International Journal of Solids and Structures最新文献_第6页

Enhanced physics-informed neural networks without labeled data for weakly and fully coupled transient thermomechanical analysis 用于弱耦合和全耦合瞬态热力学分析的无标记数据增强型物理信息神经网络

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-10-04 DOI: 10.1016/j.ijsolstr.2024.113092

Haihang Xu , Chong Wang , Haikun Jia , Zhenhai Liu , Mingxin Wan , Zhaohuan Zhang , Yonggang Zheng

In this paper, a series of enhanced physics-informed neural networks (PINN) models without labeled data is proposed to solve the weakly and fully coupled thermomechanical problems. In these models, to better predict the thermal and mechanical responses, PINNs consisting of different deep neural networks (DNN) representing temperature, displacement, and stress are specifically constructed. Furthermore, to elevate the accuracy and avoid possible training failure, several advanced algorithms are developed to ensure the effectiveness of imposing boundary conditions, refining sampling distributions, and enhancing training strategy. A notable aspect of the enhanced PINNs is their independence from expensive, labeled data, relying solely on the temporal and spatial information embedded within the sampling points. The effectiveness and accuracy of the enhanced PINNs are validated through extensive numerical examples, including heat conduction and both weakly and fully coupled thermomechanical problems. The comparation between original PINN and enhanced PINN illustrates the necessity of involving these enhanced methods. The results demonstrate the significant potential of PINN methodologies in engineering areas involving complex thermomechanical processes.

本文提出了一系列无标记数据的增强型物理信息神经网络（PINN）模型，用于解决弱耦合和全耦合热机械问题。在这些模型中，为了更好地预测热响应和机械响应，特别构建了由代表温度、位移和应力的不同深度神经网络（DNN）组成的 PINN。此外，为了提高准确性并避免可能出现的训练失败，还开发了几种先进算法，以确保施加边界条件、完善采样分布和增强训练策略的有效性。增强型 PINNs 的一个显著特点是独立于昂贵的标注数据，完全依赖于采样点中蕴含的时间和空间信息。增强型 PINNs 的有效性和准确性通过大量数值示例得到了验证，包括热传导以及弱耦合和全耦合热力学问题。原始 PINN 与增强 PINN 的比较说明了使用这些增强方法的必要性。结果表明，PINN 方法在涉及复杂热机械过程的工程领域具有巨大潜力。

{"title":"Enhanced physics-informed neural networks without labeled data for weakly and fully coupled transient thermomechanical analysis","authors":"Haihang Xu , Chong Wang , Haikun Jia , Zhenhai Liu , Mingxin Wan , Zhaohuan Zhang , Yonggang Zheng","doi":"10.1016/j.ijsolstr.2024.113092","DOIUrl":"10.1016/j.ijsolstr.2024.113092","url":null,"abstract":"<div><div>In this paper, a series of enhanced physics-informed neural networks (PINN) models without labeled data is proposed to solve the weakly and fully coupled thermomechanical problems. In these models, to better predict the thermal and mechanical responses, PINNs consisting of different deep neural networks (DNN) representing temperature, displacement, and stress are specifically constructed. Furthermore, to elevate the accuracy and avoid possible training failure, several advanced algorithms are developed to ensure the effectiveness of imposing boundary conditions, refining sampling distributions, and enhancing training strategy. A notable aspect of the enhanced PINNs is their independence from expensive, labeled data, relying solely on the temporal and spatial information embedded within the sampling points. The effectiveness and accuracy of the enhanced PINNs are validated through extensive numerical examples, including heat conduction and both weakly and fully coupled thermomechanical problems. The comparation between original PINN and enhanced PINN illustrates the necessity of involving these enhanced methods. The results demonstrate the significant potential of PINN methodologies in engineering areas involving complex thermomechanical processes.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113092"},"PeriodicalIF":3.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428678","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}

引用次数: 0

Exploring the effects of finite size and indenter shape on the contact behavior of functionally graded thermoelectric materials 探索有限尺寸和压头形状对功能分级热电材料接触行为的影响

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-10-03 DOI: 10.1016/j.ijsolstr.2024.113089

Xiaojuan Tian , Yueting Zhou , Shenghu Ding , Lihua Wang

The performance enhancement of functionally graded thermoelectric (FGTE) devices is significantly influenced by contact studies of the FGTE materials. It is unclear how the finite thickness and the punch geometry influence the FGTE materials’ contact behaviors. This paper investigates the frictionless contact problem between three types of rigid punches (flat, triangular, and cylindrical) and the FGTE strip with finite thickness. The electric-thermo-elastic parameters of the FGTE strip vary in the thickness direction according to an exponential function. Based on the Fourier integral transform and the transformation matrix method, the problem is transformed into the numerical solution of three sets of singular integral equations. The presence of singular features on either side of the punch demands the adoption of specific collocation strategies. The distribution of the normal current density, the normal energy flux, and the normal contact stress is obtained by adjusting multiple electric-thermo-elastic parameters. The contact stresses in the case of punches with varying shapes can be effectively controlled by modulating the coefficient of thermal expansion and the strip thickness, whereas the effect of the electrical conductivity, the shear modulus, and the thermoelectric load on these stresses depends on whether they are increased or decreased.

