Mechanics of Materials最新文献_第8页

A physics-based crystal plasticity model of nickel-based single crystal superalloy for different loading conditions under a wide temperature range 基于物理的镍基单晶高温合金在宽温度范围内不同加载条件下的晶体塑性模型

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-14 DOI: 10.1016/j.mechmat.2025.105528

Jiaxuan Wang , Rou Du , Liu Chen , Hansong Ma , Xiaoming Liu , Yueguang Wei

Nickel-based single crystal (NBSC) superalloys are extensively used in the fabrication of turbine blades for aero engines, where their deformation behaviours play a critical role in ensuring flight safety. The deformation behaviours are governed by complex micro-scale mechanisms, such as matrix slip, precipitate shearing, interface dislocation pile-up, dislocation climb, coarsening, and rafting. However, many existing models either inadequately account for the underlying deformation mechanisms or rely heavily on temperature-sensitive material parameters, both of which undermine their predictive accuracy and generalizability under diverse loading and thermal conditions. To address these limitations, this study develops a robust and versatile crystal plasticity model that incorporates the above mechanisms. The model decouples temperature effects from constitutive parameters to mitigate parameter sensitivity to temperature variations. Additionally, a parameter decoupling strategy is employed to reduce the number of adjustable parameters and facilitate their identification. The model is validated against experimental data for the DD6 superalloy under uniaxial tension, creep, and low-cycle fatigue tests conducted across a wide temperature range (20–980 °C). The predicted mechanical responses demonstrate good agreement with the experimental results. Finally, the model is applied to simulate the mechanical behaviour of a specimen with inclined cooling holes. The model gives a nearly linear response of creep displacement, which matches well with the experiments.

镍基单晶高温合金广泛应用于航空发动机涡轮叶片的制造，其变形行为对保证飞行安全起着至关重要的作用。变形行为受基体滑移、析出相剪切、界面位错堆积、位错爬升、粗化和漂流等复杂微观机制控制。然而，许多现有的模型要么不能充分考虑潜在的变形机制，要么严重依赖于温度敏感的材料参数，这两者都破坏了它们在不同载荷和热条件下的预测准确性和通用性。为了解决这些限制，本研究开发了一个包含上述机制的健壮且通用的晶体塑性模型。该模型将温度效应与本构参数解耦，降低了本构参数对温度变化的敏感性。此外，采用参数解耦策略减少了可调参数的数量，便于辨识。该模型通过DD6高温合金在单轴拉伸、蠕变和宽温度范围（20-980°C）下的低周疲劳试验数据进行了验证。预测的力学响应与实验结果吻合较好。最后，将该模型应用于具有倾斜冷却孔的试样的力学行为模拟。该模型给出了蠕变位移的近似线性响应，与实验结果吻合较好。

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引用次数: 0

Micromechanical modeling and property prediction of bamboo with gradient random vascular bundles 梯度随机维管束竹的微观力学模型及性能预测

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-14 DOI: 10.1016/j.mechmat.2025.105527

Yubo Hou , Adel Noori , Kairan Zhang , Yuhan Zheng , Hao Wang , Yubin Lu

Bamboo has gained significant attention in sustainable buildings for its rapid growth rate and impressive mechanical properties comparable to wood. The volume fraction and gradient arrangement of vascular bundles directly influence the mechanical properties of bamboo. This paper proposes a novel gradient random distribution method, which can accurately restore the gradient distribution of bamboo vascular bundles along the radial direction of the culm wall. The aim is to uncover the relationship between the gradient distribution pattern of vascular bundles and the mechanical properties. The gradient random distribution method helps to transform the uniform random Representative Volume Element model into a gradient random distribution numerical model using the concept of coordinate transformation. The comparative analysis was conducted between the uniform random distribution method and the gradient random distribution method to predict the effective elastic properties of bamboo vascular bundles. The results indicated that elastic modulus and shear modulus of bamboo exhibit an exponential increase from the inner to the outer layers along the radial direction of the culm wall. Larger fiber spacing can slightly decrease the corresponding shear modulus. Moreover, the gradient random distribution method is capable of predicting accurately the elastic stiffness properties of full-sized bamboo culm compared to the uniform random distribution method.

