European Journal of Mechanics A-Solids最新文献_第10页

Mechanical regulation strategy for heterogeneous piezoelectric semiconductor thermoelectric structure based on energy conversion 基于能量转换的异质压电半导体热电结构的机械调节策略

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-21 DOI: 10.1016/j.euromechsol.2024.105503

Lingyun Guo, Yizhan Yang

The piezoelectric properties inherent in piezoelectric semiconductors facilitate the manipulation of charge carrier redistribution, enabling the fabrication of electronic devices with adjustable characteristics. However, despite this capability, our understanding of the energy conversion and transfer mechanisms within such devices remains limited. By discarding the assumption of low injection and the approximation of depletion layer, a nonlinear model was developed on piezoelectric semiconductor thermoelectric structure (PS-TES), considering the penetration of hot electrons and regulation of mechanical loadings. The presented model reveals that the input electric energy is partitioned, with a portion being converted into electric potential energy stored (EPES) in non-equilibrium carriers and another portion being the energy dissipation (ED) due to the electrothermal action. Furthermore, from an energy conservation standpoint, a interesting competitive phenomenon between electric potential energy conversion and energy dissipation is obtained. The power of external electric energy input and internal electric energy conversion can be manipulated via mechanical loadings, thereby adjusting the energy conversion process of PS-TES. Finally, we found that the compressive loadings can increase EPES and reduce ED, thereby optimizing the cooling effect at cold end. While tensile loadings can reduce EPES and increase ED, thus causing the PS-TES to locally heat up and produce a heating effect. This study potentially offers a means to switch the performance of TES and provides fresh insights into energy conversion processes within piezoelectric semiconductors.

压电半导体固有的压电特性有助于操纵电荷载流子的再分布，从而制造出具有可调特性的电子器件。然而，尽管具有这种能力，我们对这类器件内部能量转换和转移机制的了解仍然有限。通过摒弃低注入假设和耗尽层近似，考虑到热电子的穿透和机械负载的调节，我们建立了压电半导体热电结构（PS-TES）的非线性模型。该模型显示，输入的电能被分割成两部分，一部分转化为储存在非平衡载流子中的电势能（EPES），另一部分则是电热作用导致的能量耗散（ED）。此外，从能量守恒的角度来看，电势能转换和能量耗散之间存在有趣的竞争现象。外部电能输入和内部电能转换的功率可通过机械负载进行调节，从而调整 PS-TES 的能量转换过程。最后，我们发现压缩载荷可以增加 EPES，减少 ED，从而优化冷端冷却效果。而拉伸负载会降低 EPES 并增加 ED，从而使 PS-TES 局部升温并产生加热效应。这项研究为改变 TES 的性能提供了一种潜在的方法，并为压电半导体内部的能量转换过程提供了新的见解。

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引用次数: 0

Comparative analysis of beam models for vertical rail vibrations under dynamic forces 动态力作用下垂直轨道振动的梁模型比较分析

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-18 DOI: 10.1016/j.euromechsol.2024.105497

Le-Hung Tran , Tuan-Manh Duong , Benjamin Claudet , Khuong Le-Nguyen , Anders Nordborg , Franziska Schmidt

An analytical model of the rails of ballasted railway track subjected to the dynamic loads are developed to study forced vertical vibration. In this work, the two rails are modelled as infinite uniform beams posed on a system of periodical supports with the help of Timoshenko beam theory. Besides, each support is considered as a beam posed on a visco-elastic foundation. A linear relation between the sleeper displacement at the crossing-points with two rails and the two reaction forces is established via the Green’s function in the frequency domain. In other words, the mechanical behaviour of the support can be written as a spring with an equivalent stiffness. By replacing this relation into the periodically supported rail models, the forced vertical vibrations of two rails are obtained analytically. This analytical model allows calculate rapidly the rail responses in different load, especially in the non-symmetric configuration. In addition, the comparison of rail responses calculated by two beam models are investigated. This work concerns the study of peaks resonances of the frequency responses functions which is useful to understand the excitations of rolling noise.