功能分级热电（FGTE）器件性能的提高在很大程度上受到 FGTE 材料接触研究的影响。目前还不清楚有限厚度和冲头几何形状如何影响 FGTE 材料的接触行为。本文研究了三种类型的刚性冲头（扁平、三角形和圆柱形）与有限厚度 FGTE 带材之间的无摩擦接触问题。FGTE 带材的电热弹性参数在厚度方向上按指数函数变化。基于傅立叶积分变换和变换矩阵法，问题被转化为三组奇异积分方程的数值求解。冲头两侧奇异特征的存在要求采用特定的定位策略。通过调整多个电热弹性参数，可以得到法向电流密度、法向能量通量和法向接触应力的分布。通过调节热膨胀系数和带材厚度可以有效控制不同形状冲头的接触应力，而电导率、剪切模量和热电负荷对这些应力的影响则取决于它们是增加还是减少。

{"title":"Exploring the effects of finite size and indenter shape on the contact behavior of functionally graded thermoelectric materials","authors":"Xiaojuan Tian , Yueting Zhou , Shenghu Ding , Lihua Wang","doi":"10.1016/j.ijsolstr.2024.113089","DOIUrl":"10.1016/j.ijsolstr.2024.113089","url":null,"abstract":"<div><div>The performance enhancement of functionally graded thermoelectric (FGTE) devices is significantly influenced by contact studies of the FGTE materials. It is unclear how the finite thickness and the punch geometry influence the FGTE materials’ contact behaviors. This paper investigates the frictionless contact problem between three types of rigid punches (flat, triangular, and cylindrical) and the FGTE strip with finite thickness. The electric-thermo-elastic parameters of the FGTE strip vary in the thickness direction according to an exponential function. Based on the Fourier integral transform and the transformation matrix method, the problem is transformed into the numerical solution of three sets of singular integral equations. The presence of singular features on either side of the punch demands the adoption of specific collocation strategies. The distribution of the normal current density, the normal energy flux, and the normal contact stress is obtained by adjusting multiple electric-thermo-elastic parameters. The contact stresses in the case of punches with varying shapes can be effectively controlled by modulating the coefficient of thermal expansion and the strip thickness, whereas the effect of the electrical conductivity, the shear modulus, and the thermoelectric load on these stresses depends on whether they are increased or decreased.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113089"},"PeriodicalIF":3.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428680","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}

引用次数: 0

Investigating the influence of stress on UV-induced degradation in cellulose acetate: A comprehensive experimental characterization 研究压力对紫外线诱导醋酸纤维素降解的影响：综合实验表征

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-10-03 DOI: 10.1016/j.ijsolstr.2024.113086

Keven Alkhoury , Chi Zhang , Guangliang Liu , Kathleen McEnnis , Laurence Brassart , Siva P.V. Nadimpalli , Shawn A. Chester

Renewable and degradable polymers have emerged in everyday applications ranging from mundane eating utensils to high-tech medical devices. However, the current literature lacks a thorough experimental characterization of the mechanical behavior change due to degradation. In this work, we characterize the microscopic chemical changes due to photo-degradation and resulting stress effects on the mechanical behavior of cellulose acetate, a renewable and degradable polymer that is used in various consumer products. Specifically, we photo-degrade this polymer under (i) traction-free conditions and (ii) under applied stress. A key finding of this work is that upon photo-degradation, this material undergoes chain scission, which affects its mechanical properties and may be further affected by the applied stress.