竹子因其快速的生长速度和可与木材媲美的令人印象深刻的机械性能而在可持续建筑中获得了极大的关注。维管束的体积分数和梯度排列直接影响竹子的力学性能。本文提出了一种新的梯度随机分布方法，可以准确地恢复竹维管束沿茎壁径向的梯度分布。目的是揭示维管束的梯度分布模式与力学性能之间的关系。梯度随机分布方法利用坐标变换的概念，将均匀随机的代表性体元模型转化为梯度随机分布的数值模型。对均匀随机分布法和梯度随机分布法预测竹维管束有效弹性特性进行了对比分析。结果表明：竹材的弹性模量和剪切模量沿茎壁径向由内层向外层呈指数增长；较大的纤维间距可使相应的剪切模量略有降低。与均匀随机分布法相比，梯度随机分布法能较准确地预测全尺寸竹竿的弹性刚度特性。

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引用次数: 0

Delineating strain-rate hardening and inertial effects on dynamic hardness of materials 描述了应变率硬化和惯性效应对材料动态硬度的影响

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-11 DOI: 10.1016/j.mechmat.2025.105523

Zahra Ghasemi , Tiago dos Santos , Debjoy D. Mallick , José A. Rodríguez-Martínez , Ankit Srivastava

We examine the interplay between strain-rate hardening and structural inertia in dynamic indentation, with the objective of identifying when dynamic hardness reflects intrinsic material response versus when it is influenced by inertia. Finite element simulations and theoretical calculations – based on a dynamic cavity expansion model – are performed for materials described by a strain- and strain-rate-dependent constitutive model with thermal softening. The analysis spans a broad range of indentation velocities, depths, material densities, and strain-rate sensitivity exponents. Our results show that at relatively low to moderate indentation velocities, dynamic hardness can be interpreted as an intrinsic material property. However, at sufficiently high velocities, the indentation response is significantly influenced by inertia-induced resistance, manifested by a rapid increase in hydrostatic stress and, consequently, in dynamic hardness. The extent of this resistance scales with indentation strain rate, indentation depth, and material density. We introduce a normalization approach that, for a given material, accounts for inertia by scaling dynamic hardness and indentation strain rate with reference functions that depend on indentation velocity. This procedure enables the identification of the loading rate at which inertia begins to dominate the indentation response and allows data across a wide range of indentation strain rates and depths to be interpreted in terms of the material’s intrinsic strain-rate-dependent constitutive behavior. The excellent agreement between finite element simulations and theoretical predictions underscores the robustness of the proposed approach and establishes a foundation for extracting strain-rate-sensitive material properties from dynamic indentation experiments.

我们研究了动态压痕中应变率硬化和结构惯性之间的相互作用，目的是确定动态硬度是反映材料的固有响应还是受惯性影响。基于动态空腔膨胀模型的有限元模拟和理论计算，对由应变和应变率相关的热软化本构模型描述的材料进行了模拟和理论计算。该分析涵盖了广泛的压痕速度、深度、材料密度和应变率灵敏度指数。我们的结果表明，在相对低到中等压痕速度下，动态硬度可以解释为材料的固有特性。然而，在足够高的速度下，压痕响应明显受到惯性诱导阻力的影响，表现为静水应力的迅速增加，从而导致动态硬度的增加。这种阻力的程度与压痕应变率、压痕深度和材料密度有关。我们引入了一种归一化方法，对于给定的材料，通过缩放动态硬度和压痕应变率与依赖于压痕速度的参考函数来解释惯性。这一过程可以确定惯性开始主导压痕响应的加载速率，并允许在大范围内的压痕应变率和深度的数据被解释为材料的固有应变率相关的本构行为。有限元模拟与理论预测之间的良好一致性强调了所提出方法的鲁棒性，并为从动态压痕实验中提取应变率敏感材料性能奠定了基础。

