Pub Date : 2024-11-04DOI: 10.1016/j.euromechsol.2024.105488
Xiangtian Shen, Yueguang Wei
Multilayered structures with slippery interfaces exhibit significant interlayer sliding during bending, enabling the design of structures with integrated functional capabilities by tailoring interfacial properties to control slip behavior and overall bending response. This study investigates the influence of different interfacial slip behaviors on the axisymmetric bending of multilayered structures, deriving analytical solutions for deflection and stiffness under two key interfacial shearing laws: Elastic Shear Stress (ESS) and Critical Shear Flow (CSF). The analytical results, validated by Finite Element Method (FEM), elucidate the impact of different shearing models on interfacial slip and overall load-displacement bending response. This study not only establishes a theoretical framework for understanding and predicting the bending behavior of circular multilayered structures with interfacial slip, but also provides valuable insights for experimental measurements and the design of functionally integrated structures.
{"title":"Slip-mediated axisymmetric bending of multilayered structures with different interfaces: Analytical solutions and design guidelines","authors":"Xiangtian Shen, Yueguang Wei","doi":"10.1016/j.euromechsol.2024.105488","DOIUrl":"10.1016/j.euromechsol.2024.105488","url":null,"abstract":"<div><div>Multilayered structures with slippery interfaces exhibit significant interlayer sliding during bending, enabling the design of structures with integrated functional capabilities by tailoring interfacial properties to control slip behavior and overall bending response. This study investigates the influence of different interfacial slip behaviors on the axisymmetric bending of multilayered structures, deriving analytical solutions for deflection and stiffness under two key interfacial shearing laws: Elastic Shear Stress (ESS) and Critical Shear Flow (CSF). The analytical results, validated by Finite Element Method (FEM), elucidate the impact of different shearing models on interfacial slip and overall load-displacement bending response. This study not only establishes a theoretical framework for understanding and predicting the bending behavior of circular multilayered structures with interfacial slip, but also provides valuable insights for experimental measurements and the design of functionally integrated structures.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105488"},"PeriodicalIF":4.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1016/j.euromechsol.2024.105479
Mayank Jain, Santosh Kapuria
Efficient structural element-based models are essential for fast simulations of wave propagation in composite structures for model-based and physics-informed data-driven structural health monitoring. This article introduces the first efficient multiphysics time-domain spectral structural element for wave propagation analysis of beam and panel-type composite structures with piezoelectric transducers (patch or full layers) containing delaminations. A general framework is presented to model multiple delaminations and transducer patches located arbitrarily. The intact host and patch transducer-bonded laminates and sub-laminates between delaminations are modelled separately using an electromechanically coupled efficient layerwise zigzag theory (ZIGT) for kinematics and a piecewise quadratic variation for the electric potential across piezoelectric layers. The high-order spectral element (SE) features a virtual electric node to model equipotential surfaces of piezoelectric transducers apart from the usual physical nodes having mechanical and internal electric degrees of freedom. A hybrid point-least squares continuity approach is employed to maintain continuity at the intersections of delaminated sub-laminates or the patch-bonded laminate with the host laminate. The model’s performance in capturing electroelastic waves’ interaction with delamination is examined with reference to the conventional finite element (FE) solution based on the ZIGT, continuum-based FE solutions, and the SE solution based on a non-layerwise version of the laminate theory. Finally, the model is used to examine the impact of interfacial location and size of delaminations on wave propagation behaviour.