可再生和可降解聚合物已出现在从普通餐具到高科技医疗设备等各种日常应用中。然而，目前的文献缺乏对降解引起的机械行为变化的全面实验表征。在这项研究中，我们描述了光降解引起的微观化学变化以及由此产生的应力对醋酸纤维素机械行为的影响，醋酸纤维素是一种可再生、可降解的聚合物，被广泛应用于各种消费品中。具体来说，我们在 (i) 无牵引条件和 (ii) 外加应力条件下对这种聚合物进行光降解。这项研究的一个重要发现是，在光降解过程中，这种材料会发生链断裂，从而影响其机械性能，并可能受到外加应力的进一步影响。

引用次数: 0

Stochastic stability of random stacking of blocks 木块随机堆叠的随机稳定性

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-10-02 DOI: 10.1016/j.ijsolstr.2024.113094

V. Denoël

The paper explores the stability of a tower obtained by stacking identical rectangular blocks on top of each other with an inherent randomness due to slight positional offsets between successive blocks. With probabilistic modeling techniques, the diffusive behavior of the stacking process is studied and the collapse is seen as a first passage time problem. In the considered model, alignment errors are idealized as independent Gaussian random variables with zero mean and given standard deviation. We derive expressions for the joint probability density functions of block positions, and analyze their correlation. The study extends to the stochastic stability of a stack of given height, by exploring the statistical characteristics of the center of gravity of the part of tower above each block. Eventually, the probabilistic analysis of collapse is developed to quantify the statistics of the number of blocks that can be heaped up before the tower topples. Although this problem may initially appear playful, it offers an illustrated introduction to first passage problems on a non homogenous process. From a practical standpoint, this analysis offers a simple understanding of the influence of alignment errors on the overall stability of a stack, which may find several fields of application.

本文探讨了通过将相同的矩形块堆叠在一起而获得的塔的稳定性，由于连续块之间存在轻微的位置偏移，因此具有固有的随机性。通过概率建模技术，研究了堆叠过程的扩散行为，并将坍塌视为第一通过时间问题。在所考虑的模型中，对齐误差被理想化为独立的高斯随机变量，具有零均值和给定的标准偏差。我们推导出区块位置的联合概率密度函数表达式，并分析了它们之间的相关性。通过探索每个塔块上方塔身部分重心的统计特征，研究扩展到给定高度塔堆的随机稳定性。最后，研究还发展了倒塌的概率分析，以量化塔倒塌前可堆起的积木数量统计。虽然这个问题最初看起来很乏味，但它为非均质过程的第一通道问题提供了一个图文并茂的介绍。从实用的角度来看，该分析提供了对齐误差对堆垛整体稳定性影响的简单理解，可应用于多个领域。

{"title":"Stochastic stability of random stacking of blocks","authors":"V. Denoël","doi":"10.1016/j.ijsolstr.2024.113094","DOIUrl":"10.1016/j.ijsolstr.2024.113094","url":null,"abstract":"<div><div>The paper explores the stability of a tower obtained by stacking identical rectangular blocks on top of each other with an inherent randomness due to slight positional offsets between successive blocks. With probabilistic modeling techniques, the diffusive behavior of the stacking process is studied and the collapse is seen as a first passage time problem. In the considered model, alignment errors are idealized as independent Gaussian random variables with zero mean and given standard deviation. We derive expressions for the joint probability density functions of block positions, and analyze their correlation. The study extends to the stochastic stability of a stack of given height, by exploring the statistical characteristics of the center of gravity of the part of tower above each block. Eventually, the probabilistic analysis of collapse is developed to quantify the statistics of the number of blocks that can be heaped up before the tower topples. Although this problem may initially appear playful, it offers an illustrated introduction to first passage problems on a non homogenous process. From a practical standpoint, this analysis offers a simple understanding of the influence of alignment errors on the overall stability of a stack, which may find several fields of application.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113094"},"PeriodicalIF":3.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428622","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}

引用次数: 0

Analytical model for flexoelectric sensing of structural response considering bonding compliance 考虑粘接顺应性的结构响应柔电传感分析模型

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-30 DOI: 10.1016/j.ijsolstr.2024.113084

Suraj Kumar Rout, Santosh Kapuria

Flexoelectricity has generated huge interest as an alternative to piezoelectricity for developing electromechanical systems such as actuators, sensors, and energy harvesters. This article presents a generic theoretical framework for the sensing mechanism of a flexoelectric sensor bonded to a host beam through an adhesive layer. The model incorporates piezoelectric and flexoelectric effects and considers both shear-lag and peel stresses at the sensor-beam interface. The formulation also includes the electric field gradient terms that are often overlooked. Consistent one-dimensional constitutive relations and governing equations of equilibrium are derived from the electric Gibb’s energy density function and extended Hamilton’s principle. The sensor is assumed to follow the Euler–Bernoulli beam-type membrane and bending deformation behaviour. Closed-form solutions are obtained for the interfacial stresses by analytically solving a seventh-order non-homogeneous ordinary differential equation, satisfying the stress-free boundary conditions at the sensor edges. The induced electric potential at the sensor top is derived by solving a fourth-order differential equation obtained from the charge balance equation, satisfying the electric boundary conditions. For validation, the sensor output is compared with the results of the existing non-rigid bonding piezoelectric sensor model. Numerical results show a significant impact of non-rigid bonding and the electric field gradient terms on the induced electric potential. Further, the importance of bonding compliance on the interfacial stress distributions is illustrated. Finally, the effects of adhesive and transducer thicknesses on the peak amplitudes of interfacial stresses and sensory potential are presented.

