Article
Materials Science, Multidisciplinary
J. Joe, A. Wang, J. R. Barber
Summary: We have developed a theoretical model to predict the load-displacement relation and probability density function for gaps between contacting rough surfaces. The predictions of this theory were compared with numerical results, demonstrating good agreement.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Chemical
Joseph M. Monti, Antoine Sanner, Lars Pastewka
Summary: Understanding the distribution of interfacial separations between rough surfaces is crucial for estimating adhesive forces. By assuming non-adhesive, frictionless contact between self-affine surfaces, a power-law divergence for small gaps is derived. The characteristic length scale is determined by the product of rms surface slope and mean diameter of contacting regions, and these findings apply to weakly adhesive contacts as well, connecting to recent theories on adhesion between rough surfaces.
Article
Materials Science, Multidisciplinary
Yang Xu, Julien Scheibert, Nikolaj Gadegaard, Daniel M. Mulvihill
Summary: This study proposes a statistical model based on experimentally observed phenomena and contact mechanics laws, which successfully reproduces macroscopic responses observed in friction experiments and demonstrates the influence of microscale interface properties on static friction and contact area evolution.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mathematics, Interdisciplinary Applications
Robert L. Jackson, Yang Xu, Swarna Saha, Kyle D. Schulze
Summary: This study uses the boundary element method to predict the real contact area of perfectly elastic rough surfaces, aiming to confirm the linear relationship between contact area, root-mean-square slope, and applied load predicted by fractal diffusion-based rough surface contact theory. However, experimental results reveal a complex response that deviates from the expected behavior. Further evaluation of the variation in root-mean-square slope and system spectrum related to contact features is needed to understand why this discrepancy occurs in some types of surfaces and not others.
FRACTAL AND FRACTIONAL
(2021)
Article
Mechanics
Sihe Wang, Weike Yuan, Xuanming Liang, Gangfeng Wang
Summary: This paper presents an analytical contact model for elastic or elastic-perfectly plastic Gaussian rough surfaces and validates it with finite element simulations. The model accurately predicts the contact behavior, showing good agreement with the simulation results. Additionally, the influence of plastic deformation on the contact response is characterized by introducing a dimensionless plasticity parameter.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Engineering, Chemical
Shijun Yin, Gianluca Costagliola, Jean-Francois Molinari
Summary: We investigate the persistence of micro-contacts between two elastic random rough surfaces using a simple model, finding that the original contact clusters gradually disappear and are replaced by new ones, while the real contact area remains constant. This study sheds light on the microscopic origins of phenomenological rate-and-state friction laws and memory effects observed in frictional sliding.
Article
Mechanics
Xuan-Ming Liang, Chun-Yun Jiang, Meng-Rui Wang, Wan-lin Dai, Gang-Feng Wang
Summary: In this study, an optical apparatus is designed to accurately capture the real contact areas between rough metallic samples and flat quartz glass using the frustrated total internal reflection technique and an Otsu method. The incremental equivalent contact model developed by the researchers is employed to predict the load-area relationship, and it shows good agreement with experimentally measured results for samples of various materials and morphologies, confirming the efficiency of the model.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Engineering, Mechanical
G. F. Wang, X. M. Liang, D. Yan
Summary: A new method for determining the relationship between real contact area and surface separation is proposed in this study. The model predicts a linear relationship between real contact area and load within a realistic separation range and shows good agreement with direct finite element calculations. The model is not limited to isotropic Gaussian surfaces and provides a general approach to studying the contact of rough surfaces.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Chemical
Anle Wang, Martin H. Mueser
Summary: In this work, the elastic contact between isotropic and anisotropic, rigid, randomly rough surfaces and linearly elastic counterfaces, as well as the subsequent Reynolds flow through the gap between them, is numerically studied. The percolation threshold is found to be dependent on fluid flow direction in anisotropic systems, and a critical contact area near 0.415 is confirmed. Effective-medium treatments provide accurate expressions for Reynolds fluid flow conductances.
Article
Materials Science, Multidisciplinary
B. N. J. Persson
Summary: This theory explains the contact mechanics of randomly rough surfaces by studying the interface at different levels of magnification. It takes into account the surface roughness and its impact on the distribution of contact stress and interfacial gap. The theory is versatile and can be applied to various types of solids and layered materials. Its applications include studying leakage, contact stiffness, electric and thermal contact resistance, rubber friction, adhesion, and mixed lubrication.
