–plastic lattice-spring model based on sapphire crystal structure and its application to impact characterisation studies","authors":"Yongqiang Li","doi":"10.1016/j.ijsolstr.2024.113097","DOIUrl":"10.1016/j.ijsolstr.2024.113097","url":null,"abstract":"<div><div>A thirteen-node octahedral three-dimensional lattice-spring model based on the sapphire crystal structure is established by applying the parameter mapping theory, and the finite element stiffness matrix is mapped into the linear spring stiffness coefficients of the lattice-spring model according to the parameter mapping method, so that the selection of the spring stiffness coefficients has a strict mathematical derivation. The elastic–plastic potential function that unifies the elastic–plastic characteristics of the material and the fracture energy is established. The lattice-spring model is tested by three algorithms, including longitudinal wave velocity, three-dimensional crack extension path under dynamic indentation, and impact compression deformation and lattice size sensitivity test, and the test results show that the established three-dimensional lattice-spring model has a high computational accuracy. The correctness of the calculation of the lattice-spring model is verified by comparing the calculation of the evolution process of spherical impact damage on the edge of sapphire under different crystal directions with the experiment.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"306 ","pages":"Article 113097"},"PeriodicalIF":3.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-10DOI: 10.1016/j.ijsolstr.2024.113103
Gioacchino Alotta, Andrea Francesco Russillo, Giuseppe Failla
Nonlocal theories are well established to model statics and dynamics of small-size structures. Recent studies investigated elastic wave propagation in nonlocal beams and attention focused on periodic nonlocal beams, either endowed with resonators or resting on supports, for relevant applications at small scale. In this context, this work proposes a stress-driven nonlocal Timoshenko beam formulation and develops an original and comprehensive analytical/computational framework for wave propagation analysis in bare and periodic beams.
The framework addresses infinite and finite beams. First, exact analytical expressions are derived for the dispersion curves of the bare beam, which provide full insight into the effects of nonlocality. Second, an exact Plane Wave Expansion method is devised for periodic beams, either equipped with mass-spring resonators or resting on elastic supports; both and dispersion curves are derived in this work, where is the frequency and is the wave number. Third, an approximate homogenization approach is formulated to estimate opening frequencies and sizes of band gaps induced by mass-spring resonators. Finally, a two-field finite element method is proposed to calculate the transmittance of finite periodic beams.
Numerical applications investigate the dispersion diagram of bare and periodic beams for different internal lengths of the stress-driven nonlocal model. Remarkably, results for finite periodic beams validate the predictions from wave propagation analysis of corresponding infinite ones. Moreover, parametric analyses show the capability of the stress-driven nonlocal model in capturing typical small-size effects.
{"title":"Elastic wave propagation in periodic stress-driven nonlocal Timoshenko beams","authors":"Gioacchino Alotta, Andrea Francesco Russillo, Giuseppe Failla","doi":"10.1016/j.ijsolstr.2024.113103","DOIUrl":"10.1016/j.ijsolstr.2024.113103","url":null,"abstract":"<div><div>Nonlocal theories are well established to model statics and dynamics of small-size structures. Recent studies investigated elastic wave propagation in nonlocal beams and attention focused on periodic nonlocal beams, either endowed with resonators or resting on supports, for relevant applications at small scale. In this context, this work proposes a stress-driven nonlocal Timoshenko beam formulation and develops an original and comprehensive analytical/computational framework for wave propagation analysis in bare and periodic beams.</div><div>The framework addresses infinite and finite beams. First, exact analytical expressions are derived for the dispersion curves of the bare beam, which provide full insight into the effects of nonlocality. Second, an exact Plane Wave Expansion method is devised for periodic beams, either equipped with mass-spring resonators or resting on elastic supports; both <span><math><mrow><mi>ω</mi><mrow><mo>(</mo><mi>q</mi><mo>)</mo></mrow></mrow></math></span> and <span><math><mrow><mi>q</mi><mrow><mo>(</mo><mi>ω</mi><mo>)</mo></mrow></mrow></math></span> dispersion curves are derived in this work, where <span><math><mi>ω</mi></math></span> is the frequency and <span><math><mi>q</mi></math></span> is the wave number. Third, an approximate homogenization approach is formulated to estimate opening frequencies and sizes of band gaps induced by mass-spring resonators. Finally, a two-field finite element method is proposed to calculate the transmittance of finite periodic beams.</div><div>Numerical applications investigate the dispersion diagram of bare and periodic beams for different internal lengths of the stress-driven nonlocal model. Remarkably, results for finite periodic beams validate the predictions from wave propagation analysis of corresponding infinite ones. Moreover, parametric analyses show the capability of the stress-driven nonlocal model in capturing typical small-size effects.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"306 ","pages":"Article 113103"},"PeriodicalIF":3.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.ijsolstr.2024.113096