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引用次数: 0

Effect of microdamage on the failure of open-hole UD GFRP laminates: A combined experimental and numerical study 微损伤对开孔UD玻璃钢复合材料破坏的影响：实验与数值相结合的研究

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-10 DOI: 10.1016/j.mechmat.2025.105524

Özgün Şener , Altan Kayran

The effect of microdamaging on the failure of unidirectional Interglas 92145/CR80 GFRP laminates is studied through experiments and a numerical approach combining Enhanced Schapery Theory (EST) and Crack Band Theory (CBT). Open-hole tension tests with various layer configurations, along with flat tensile tests were conducted to examine failure modes and their progression. The initiation and development of failure mechanisms were tracked experimentally using DIC imaging. In the numerical model, the matrix microdamage is represented through dissipated energy-dependent functions derived from standardized mechanical tests. Without discretely modeling splitting cracks, the numerical approach captured narrow zones of fiber and matrix failure coincident with experimentally observed crack paths. Axial, transverse, and shear strain fields from the physical and virtual tests were compared at the critical stages of the testing regimen. Comparison of the strain fields, as well as stress-strain curves from the numerical and experimental studies showed good agreement, suggesting that incorporation of microdamage modeling—rarely implemented in progressive failure analyses—offers potential for improving failure predictions in GFRP laminates.

结合增强Schapery理论（EST）和裂纹带理论（CBT），通过实验和数值方法研究了微损伤对单向interglass 92145/CR80玻璃钢层合板失效的影响。进行了各种层构型的裸眼拉伸试验，以及平面拉伸试验，以检查破坏模式及其进展。实验中使用DIC成像技术跟踪了失效机制的发生和发展。在数值模型中，通过标准化力学试验的耗散能量依赖函数来表示基体微损伤。数值方法没有对劈裂裂纹进行离散建模，而是捕获了与实验观察到的裂纹路径一致的纤维和基体的狭窄破坏区域。在试验方案的关键阶段，比较了物理和虚拟试验的轴向、横向和剪切应变场。应变场的比较，以及数值和实验研究的应力-应变曲线显示出良好的一致性，表明微损伤模型的结合-很少在渐进破坏分析中实施-提供了改进GFRP层合板的破坏预测的潜力。

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引用次数: 0

Achieving geometric accuracy in FFT-based micromechanical models using conformal grid 利用保形网格实现基于fft的微力学模型的几何精度

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-01 DOI: 10.1016/j.mechmat.2025.105512

Miroslav Zecevic, Ricardo A. Lebensohn, Laurent Capolungo

Owing to its efficiency, simplicity and robustness, the FFT-based method has become the standard for computation of mechanical fields in a heterogeneous periodic unit cell. One of the main disadvantages of the FFT-based method is the inaccurate representation of the initial microstructure on a regular grid of voxels, which can be alleviated through the use of distorted initial grids. In this paper, a method for generation of distorted initial grids conforming to the microstructural features (e.g. straight/curved boundaries) is proposed. The method determines the positions of the grid nodes in the initial configuration by solving a system of springs connecting the nodes. Microstructures consisting of layers, Voronoi tessellation and circular/spherical inclusions are considered, and mechanical fields simulated using the FFT-based method. It is found that distorted initial grids, conforming to the microstructural features, lead to more accurate mechanical fields in comparison to the corresponding non-distorted initial grid solution. The effect of initial grid distortion on the convergence of the FFT-based method is analyzed and discussed.

