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Towards Tolerance Specifications for the Elastic Buckling Design of Axially Loaded Cylinders 轴向载荷圆柱弹性屈曲设计公差规范探讨
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-25 DOI: 10.1115/1.4063032
R. Groh, J. Croll
The quest for safe lower bounds to the elastic buckling of axially loaded circular cylindrical shells has exercised researchers for the past 100 years. Recent work bringing together the capabilities of non-linear numerical simulation, interpreted within the context of extended linear classical theory, has come close to achieving this goal of defining safe lower bounds. This paper briefly summarises important predictions from previous work and presents new simulations confirming them. In particular, we show that for a specified maximum amplitude of the most sensitive, eigenmode-based geometric imperfections, normalised with respect to the shell thickness, lower bounds to the buckling loads remain constant beyond a well-defined value of the Batdorf parameter. Furthermore, we demonstrate how this convenient means of presenting the imperfection-sensitive buckling loads can be reinterpreted to develop practical design curves providing safe, but not overly conservative, design loads for monocoque cylinders with a given maximum permitted tolerance of geometric imperfection. Hence, once the allowable manufacturing tolerance is specified during design or is measured post-manufacturing, the greatest expected knockdown factor for a shell of any geometry is defined. With the recent research interest in localised imperfections, we also attempt to reconcile their relation to the more classical, periodic, and eigenmode-based imperfections. Overall, this paper provides analytical and computational arguments that motivate a shift in focus in defect-tolerant design of thin-walled cylinders, away from the knockdown experienced for a specific geometric imperfection, towards the worst possible knockdown expected for a specified manufacturing tolerance.
对轴向载荷下圆柱壳弹性屈曲的安全下界的探索已经困扰了研究人员100多年。最近的工作将非线性数值模拟的能力结合在一起,在扩展的线性经典理论的背景下进行解释,已经接近实现定义安全下界的目标。本文简要总结了以往工作的重要预测,并提出了新的模拟来证实这些预测。特别是,我们表明,对于最敏感的,基于特征模态的几何缺陷的指定最大振幅,相对于壳厚度归一化,屈曲载荷的下界保持恒定,超出定义良好的Batdorf参数值。此外,我们还演示了如何重新解释这种方便的方法来表示对缺陷敏感的屈曲载荷,从而开发出实用的设计曲线,为具有给定最大几何缺陷允许容限的单体汽缸提供安全但不过于保守的设计载荷。因此,一旦在设计期间指定了允许制造公差或在制造后测量了公差,就可以定义任何几何形状壳体的最大期望击倒系数。随着最近对局部缺陷的研究兴趣,我们也试图调和它们与更经典的、周期的和基于特征模的缺陷的关系。总体而言,本文提供了分析和计算论据,激发了薄壁圆柱体容错设计的焦点转移,从特定几何缺陷的击倒经历转向指定制造公差预期的最坏的击倒。
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引用次数: 0
A numerical study on the ballistic performance of projectiles formed by shaped charge 装药成型弹丸弹道性能的数值研究
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-20 DOI: 10.1115/1.4063002
Yagmur Gocmen, Can Erdogan, T. Yalçinkaya
In this work, a numerical analysis of shaped charge impact process is conducted to investigate the jet formation process and its penetration performance on metal targets. Numerical results are compared with experimental data from published literature for liners made up of copper and iron. Conical and bowl-shaped liner geometries are simulated with various configurations to observe their effects on projectile shape and penetration capability using the finite element (FE) method. The exact shape of the explosively formed projectile at the onset of impact is modeled as a rigid 3D body to simulate the penetration process. #45 and Armox 500T steels are used as the target materials, and the material behavior and failure mechanisms are modeled using the Johnson-Cook (JC) plasticity and damage models. In addition to the FE method, smoothed particle hydrodynamics (SPH) is utilized as well to evaluate its capacity in predicting the failure behavior of the metal targets. It is concluded that the FE method outperforms the SPH method at predicting failure modes while SPH can still be used to predict residual velocity and hole diameters. Armox 500T demonstrates a higher impact resistance compared to #45 steel. Liner geometry is found to significantly affect penetration performance. Sharper and thinner projectiles formed from liners with small cone angles are shown to be highly efficient in penetrating through armor steel targets.