Nehemiah Mork, Antonia Antoniou, Michael J. Leamy
Digital image correlation (DIC) is an increasingly popular and effective non-contact method for measuring full-field displacements and strains of deformable bodies under load. Current DIC methods applied to bodies undergoing large displacements and rotations require a large measurement area for both the reference (i.e., undeformed) image and the deformed images. This can limit the resulting resolution of the displacement and strain fields. To address this issue, we propose a two-stage dynamic DIC method capable of measuring displacements and strains under material convection with high resolution. During the first stage, the reference image is assembled from smaller, high-resolution images of the undeformed object obtained using a spatially-fixed or moving frame. Following capture, each sub-image is rigidly translated and rotated into its appropriate place, thereby producing a full, high-resolution image of the reference body. In stage two, images of the loaded and deformed body, again obtained using a small camera frame with high resolution, are aligned with matching regions of the undeformed composite image using BRISK feature detection before performing DIC. We demonstrate the method on a contact problem whereby an elastomeric roller travels along a rigid surface. In doing so, we obtain fine-resolution measurements of the state of strain of the region of the roller sidewall in contact with the substrate, even as new material convects through the region of interest. We present these measurements as a series of images and videos capturing strain evolution as the roller transitions from static loads to a fully dynamic steady-state, documenting the effectiveness of the method.
{"title":"Dynamic digital image correlation method for rolling convective contact","authors":"Nehemiah Mork, Antonia Antoniou, Michael J. Leamy","doi":"10.1016/j.ijsolstr.2024.113096","DOIUrl":"10.1016/j.ijsolstr.2024.113096","url":null,"abstract":"<div><div>Digital image correlation (DIC) is an increasingly popular and effective non-contact method for measuring full-field displacements and strains of deformable bodies under load. Current DIC methods applied to bodies undergoing large displacements and rotations require a large measurement area for both the reference (i.e., undeformed) image and the deformed images. This can limit the resulting resolution of the displacement and strain fields. To address this issue, we propose a two-stage dynamic DIC method capable of measuring displacements and strains under material convection with high resolution. During the first stage, the reference image is assembled from smaller, high-resolution images of the undeformed object obtained using a spatially-fixed or moving frame. Following capture, each sub-image is rigidly translated and rotated into its appropriate place, thereby producing a full, high-resolution image of the reference body. In stage two, images of the loaded and deformed body, again obtained using a small camera frame with high resolution, are aligned with matching regions of the undeformed composite image using BRISK feature detection before performing DIC. We demonstrate the method on a contact problem whereby an elastomeric roller travels along a rigid surface. In doing so, we obtain fine-resolution measurements of the state of strain of the region of the roller sidewall in contact with the substrate, even as new material convects through the region of interest. We present these measurements as a series of images and videos capturing strain evolution as the roller transitions from static loads to a fully dynamic steady-state, documenting the effectiveness of the method.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"306 ","pages":"Article 113096"},"PeriodicalIF":3.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.ijsolstr.2024.113098
Qing Lv , Yaqiong Tang , Xuechi Wang , Tuanjie Li
This paper develops a versatile and effective force-density framework for the flexible multi-body dynamic analysis of clustered tensegrity structures. In this framework, the force density is selected as the basic variable instead of force, and the clustered tensegrity structure is mathematically described in a vector and matrix form, encompassing topology, geometry, material, and force properties. A non-negative variable is defined as an indicator of the member stress state, and a complementary function is constructed to address the discontinuity issues that arise from the unidirectional axial stiffness of cables. Dynamic formulas are established within this force-density framework, with nodal coordinates selected as generalized parameters and formulations constructed in a matrix form. A complementary framework is established as an alternative for solving the dynamic equations, transforming the isolated steps of Newton’s iteration and cable state judgment (slack or tension) into a unified one, bringing more potential for improving solving efficiency. Numerical simulations are carried out to validate the approach, demonstrating that it effectively reveals the dynamic oscillation, tension changes, and cable slack behavior of clustered tensegrity structures during shape control. Comparative studies highlight the advantage of computational efficiency. The method proposed in this paper provides a robust mathematical model for studying clustered tensegrity structures, particularly regarding the shape control of deployable, active, and intelligent structures, aiding in understanding dynamic oscillation, tension changes, and cable slack behavior during their deformation. The methods can also be applied to cable net structures and other prestressed pin-jointed systems.