基于fft的方法由于其高效、简单和鲁棒性，已成为计算非均匀周期单元胞中力学场的标准方法。基于fft的方法的主要缺点之一是初始微观结构在规则体素网格上的不准确表示，可以通过使用扭曲的初始网格来缓解这一问题。本文提出了一种生成符合微观结构特征（如直/弯边界）的畸变初始网格的方法。该方法通过求解连接节点的弹簧系统来确定网格节点在初始构型中的位置。考虑了由层、Voronoi镶嵌和圆形/球形夹杂组成的微观结构，并使用基于fft的方法模拟了力学场。结果表明，与非畸变初始网格解相比，畸变初始网格解得到的力学场更为精确，且符合微观结构特征。分析和讨论了初始网格畸变对基于fft的方法收敛性的影响。

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引用次数: 0

A viscoplasticity model with an invariant-based non-Newtonian flow rule for unidirectional thermoplastic composites 单向热塑复合材料粘塑性模型与基于不变量的非牛顿流动规则

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-09-30 DOI: 10.1016/j.mechmat.2025.105507

P. Hofman, D. Kovačević, F.P. van der Meer, L.J. Sluys

A three-dimensional mesoscopic viscoplasticity model for simulating rate-dependent plasticity and creep in unidirectional thermoplastic composites is presented. The constitutive model is a transversely isotropic extension of an isotropic finite strain viscoplasticity model for neat polymers. Rate-dependent plasticity and creep are described by a non-Newtonian flow rule where the viscosity of the material depends on an equivalent stress measure through an Eyring-type relation. In the present formulation, transverse isotropy is incorporated by defining the equivalent stress measure and flow rule as functions of transversely isotropic stress invariants. In addition, the Eyring-type viscosity function is extended with anisotropic pressure dependence. As a result of the formulation, plastic flow in fiber direction is effectively excluded and pressure dependence of the polymer matrix is accounted for. The re-orientation of the transversely isotropic plane during plastic deformations is incorporated in the constitutive equations, allowing for an accurate large deformation response. The formulation is fully implicit and a consistent linearization of the algorithmic constitutive equations is performed to derive the consistent tangent modulus. The performance of the mesoscopic constitutive model is assessed through a comparison with a micromechanical model for carbon/PEEK, with the original isotropic viscoplastic version for the polymer matrix and with hyperelastic fibers. The micromodel is first used to determine the material parameters of the mesoscale model with a few stress–strain curves. It is demonstrated that the mesoscale model gives a similar response to the micromodel under various loading conditions. Finally, the mesoscale model is validated against off-axis experiments on unidirectional thermoplastic composite plies.

提出了一种用于模拟单向热塑性复合材料速率相关塑性和蠕变的三维细观粘塑性模型。本构模型是纯聚合物的各向同性有限应变粘塑性模型的横向各向同性扩展。速率相关的塑性和蠕变由非牛顿流动规则描述，其中材料的粘度取决于等效应力测量，通过eyring型关系。在本公式中，通过将等效应力测量和流动规律定义为横向各向同性应力不变量的函数，纳入了横向各向同性。此外，对eyring型黏度函数进行了扩展，使其具有各向异性压力依赖性。由于该配方，有效地排除了纤维方向的塑性流动，并考虑了聚合物基体的压力依赖性。在塑性变形过程中，横向各向同性平面的重新定向被纳入本构方程，允许精确的大变形响应。该公式是完全隐式的，并对算法本构方程进行了一致线性化，以导出一致切线模量。通过与碳/PEEK的微观力学模型、聚合物基体的原始各向同性粘塑性模型和超弹性纤维的微观力学模型的比较，评估了介观本构模型的性能。首先采用微观模型确定具有少量应力-应变曲线的中尺度模型的材料参数。结果表明，在不同的加载条件下，中尺度模型与微观模型具有相似的响应。最后，通过对单向热塑性复合材料层的离轴实验对中尺度模型进行了验证。

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引用次数: 0

Investigating the interfacial behavior of van der Waals heterostructures with nano-inclusions: Molecular dynamics simulation and theoretical analysis 范德华异质结构与纳米内含物的界面行为研究：分子动力学模拟与理论分析

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-09-30 DOI: 10.1016/j.mechmat.2025.105514