为研究有砟轨道的受迫垂直振动，我们开发了一个承受动载荷的有砟轨道分析模型。在这项工作中，借助季莫申科梁理论，将两根钢轨模拟为周期支撑系统上的无限均匀梁。此外，每个支撑都被视为粘弹性地基上的梁。通过频域中的格林函数，在与两根钢轨交叉点处的枕木位移与两个反作用力之间建立了线性关系。换句话说，支撑的机械性能可以写成具有等效刚度的弹簧。将这一关系代入周期性支撑的钢轨模型中，就能分析得出两根钢轨的受力垂直振动。这种分析模型可以快速计算不同载荷下的轨道响应，尤其是在非对称配置下。此外，还对两种梁模型计算出的轨道响应进行了比较研究。这项工作涉及频率响应函数峰值共振的研究，这有助于了解滚动噪声的激励。

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引用次数: 0

Viscoelastic–viscoplastic model with ductile damage accounting for tension–compression asymmetry and hydrostatic pressure effect for polyamide 66 具有韧性损伤的粘弹性-粘塑性模型，考虑到聚酰胺 66 的拉伸-压缩不对称和静水压力效应

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-17 DOI: 10.1016/j.euromechsol.2024.105491

Soheil Satouri , George Chatzigeorgiou , Fodil Meraghni , Gilles Robert

This paper proposes a model for predicting the complex inelastic mechanical response of polyamide 66. Polyamide 66 is a semi-crystalline pressure-sensitive polymer that exhibits asymmetric yielding behavior, in which the yield strength is slightly higher in compression. With this in mind, an

I_{1}

-

J_{2}

yield function considering the asymmetric behavior and the hydrostatic pressure effect is presented and integrated into a phenomenological viscoelastic–viscoplastic model accounting for ductile damage. The corresponding thermodynamic framework and constitutive laws are discussed. Then, an experimental approach is presented to identify the model parameters through mechanical tests with different loading paths to capture the active mechanisms. The experimental findings obtained from uni-axial and multi-axial (tension-torsion) mechanical tests and the numerical model are used in an optimization algorithm to identify the model parameters. A parametric analysis is performed to study the effect of the asymmetric behavior on the state variables under different loading conditions using the identified parameters. The present model responses are in good agreement with the experimental data, and the combination of the experimental and numerical results demonstrates and states the asymmetric behavior of polyamide at relative humidity (RH) of 50%, which is captured by the suggested model. It is also worth pointing out that the parametric study conducted on a notched plate using finite element simulations showcases the structural computation capabilities of the proposed model.

本文提出了一种预测聚酰胺 66 复杂非弹性机械响应的模型。聚酰胺 66 是一种半结晶压敏聚合物，具有不对称屈服行为，其中压缩屈服强度略高。有鉴于此，我们提出了一种考虑到非对称行为和静水压力效应的 I1-J2 屈服函数，并将其整合到一个考虑到韧性损伤的粘弹性-粘塑性现象学模型中。讨论了相应的热力学框架和构成定律。然后，介绍了一种实验方法，通过不同加载路径的机械测试来确定模型参数，以捕捉活跃机制。从单轴和多轴（拉伸-扭转）机械测试以及数值模型中获得的实验结果被用于优化算法，以确定模型参数。使用确定的参数进行参数分析，以研究不同加载条件下非对称行为对状态变量的影响。本模型的响应与实验数据十分吻合，实验和数值结果的结合证明并阐述了聚酰胺在相对湿度（RH）为 50%时的非对称行为，建议的模型捕捉到了这一行为。还值得指出的是，利用有限元模拟对缺口板进行的参数研究展示了所建议模型的结构计算能力。

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引用次数: 0

The influence of bi-directional material gradation on a mode-III crack in functionally graded material via strain gradient elasticity theory 通过应变梯度弹性理论研究双向材料梯度对功能梯度材料模态 III 裂纹的影响