{"title":"A force-density framework for flexible multi-body dynamic analysis of clustered tensegrity structures","authors":"Qing Lv , Yaqiong Tang , Xuechi Wang , Tuanjie Li","doi":"10.1016/j.ijsolstr.2024.113098","DOIUrl":"10.1016/j.ijsolstr.2024.113098","url":null,"abstract":"<div><div>This paper develops a versatile and effective force-density framework for the flexible multi-body dynamic analysis of clustered tensegrity structures. In this framework, the force density is selected as the basic variable instead of force, and the clustered tensegrity structure is mathematically described in a vector and matrix form, encompassing topology, geometry, material, and force properties. A non-negative variable is defined as an indicator of the member stress state, and a complementary function is constructed to address the discontinuity issues that arise from the unidirectional axial stiffness of cables. Dynamic formulas are established within this force-density framework, with nodal coordinates selected as generalized parameters and formulations constructed in a matrix form. A complementary framework is established as an alternative for solving the dynamic equations, transforming the isolated steps of Newton’s iteration and cable state judgment (slack or tension) into a unified one, bringing more potential for improving solving efficiency. Numerical simulations are carried out to validate the approach, demonstrating that it effectively reveals the dynamic oscillation, tension changes, and cable slack behavior of clustered tensegrity structures during shape control. Comparative studies highlight the advantage of computational efficiency. The method proposed in this paper provides a robust mathematical model for studying clustered tensegrity structures, particularly regarding the shape control of deployable, active, and intelligent structures, aiding in understanding dynamic oscillation, tension changes, and cable slack behavior during their deformation. The methods can also be applied to cable net structures and other prestressed pin-jointed systems.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113098"},"PeriodicalIF":3.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.ijsolstr.2024.113095
Teik-Cheng Lim
The fragmentation-reconstitution (FR) metamaterial has recently been shown to be a suitable candidate for producing Poisson’s ratio discontinuity at the original state. A new FR metamaterial is introduced herein that additionally permits sign-switching of Poisson’s ratio upon stress reversal along one axis. This was achieved by the use of rotating rhombi in which every rhombus can be further fragmented into six sub-units. The latter consists of two non-rotating smaller rhombi and four rotating isosceles triangles. While results show that the metamaterial exhibits sign-switching of Poisson’s ratio upon stress reversal along one axis due to differing mechanism, this is not so for loading in the other on-axis direction due to the dimension being maximum in that direction. Instead, there are two compression pathways which can lead to either fragmentation or reconstitution modes of deformation. The predisposition for each pathway is proposed by means of charge attachments. The uniqueness of this metamaterial avails its use for applications that are not attainable by other materials and metamaterials.