基于模型和物理信息数据驱动的结构健康监测中，高效的结构元素模型对于复合材料结构中波传播的快速模拟至关重要。本文介绍了第一种高效的多物理场时域频谱结构元素，用于分析带有压电传感器（贴片或全层）、含有分层的梁式和板式复合材料结构的波传播。本文提出了一个通用框架，用于模拟多个分层和任意位置的传感器贴片。采用机电耦合的高效分层之字形理论 (ZIGT) 分别对完整的主机和贴片换能器结合层以及分层之间的子层板进行运动学建模，并采用片式二次变化对跨压电层的电动势进行建模。高阶谱元（SE）除了具有机械和内部电动自由度的常规物理节点外，还具有一个虚拟电动节点，用于模拟压电传感器的等电位表面。该模型采用混合点最小二乘法连续性方法，以保持分层子层压板或贴片粘合层压板与主层压板交汇处的连续性。参照基于 ZIGT 的传统有限元 (FE) 解法、基于连续体的 FE 解法和基于层压板理论非分层版本的 SE 解法，检验了该模型在捕捉电弹性波与分层相互作用方面的性能。最后，利用该模型研究了分层的界面位置和大小对波传播行为的影响。
{"title":"Efficient layerwise multiphysics spectral element model for delaminated composite strips with PWAS transducers","authors":"Mayank Jain, Santosh Kapuria","doi":"10.1016/j.euromechsol.2024.105479","DOIUrl":"10.1016/j.euromechsol.2024.105479","url":null,"abstract":"<div><div>Efficient structural element-based models are essential for fast simulations of wave propagation in composite structures for model-based and physics-informed data-driven structural health monitoring. This article introduces the first efficient multiphysics time-domain spectral structural element for wave propagation analysis of beam and panel-type composite structures with piezoelectric transducers (patch or full layers) containing delaminations. A general framework is presented to model multiple delaminations and transducer patches located arbitrarily. The intact host and patch transducer-bonded laminates and sub-laminates between delaminations are modelled separately using an electromechanically coupled efficient layerwise zigzag theory (ZIGT) for kinematics and a piecewise quadratic variation for the electric potential across piezoelectric layers. The high-order spectral element (SE) features a virtual electric node to model equipotential surfaces of piezoelectric transducers apart from the usual physical nodes having mechanical and internal electric degrees of freedom. A hybrid point-least squares continuity approach is employed to maintain continuity at the intersections of delaminated sub-laminates or the patch-bonded laminate with the host laminate. The model’s performance in capturing electroelastic waves’ interaction with delamination is examined with reference to the conventional finite element (FE) solution based on the ZIGT, continuum-based FE solutions, and the SE solution based on a non-layerwise version of the laminate theory. Finally, the model is used to examine the impact of interfacial location and size of delaminations on wave propagation behaviour.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105479"},"PeriodicalIF":4.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.euromechsol.2024.105483
Wei Wei , Jianhui Li , Dan Lin , Fufa Wu , Xinhua Yang
A constitutive model, which reflects the non-linear response association between microstructural motion and thermodynamic entropy production, is improved in this study. Two critical stress amplitudes associated with two microstructural movement mechanisms are considered in the improved constitutive model. The determination procedures for the parameters of the presented model are developed. Entropy generation data from three materials computed by two calculation methodologies, collected from the experiment and literature, are used to validate the improved model. Subsequently, a rapid fatigue life estimation method is proposed by using the accumulated entropy corresponding to fatigue damage, i.e. FFE, related to irreversible inelastic microstructural motion. Fatigue tests of welded joints fabricated by Q310NQL2 and Q345NQR2 steels, Q235 steel specimens, as well as experimental data, stainless steel specimens, collected from the literature, are employed to determine the values of the parameters of the developed model. The model is then used to forecast the S–N curve of butt joints with a 50% survival probability, and on this basis, the S–N curve with a certain confidence level is well estimated by the improved statistical method. This enhanced model may offer a fast forecast of the P–S–N curve at a certain confidence level within a limited set of tested data ranges.