挠电作为压电的替代品，在开发致动器、传感器和能量收集器等机电系统方面引起了极大的兴趣。本文为通过粘合剂层粘合到主梁上的柔电传感器的传感机制提出了一个通用理论框架。该模型包含压电和挠电效应，并考虑了传感器与横梁界面上的剪切滞后应力和剥离应力。该模型还包括经常被忽视的电场梯度项。根据电吉布斯能量密度函数和扩展的汉密尔顿原理推导出一致的一维构成关系和支配平衡方程。假定传感器遵循欧拉-伯努利梁式膜和弯曲变形行为。在满足传感器边缘无应力边界条件的前提下，通过分析求解七阶非均质常微分方程，得到了界面应力的闭式解。传感器顶部的感应电动势是通过求解电荷平衡方程得到的四阶微分方程得出的，满足电动边界条件。为进行验证，将传感器输出与现有非刚性结合压电传感器模型的结果进行了比较。数值结果表明，非刚性结合和电场梯度项对感应电动势有显著影响。此外，还说明了粘合顺应性对界面应力分布的重要性。最后，介绍了粘合剂和传感器厚度对界面应力和感应电势峰值振幅的影响。

{"title":"Analytical model for flexoelectric sensing of structural response considering bonding compliance","authors":"Suraj Kumar Rout, Santosh Kapuria","doi":"10.1016/j.ijsolstr.2024.113084","DOIUrl":"10.1016/j.ijsolstr.2024.113084","url":null,"abstract":"<div><div>Flexoelectricity has generated huge interest as an alternative to piezoelectricity for developing electromechanical systems such as actuators, sensors, and energy harvesters. This article presents a generic theoretical framework for the sensing mechanism of a flexoelectric sensor bonded to a host beam through an adhesive layer. The model incorporates piezoelectric and flexoelectric effects and considers both shear-lag and peel stresses at the sensor-beam interface. The formulation also includes the electric field gradient terms that are often overlooked. Consistent one-dimensional constitutive relations and governing equations of equilibrium are derived from the electric Gibb’s energy density function and extended Hamilton’s principle. The sensor is assumed to follow the Euler–Bernoulli beam-type membrane and bending deformation behaviour. Closed-form solutions are obtained for the interfacial stresses by analytically solving a seventh-order non-homogeneous ordinary differential equation, satisfying the stress-free boundary conditions at the sensor edges. The induced electric potential at the sensor top is derived by solving a fourth-order differential equation obtained from the charge balance equation, satisfying the electric boundary conditions. For validation, the sensor output is compared with the results of the existing non-rigid bonding piezoelectric sensor model. Numerical results show a significant impact of non-rigid bonding and the electric field gradient terms on the induced electric potential. Further, the importance of bonding compliance on the interfacial stress distributions is illustrated. Finally, the effects of adhesive and transducer thicknesses on the peak amplitudes of interfacial stresses and sensory potential are presented.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113084"},"PeriodicalIF":3.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428620","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}

引用次数: 0

An alternative stress boundary condition in small deformations and its application to soft elastic composites and structures 小变形中的另一种应力边界条件及其在软弹性复合材料和结构中的应用

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-30 DOI: 10.1016/j.ijsolstr.2024.113088

Molin Sun , Ming Dai , Peter Schiavone

Linear elasticity theory has been used extensively in the study of the elastic behavior of various perforated structures and composite materials requiring the accompaniment of appropriate boundary conditions to derive qualitatively correct and quantitatively referential solutions. When incorporating conventional boundary conditions, however, linear elasticity theory fails to predict certain essential phenomena associated with perforate structures and composite materials even when they undergo small deformations. For example, a soft elastic porous medium is appreciably stiffened when inflated despite the fact that the internal air pressure is significantly lower than the modulus of the medium itself. In this paper, we propose an improved stress boundary condition by simply incorporating a small change in the normal to the boundary during deformation. We show via numerical examples that in the context of linear elasticity theory, the use of this improved boundary condition offers the possibility of predicting the influence of initial or residual stress in a perforated structure on the elastic response of the structure to external loadings (which can never be captured with the use of conventional boundary conditions). We perform also large-deformation-based finite element simulations to verify the accuracy of the closed-form results obtained from the improved boundary condition for a soft elastic perforated structure with initial internal pressure. We believe that the idea presented in this paper will extend the applicability of linear elasticity theory and yield more accurate referential analytic results for soft elastic structures and composites.