{"title":"A metamaterial with sign-switching and discontinuous Poisson’s ratio","authors":"Teik-Cheng Lim","doi":"10.1016/j.ijsolstr.2024.113095","DOIUrl":"10.1016/j.ijsolstr.2024.113095","url":null,"abstract":"<div><div>The fragmentation-reconstitution (FR) metamaterial has recently been shown to be a suitable candidate for producing Poisson’s ratio discontinuity at the original state. A new FR metamaterial is introduced herein that additionally permits sign-switching of Poisson’s ratio upon stress reversal along one axis. This was achieved by the use of rotating rhombi in which every rhombus can be further fragmented into six sub-units. The latter consists of two non-rotating smaller rhombi and four rotating isosceles triangles. While results show that the metamaterial exhibits sign-switching of Poisson’s ratio upon stress reversal along one axis due to differing mechanism, this is not so for loading in the other on-axis direction due to the dimension being maximum in that direction. Instead, there are two compression pathways which can lead to either fragmentation or reconstitution modes of deformation. The predisposition for each pathway is proposed by means of charge attachments. The uniqueness of this metamaterial avails its use for applications that are not attainable by other materials and metamaterials.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113095"},"PeriodicalIF":3.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-05DOI: 10.1016/j.ijsolstr.2024.113099
Ziheng Wang , Chaofan Feng , Dongjie Jiang
Under cyclic loads, superelastic shape memory alloys (SMAs) exhibit stress–strain responses featured by functional fatigue, i.e., degradation of superelasticity and accumulation of irrecoverable deformation as cycling number increases, together with an asymmetry between tensile and compressive responses. Comprehensive understanding and modeling of these material complexities are crucial for the design and analysis of various superelastic SMA structures in practical applications. This work has developed a novel constitutive model based on irreversible thermodynamics to account for functional fatigue with tension–compression asymmetry. A potential function, defined as a weighted sum of two potentials that are calibrated against the tensile and compressive responses respectively, is employed to generate the asymmetric responses, and functional fatigue is represented by degradation of superelastic properties and growth of plastic strain as martensitic transformation accumulates. The model is adopted in numerical simulations for superelastic SMA tubes under cyclic lateral compression, which is experimentally investigated as a model problem. The agreement between simulations and experiments shows the validity and effectiveness of this constitutive modeling. Through additional finite element simulations incorporating this model, the effects of tension–compression asymmetry under cycling and diameter-to-thickness ratio of the tubular geometry upon mechanical responses of laterally compressed SMA tubes are also unveiled.
在循环载荷作用下，超弹性形状记忆合金（SMA）表现出以功能疲劳为特征的应力-应变响应，即随着循环次数的增加，超弹性下降，不可恢复的变形累积，以及拉伸和压缩响应之间的不对称。对这些材料复杂性的全面理解和建模对于设计和分析实际应用中的各种超弹性 SMA 结构至关重要。这项研究基于不可逆热力学开发了一种新的构成模型，用于解释具有拉伸-压缩不对称的功能疲劳。该模型采用了一个电位函数（定义为两个电位的加权和，分别针对拉伸和压缩响应进行校准）来生成非对称响应，并通过超弹性性能的退化和马氏体转变累积时塑性应变的增长来表示功能疲劳。该模型用于循环横向压缩条件下超弹性 SMA 管的数值模拟，并作为模型问题进行了实验研究。模拟与实验之间的一致性表明了该构成模型的有效性。通过结合该模型的额外有限元模拟，还揭示了循环下拉伸-压缩不对称以及管材几何形状的直径-厚度比对横向压缩 SMA 管机械响应的影响。
{"title":"Constitutive modeling of functional fatigue with tension–compression asymmetry for superelastic NiTi shape memory alloy","authors":"Ziheng Wang , Chaofan Feng , Dongjie Jiang","doi":"10.1016/j.ijsolstr.2024.113099","DOIUrl":"10.1016/j.ijsolstr.2024.113099","url":null,"abstract":"<div><div>Under cyclic loads, superelastic shape memory alloys (SMAs) exhibit stress–strain responses featured by functional fatigue, i.e., degradation of superelasticity and accumulation of irrecoverable deformation as cycling number increases, together with an asymmetry between tensile and compressive responses. Comprehensive understanding and modeling of these material complexities are crucial for the design and analysis of various superelastic SMA structures in practical applications. This work has developed a novel constitutive model based on irreversible thermodynamics to account for functional fatigue with tension–compression asymmetry. A potential function, defined as a weighted sum of two potentials that are calibrated against the tensile and compressive responses respectively, is employed to generate the asymmetric responses, and functional fatigue is represented by degradation of superelastic properties and growth of plastic strain as martensitic transformation accumulates. The model is adopted in numerical simulations for superelastic SMA tubes under cyclic lateral compression, which is experimentally investigated as a model problem. The agreement between simulations and experiments shows the validity and effectiveness of this constitutive modeling. Through additional finite element simulations incorporating this model, the effects of tension–compression asymmetry under cycling and diameter-to-thickness ratio of the tubular geometry upon mechanical responses of laterally compressed SMA tubes are also unveiled.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113099"},"PeriodicalIF":3.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-05DOI: 10.1016/j.ijsolstr.2024.113091