本文对聚能装药冲击过程进行了数值分析,研究了射流的形成过程及其对金属靶的穿透性能。将数值结果与已发表文献中铜和铁内衬的实验数据进行了比较。采用有限元方法模拟了不同构型的锥形和碗状衬管几何形状,以观察其对弹丸形状和穿透能力的影响。爆炸成型弹丸在撞击开始时的确切形状被建模为刚性三维物体,以模拟穿透过程#使用45和Armox 500T钢作为目标材料,并使用Johnson Cook(JC)塑性和损伤模型对材料行为和失效机制进行建模。除了有限元方法外,还利用光滑粒子流体动力学(SPH)来评估其预测金属靶失效行为的能力。结果表明,有限元方法在预测失效模式方面优于SPH方法,而SPH方法仍可用于预测残余速度和孔径。与#45钢相比,Armox 500T具有更高的抗冲击性。发现衬管几何形状会显著影响穿透性能。由具有小锥角的内衬形成的更锋利、更薄的射弹被证明在穿透装甲钢目标方面是高效的。
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引用次数: 0
Deformation Decomposition versus Energy Decomposition for Chemo- and Poro- Mechanics 化学和孔隙力学的变形分解与能量分解
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-18 DOI: 10.1115/1.4062967
Janel Chua, M. Karimi, Peter F. Kozlowski, M. Massoudi, S. Narasimhachary, K. Kadau, G. Gazonas, K. Dayal
We briefly compare the structure of two popular models to model poro- and chemo- mechanics wherein a fluid phase is transported within a solid phase. The multiplicative deformation decomposition has been used to model permanent inelastic shape change in plasticity and thermal expansion. However, the energetic decomposition provides a more transparent structure and advantages, such as to couple to phase-field fracture, for problems of poro- and chemo- mechanics.
我们简要比较了两种流行模型的结构,以模拟多孔力学和化学力学,其中液相在固相中传输。乘法变形分解已被用于建模塑性和热膨胀中的永久非弹性形状变化。然而,能量分解为孔隙力学和化学力学问题提供了更透明的结构和优势,例如耦合到相场断裂。
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引用次数: 0
Large Deflection Effects on the Energy Release Rate and Mode Partitioning of the Single Cantilever Beam Sandwich Debond Configuration 大挠度对单悬臂梁夹层结构能量释放率和模态划分的影响
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-11 DOI: 10.1115/1.4062936
Daniel Okegbu, G. Kardomateas
This paper investigates the effects of large deflections on the energy release rate and mode partitioning of face/core debonds for the Single Cantilever Beam Sandwich Composite testing configuration, which is loaded with an applied shear force and/or a bending moment. Studies in this topic have been done by employing geometrically linear theories (either Euler-Bernoulli or Timoshenko beam theory). This assumes that the deflection at the tip of the loaded debonded part is small, which is not always the case. To address this effect, we employ the elastica theory, which is a nonlinear theory, for the debonded part. An elastic foundation analysis and the linear Euler Bernoulli theory is employed for the “joined” section where a series of springs exists between the face and the substrate (core and bottom face). A closed form expression for the energy release rate is derived by use of the J-integral. Another closed form expression for the energy release rate is derived from the energy released by a differential spring as the debond propagates. Furthermore, a mode partitioning angle is defined based on the displacement field solution. Results for a range of core materials are in very good agreement with the corresponding ones from a finite element analysis. The results show that large deflection effects reduce the energy release rate but do not have a noteworthy effect on the mode partitioning. A small deflection assumption can significantly overestimate the energy release rate for relatively large applied loads and/or relatively long debonds.