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-16 DOI: 10.1016/j.euromechsol.2024.105496

Rakesh Kumar Sharma , Kamlesh Jangid , Y. Eugene Pak

In contrast to classical mechanics, which primarily relies on continuum assumptions and neglects micro-structural effects, the strain gradient elasticity (SGE) theory represents a paradigm shift in understanding the mechanical behavior of materials at small length scales. In this article, the influence of the bi-directional material gradation on a mode-III crack in functionally graded material via SGE theory is studied. The SGE theory uses two material characteristic lengths,

ℓ

and

ℓ^{'}

, to account for volumetric and surface strain-gradient factors, respectively. Our investigation is centered on a material gradation model assumed to vary exponentially, with the shear modulus represented as

G (x, y) = G_{0} e^{β x + γ y}

, where

β

and

γ

are material gradation constants. To address the crack boundary value problem under consideration, we employ a methodology combining Fourier transforms and an innovative hyper-singular integro-differential equation approach. Using this approach, we systematically formulate a system of equations, which can be solved by selecting suitable collocation points. The closed-form analytical expressions are derived for the standard fracture parameters such as crack surface displacement (CSD), stress intensity factor (SIF), and energy release rate (ERR). Numerical studies are illustrated for the derived standard fractures, and the influence of these parameters

β

,

γ

,

ℓ

,

ℓ^{'}

, and applied shear load is graphically presented. Through comprehensive analysis, our aim is to provide insights into the complex interplay between material parameters, loading conditions, and crack behavior in functionally graded materials.

经典力学主要依赖连续性假设，忽略了微观结构效应，与之相反，应变梯度弹性（SGE）理论代表了理解材料在小长度尺度上力学行为的范式转变。本文通过 SGE 理论研究了双向材料梯度对功能梯度材料模态 III 裂纹的影响。SGE 理论使用两个材料特征长度，即 ℓ 和 ℓ′，来分别考虑体积和表面应变梯度因素。我们的研究以假定为指数变化的材料级配模型为中心，剪切模量表示为 G(x,y)=G0eβx+γy ，其中 β 和 γ 是材料级配常数。为了解决所考虑的裂缝边界值问题，我们采用了一种结合傅立叶变换和创新超弦积分微分方程的方法。利用这种方法，我们系统地提出了一个方程组，通过选择合适的定位点可以求解该方程组。我们推导出了裂纹表面位移（CSD）、应力强度因子（SIF）和能量释放率（ERR）等标准断裂参数的闭式解析表达式。对推导出的标准断裂进行了数值研究，并以图表形式展示了这些参数 β、γ、ℓ、ℓ′ 和施加的剪切载荷的影响。通过综合分析，我们希望深入了解功能分级材料中材料参数、加载条件和裂纹行为之间复杂的相互作用。

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引用次数: 0

Improved tangential interpolation-based multi-input multi-output modal analysis of a full aircraft 基于切向插值的全机多输入多输出模态分析改进版

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-16 DOI: 10.1016/j.euromechsol.2024.105495

Gabriele Dessena , Marco Civera

In the field of Structural Dynamics, modal analysis is the foundation of System Identification and vibration-based inspection. However, despite their widespread use, current state-of-the-art methods for extracting modal parameters from multi-input multi-output (MIMO) frequency domain data are still affected by many technical limitations. Mainly, they can be computationally cumbersome and/or negatively affected by close-in-frequency modes. The Loewner Framework (LF) was recently proposed to alleviate these problems with the limitation of working with single-input data only. This work proposes a computationally improved version of the LF, or iLF, to extract modal parameters more efficiently. Also, the proposed implementation is extended in order to handle MIMO data in the frequency domain. This new implementation is compared to state-of-the-art methods such as the frequency domain implementations of the Least Square Complex Exponential method and the Numerical Algorithm for Subspace State Space System Identification on numerical and experimental datasets. More specifically, a finite element model of a 3D Euler–Bernoulli beam is used for the baseline comparison and the noise robustness verification of the proposed MIMO iLF algorithm. Then, an experimental dataset from MIMO ground vibration tests of a trainer jet aircraft with over 91 accelerometer channels is chosen for the algorithm validation on a real-life application. Its validation is carried out with known results from a single-input multi-output dataset of the starboard wing of the same aircraft. Excellent results are achieved in terms of accuracy, robustness to noise, and computational performance by the proposed improved MIMO method, both on the numerical and the experimental datasets. The MIMO iLF MATLAB implementation is shared in the work supplementary material.