Fan Yang , Puhao Li , Zhengmiao Guo , Xiaoyan Li , Jinfeng Zhao , Lihua Wang , Zheng Zhong
There has been an increasing interest among the material research community in the pursuit of enhancing the designability of mechanical properties. The existing approaches usually resorted to sophisticated algorithms (such as machine learning) for the reverse design of materials with specific properties. Different from these existing approaches, here we propose a new approach to create lattice metamaterials with continuously controllable mechanical properties by continuously adjusting the geometric parameters of a unique cell topology originated from the projection of four-dimensional hypercubes. The cells contain an inner region and an outer region, each with different deformation characteristics. For example, the inner region is a stretching-dominated simple cubic (SC) unit cell, while the outer region is a bending-dominated body-centered cubic (BCC) unit cell. Specifically, both stiffness and strength isotropy can be simultaneously realized. The proposed lattice metamaterial exhibits intriguing feature of dual stress plateaus. These plateaus can be effectively controlled by adjusting the geometric parameters of inner and outer regions, which enables these lattice metamaterials to hold promising application prospects in the energy absorption scenarios, such as vehicle and pedestrian protection. Such lattice metamaterial design can be used to realize the gradient distribution of mechanical properties through continuous transition of cell topology without introduction of inefficient interfaces, providing a new approach for the design of heterogeneous metamaterials used in the scenarios involving non-uniform stress distribution.
{"title":"Lattice metamaterials with controllable mechanical properties inspired by projection of four-dimensional hypercubes","authors":"Fan Yang , Puhao Li , Zhengmiao Guo , Xiaoyan Li , Jinfeng Zhao , Lihua Wang , Zheng Zhong","doi":"10.1016/j.ijsolstr.2024.113091","DOIUrl":"10.1016/j.ijsolstr.2024.113091","url":null,"abstract":"<div><div>There has been an increasing interest among the material research community in the pursuit of enhancing the designability of mechanical properties. The existing approaches usually resorted to sophisticated algorithms (such as machine learning) for the reverse design of materials with specific properties. Different from these existing approaches, here we propose a new approach to create lattice metamaterials with continuously controllable mechanical properties by continuously adjusting the geometric parameters of a unique cell topology originated from the projection of four-dimensional hypercubes. The cells contain an inner region and an outer region, each with different deformation characteristics. For example, the inner region is a stretching-dominated simple cubic (SC) unit cell, while the outer region is a bending-dominated body-centered cubic (BCC) unit cell. Specifically, both stiffness and strength isotropy can be simultaneously realized. The proposed lattice metamaterial exhibits intriguing feature of dual stress plateaus. These plateaus can be effectively controlled by adjusting the geometric parameters of inner and outer regions, which enables these lattice metamaterials to hold promising application prospects in the energy absorption scenarios, such as vehicle and pedestrian protection. Such lattice metamaterial design can be used to realize the gradient distribution of mechanical properties through continuous transition of cell topology without introduction of inefficient interfaces, providing a new approach for the design of heterogeneous metamaterials used in the scenarios involving non-uniform stress distribution.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113091"},"PeriodicalIF":3.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-05DOI: 10.1016/j.ijsolstr.2024.113093
Shenghao Chen, Qun Li, Yingxuan Dong, Junling Hou
The complex microstructural characteristics inherent in short fiber reinforced rubber composites (SFRRCs) impose considerable computational burdens in predicting the mechanical behavior of such composite materials. To address this challenge, this research extends the applicability of the homogeneous model predicated on the orientation averaging method to encompass composite materials featuring hyperelastic matrices. Combined with finite element method, a comprehensive mechanical response database encompassing various volume fractions and fiber orientation distributions is established. Leveraging this database, a micromechanics-based artificial neural network (ANN) model is meticulously designed to rapidly predict the mechanical response of SFRRCs across varying volume fractions and fiber orientation distributions, utilizing a fixed strain step strategy. To ascertain the efficacy and precision of the developed ANN model, representative volume elements portraying both planar and three-dimensional random distributions of composites are constructed and subjected to finite element analysis. Results indicate that the predicted outcomes from the ANN model align closely with finite element calculations within a certain strain range, while significantly reducing computational costs.