Liqun Lou , Peijian Chen , Hao Liu , Guangjian Peng , Juan Peng

Interfacial properties of van der Waals (vdW) heterostructures are of crucial significance for precision instruments, microelectronics, mechanical and electrical engineering and so on. However, the lack of study on interfacial response of vdW heterostructures with nanoparticle greatly hinders the reliability and stability of various novel devices. Herein, we perform theoretical analysis and molecular dynamics simulation to explore the configuration and cohesive energy of vdW heterostructures with nano-inclusions. It is found that our proposed model functions well to predict morphologies of vdW heterostructure at the equilibrium state. The parameters dominating the formed morphology of vdW heterostructures are clarified. What is more, the interfacial behavior of vdW heterostructures can be modified by tuning the size, number, aggregation and interfacial interactions of nano-inclusions. The results should be helpful for not only improving the knowledge of surface/interface mechanics, but also guiding applications of two-dimensional materials and the corresponding vdW heterostructures.

范德华异质结构的界面特性在精密仪器、微电子、机电工程等领域具有重要意义。然而，缺乏对vdW异质结构与纳米颗粒界面响应的研究，极大地阻碍了各种新型器件的可靠性和稳定性。本文通过理论分析和分子动力学模拟来探讨含有纳米包体的vdW异质结构的构型和内聚能。结果表明，该模型能较好地预测vdW异质结构在平衡态的形貌。阐明了决定vdW异质结构形成形态的参数。此外，可以通过调节纳米夹杂物的大小、数量、聚集和界面相互作用来改变vdW异质结构的界面行为。研究结果不仅有助于提高表面/界面力学知识，而且对二维材料和相应的vdW异质结构的应用具有指导意义。

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引用次数: 0

Variationally consistent microstructure evolution and microsphere-based reconvexification for damage with application to arterial tissues 动脉组织损伤的显微结构演化与微球再凸化

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-09-29 DOI: 10.1016/j.mechmat.2025.105495

Jan Melchior, Maximilian Köhler, Daniel Balzani

Modeling the softening of arterial tissue, as it can be observed in terms of strain softening preceding atherosclerotic plaque rupture or in terms of stress-softening during balloon angioplasty, places special demands on the material formulations employed. In the context of finite-element discretized boundary value problems, the softening of the material is typically associated with a non-convex strain energy, which leads to an ill-posed behavior, i.e., mesh-dependency. In this work, we discuss the applicability of a material model for strain-softening that is based on the repeated construction of the convex envelope of an initially non-convex strain energy. The model possesses an evolving property that is exploited for the description of material softening. We propose an accurate and efficient convexification method, which is based on the reformulation of the convexity requirement in terms of a new optimization problem. Furthermore, we adopt the formulation to model softening in arterial tissue by combining a microsphere approach with a new orientation distribution function representing the dispersion of collagen fibers and show its capability to represent experimental data. Finally, we provide the derivation of a variationally sound approach to damage microstructure evolution and analyze some unique aspects significantly limiting the applicability to strain-softening.

在动脉粥样硬化斑块破裂前的应变软化或球囊血管成形术期间的应力软化方面，可以观察到动脉组织的软化建模，这对所采用的材料配方提出了特殊要求。在有限元离散边值问题的背景下，材料的软化通常与非凸应变能相关，这导致了不适定行为，即网格依赖。在这项工作中，我们讨论了基于初始非凸应变能的凸包络的重复构造的应变软化材料模型的适用性。该模型具有可用于描述材料软化的演化特性。针对一个新的优化问题，提出了一种精确高效的凸化方法，该方法基于对凸性要求的重新表述。此外，我们将微球方法与代表胶原纤维分散的新取向分布函数相结合，采用该配方来模拟动脉组织中的软化，并展示其表示实验数据的能力。最后，我们推导了一种损伤微观结构演变的变响方法，并分析了一些显著限制应变软化适用性的独特方面。

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引用次数: 0

Enhanced high-temperature creep resistance in gradient nanograined Fe-Zr alloy via gradient Zr segregation stabilizing grain boundary 通过梯度Zr偏析稳定晶界提高梯度纳米晶Fe-Zr合金的高温抗蠕变性能

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-09-27 DOI: 10.1016/j.mechmat.2025.105513