{"title":"An improved constitutive model for rapid fatigue properties evaluation based on fatigue damage entropy","authors":"Wei Wei , Jianhui Li , Dan Lin , Fufa Wu , Xinhua Yang","doi":"10.1016/j.euromechsol.2024.105483","DOIUrl":"10.1016/j.euromechsol.2024.105483","url":null,"abstract":"<div><div>A constitutive model, which reflects the non-linear response association between microstructural motion and thermodynamic entropy production, is improved in this study. Two critical stress amplitudes associated with two microstructural movement mechanisms are considered in the improved constitutive model. The determination procedures for the parameters of the presented model are developed. Entropy generation data from three materials computed by two calculation methodologies, collected from the experiment and literature, are used to validate the improved model. Subsequently, a rapid fatigue life estimation method is proposed by using the accumulated entropy corresponding to fatigue damage, i.e. FFE, related to irreversible inelastic microstructural motion. Fatigue tests of welded joints fabricated by Q310NQL2 and Q345NQR2 steels, Q235 steel specimens, as well as experimental data, stainless steel specimens, collected from the literature, are employed to determine the values of the parameters of the developed model. The model is then used to forecast the <em>S–N</em> curve of butt joints with a 50% survival probability, and on this basis, the <em>S–N</em> curve with a certain confidence level is well estimated by the improved statistical method. This enhanced model may offer a fast forecast of the <em>P–S–N</em> curve at a certain confidence level within a limited set of tested data ranges.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105483"},"PeriodicalIF":4.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.euromechsol.2024.105486
Hanqing Zhang , Yingli Li , Lihua Tang , Song Yao , Yong Peng
Topological metamaterials demonstrate unprecedented wave manipulation abilities with topologically protected robustness, which have been extensively investigated in one-dimensional (1D) and two-dimensional (2D) mechanical systems, but less explored in three-dimensional (3D) systems. In this study, a 3D topological mechanical metamaterial with periodically stacked sandwich metamaterial plates is proposed to achieve 2D topological surface wave transport in a relatively low-frequency range. An innovative chiral compression-torsion coupling core is employed on the sandwich metamaterial plate to lower the band frequency. Analogous to the quantum valley Hall effect, the two-fold topological nodal line is lifted by breaking the spatial inversion symmetry, opening a topological band gap. By supercell analysis, the topological interface state is demonstrated to appear at the interface of two topologically different domains, and the topological boundary state can also be excited under appropriate free or fixed boundary conditions. Taking advantage of the 3D periodicity, the wave propagation based on both topological interface states and boundary states is examined in both 2D flat plates and 3D structures, realizing 1D topological waveguide and 2D topological surface wave transport respectively. It is found that mode symmetry matching is crucial for constructing the topological wave transport with both interface and boundary states. Leveraging the dependence of boundary states on boundary conditions, this work innovatively presents route-switchable and layer-selective wave manipulation by controlling boundary conditions without complicated structure design, enriching the strategies for tunable elastic wave manipulation. Besides, the topologically protected surface wave transport is demonstrated by introducing defects and disorders. These findings provide new insights into the topological transport of elastic waves in 3D mechanical metamaterials and contribute to the development of intelligent and robust devices for various purposes, such as vibration mitigation, energy harvesting, and signal sensing.