短纤维增强橡胶复合材料（SFRRCs）固有的复杂微观结构特征给预测此类复合材料的机械行为带来了相当大的计算负担。为了应对这一挑战，本研究扩展了以取向平均法为基础的均质模型的适用范围，将具有超弹性基体的复合材料也包括在内。结合有限元方法，建立了一个包含各种体积分数和纤维取向分布的综合机械响应数据库。利用该数据库，精心设计了基于微观力学的人工神经网络（ANN）模型，采用固定应变步长策略，快速预测不同体积分数和纤维取向分布的 SFRRC 的机械响应。为了确定所开发的 ANN 模型的有效性和精确性，构建了复合材料平面和三维随机分布的代表性体积元素，并对其进行了有限元分析。结果表明，在一定应变范围内，ANN 模型的预测结果与有限元计算结果非常接近，同时大大降低了计算成本。
{"title":"A micromechanics-based artificial neural networks model for rapid prediction of mechanical response in short fiber reinforced rubber composites","authors":"Shenghao Chen, Qun Li, Yingxuan Dong, Junling Hou","doi":"10.1016/j.ijsolstr.2024.113093","DOIUrl":"10.1016/j.ijsolstr.2024.113093","url":null,"abstract":"<div><div>The complex microstructural characteristics inherent in short fiber reinforced rubber composites (SFRRCs) impose considerable computational burdens in predicting the mechanical behavior of such composite materials. To address this challenge, this research extends the applicability of the homogeneous model predicated on the orientation averaging method to encompass composite materials featuring hyperelastic matrices. Combined with finite element method, a comprehensive mechanical response database encompassing various volume fractions and fiber orientation distributions is established. Leveraging this database, a micromechanics-based artificial neural network (ANN) model is meticulously designed to rapidly predict the mechanical response of SFRRCs across varying volume fractions and fiber orientation distributions, utilizing a fixed strain step strategy. To ascertain the efficacy and precision of the developed ANN model, representative volume elements portraying both planar and three-dimensional random distributions of composites are constructed and subjected to finite element analysis. Results indicate that the predicted outcomes from the ANN model align closely with finite element calculations within a certain strain range, while significantly reducing computational costs.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113093"},"PeriodicalIF":3.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-05DOI: 10.1016/j.ijsolstr.2024.113101
Xin Li, Dingcong Zhang, Jiashen Guan, Ju Liu, Hongyan Yuan
The main purpose of this work is to develop a three-dimensional (3D) viscoelastic rod model for hard-magnetic soft (HMS) rods under large deformation which are widely used active structures in soft robotics. To do so, the Simo’s viscoelasticity theory has been rationally incorporated into the geometrically exact 3D curved rod model. The proposed model includes the deformation modes of axial tension, shear, bending, and torsion, which is applicable to the HMS rods with arbitrarily initial curved and twisted geometries under 3D large deformation. The viscoelastic constitutive equations of the HMS rod in the present formulation are formulated, which include the general relaxation functions. To obtain the expression for the magnetic load, the rotation-based magnetic free energy density is introduced, and the governing equations of the HMS rod with magnetic load and body force are presented. To obtain the numerical implementation, an implicit time integration algorithm that simply extends the generalized-α method for the rotation group, and the corresponding variational formulation and its linearization of the rod model are derived. To validate the model, five numerical examples, including 2D dynamic buckling, 3D static, and 3D dynamic problem are presented. The dynamic problems include the dynamic snap-through behavior of a bistable HMS arch and damped oscillation of a quarter arc cantilever under 3D deformation. The simulation results show good agreement with the results reported in the literature.
