A continuum-based computational contact model is employed to study coupled adhesion and friction in gecko spatulae. Nonlinear finite element analysis is carried out to simulate spatula peeling from...
Last. Sachin S. Gautam(IITG: Indian Institute of Technology Guwahati)H-Index: 6
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ABSTRACTThe present work investigates the normal and tangential peeling behaviour of a gecko spatula using a coupled adhesion-friction model. The objective is to explain the strong attachment and e...
The rapid control of surface attachment is a key feature of natural adhesive systems used for locomotion, and a property highly desirable for man-made adhesives. Here, we describe the challenges of...
ABSTRACTWe develop two new continuum contact models for coupled adhesion and friction, and discuss them in the context of existing models proposed in the literature. Our new models are able to desc...
#1Zhilong Peng(BIT: Beijing Institute of Technology)H-Index: 11
#2Hanbin Yin(BIT: Beijing Institute of Technology)H-Index: 1
Last. Shaohua Chen(BIT: Beijing Institute of Technology)
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: Compared with the classical Kendall's model to analyze the steady-state peeling behavior of an infinite length film attaching to a rigid substrate, this paper establishes a model of a finite length thin film adhering on a rigid substrate and analyzes the influence of film's initial adhesion length, film stiffness, and initial cantilever length of films on the whole interface peeling behavior. Both theoretical prediction and finite element calculation are carried out. The typical relationship b...
#1Xuyan Hou(HIT: Harbin Institute of Technology)H-Index: 6
#2Yilin Su(HIT: Harbin Institute of Technology)H-Index: 3
Last. Zongquan Deng(HIT: Harbin Institute of Technology)H-Index: 24
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According to the on-orbit servicing requirements of spacecraft, this article presents a new type of space-climbing robot that can climb onto the target spacecraft for repairing, rescuing, and removing orbital debris. This robot mobile system is composed of a piezoelectric actuation leg, microadhesive feet, and others. In the environment of zero gravity, the space-climbing robot can cross obstacles through crawling movement and turnover movement. The gripping force of the robot is supplied by the...
Last. Metin Sitti(MPG: Max Planck Society)H-Index: 93
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A facile approach is proposed for superior conformation and adhesion of wearable sensors to dry and wet skin. Bioinspired skin-adhesive films are composed of elastomeric microfibers decorated with conformal and mushroom-shaped vinylsiloxane tips. Strong skin adhesion is achieved by crosslinking the viscous vinylsiloxane tips directly on the skin surface. Furthermore, composite microfibrillar adhesive films possess a high adhesion strength of 18 kPa due to the excellent shape adaptation of the vi...
#1Zhilong Peng(BIT: Beijing Institute of Technology)H-Index: 11
#2Cong Wang(CAS: Chinese Academy of Sciences)H-Index: 3
Last. Shaohua Chen(BIT: Beijing Institute of Technology)
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Inspired by gecko adhesion in humid environments, a modified Kendall's model is established in order to investigate the effect of relative humidity on the interfacial peeling behavior of a thin film adhering on a rigid substrate. When the humidity is less than 90%, a monolayer of water molecules adsorbed on the substrate surface induces a strong disjoining pressure at the interface. As a result, the steady-state peel-off force between the thin film and substrate is significantly enhanced. When t...
Many arthropods and small vertebrates use adhesive pads for climbing. These biological adhesives have to meet conflicting demands: attachment must be strong and reliable, yet detachment should be fast and effortless. Climbing animals can rapidly and reversibly control their pads' adhesive strength by shear forces, but the mechanisms underlying this coupling have remained unclear. Here, we show that adhesive forces of stick insect pads closely followed the predictions from tape peeling models whe...
#1Yu Sekiguchi(TITech: Tokyo Institute of Technology)H-Index: 8
#2Kunio Takahashi(TITech: Tokyo Institute of Technology)H-Index: 23
Last. Chiaki Sato(TITech: Tokyo Institute of Technology)H-Index: 15
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An adhesion model of an oblique structure with an adhesive tip is proposed by considering a limiting stress for adhesion to describe the detachment mechanism of gecko foot hairs. When a force is applied to the root of the oblique structure, normal and shear stresses are generated at contact and the adhesive tip is detached from the surface when reaching the limiting stress. An adhesion criterion that considers both the normal and shear stresses is introduced, and the asymmetric detachment of the...
Inspired by the experimental observation that the maximum peeling force of elastic films on rigid substrates does not always emerge at the steady-state peeling stage, but sometimes at the initial one, a theoretical model is established in this paper, in which not only the effect of the film's bending stiffness on the peeling force is considered, but also the whole peeling process, from the initiation of debonding to the steady-state stage, is characterized. Typical peeling force-displacement cur...
#1Vishal Agrawal(IITG: Indian Institute of Technology Guwahati)H-Index: 3
#2Sachin S. Gautam(IITG: Indian Institute of Technology Guwahati)H-Index: 6
Numerical solution of adhesive peeling problems presents significant computational challenges. This is due to the large peeling stresses that occur in the very narrow zone ahead of the peeling front. The available literature offers solutions using either higher-order Lagrange-enriched finite-element (FE) or non-uniform rational B-spline (NURBS)-enriched FE strategies. However, no work that fully utilizes the intrinsic advantageous features of isogeometric analysis and systemically explores the i...
Last. Zongwu Xie(HIT: Harbin Institute of Technology)
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Gecko has the ability to climb flexibly on various natural surfaces because of its fine layered adhesion system of foot, which has motivated researchers to carry out a lot of researches on it. Significant progresses have been made in the gecko-like dry adhesive surfaces in the past 2 decades, such as the mechanical measurement of adhesive characteristics, the theoretical modeling of adhesive mechanism and the production of synthetic dry adhesive surfaces. Relevant application researches have bee...
Contact involving soft materials often combines dry adhesion, sliding friction, and large deformations. At the local level, these three aspects have been simultaneously captured only in the theoretical framework proposed by Mergel et al. (2019) (arXiv:1803.00046). We here develop a corresponding, nonlinear finite element framework that captures 3D finite-strain contact of two deformable bodies. This framework includes the two models by Mergel et al. (2019), and is suitable to investigate sliding...
Bayesian regularization-backpropagation neural network (BR-BPNN), a machine learning algorithm, is employed to predict some aspects of the gecko spatula peeling such as the variation of the maximum normal and tangential pull-off forces and the resultant force angle at detachment with the peeling angle. The input data is taken from finite element (FE) peeling results. The neural network is trained with 75% of the FE dataset. The remaining 25% are utilized to predict the peeling behavior. The trai...