{"title":"Topological elastic wave transport and manipulation in three-dimensional metamaterials stacked with sandwich plates","authors":"Hanqing Zhang , Yingli Li , Lihua Tang , Song Yao , Yong Peng","doi":"10.1016/j.euromechsol.2024.105486","DOIUrl":"10.1016/j.euromechsol.2024.105486","url":null,"abstract":"<div><div>Topological metamaterials demonstrate unprecedented wave manipulation abilities with topologically protected robustness, which have been extensively investigated in one-dimensional (1D) and two-dimensional (2D) mechanical systems, but less explored in three-dimensional (3D) systems. In this study, a 3D topological mechanical metamaterial with periodically stacked sandwich metamaterial plates is proposed to achieve 2D topological surface wave transport in a relatively low-frequency range. An innovative chiral compression-torsion coupling core is employed on the sandwich metamaterial plate to lower the band frequency. Analogous to the quantum valley Hall effect, the two-fold topological nodal line is lifted by breaking the spatial inversion symmetry, opening a topological band gap. By supercell analysis, the topological interface state is demonstrated to appear at the interface of two topologically different domains, and the topological boundary state can also be excited under appropriate free or fixed boundary conditions. Taking advantage of the 3D periodicity, the wave propagation based on both topological interface states and boundary states is examined in both 2D flat plates and 3D structures, realizing 1D topological waveguide and 2D topological surface wave transport respectively. It is found that mode symmetry matching is crucial for constructing the topological wave transport with both interface and boundary states. Leveraging the dependence of boundary states on boundary conditions, this work innovatively presents route-switchable and layer-selective wave manipulation by controlling boundary conditions without complicated structure design, enriching the strategies for tunable elastic wave manipulation. Besides, the topologically protected surface wave transport is demonstrated by introducing defects and disorders. These findings provide new insights into the topological transport of elastic waves in 3D mechanical metamaterials and contribute to the development of intelligent and robust devices for various purposes, such as vibration mitigation, energy harvesting, and signal sensing.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105486"},"PeriodicalIF":4.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.euromechsol.2024.105485
Ayşe Polat , Babür Deliktaş , Murat Yazıcı , George Z. Voyiadjis
The areas where the weld line is located are weak areas in terms of impact strength and tensile strength, which negatively affects the overall strength of the final product. It can also cause visual defects on the surface and create an aesthetically undesirable situation. The injection molding process introduces anisotropic behaviors in materials, particularly in weld-line areas, which are proned to mechanical weaknesses. This study aims to enhance the predictability of the mechanical performance of injection-molded fiber-reinforced thermoplastic composites (FRPs) through a comprehensive computational modeling technique. By using software such as MOLDEX3D and DIGIMAT RP, this research integrates real-time data on fiber orientation and weld-line effects into the finite element analysis (FEA) models. Simulations of 40% glass fiber reinforced polyamide (PA6) revealed the impact of different gate numbers on mechanical strength, highlighting the influence of weld-line regions. The findings suggest that incorporating fiber orientation and weld-line data significantly improves the accuracy of FEA models, leading to better predictions in the performance of the parts.
焊缝所在区域是冲击强度和拉伸强度的薄弱区域，会对最终产品的整体强度产生负面影响。它还会造成表面视觉缺陷，影响美观。注塑成型工艺会在材料中引入各向异性行为，尤其是在容易出现机械缺陷的焊缝区域。本研究旨在通过综合计算建模技术，提高注塑成型纤维增强热塑性复合材料（FRP）机械性能的可预测性。通过使用 MOLDEX3D 和 DIGIMAT RP 等软件，本研究将纤维取向和焊接线效应的实时数据整合到有限元分析（FEA）模型中。对 40% 玻璃纤维增强聚酰胺（PA6）的模拟显示了不同浇口数对机械强度的影响，突出了焊缝区域的影响。研究结果表明，加入纤维取向和焊接线数据可显著提高有限元分析模型的准确性，从而更好地预测部件的性能。