这项工作的主要目的是为软机器人技术中广泛使用的主动结构--大变形下的硬磁软（HMS）杆开发一种三维（3D）粘弹性杆模型。为此，Simo 的粘弹性理论被合理地融入到几何精确的三维曲面杆模型中。所提出的模型包括轴向拉伸、剪切、弯曲和扭转等变形模式，适用于三维大变形条件下具有任意初始弯曲和扭曲几何形状的 HMS 杆件。本公式中的 HMS 杆件粘弹性构成方程包括一般松弛函数。为了获得磁载荷的表达式，引入了基于旋转的磁自由能密度，并给出了带磁载荷和体力的 HMS 杆件的支配方程。为了实现数值计算，对旋转组的广义α法进行了简单扩展的隐式时间积分算法，并推导出了相应的变分公式及其杆模型的线性化。为了验证模型，介绍了五个数值示例，包括二维动态屈曲、三维静态和三维动态问题。动态问题包括双稳态 HMS 拱门的动态屈曲行为和四分之一弧形悬臂在三维变形下的阻尼振动。模拟结果与文献报道的结果非常吻合。
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Pub Date : 2024-10-05DOI: 10.1016/j.ijsolstr.2024.113090
Bin Yang , Juhyeong Lee , Yuchen Zhou , Xiaoshan Liu , C. Guedes Soares , Kunkun Fu , Dongmin Yang
In this study, lightning strike damage of woven carbon fibre-reinforced polymer laminates (W-CFRPs) and woven composite honeycomb sandwich panels (W-CHSPs) are simulated using the proposed sequential thermal-electrical–mechanical finite element (FE) coupling model incorporating dielectric breakdown of materials. Surface current with an amplitude of 200 kA and corresponding lightning shockwave overpressure were applied on each composite. The FE model coupled with LaRC05 criterion was used to study the failure behaviours of intralaminar damage and interlaminar delamination of the W-CFRPs and W-CHSPs. A series of lightning strike tests were performed to validate the FE model. Detailed lightning damage assessments and mechanisms were characterized by a combination of visual inspection, image processing, ultrasonic scanning and micro computed tomography (Micro-CT) and showed good agreements with the FE-predicted results. It can be concluded that shockwave overpressure significantly impacts lightning-induced damages, thereby supporting the effectiveness of the newly proposed sequential thermal-electrical–mechanical coupling model, which demonstrates improved predictive accuracy.
本研究采用所提出的包含材料介电击穿的热-电-机有限元（FE）耦合序列模型，模拟了编织碳纤维增强聚合物层压板（W-CFRP）和编织复合蜂窝夹芯板（W-CHSP）的雷击损伤。在每种复合材料上施加了幅值为 200 kA 的表面电流和相应的雷电冲击波超压。该 FE 模型与 LaRC05 准则相结合，用于研究 W-CFRP 和 W-CHSP 的层内损伤和层间分层的破坏行为。为验证 FE 模型，进行了一系列雷击试验。通过结合目视检查、图像处理、超声波扫描和微型计算机断层扫描（Micro-CT），对详细的雷击损伤评估和机制进行了表征，结果显示与有限元模型的预测结果一致。可以得出结论，冲击波超压对雷电诱发的损坏有显著影响，从而支持了新提出的热-电-机耦合顺序模型的有效性，该模型显示出更高的预测精度。
{"title":"Coupled thermal-electrical–mechanical characteristics of lightning damage in woven composite honeycomb sandwich structures","authors":"Bin Yang , Juhyeong Lee , Yuchen Zhou , Xiaoshan Liu , C. Guedes Soares , Kunkun Fu , Dongmin Yang","doi":"10.1016/j.ijsolstr.2024.113090","DOIUrl":"10.1016/j.ijsolstr.2024.113090","url":null,"abstract":"<div><div>In this study, lightning strike damage of woven carbon fibre-reinforced polymer laminates (W-CFRPs) and woven composite honeycomb sandwich panels (W-CHSPs) are simulated using the proposed sequential thermal-electrical–mechanical finite element (FE) coupling model incorporating dielectric breakdown of materials. Surface current with an amplitude of 200 kA and corresponding lightning shockwave overpressure were applied on each composite. The FE model coupled with LaRC05 criterion was used to study the failure behaviours of intralaminar damage and interlaminar delamination of the W-CFRPs and W-CHSPs. A series of lightning strike tests were performed to validate the FE model. Detailed lightning damage assessments and mechanisms were characterized by a combination of visual inspection, image processing, ultrasonic scanning and micro computed tomography (Micro-CT) and showed good agreements with the FE-predicted results. It can be concluded that shockwave overpressure significantly impacts lightning-induced damages, thereby supporting the effectiveness of the newly proposed sequential thermal-electrical–mechanical coupling model, which demonstrates improved predictive accuracy.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113090"},"PeriodicalIF":3.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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