线性弹性理论被广泛应用于研究各种穿孔结构和复合材料的弹性行为，需要适当的边界条件来得出定性正确和定量参考的解决方案。然而，在结合传统边界条件时，线性弹性理论无法预测与穿孔结构和复合材料相关的某些基本现象，即使它们发生微小变形时也是如此。例如，软弹性多孔介质在充气时会明显变硬，尽管内部气压明显低于介质本身的模量。在本文中，我们提出了一种改进的应力边界条件，只需在变形过程中加入边界法线的微小变化即可。我们通过数值示例表明，在线性弹性理论的背景下，使用这种改进的边界条件可以预测穿孔结构中的初始应力或残余应力对结构对外部载荷的弹性响应的影响（使用传统边界条件永远无法捕捉到这种影响）。我们还进行了基于大变形的有限元模拟，以验证改进边界条件对具有初始内压的软弹性穿孔结构的闭式结果的准确性。我们相信，本文提出的想法将扩展线性弹性理论的适用范围，并为软弹性结构和复合材料提供更精确的参考解析结果。

{"title":"An alternative stress boundary condition in small deformations and its application to soft elastic composites and structures","authors":"Molin Sun , Ming Dai , Peter Schiavone","doi":"10.1016/j.ijsolstr.2024.113088","DOIUrl":"10.1016/j.ijsolstr.2024.113088","url":null,"abstract":"<div><div>Linear elasticity theory has been used extensively in the study of the elastic behavior of various perforated structures and composite materials requiring the accompaniment of appropriate boundary conditions to derive qualitatively correct and quantitatively referential solutions. When incorporating conventional boundary conditions, however, linear elasticity theory fails to predict certain essential phenomena associated with perforate structures and composite materials even when they undergo small deformations. For example, a soft elastic porous medium is appreciably stiffened when inflated despite the fact that the internal air pressure is significantly lower than the modulus of the medium itself. In this paper, we propose an improved stress boundary condition by simply incorporating a small change in the normal to the boundary during deformation. We show via numerical examples that in the context of linear elasticity theory, the use of this improved boundary condition offers the possibility of predicting the influence of initial or residual stress in a perforated structure on the elastic response of the structure to external loadings (which can never be captured with the use of conventional boundary conditions). We perform also large-deformation-based finite element simulations to verify the accuracy of the closed-form results obtained from the improved boundary condition for a soft elastic perforated structure with initial internal pressure. We believe that the idea presented in this paper will extend the applicability of linear elasticity theory and yield more accurate referential analytic results for soft elastic structures and composites.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113088"},"PeriodicalIF":3.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428619","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}

引用次数: 0

A non-isothermal breakage-damage model for plastic-bonded granular materials incorporating temperature, pressure, and rate dependencies 包含温度、压力和速率相关性的塑性粘结颗粒材料非等温破损模型

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-29 DOI: 10.1016/j.ijsolstr.2024.113085

Yazeed Kokash , Richard Regueiro , Nathan Miller , Yida Zhang

Plastic-bonded granular materials (PBM) are widely used in industrial sectors, including building construction, abrasive applications, and defense applications such as plastic-bonded explosives. The mechanical behavior of PBM is highly nonlinear, irreversible, rate dependent, and temperature sensitive governed by various micromechanical attributions such as grain crushing and binder damage. This paper presents a thermodynamically consistent, microstructure-informed constitutive model to capture these characteristic behaviors of PBM. Key features of the model include a breakage internal variable to upscale the grain-scale information to the continuum level and to predict grain size evolution under mechanical loading. In addition, a damage internal state variable is introduced to account for the damage, deterioration, and debonding of the binder matrix upon loading. Temperature is taken as a fundamental external state variable to handle non-isothermal loading paths. The proposed model is able to capture with good accuracy several important aspects of the mechanical properties of PBM, such as pressure-dependent elasticity, pressure-dependent yield strength, brittle-to-ductile transition, temperature dependency, and rate dependency in the post-yielding regime. The model is validated against multiple published datasets obtained from confined and unconfined compression tests, covering various PBM compositions, confining pressures, temperatures, and strain rates.