{"title":"Computational modeling of weld-line impacts on mechanical behavior of fiber-reinforced thermoplastics","authors":"Ayşe Polat , Babür Deliktaş , Murat Yazıcı , George Z. Voyiadjis","doi":"10.1016/j.euromechsol.2024.105485","DOIUrl":"10.1016/j.euromechsol.2024.105485","url":null,"abstract":"<div><div>The areas where the weld line is located are weak areas in terms of impact strength and tensile strength, which negatively affects the overall strength of the final product. It can also cause visual defects on the surface and create an aesthetically undesirable situation. The injection molding process introduces anisotropic behaviors in materials, particularly in weld-line areas, which are proned to mechanical weaknesses. This study aims to enhance the predictability of the mechanical performance of injection-molded fiber-reinforced thermoplastic composites (FRPs) through a comprehensive computational modeling technique. By using software such as MOLDEX3D and DIGIMAT RP, this research integrates real-time data on fiber orientation and weld-line effects into the finite element analysis (FEA) models. Simulations of 40% glass fiber reinforced polyamide (PA6) revealed the impact of different gate numbers on mechanical strength, highlighting the influence of weld-line regions. The findings suggest that incorporating fiber orientation and weld-line data significantly improves the accuracy of FEA models, leading to better predictions in the performance of the parts.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105485"},"PeriodicalIF":4.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.euromechsol.2024.105481
Cunyao Shan, Jianliang Sun, Yan Peng
As an excellent pressure structure, circumferentially corrugated shells have been widely used in many fields, such as ocean engineering and aerospace. At present, the circumferentially corrugated shells have only obtained good buckling performance in tests and finite element analysis. However, the corrugated shells have not been further analyzed in theory, and some new problems have been found in tests. The geometrical parameters of shell structures determine the stress distributions and stiffness anisotropy, and the von Mises stress and local stiffness determine the collapse form and collapse location. The relationship between them has not been explained. The study of this problem will be beneficial to establish the active design theory of the circumferentially corrugated shells. Therefore, this paper aims to investigate the von Mises stress and stiffness anisotropy of the circumferentially corrugated shells. Some corrugated shells with uniform thickness and some corrugated shells with non-uniform thickness are established. The parameters used to represent the corrugated structure and the degree of stiffness anisotropy are proposed. The influence of corrugation parameters on the stress distributions and stiffness anisotropy is studied by finite element method and theoretical analysis, the mechanical behaviors of two types of shells under uniform lateral external pressure is perfectly explained. It provides a direction for the design and optimization of these shells. In addition, a new circumferentially corrugated shell is proposed at the end of this paper. It has good mechanical properties, which will make it possible to further reduce its weight.
作为一种优良的受压结构，圆周波纹壳已被广泛应用于海洋工程和航空航天等诸多领域。目前，圆周波纹壳仅在试验和有限元分析中获得了良好的屈曲性能。但波纹壳的理论分析还不够深入，在试验中也发现了一些新问题。壳体结构的几何参数决定了应力分布和刚度各向异性，而 von Mises 应力和局部刚度决定了坍塌形式和坍塌位置。它们之间的关系尚未得到解释。对这一问题的研究将有利于建立圆周波纹壳的主动设计理论。因此，本文旨在研究圆周波纹壳的 von Mises 应力和刚度各向异性。本文建立了一些厚度均匀的波纹壳和一些厚度不均匀的波纹壳。提出了用于表示波纹结构和刚度各向异性程度的参数。通过有限元法和理论分析，研究了波纹参数对应力分布和刚度各向异性的影响，完美地解释了两类壳体在均匀侧向外压作用下的力学行为。这为这些壳体的设计和优化提供了方向。此外，本文最后还提出了一种新型圆周波纹壳。这种壳体具有良好的机械性能，可以进一步减轻重量。
{"title":"Stress distributions and stiffness anisotropy of circumferentially corrugated shells under uniform external pressure","authors":"Cunyao Shan, Jianliang Sun, Yan Peng","doi":"10.1016/j.euromechsol.2024.105481","DOIUrl":"10.1016/j.euromechsol.2024.105481","url":null,"abstract":"<div><div>As an excellent pressure structure, circumferentially corrugated shells have been widely used in many fields, such as ocean engineering and aerospace. At present, the circumferentially corrugated shells have only obtained good buckling performance in tests and finite element analysis. However, the corrugated shells have not been further analyzed in theory, and some new problems have been found in tests. The geometrical parameters of shell structures determine the stress distributions and stiffness anisotropy, and the von Mises stress and local stiffness determine the collapse form and collapse location. The relationship between them has not been explained. The study of this problem will be beneficial to establish the active design theory of the circumferentially corrugated shells. Therefore, this paper aims to investigate the von Mises stress and stiffness anisotropy of the circumferentially corrugated shells. Some corrugated shells with uniform thickness and some corrugated shells with non-uniform thickness are established. The parameters used to represent the corrugated structure and the degree of stiffness anisotropy are proposed. The influence of corrugation parameters on the stress distributions and stiffness anisotropy is studied by finite element method and theoretical analysis, the mechanical behaviors of two types of shells under uniform lateral external pressure is perfectly explained. It provides a direction for the design and optimization of these shells. In addition, a new circumferentially corrugated shell is proposed at the end of this paper. It has good mechanical properties, which will make it possible to further reduce its weight.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105481"},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.euromechsol.2024.105484