本文研究了在施加剪切力和/或弯矩的情况下,大挠度对单悬臂梁-夹层复合材料试验配置的面/芯脱胶的能量释放率和模式划分的影响。本课题的研究采用了几何线性理论(Euler-Bernoulli或Timoshenko梁理论)。这是假设加载脱胶部分尖端的挠度很小,但情况并非总是如此。为了解决这种影响,我们对脱粘部分采用了弹性理论,这是一种非线性理论。弹性基础分析和线性欧拉-伯努利理论用于“连接”部分,其中表面和基底(核心和底面)之间存在一系列弹簧。利用J积分导出了能量释放率的闭合表达式。能量释放率的另一个闭合形式表达式是从脱粘传播时由差动弹簧释放的能量导出的。此外,基于位移场解定义了模式划分角。一系列堆芯材料的结果与有限元分析的相应结果非常一致。结果表明,大的偏转效应降低了能量释放率,但对模式划分没有显著影响。对于相对较大的施加载荷和/或相对较长的脱胶,小挠度假设可能会显著高估能量释放率。
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引用次数: 0
ON THE INTERACTION OF DAMAGE EVOLUTION AND THERMAL BUCKLING IN STEPPED CIRCULAR BI-LAMINATES 阶梯圆形双层板损伤演化与热屈曲相互作用研究
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-11 DOI: 10.1115/1.4062935
Shuo Xu, W. Bottega
The behavior and evolution of stepped circular bi-laminates with edge damage under uniform thermal load are studied. The problem is treated as a moving intermediate boundaries problem in the calculus of variations. Varying boundaries are allowed for the evolving damage region from the smaller substructure's edge and the progressing/regressing sliding contact region adjacent to the intact composite structure. Transversality conditions define the locations of propagating boundaries for equilibrium configurations of the evolving composite structure, along with equilibrium equations and interior/exterior boundary conditions. The influence and progression of different contact configurations and detached segment behaviors on the overall composite structure evolution are evaluated. Closed-form analytical solutions for the geometrically non-linear problem yield expressions for the critical buckling load. The analytical solutions provide explicit forms of the total energy release rate along the delamination front and conditions for the propagation of the contact zone boundary. Numerical simulations unveil a rich evolution process, involving contact progression/recession, metamorphosis, buckling, and detachment progression during pre-buckling, sling-shot buckling, and post-buckling phases. These behaviors depend on material properties, sublaminates' geometry, initial damage size, and interfacial bond strength. The study explores the behavior of stepped circular bi-laminates with edge damage under thermal load, addressing their evolution, critical buckling loads, and characteristic damage propagation.
研究了具有边缘损伤的阶梯圆形双层板在均匀热载荷作用下的性能和演化过程。将该问题作为变分学中的移动中间边界问题来处理。允许从较小的子结构边缘和靠近完整复合材料结构的前进/后退滑动接触区域演变的损伤区域的边界变化。横向性条件与平衡方程和内外边界条件一起定义了复合材料结构演化平衡构型传播边界的位置。评估了不同接触形态和分离段行为对复合材料整体结构演化的影响和进展。几何非线性问题临界屈曲载荷屈服表达式的封闭解析解。解析解提供了沿分层前沿总能量释放率的显式形式和接触带边界扩展的条件。数值模拟揭示了丰富的演化过程,包括前屈曲、弹弓屈曲和后屈曲阶段的接触进展/衰退、变形、屈曲和脱离进展。这些行为取决于材料性能、亚层板的几何形状、初始损伤尺寸和界面结合强度。研究了阶梯圆形双层压板在热载荷作用下的边缘损伤行为,研究了其演化、临界屈曲载荷和特征损伤传播。
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引用次数: 0
Static wetting of a liquid droplet on a soft elastic substrate 软弹性衬底上液滴的静态润湿
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-07 DOI: 10.1115/1.4062906
Jian Wu, C. Ru
A refined spherical cap model, combined with an elastic foundation model for the elastic substrate, is proposed to study static wetting of a liquid droplet on a soft elastic substrate. The strain energy of the substrate is evaluated by the JKR (Johnson-Kendall-Roberts) model, and the increase of the surface energy of the substrate outside the contact zone is calculated based on the elastic foundation model. The total potential energy of the droplet-substrate system is given in terms of four geometrical parameters: the contact radius, the contact angle of the droplet, the deflection angle inside the contact zone, and the maximum downward displacement of the substrate surface at the contact zone center. The equilibrium state is determined based on the stationary condition of total potential energy. The present model reduces to the Young's equation for a rigid substrate and to the Neumann's triangle for a liquid-like substrate. Three equations are given to determine the liquid droplet shape in terms of surface energies and substrate's elastic modulus. Reasonable agreement with existing experimental data and simulation results shows that the present model with derived formulas has the potential to catch the role of substrate's elastic deformation on static wetting and fill the gap between the Young's equation and the Neumann's triangle for a soft elastic substrate.