塑料粘结颗粒材料（PBM）广泛应用于工业领域，包括建筑施工、研磨应用和国防应用（如塑料粘结炸药）。PBM 的机械行为具有高度非线性、不可逆、速率依赖性和温度敏感性等特点，受晶粒破碎和粘结剂损坏等各种微观机械属性的制约。本文提出了一种热力学上一致的、以微观结构为基础的构成模型，以捕捉 PBM 的这些特征行为。该模型的主要特征包括一个断裂内部变量，用于将晶粒尺度信息提升到连续水平，并预测机械加载下的晶粒尺寸演变。此外，还引入了一个损坏内部状态变量，用于解释加载时粘合剂基体的损坏、劣化和脱粘。温度作为基本外部状态变量，用于处理非等温加载路径。所提出的模型能够准确捕捉 PBM 力学性能的几个重要方面，如压力相关弹性、压力相关屈服强度、脆性到韧性转变、温度相关性以及屈服后状态的速率相关性。该模型根据多个已公布的数据集进行了验证，这些数据集来自密闭和非密闭压缩试验，涵盖了各种 PBM 成分、密闭压力、温度和应变率。

{"title":"A non-isothermal breakage-damage model for plastic-bonded granular materials incorporating temperature, pressure, and rate dependencies","authors":"Yazeed Kokash , Richard Regueiro , Nathan Miller , Yida Zhang","doi":"10.1016/j.ijsolstr.2024.113085","DOIUrl":"10.1016/j.ijsolstr.2024.113085","url":null,"abstract":"<div><div>Plastic-bonded granular materials (PBM) are widely used in industrial sectors, including building construction, abrasive applications, and defense applications such as plastic-bonded explosives. The mechanical behavior of PBM is highly nonlinear, irreversible, rate dependent, and temperature sensitive governed by various micromechanical attributions such as grain crushing and binder damage. This paper presents a thermodynamically consistent, microstructure-informed constitutive model to capture these characteristic behaviors of PBM. Key features of the model include a breakage internal variable to upscale the grain-scale information to the continuum level and to predict grain size evolution under mechanical loading. In addition, a damage internal state variable is introduced to account for the damage, deterioration, and debonding of the binder matrix upon loading. Temperature is taken as a fundamental external state variable to handle non-isothermal loading paths. The proposed model is able to capture with good accuracy several important aspects of the mechanical properties of PBM, such as pressure-dependent elasticity, pressure-dependent yield strength, brittle-to-ductile transition, temperature dependency, and rate dependency in the post-yielding regime. The model is validated against multiple published datasets obtained from confined and unconfined compression tests, covering various PBM compositions, confining pressures, temperatures, and strain rates.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113085"},"PeriodicalIF":3.4,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428683","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}

引用次数: 0

Does static friction information predict the onset of sliding for soft material? 静摩擦信息是否能预测软材料滑动的开始？

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-28 DOI: 10.1016/j.ijsolstr.2024.113087

Huixin Wei , Zhiyong Wang , Xinhao Tu , Xuanshi Cheng , Linan Li , Shibin Wang , Chuanwei Li

Friction behavior between soft and hard materials has long been a question of great interest in the fields of artificial joints, human skin contact, robotic grippers, and others. In this study, we presented a combination of theoretical and experimental analyses to investigate the friction behavior of soft materials. Using some geometric and stick–slip features in the early stage of static friction, the friction property of the interface between a soft material and a hard material is determined. Moreover, the onset of slip, the threshold force at which a friction interface begins to slide, is also predicted by a theoretical model. The predictive ability of this model may provide insights for improving interaction property recognition, as well as for developing fine tactile feedback and dexterous operation of robotic grasping.

长期以来，软硬材料之间的摩擦行为一直是人工关节、人体皮肤接触、机器人抓手等领域备受关注的问题。在本研究中，我们结合理论和实验分析，对软材料的摩擦行为进行了研究。利用静摩擦早期的一些几何特征和粘滑特征，确定了软材料和硬材料之间界面的摩擦特性。此外，理论模型还预测了滑移的起始点，即摩擦界面开始滑动的阈值力。该模型的预测能力可为改进交互属性识别、开发精细触觉反馈和机器人抓取的灵巧操作提供启示。

引用次数: 0

Effect of path-dependent plasticity on springback in reverse bending and its application to roll forming 路径依赖塑性对反向弯曲回弹的影响及其在滚压成形中的应用

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-28 DOI: 10.1016/j.ijsolstr.2024.113079

Kyucheol Jeong , Keun-ho Kim , Shin-Yeong Lee , Hyuk Jong Bong , Seongyong Yoon , Jonghun Yoon