Article
Materials Science, Multidisciplinary
M. R. Marulli, J. Bonari, J. Reinoso, M. Paggi
Summary: Indentation tests are widely used to characterize the mechanical and fracture properties of materials. This study proposes an efficient theoretical and computational framework to simulate indentation-induced cracking phenomena caused by non-conforming contacts with arbitrary-shaped indenters. The framework combines MPJR interface finite elements and a phase-field model for crack evolution. Numerical predictions successfully capture the effects of surface roughness on crack initiation and radius.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Mechanical
L. J. Oestringer, C. Proppe
Summary: This paper presents a transient thermomechanical contact model for two sliding bodies with rough surfaces. By solving the underlying equations for mechanical, thermal, and thermoelastic submodels, dimensionless influence functions for a loaded rectangular element on a halfspace are derived. The submodels are then combined into one thermomechanical simulation model, coupling the heat flux to the frictional power without using a prescribed friction coefficient. The solution process is described in detail. Calculations are performed for two nominally flat but periodic rough surfaces, and the obtained transient friction coefficient is discussed in particular.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Chemical
Jamal Choudhry, Andreas Almqvist, Roland Larsson
Summary: A multi-scale flash temperature model has been developed and validated, showing its adaptability in predicting flash contact temperatures in various sliding systems. The study investigated the impact of different surface roughness parameters on flash temperatures, revealing that changes in these parameters can affect the maximum flash temperature without influencing the average interface temperature. The model's predictions were confirmed through experimental data, emphasizing the importance of incorporating a wear model in simulating flash temperature development in sliding systems.
Article
Biochemical Research Methods
Alejandro Torres-Sanchez, Max Kerr Winter, Guillaume Salbreux
Summary: We propose a modelling and simulation framework for cell aggregates in three dimensions based on interacting active surfaces. The framework captures cell mechanics, inter-cell forces, and the effect of adhesion molecules. We discretize the model equations using a finite element method and implement it in C++. This framework allows for the systematic exploration of the mechanics of cell aggregates at the cell to tissue-scale, which is important in the morphogenesis of embryos and organoids.
PLOS COMPUTATIONAL BIOLOGY
(2022)
Article
Engineering, Multidisciplinary
Han Hu, Anas Batou, Huajiang Ouyang
Summary: This paper addresses the issue of frictional contact between an elastomer and a rigid body with randomly rough surfaces. The research is based on a framework for generating random geometries and a robust frictional contact algorithm, both realized through the approach of Isogeometric analysis (IGA). Numerical experiments show that factors such as the roughness and correlation length of the random surface, as well as the external traction, have a significant influence on the ratios characterizing the frictional contact.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Chemical
G. Violano, L. Afferrante, A. Papangelo, M. Ciavarella
Summary: The new criterion for stickiness in solids with random fractal roughness, based on Persson's theory with DMT-type adhesion, shows that stickiness is unaffected by the truncation of the PSD spectrum at short wavelengths. With typical nanometer values of attractive forces, the criterion justifies the well-known Dalhquist criterion for stickiness, which requires adhesives to have an elastic modulus below about 1 MPa.
JOURNAL OF ADHESION
(2021)
Article
Engineering, Mechanical
A. Nitti, M. Stender, N. Hoffmann, A. Papangelo
Summary: The study focuses on the problem of vibration localization in slender design airfoils in aerospace and aeronautical engineering, considering a rotor model obtained by coupling multiple airfoils. The nonlinear dynamical response of the rotor and the emergence of localized vibrating solutions are studied, with particular attention to different localized states depending on the airstream velocity. Homogeneous and slightly localized states are found to be more likely to appear compared to strongly localized states.
NONLINEAR DYNAMICS
(2021)
Article
Engineering, Chemical
Antonio Papangelo, Michele Ciavarella
Summary: Researchers found that the Persson and Tosatti theory provided satisfactory predictions of adhesion work during loading, but a much larger effective work of adhesion was observed during unloading, indicating that this is not an intrinsic property. Different behaviors during loading and unloading may require the use of different criteria for analysis.