在结构动力学领域，模态分析是系统识别和振动检测的基础。然而，尽管得到了广泛应用，目前从多输入多输出（MIMO）频域数据中提取模态参数的最先进方法仍受到许多技术限制的影响。主要是计算繁琐和/或受到近频模态的负面影响。最近提出的 Loewner 框架（LF）可以缓解这些问题，但其局限性在于只能处理单输入数据。这项工作提出了一个计算改进版的 LF，即 iLF，以更有效地提取模态参数。同时，为了处理频域中的多输入多输出数据，对所提出的实现方法进行了扩展。在数值和实验数据集上，将这种新的实现方法与最先进的方法（如最小平方复指数法的频域实现方法和子空间状态空间系统识别的数值算法）进行了比较。更具体地说，三维欧拉-伯努利波束的有限元模型用于基线比较和所提 MIMO iLF 算法的噪声鲁棒性验证。然后，在实际应用中选择了来自一架教练喷气式飞机 MIMO 地面振动测试的实验数据集，该数据集拥有超过 91 个加速度计通道，用于算法验证。该算法与同一飞机右侧机翼单输入多输出数据集的已知结果进行了验证。在数值数据集和实验数据集上，所提出的改进型 MIMO 方法在精确度、对噪声的鲁棒性和计算性能方面都取得了优异的结果。MIMO iLF MATLAB 实现在工作补充材料中共享。

{"title":"Improved tangential interpolation-based multi-input multi-output modal analysis of a full aircraft","authors":"Gabriele Dessena , Marco Civera","doi":"10.1016/j.euromechsol.2024.105495","DOIUrl":"10.1016/j.euromechsol.2024.105495","url":null,"abstract":"<div><div>In the field of Structural Dynamics, modal analysis is the foundation of System Identification and vibration-based inspection. However, despite their widespread use, current state-of-the-art methods for extracting modal parameters from multi-input multi-output (MIMO) frequency domain data are still affected by many technical limitations. Mainly, they can be computationally cumbersome and/or negatively affected by close-in-frequency modes. The Loewner Framework (LF) was recently proposed to alleviate these problems with the limitation of working with single-input data only. This work proposes a computationally improved version of the LF, or iLF, to extract modal parameters more efficiently. Also, the proposed implementation is extended in order to handle MIMO data in the frequency domain. This new implementation is compared to state-of-the-art methods such as the frequency domain implementations of the Least Square Complex Exponential method and the Numerical Algorithm for Subspace State Space System Identification on numerical and experimental datasets. More specifically, a finite element model of a 3D Euler–Bernoulli beam is used for the baseline comparison and the noise robustness verification of the proposed MIMO iLF algorithm. Then, an experimental dataset from MIMO ground vibration tests of a trainer jet aircraft with over 91 accelerometer channels is chosen for the algorithm validation on a real-life application. Its validation is carried out with known results from a single-input multi-output dataset of the starboard wing of the same aircraft. Excellent results are achieved in terms of accuracy, robustness to noise, and computational performance by the proposed improved MIMO method, both on the numerical and the experimental datasets. The MIMO iLF MATLAB implementation is shared in the work supplementary material.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"110 ","pages":"Article 105495"},"PeriodicalIF":4.4,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

The combination of random and controllable--- design strategy and mechanical properties of directional random porous structures inspired by Wolff's law 随机与可控的结合--受沃尔夫定律启发的定向随机多孔结构的设计策略与力学性能