Daqian Xu , Zhifeng Huang , Hao Li , Vladyslav Turlo , Like Xu , Qiang Shen , Fei Chen

Fine and ultrafine grains in the gradient nanograined (GNG) structure exhibit low creep resistance. As these grains grow, they will further influence the hetero-deformation behavior when interacting with coarse grains under tensile loading. Solute segregation could be effective for stabilizing nanograins, but the distribution of solute atoms and its influence on the structure-performance relationship in the GNG structure remain unclear. Here, the Zr solute segregation gradient is found energetically favorable in the Fe-Zr GNG alloy based on molecular dynamics simulations, where the solute concentration at GBs shows a gradient distribution across the GNG structure. This dual heterogeneity contributes to improved creep resistance while also retaining the hetero-deformation induced strengthening nature of the GNG structure. A pseudo-composite structure is then demonstrated from the dual heterogeneity structure design: the finer grain region with higher segregation concentration, which acts as the thermodynamical stabilizer to enhance creep resistance; and the coarser grain region with smaller segregation concentration, which acts as plastic deformer to provide necessary hetero-deformation accommodation ability. Our work introduces segregation-induced concentration gradient into traditional heterogeneous materials and presents a new route for improving the creep resistance and tensile properties of heterostructure materials.

梯度纳米晶（GNG）结构中的细晶粒和超细晶粒表现出较低的抗蠕变性能。随着这些晶粒的长大，它们将进一步影响拉伸载荷下与粗晶粒相互作用时的异质变形行为。溶质偏析可以有效地稳定纳米颗粒，但在GNG结构中，溶质原子的分布及其对结构-性能关系的影响尚不清楚。基于分子动力学模拟，发现Fe-Zr GNG合金中Zr溶质偏析梯度在能量上是有利的，其中GBs处的溶质浓度在整个GNG结构中呈现梯度分布。这种双重非均质性有助于提高抗蠕变性能，同时也保留了GNG结构的非均质变形强化性质。通过双非均质结构设计，得到了伪复合结构：具有较高偏析浓度的细晶区作为热稳定剂，增强了材料的抗蠕变性能；晶粒较粗，偏析浓度较小，起到塑性变形的作用，提供了必要的异质变形调节能力。本研究将偏析诱导浓度梯度引入到传统异质材料中，为提高异质结构材料的抗蠕变性能和拉伸性能提供了一条新的途径。

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引用次数: 0

Mechanical structure–property relations in flexible silica-aerogels 柔性硅气凝胶的力学结构-性能关系

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-09-27 DOI: 10.1016/j.mechmat.2025.105510

Max Zinke , Barbara Milow , Gunnar Seide , Ameya Rege

Flexible aerogels exhibit unique mechanical properties, yet standardisation in their testing methodologies remains limited. This study investigates the tensile and compressive behaviour of flexible aerogels through experimental and computational approaches. Cyclic compression tests are performed to assess damage evolution, while digital image correlation is utilised to measure lateral strain and evaluate the influence of different spraying patterns on strain measurement accuracy. Challenges associated with tensile and compressive testing are critically analysed, highlighting inconsistencies in current practices. Finite element modelling is employed to examine the role of friction in inducing the barrelling effect under compressive loads. The findings underscore the necessity for standardised mechanical testing protocols for flexible aerogels and provide insights into their deformation behaviour under various loading conditions.

柔性气凝胶具有独特的机械性能，但其测试方法的标准化仍然有限。本研究通过实验和计算方法研究了柔性气凝胶的拉伸和压缩行为。通过循环压缩试验评估损伤演化，利用数字图像相关技术测量侧向应变，评估不同喷射方式对应变测量精度的影响。与拉伸和压缩测试相关的挑战进行了批判性分析，突出了当前实践中的不一致之处。采用有限元模型研究了在压缩载荷作用下摩擦对桶管效应的影响。研究结果强调了对柔性气凝胶进行标准化力学测试的必要性，并为其在各种加载条件下的变形行为提供了见解。

引用次数: 0