Juanjuan Guo , Zhiwen Gao , Cennan Zhang , Hua Li , Jizeng Wang
Twisted and coiled polymer actuators (TCPA) represent a type of artificial muscle predominantly composed of viscoelastic polymers in their precursor fibers. An integral form of the viscoelastic constitutive model has been developed to predict the mechanical deformation of the precursor fibers. The model successfully accounts for the first-cycle effect and the creep deformation near the glass transition temperature of the precursor fibers. Combined with the multilayer model by Gao and Wang (2024 Smart Mater. Struct. 33 045031), which predicts the effective mechanical and thermal properties of TCPA, the proposed viscoelastic constitutive model accurately predicts the thermo-mechanical response of TCPA under the heating and cooling cycle and applied loads. It is noted that the driving strain of TCPA is sensitive to the heating and cooling cycles. When the cycle duration is short, the proposed viscoelastic model can be simplified to a linear elastic model. The numerical implementation of the viscoelastic constitutive model is detailed, with validation conducted on two polymer materials, polypropylene, and polyamide 66. The proposed constitutive model can effectively predict the driving response of TCPA under complex loading conditions.
{"title":"Driving response analysis of twisted and coiled polymer actuators by considering the viscoelastic behavior of their precursor fibers","authors":"Juanjuan Guo , Zhiwen Gao , Cennan Zhang , Hua Li , Jizeng Wang","doi":"10.1016/j.euromechsol.2024.105484","DOIUrl":"10.1016/j.euromechsol.2024.105484","url":null,"abstract":"<div><div>Twisted and coiled polymer actuators (TCPA) represent a type of artificial muscle predominantly composed of viscoelastic polymers in their precursor fibers. An integral form of the viscoelastic constitutive model has been developed to predict the mechanical deformation of the precursor fibers. The model successfully accounts for the first-cycle effect and the creep deformation near the glass transition temperature of the precursor fibers. Combined with the multilayer model by Gao and Wang (2024 Smart Mater. Struct. <strong>33</strong> 045031), which predicts the effective mechanical and thermal properties of TCPA, the proposed viscoelastic constitutive model accurately predicts the thermo-mechanical response of TCPA under the heating and cooling cycle and applied loads. It is noted that the driving strain of TCPA is sensitive to the heating and cooling cycles. When the cycle duration is short, the proposed viscoelastic model can be simplified to a linear elastic model. The numerical implementation of the viscoelastic constitutive model is detailed, with validation conducted on two polymer materials, polypropylene, and polyamide 66. The proposed constitutive model can effectively predict the driving response of TCPA under complex loading conditions.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"109 ","pages":"Article 105484"},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.euromechsol.2024.105480
Abir Abdessalem , Sahbi Tamboura , Mohammadali Shirinbayan , Mohamed Amine Laribi , Hachmi Ben Daly , Joseph Fitoussi
Industrial sheet molding compound (SMC) composite structures are susceptible to environmental degradation, primarily from moisture and temperature. Furthermore, these materials are subjected to fatigue loading. It is therefore necessary to generate Wohler curves for a range of service conditions, taking into account exposure time and temperature. Given the time-consuming nature of these preliminary characterizations, this paper presents an innovative approach to rapid fatigue life prediction using both monotonic and fatigue tests. The core concept of the proposed model is to establish an equation of state that correlates first-cycle macroscopic damage to fatigue life. By coupling this relationship with micromechanical modelling of quasi-static damage, we can rapidly determine SN curves for any considered aged state. The methodology also integrates the microstructure as an input, significantly reducing the need for extensive experimental characterization. A comparison between experimental and simulated Wöhler curves shows excellent agreement over different ageing conditions for SMC composites.