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-16 DOI: 10.1016/j.euromechsol.2024.105502

Xiaofei Ma, Ce Guo, Yu Wang, Hongqian Wang

Porous structures have received extensive attention due to their excellent mechanical properties. Inspired by Wolff's law, a new design method for directional random porous structures (DRPS) that is based on principal stress lines is proposed. Considering three working conditions, namely, cantilever bending, shearing and compression, the mechanical properties and deformation modes of a directional random porous structure in the loading direction were studied via numerical simulation. The results show that the directional random porous structure significantly reduces both the maximum stress and deformation, as well as the stress concentration within the model. The design model was prepared via a light curing process with the photosensitive resin R4000 as the raw material, and its deformation pattern and mechanical behaviour under local and overall compression conditions were investigated. During local compression loading, the selection of different principal stress lines affects the mechanical properties of the structure. Selecting a dense area of principal stress lines with a large transfer stress as the directional growth design area can result in better strengthening efficiency. The experimental results under overall compressive loading conditions show that the design method proposed in this paper can substantially improve the mechanical properties of the structure in the strengthening direction while ensuring the mechanical properties in the non-strengthening direction, in which the modulus of elasticity, ultimate compressive strength and specific energy absorption (SEA) were improved by up to approximately 140.97%, 58.59 % and 51.32 %, respectively.

多孔结构因其优异的机械性能而受到广泛关注。受沃尔夫定律的启发，本文提出了一种基于主应力线的定向随机多孔结构（DRPS）新设计方法。考虑到悬臂弯曲、剪切和压缩三种工况，通过数值模拟研究了定向随机多孔结构在加载方向上的力学性能和变形模式。结果表明，定向随机多孔结构显著降低了最大应力和变形，以及模型内的应力集中。以光敏树脂 R4000 为原料，通过光固化工艺制备了设计模型，并研究了其在局部和整体压缩条件下的变形模式和力学行为。在局部压缩加载过程中，不同主应力线的选择会影响结构的机械性能。选择传递应力较大的主应力线密集区域作为定向生长设计区域，可以获得更好的强化效率。整体压缩加载条件下的实验结果表明，本文提出的设计方法可以在保证非加固方向力学性能的同时，大幅提高结构在加固方向的力学性能，其中弹性模量、极限抗压强度和比能量吸收（SEA）分别提高了约 140.97%、58.59% 和 51.32%。

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引用次数: 0

Buckling-based topology optimization for underwater pressure hull with modified parameterized level-set method 基于屈曲的水下压力船体拓扑优化与修正参数化水平集法

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-14 DOI: 10.1016/j.euromechsol.2024.105499

Yuanteng Jiang , Tengwu He , Min Zhao

Buckling is a common phenomenon in compression structures, and its occurrence will cause significant damage, especially in the application of underwater pressure hulls. In this paper, a new mathematical model based on an improved parameterized level-set method is developed to solve fundamental buckling load factor maximization and buckling-constraint topology optimization problems, and further the continuous descriptions of normal velocities are derived using the theory of the shape derivative and bifurcation analysis. In this model, a regularization term is introduced to ensure numerical stability, and an augmented Lagrange multiplier is presented to realize stable transitions of both optimization problems during the convergence process. Besides, Kreisslmeier–Steinhauser function is employed to aggregate multiple buckling load factors to a differentiable one. In this case, an easily implemented method is proposed to discretize normal velocities to every nodal point in the design area. By means of the developed method, the clear contours of the optimal structures are obtained, and the pseudo-buckling modes during optimization process is alleviated. To further prove the effectiveness, three-dimensional cases of underwater cylindrical pressure hull are extended, and corresponding buckling-based problems are solved, in which the optimal results with clearer contour and more details are approached. The current method can be used to deal with the similar buckling-based problems of underwater pressure hulls and the final structures are more easily manufactured in practical application.