Article
Mechanics
M. Ciavarella, A. Papangelo
Summary: This study presents simple results for crack propagation in finite size specimens of viscoelastic materials, including the maximum velocity at which a crack may become unstable and the reduction in toughness enhancement compared to infinite systems. Different theories predict qualitative differences, with some suggesting instability while others propose stability without amplification beyond that of infinite systems. Further clarification of these differences is needed for future research.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Chemical
A. Papangelo, M. Ciavarella
Summary: Macroscopic adhesion is rare in industry but common in nature. Viscoelastic properties of materials result in toughness increasing with rate-dependent behavior, playing a crucial role in adhesion enhancement.
JOURNAL OF ADHESION
(2022)
Letter
Engineering, Mechanical
M. Ciavarella
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Mechanics
M. Ciavarella
Summary: This article discusses the applicability of energy balance for large cracks and introduces the influence of liquid materials and viscoelasticity on flaw sensitivity. A comparison is made between different theories using a simple Dugdale model, revealing significant differences.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Chemical
J. Joe, J. R. Barber, B. Raeymaekers
Summary: This paper investigates the load-displacement relationship between two rough surfaces and provides best-fit regression equations for straightforward numerical solutions of fractal models in engineering applications. The results indicate that the load-displacement relationship between random rough surfaces is best approximated by an exponential function and a complementary error function, depending on the magnitude of the gap between the surfaces. The study enables the application of complex contact models to engineering problems in a direct manner.
Article
Engineering, Mechanical
M. Ciavarella, A. Papangelo, R. McMeeking
Summary: Crack growth in viscoelastic materials is studied using cohesive models and steady state theories. Experimental results show that crack propagation speed reaches a steady state quickly, while the external work rate has a longer transient effect. The initial dissipation rate at low crack propagation speeds can be significantly higher than the limit governed by the ratio of instantaneous to relaxed modulus.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Mechanics
N. Cwiekala, J. R. Barber, D. A. Hills
Summary: This paper investigates the elastic problem of a circular disk shrink fitted into a hole in an elastically similar plane with a frictional interface, under the application of a time-varying radial force and torque. Edge dislocation distributions are used to represent slip, and the evolution of slip zone extent and position, as well as the magnitude of slip displacements, is studied. Conditions for continuous slip, leading to a solution independent of history or load path, are derived. The obtained results pave the way for the study of the shakedown behavior of a continuous coupled contact.
MECHANICS RESEARCH COMMUNICATIONS
(2022)
Article
Engineering, Mechanical
Michele Ciavarella, Luigi Romano, J. R. Barber
Summary: The problem of a wheel under tractive rolling of Carter is revisited here by considering slip-dependent friction force. By assuming a change from static to dynamic friction coefficient occurs over a small distance, a fracture mechanics solution for shear tractions is developed, which explains some aspects of falling friction creepage forces observed in experiments. The agreement with experimental results is discussed, suggesting the potential inclusion of rate-dependent effects in friction. Additionally, a simple strip theory is used to estimate the 3D effects, which result in reduced singularity strength at the edges and lower peak pressure.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
M. Ciavarella, T. Zhang, R. M. McMeeking
Summary: This study analyzes crack growth in viscoelastic material and computes the work done and dissipation per unit area of crack growth under applied load. The results suggest that crack growth models based on quantifying the dissipation per unit area are not applicable to components with finite geometry, while models based on a rupture process zone are easier to implement.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mechanics
N. Cwiekala, J. R. Barber, D. A. Hills
Summary: The paper focuses on the plane elastic problem of a circular disc shrink fitted into a hole in an elastically similar plane, with a frictional interface. The disc is subjected to a radial force and torque that vary with time. The steady-state response is shown to depend on the loading history, unlike Melan's theorem for elastic-plastic shakedown, due to the normal-tangential coupling in this frictional system.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Mechanical
James R. Barber, Michele Ciavarella
Summary: A refined beam model is developed by solving the exact elasticity problem of a free layer and expanding the resulting displacement in powers of the wavenumber. The method provides a criterion for determining the accuracy of the ordinary differential equation used in the model.
JOURNAL OF STRAIN ANALYSIS FOR ENGINEERING DESIGN
(2023)