提出了一种改进的球帽模型,结合弹性基底的弹性地基模型,研究了软弹性基底上液滴的静态润湿问题。采用JKR (Johnson-Kendall-Roberts)模型计算基体的应变能,采用弹性基础模型计算接触区外基体的表面能增量。液滴-衬底体系的总势能由四个几何参数给出:接触半径、液滴的接触角、接触区内的偏转角和衬底表面在接触区中心处的最大向下位移。平衡态是根据总势能的平稳条件确定的。目前的模型对刚性衬底可简化为杨氏方程,对类液体衬底可简化为诺伊曼三角。给出了用表面能和基体弹性模量确定液滴形状的三个方程。与已有实验数据和仿真结果的合理吻合表明,该模型及其推导公式有可能捕捉基材弹性变形对静态润湿的作用,填补了软弹性基材的杨氏方程和诺伊曼三角形之间的空白。
{"title":"Static wetting of a liquid droplet on a soft elastic substrate","authors":"Jian Wu, C. Ru","doi":"10.1115/1.4062906","DOIUrl":"https://doi.org/10.1115/1.4062906","url":null,"abstract":"\u0000 A refined spherical cap model, combined with an elastic foundation model for the elastic substrate, is proposed to study static wetting of a liquid droplet on a soft elastic substrate. The strain energy of the substrate is evaluated by the JKR (Johnson-Kendall-Roberts) model, and the increase of the surface energy of the substrate outside the contact zone is calculated based on the elastic foundation model. The total potential energy of the droplet-substrate system is given in terms of four geometrical parameters: the contact radius, the contact angle of the droplet, the deflection angle inside the contact zone, and the maximum downward displacement of the substrate surface at the contact zone center. The equilibrium state is determined based on the stationary condition of total potential energy. The present model reduces to the Young's equation for a rigid substrate and to the Neumann's triangle for a liquid-like substrate. Three equations are given to determine the liquid droplet shape in terms of surface energies and substrate's elastic modulus. Reasonable agreement with existing experimental data and simulation results shows that the present model with derived formulas has the potential to catch the role of substrate's elastic deformation on static wetting and fill the gap between the Young's equation and the Neumann's triangle for a soft elastic substrate.","PeriodicalId":54880,"journal":{"name":"Journal of Applied Mechanics-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44820090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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
Conformal Theoretical Modeling of Arbitrary Shape Flexible Electronic Sensors Mounted onto General Curved Surface Substrate 安装在一般曲面基板上的任意形状柔性电子传感器的保形理论建模
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-07 DOI: 10.1115/1.4062905
Shihang Wang, Jie Jin, Deqing Mei, Yan-cheng Wang
Stretchable and flexible electronic sensors have been attracted due to their conformal integration onto complex curved surfaces for novel applications. Whereas, the mounting strains generated by the geometric mismatch of substrate surface and electronic sensors may cause non-conformal contact at the interface, thus would induce non-negligible effects on the performance of sensors. To figure out the influence rules of the shaped of electronic sensors and their geometric parameters on conformal contacts, this paper presents a novel conformal model to study the arbitrary shaped film as flexible sensors mounted onto general curved surface substrates. The principle of energy minimization and the method of integral summation play vital roles during the modeling, and three types of films with various shapes including rectangular, oval and hexagonal mounted onto bicurvature substrate are investigated. The influences of three dimensionless shape parameters of oval and hexagonal film/substrate contacts on dimensionless strain energy for conformal mounting are analyzed. The strain and critical dimensionless strain energy of three kinds of films/bicurvature substrate contacts are calculated and compared under the same conformal area. The results demonstrated that the contour shape of electronic sensor has a great effect on conformal mounting and strain. Thus, the developed conformal model would have great significance in guiding the design of flexible electronic devices and sensors when applied to general curved surface.