屈曲是受压结构中的一种常见现象，其发生会造成重大损害，尤其是在水下压力船体的应用中。本文基于改进的参数化水平集方法建立了一个新的数学模型，用于求解基本屈曲载荷系数最大化和屈曲约束拓扑优化问题，并进一步利用形状导数理论和分岔分析推导出法向速度的连续描述。在该模型中，引入了正则化项以确保数值稳定性，并提出了一个增强拉格朗日乘法器，以实现这两个优化问题在收敛过程中的稳定转换。此外，还采用 Kreisslmeier-Steinhauser 函数将多个屈曲载荷系数汇总为一个可变系数。在这种情况下，我们提出了一种易于实施的方法来离散化设计区域内每个节点的法向速度。通过所开发的方法，可以获得最佳结构的清晰轮廓，并缓解优化过程中的伪屈曲模式。为了进一步证明该方法的有效性，扩展了水下圆柱形压力船体的三维案例，并求解了相应的基于屈曲的问题，在这些案例中，得到了轮廓更清晰、细节更丰富的最优结果。目前的方法可用于处理水下压力船体的类似屈曲问题，而且最终结构在实际应用中更易于制造。

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引用次数: 0

Atomistic investigation of interface adherence mechanism of structural indenter nanocoining single crystal aluminum 结构压头纳米压入单晶铝的界面粘附机理的原子学研究

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-13 DOI: 10.1016/j.euromechsol.2024.105500

Zaizhen Lou , Yongda Yan , Xin Yang , Hailong Cui , Chen Li , Yanquan Geng

The utilization of nanoimprint technology has become widespread in various industries. Nanocoining, a new type of nanoimprinting technology, is essentially graphic copying. Ensuring the indenter's accuracy and the transfer's integrity is crucial. Structured tool (ST)-metal workpiece interface commonly exists in adherence phenomenon during the nanoimprint. To reduce the adherence of workpieces in ST, it is remarkable to illustrate the adhesion mechanism. The molecular dynamic simulation model for indenting aluminum with a diamond ST indenter was established, and the influence of critical process parameters on adhesion, including the indenter geometry, indenter temperature, and indenter speed, was investigated. The results demonstrate that various factors significantly influence adhesion, including the van der Waals force, surface energy, temperature, mechanical embedding, diffusion, and holding stage. The mechanism of adhesion can be composed of three parts: the mechanical embedding caused by the large range of cavity filling of the indenter, the slow thermal diffusion and thermal migration of aluminum atoms along the indenter and the combined effect of thermal-tensile stress in the demolding process. The intensity of adhesion is affected by several factors, namely the degree of plastic deformation during loading and unloading, atomic thermal migration caused by system temperature, and the magnitude of tensile stress during the demolding stage. The geometry of the indenter exerts the most significant influence on the van der Waals force, surface energy, imprinting force, and unloading force. Additionally, the omission of the holding stage during processing contributes to a reduction in adhesion. This study provides atomic-level insights into the adhesive properties of metallic materials in the nanocoining process.

纳米压印技术已在各行各业得到广泛应用。纳米压印是一种新型的纳米压印技术，其本质是图形复制。确保压头的精度和转移的完整性至关重要。在纳米压印过程中，结构工具（ST）-金属工件界面通常存在粘附现象。为了减少 ST 中工件的粘附，说明粘附机理是非常重要的。建立了用金刚石 ST 压头压入铝的分子动力学模拟模型，并研究了压头几何形状、压头温度和压头速度等关键工艺参数对附着力的影响。结果表明，范德华力、表面能、温度、机械嵌入、扩散和保持阶段等各种因素都会对附着力产生重大影响。粘附机理可由三部分组成：压头空腔填充范围大导致的机械嵌入、铝原子沿压头的缓慢热扩散和热迁移以及脱模过程中的热拉伸应力的共同作用。粘附强度受几个因素的影响，即加载和卸载过程中的塑性变形程度、系统温度引起的原子热迁移以及脱模阶段拉伸应力的大小。压头的几何形状对范德华力、表面能、压印力和卸载力的影响最大。此外，在加工过程中省略保持阶段也会导致附着力降低。这项研究从原子层面揭示了金属材料在纳米压印过程中的粘附特性。