This study investigates springback behavior in martensitic advanced high-strength steels (AHSS) undergoing pure bending and reverse bending sequences. The comparison between a conventional isotropic hardening model and the Homogeneous Anisotropic Hardening (HAH20) model had been made, which accounts for non-isotropic hardening effects. Both models were calibrated using uniaxial tensile, cyclic, and loading–unloading tests. The results show that the HAH20 model predicts a higher initial springback compared to the isotropic model. However, reverse bending significantly reduces the overall springback for both models due to a minimized recovery moment. In scenarios with reverse bending, a specific strain exists where both models predict identical springback due to the secondary Bauschinger effect in tensile stress. This phenomenon is also observed in roll forming, a sequential bending process that incorporates reverse bending steps. Experimental findings from roll forming confirm a decrease in springback after the reverse bending stage. Furthermore, the study explores the impact of non-isotropic hardening on the part crashworthiness with the calibration of cross-loading effects. The Bauschinger effect and cross-loading contraction were found to reduce the maximum crash load by 6.2%.

本研究调查了马氏体高级高强度钢（AHSS）在纯弯曲和反向弯曲序列中的回弹行为。比较了传统的各向同性硬化模型和考虑了非各向同性硬化效应的均匀各向异性硬化（HAH20）模型。使用单轴拉伸、循环和加载-卸载试验对两种模型进行了校准。结果表明，与各向同性模型相比，HAH20 模型预测的初始回弹较高。然而，由于恢复力矩最小，反向弯曲大大降低了两种模型的整体回弹。在反向弯曲的情况下，由于拉伸应力的二次鲍辛格效应，两种模型预测的回弹都相同。这种现象在滚压成形中也能观察到，滚压成形是一种包含反向弯曲步骤的连续弯曲工艺。滚压成形的实验结果证实，反向弯曲阶段后回弹会减少。此外，该研究还通过校准交叉载荷效应，探讨了非各向同性硬化对零件耐撞性的影响。研究发现，鲍辛格效应和交叉载荷收缩可将最大碰撞载荷降低 6.2%。

{"title":"Effect of path-dependent plasticity on springback in reverse bending and its application to roll forming","authors":"Kyucheol Jeong , Keun-ho Kim , Shin-Yeong Lee , Hyuk Jong Bong , Seongyong Yoon , Jonghun Yoon","doi":"10.1016/j.ijsolstr.2024.113079","DOIUrl":"10.1016/j.ijsolstr.2024.113079","url":null,"abstract":"<div><div>This study investigates springback behavior in martensitic advanced high-strength steels (AHSS) undergoing pure bending and reverse bending sequences. The comparison between a conventional isotropic hardening model and the Homogeneous Anisotropic Hardening (HAH20) model had been made, which accounts for non-isotropic hardening effects. Both models were calibrated using uniaxial tensile, cyclic, and loading–unloading tests. The results show that the HAH20 model predicts a higher initial springback compared to the isotropic model. However, reverse bending significantly reduces the overall springback for both models due to a minimized recovery moment. In scenarios with reverse bending, a specific strain exists where both models predict identical springback due to the secondary Bauschinger effect in tensile stress. This phenomenon is also observed in roll forming, a sequential bending process that incorporates reverse bending steps. Experimental findings from roll forming confirm a decrease in springback after the reverse bending stage. Furthermore, the study explores the impact of non-isotropic hardening on the part crashworthiness with the calibration of cross-loading effects. The Bauschinger effect and cross-loading contraction were found to reduce the maximum crash load by 6.2%.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113079"},"PeriodicalIF":3.4,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428618","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}

引用次数: 0

Unravelling electromechanical mechanism of mechanoreceptor inspired capacitive pressure sensor considering size effect 考虑尺寸效应，揭示受机械感受器启发的电容式压力传感器的机电机制

IF 3.4 3区工程技术 Q1 MECHANICS

International Journal of Solids and Structures

Pub Date : 2024-09-24 DOI: 10.1016/j.ijsolstr.2024.113083

Wenxuan Ding , Yonglin Chen , Wenbin Kang , Zhuangjian Liu , Peng Wang , Weidong Yang