可拉伸和柔性电子传感器由于其在复杂曲面上的保形集成而被吸引用于新的应用。然而,由基板表面和电子传感器的几何失配产生的安装应变可能导致界面处的非共形接触,从而对传感器的性能产生不可忽略的影响。为了找出电子传感器形状及其几何参数对共形接触的影响规律,本文提出了一种新的共形模型来研究安装在一般曲面基板上的任意形状薄膜作为柔性传感器。能量最小化原理和积分求和方法在建模过程中起着至关重要的作用,研究了三种不同形状的薄膜,包括矩形、椭圆形和六边形,它们安装在双曲率基底上。分析了椭圆和六边形薄膜/衬底接触的三个无量纲形状参数对保形安装无量纲应变能的影响。计算并比较了三种薄膜/双曲率衬底接触在相同保形面积下的应变和临界无量纲应变能。结果表明,电子传感器的外形形状对保形安装和应变有很大影响。因此,当应用于一般曲面时,所开发的保形模型对指导柔性电子器件和传感器的设计具有重要意义。
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引用次数: 0
Ice Adhesion Characterization Using Mode-I and Mode-II Fracture Configurations 使用I型和II型断裂形态的冰粘附特性
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-07 DOI: 10.1115/1.4062908
B. Dawood, Denizhan Yavas, A. Bastawros
The ice buildup on airborne structures operating in cold weather conditions has detrimental impacts on both their safety and performance. Due to practical applications, there has been a significant interest in ice removal strategies. However, the current body of literature lacks comprehensive insights into the mechanistic aspects of the ice adhesion/breakage process, resulting in a wide range of reported adhesion strengths that differ by two orders of magnitude. To address this gap, we employed a fracture mechanics-based approach to investigate the fracture behavior of a typical ice/aluminum interface in terms of mode-I and II fractures. We examine a range of surface roughness values spanning 0.05-5 micrometers. An experimental framework employing a single cantilever beam and direct shear tests were developed. The near mode-I and II interfacial fracture toughness and strength values were extracted from the experimentally measured force and displacement by both analytical and numerical models employing cohesive surfaces. The combined experimental and numerical results show that ice adhesion is primarily driven by cohesive interfacial failure, which exhibits almost mode-independent fracture behavior. Mode-I fracture shows directional instability of crack propagation, which is attributed to thermally induced residual tensile stress within the ice layer. The fractographic inspection reveals similar ice-grain size over the examined range of substrate roughness values. For the examined range of surface roughness and temperature, which induces the Wenzel state with full surface wetting at the interface, ice adhesion is insensitive to the interfacial roughness and fracture modes.
在寒冷天气条件下运行的机载结构上的结冰对其安全和性能都有不利的影响。由于实际应用,人们对除冰策略有了很大的兴趣。然而,目前的文献缺乏对冰粘附/破裂过程的机制方面的全面了解,导致报道的粘附强度相差两个数量级。为了解决这一问题,我们采用了基于断裂力学的方法来研究典型冰/铝界面在i型和II型裂缝方面的断裂行为。我们检查的表面粗糙度值范围跨越0.05-5微米。开发了采用单悬臂梁和直剪试验的试验框架。采用黏聚面解析模型和数值模型,从实验测得的力和位移中提取出近ⅰ型和近ⅱ型界面断裂韧性和强度值。实验和数值结果表明,冰的黏结主要是由黏结界面破坏驱动的,表现出与模式无关的断裂行为。i型断裂表现出裂纹扩展的方向性不稳定性,这主要归因于热致残余拉应力。断口学检查显示,在衬底粗糙度值的检查范围内,类似的冰晶尺寸。在表面粗糙度和温度的检测范围内,冰的粘附对界面粗糙度和断裂模式不敏感,而温泽尔状态是界面表面完全湿润的状态。
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引用次数: 0
Characterizing the adhesion between thin films and rigid substrates using DIC-informed inverse finite elements and the blister test 使用DIC告知的逆有限元和泡罩试验表征薄膜和刚性基底之间的粘附性
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-07 DOI: 10.1115/1.4062907
Drishya Dahal, Juan-Sebastian Rincon-Tabares, D. Y. Risk-Mora, B. R. Rincon Troconis, David Restrepo