工业用片状模塑料（SMC）复合材料结构容易受到环境退化的影响，主要是湿度和温度的影响。此外，这些材料还要承受疲劳载荷。因此，有必要在考虑暴露时间和温度的情况下，生成一系列使用条件下的 Wohler 曲线。鉴于这些初步特性分析非常耗时，本文提出了一种利用单调试验和疲劳试验快速预测疲劳寿命的创新方法。所提模型的核心理念是建立一个状态方程，将第一周期宏观损伤与疲劳寿命联系起来。通过将这种关系与准静态损伤的微观机械建模相结合，我们可以快速确定任何考虑老化状态的 SN 曲线。该方法还集成了微观结构作为输入，大大减少了对大量实验表征的需求。实验和模拟沃勒曲线之间的比较显示，在 SMC 复合材料的不同老化条件下，两者的一致性非常好。
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Pub Date : 2024-10-29DOI: 10.1016/j.euromechsol.2024.105478
Qi Zhang , Zheng H. Zhu
This study develops a novel 8-node isoparametric hexahedral element using the Nodal Position Finite Element Method (NPFEM) for elastodynamic analysis of rotating solids. The element also incorporates the flexural modes directly into its element shape function to alleviate the shear locking when modeling the bending deformation of solids. Unlike conventional displacement-based finite element methods, which require the decoupling of elastic deformation from rigid-body motions, the NPFEM eliminates this process by directly representing strain and kinetic energies through nodal position coordinates, which avoids potential approximation errors in the decoupling process. To validate the accuracy and efficacy of this new NPFEM solid element, numerical simulations of a beam under static and dynamic loads are conducted and benchmarked against the theoretical solutions. Then, dynamic analysis of a rotating blade demonstrates that the NPFEM element can directly account for the centrifugal stiffening effect and superharmonic resonance of rotating blades without resorting to conventional methods. The successful implementation of this NPFEM element in complex simulations highlights its potential to provide significant advancements in computational mechanics.
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Pub Date : 2024-10-28DOI: 10.1016/j.euromechsol.2024.105470
M. Magri
Electro-chemo-mechanics plays a critical role in the performance and longevity of energy storage systems, such as lithium-ion batteries and hydrogen energy storage. These systems involve multi-material composites comprising both liquid and solid phases, with their behavior influenced by processes in the bulk phases and at their interfaces.
Traditional multi-phase theoretical and numerical models often adopt a discrete representation of material interfaces, introducing discontinuities in the problem’s fields. The numerical implementation is carried out using special interface elements, a methodology that requires conformal meshes and is not always supported by open-source computing platforms.
This paper introduces a novel modeling framework that employs a diffuse representation of material interfaces, inspired by the phase-field method. From a modeling perspective, this approach allows for the consistent coupling of bulk and interface electro-chemo-mechanical processes, adhering to thermodynamic principles. Numerically, the proposed model is particularly suited for simulating real material microstructures using regular meshes, facilitating advanced numerical implementations.
The methodology is detailed for a generic multi-material electro-chemo-mechanical system and applied specifically to Li-ion batteries. Numerical examples demonstrate the model’s effectiveness in simulating coupled interface processes without resorting to interface elements. This work provides a significant advancement in the simulation of electro-chemo-mechanical systems, offering a robust tool for studying the complex interplay of bulk and interface processes.
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