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引用次数: 0

Research on mechanical behavior of particle/matrix interface in composite solid propellant 复合固体推进剂中颗粒/基质界面的力学行为研究

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-12 DOI: 10.1016/j.euromechsol.2024.105498

Zijie Zou , Hongfu Qiang , Fengtao Zhang , Xueren Wang , Yiyi Li

In the mesostructure of composite solid propellant, the interface formed between solid particle and matrix is a region with very special physical and chemical properties, and the mechanical behavior of the interface will directly affect the mechanical properties of the propellant. This article derived a viscoelastic cohesive constitutive model to describe the mechanical behavior of the interface. subsequently a particle/matrix interface specimen was design to measure the interface mechanical properties under different conditions. To this end, the parameters of the constitutive model were solved through a combination of experimental data fitting and inversion. It was found that the interface behavior exhibits strong rate and temperature correlations, and the cohesive constitutive model can effectively describe this characteristic.

在复合固体推进剂的介观结构中，固体颗粒与基体之间形成的界面是一个具有非常特殊的物理和化学性质的区域，界面的力学行为将直接影响推进剂的力学性能。本文推导了一个粘弹性内聚构成模型来描述界面的力学行为，随后设计了一个颗粒/基质界面试样来测量不同条件下的界面力学性能。为此，通过实验数据拟合和反演相结合的方法求解了构成模型的参数。结果发现，界面行为表现出很强的速率和温度相关性，而内聚构成模型可以有效地描述这一特性。

引用次数: 0

Vibration suppression of suspended cables with three-to-one internal resonances via time-delay feedback 通过延时反馈抑制具有三比一内部共振的悬索的振动

IF 4.4 2区工程技术 Q1 MECHANICS

European Journal of Mechanics A-Solids

Pub Date : 2024-11-10 DOI: 10.1016/j.euromechsol.2024.105487

Jian Peng , Yanan Li , Stefano Lenci , Xiangzhan Yang , Lianhua Wang

Based on the time-delay feedback control, the vibration suppression of suspended cables with three-to-one internal resonances are investigated. Initially, the nonlinear differential equation of motion for a suspended cable under time-delay feedback control is considered, and a discrete model is derived using the Galerkin method. Subsequently, the method of multiple scales is employed to perturbatively solve the discrete time-delay differential equation, determining the modulation equations around the first primary resonance. Steady-state and periodic solutions of the modulation equations are detected numerically. Numerical results indicate that the internal resonance enhances the nonlinear dynamical complexity of the controlled suspended cable. It is observed that the time delay and control gain affect the controlled system: in particular, an increase in control gain leads to a reduction in response amplitude. By adjusting the time delay and control gain, the critical excitation can be altered, an aspect that could be very useful from a practical point of view. This research sheds light on the intricate dynamics of suspended cable and provides a theoretical foundation for designing more effective control strategies in engineering applications.

基于延时反馈控制，研究了具有三比一内部共振的悬索的振动抑制问题。首先，考虑了延时反馈控制下悬索的非线性运动微分方程，并利用 Galerkin 方法推导出离散模型。随后，采用多尺度法对离散时延微分方程进行扰动求解，确定了第一个主谐振周围的调制方程。数值检测了调制方程的稳态解和周期解。数值结果表明，内部共振增强了受控悬索的非线性动力学复杂性。据观察，时间延迟和控制增益会影响受控系统：特别是，控制增益的增加会导致响应振幅的减小。通过调整时间延迟和控制增益，可以改变临界激励，这在实际应用中非常有用。这项研究揭示了悬挂缆索错综复杂的动力学特性，为在工程应用中设计更有效的控制策略奠定了理论基础。

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引用次数: 0