Characterizing the adhesion between thin films and rigid substrates is crucial in engineering applications. Still, existing standard methods suffer from issues such as poor reproducibility, difficulties in quantifying adhesion parameters, or overestimation of adhesion strength and fracture energy. Recent studies have shown that the blister test (BT) is a superior method for characterizing adhesion, as it provides a quantifiable measurement of mix-mode fracture energy, and it is highly reproducible. In this paper, we present a novel method to characterize mechanical mix-mode adhesion between thin films and rigid substrates using the BT. Our method combines the full triaxial displacement field obtained through Digital Image Correlation with inverse Finite Element Method simulations using Cohesive Zone Elements. This approach eliminates the need for making any mechanistic or kinematic assumptions of the blister formation and allows the characterization of the full traction-separation law governing the adhesion between the film and the substrate. To demonstrate the efficacy of this methodology, we conducted a case study analyzing the adhesion mechanics of a polymeric pressure-sensitive adhesive on an aluminum substrate. Our results indicate that the proposed technique is a reliable and effective method for characterizing the mix-mode traction separation law governing the mechanical behavior of the adhesive interface and could have broad applications in the field of materials science and engineering. Also, by providing a comprehensive understanding of the adhesion mechanics between thin films and rigid substrates, our method can aid in the design and optimization of adhesively bonded structures
表征薄膜和刚性基底之间的粘附性在工程应用中至关重要。尽管如此,现有的标准方法仍存在再现性差、难以量化粘附参数或高估粘附强度和断裂能等问题。最近的研究表明,泡罩试验(BT)是表征附着力的一种优越方法,因为它提供了混合模式断裂能的可量化测量,并且具有高度的可重复性。在本文中,我们提出了一种使用BT来表征薄膜和刚性基底之间的机械混合模式粘附的新方法。我们的方法将通过数字图像相关获得的全三轴位移场与使用内聚区单元的逆有限元法模拟相结合。这种方法消除了对泡罩形成进行任何机械或运动学假设的需要,并允许表征控制膜和基底之间粘附力的完全牵引分离定律。为了证明这种方法的有效性,我们进行了一个案例研究,分析了聚合物压敏粘合剂在铝基板上的粘合力学。我们的结果表明,所提出的技术是一种可靠有效的方法,可以表征控制粘合剂界面力学行为的混合模式牵引分离定律,并在材料科学和工程领域具有广泛的应用。此外,通过全面了解薄膜和刚性基底之间的粘合力学,我们的方法可以帮助设计和优化粘合结构
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引用次数: 0
Scaling Effect of Dry Adhesion for Microfibrils and Transition Size to Flaw Insensitivity 微纤维干燥粘附的结垢效应及向缺陷不敏感的过渡尺寸
IF 2.6 4区 工程技术 Q2 Engineering Pub Date : 2023-07-03 DOI: 10.1115/1.4062884
Xuan Zhang, Xiaoyan Li
The mechanics of detachment (e.g., a cylindrical fibril separating from a dissimilar substrate) has been treated in the perspectives of contact mechanics and fracture mechanics theory along with numerical simulations, but systematic experimental studies on the adhesion of an individual microfibrils is still scarce. In this work, we conducted detailed experiment on the adhesion tests of individual cylindrical microfibrils within a large range of varying diameters from 4 to 400 mm made of three different polyurethanes with moduli among ~1-40 MPa. We confirmed the scaling effect of an individual microfibril, i.e. the adhesion sad of the individual fibril scales with fibrillar diameters D with an exponent of ~ -0.4 to -0.45. As the fibrillar diameter is reduced below 10 mm, the adhesion becomes unchanged and size-insensitive. This result is in good agreement with the theoretical predictions. Furthermore, the effects of the Young's modulus and retraction rates during the adhesion tests on the adhesion strength were also investigated. Our experimental work will provide a guide for optimal design of the micron-scale surfaces with improved adhesion.
分离的力学(例如,圆柱形纤维从不同的基质中分离)已经从接触力学和断裂力学理论以及数值模拟的角度进行了处理,但对单个微纤维粘附的系统实验研究仍然很少。在这项工作中,我们对直径从4到400 mm不等的圆柱形微纤维进行了详细的粘附测试,这些微纤维由三种不同的聚氨酯制成,模量在~1-40 MPa之间。我们证实了单个微纤维的结垢效应,即单个微纤维在纤维直径为D的尺度上的粘附力,其指数为~ -0.4 ~ -0.45。当纤维直径减小到10mm以下时,粘连变得不变并且对尺寸不敏感。这一结果与理论预测相吻合。此外,还研究了粘结试验中杨氏模量和缩回率对粘结强度的影响。我们的实验工作将为微米级表面的优化设计提供指导。
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引用次数: 0
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