The rapid development of intelligent sensing technologies, including electronic skins, wearable devices and robots, has put forward an urgent demand for various tactile biomimetic sensors. However, the design of tactile sensors is mostly based on independent experimental research and lack theoretical guidance at present. In this work, drawing inspiration from human skin microstructure mechanoreceptors responsible for tactile sensation, we proposed a capacitive pressure sensor model featuring a biomimetic conformal microstructured electrode with a round-crown shape. Moreover, at the micrometer scale, size effect profoundly influences the mechanical behavior of sensing materials and microstructured devices. Firstly, we conducted in-depth research on the electromechanical behavior of conformal microstructured electrode pressure sensor, considering the size effect based on couple stress elasticity and Hertz contact theory. We validated the effectiveness of the model by comparing it with experimental and simulation results of human skin. Through numerical simulation, we further verified that the theoretical model of a single microstructured electrode can be utilized for calculating microstructured electrode arrays. Furthermore, our analysis reveals that the geometric morphology and material properties of the dielectric layer, the arrangement density of the microstructured electrode arrays, along with the radius of the round-crown shaped microstructured electrode are the dominant parameters influencing the electromechanical sensitivity through parameter analysis. Finally, we devised a high-k (high dielectric permittivity) polymer composites dielectric layer with a tunable Poisson’s ratio structure, offering a feasible approach to achieving highly sensitive capacitive microstructure sensors. This theoretical model that takes into account the size effect in microstructured electrode contact problem provides theoretical insights that can guide the optimization design of high-performance tactile sensors.

电子皮肤、可穿戴设备和机器人等智能传感技术的快速发展，对各种触觉仿生传感器提出了迫切需求。然而，目前触觉传感器的设计大多基于独立的实验研究，缺乏理论指导。在这项工作中，我们从负责触觉感受的人体皮肤微结构机械感受器中汲取灵感，提出了一种电容式压力传感器模型，其特点是具有圆冠形状的仿生物共形微结构电极。此外，在微米尺度上，尺寸效应深刻影响着传感材料和微结构器件的机械行为。首先，我们基于耦合应力弹性和赫兹接触理论，考虑尺寸效应，对保形微结构电极压力传感器的机电行为进行了深入研究。通过与人体皮肤的实验和仿真结果进行比较，我们验证了模型的有效性。通过数值模拟，我们进一步验证了单个微结构电极的理论模型可用于计算微结构电极阵列。此外，通过参数分析，我们发现介电层的几何形态和材料特性、微结构电极阵列的排列密度以及圆冠形微结构电极的半径是影响机电灵敏度的主要参数。最后，我们设计了一种具有可调泊松比结构的高 k（高介电常数）聚合物复合材料介电层，为实现高灵敏度电容式微结构传感器提供了一种可行的方法。该理论模型考虑了微结构电极接触问题中的尺寸效应，为高性能触觉传感器的优化设计提供了理论依据。

{"title":"Unravelling electromechanical mechanism of mechanoreceptor inspired capacitive pressure sensor considering size effect","authors":"Wenxuan Ding , Yonglin Chen , Wenbin Kang , Zhuangjian Liu , Peng Wang , Weidong Yang","doi":"10.1016/j.ijsolstr.2024.113083","DOIUrl":"10.1016/j.ijsolstr.2024.113083","url":null,"abstract":"<div><div>The rapid development of intelligent sensing technologies, including electronic skins, wearable devices and robots, has put forward an urgent demand for various tactile biomimetic sensors. However, the design of tactile sensors is mostly based on independent experimental research and lack theoretical guidance at present. In this work, drawing inspiration from human skin microstructure mechanoreceptors responsible for tactile sensation, we proposed a capacitive pressure sensor model featuring a biomimetic conformal microstructured electrode with a round-crown shape. Moreover, at the micrometer scale, size effect profoundly influences the mechanical behavior of sensing materials and microstructured devices. Firstly, we conducted in-depth research on the electromechanical behavior of conformal microstructured electrode pressure sensor, considering the size effect based on couple stress elasticity and Hertz contact theory. We validated the effectiveness of the model by comparing it with experimental and simulation results of human skin. Through numerical simulation, we further verified that the theoretical model of a single microstructured electrode can be utilized for calculating microstructured electrode arrays. Furthermore, our analysis reveals that the geometric morphology and material properties of the dielectric layer, the arrangement density of the microstructured electrode arrays, along with the radius of the round-crown shaped microstructured electrode are the dominant parameters influencing the electromechanical sensitivity through parameter analysis. Finally, we devised a high-<em>k</em> (high dielectric permittivity) polymer composites dielectric layer with a tunable Poisson’s ratio structure, offering a feasible approach to achieving highly sensitive capacitive microstructure sensors. This theoretical model that takes into account the size effect in microstructured electrode contact problem provides theoretical insights that can guide the optimization design of high-performance tactile sensors.</div></div>","PeriodicalId":14311,"journal":{"name":"International Journal of Solids and Structures","volume":"305 ","pages":"Article 113083"},"PeriodicalIF":3.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327330","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}

引用次数: 0