Article
Acoustics
Qiang Zhang, Shengchun Piao, Hongjuan Chen
Summary: A theoretical model of the intermittent contact mechanism of linear piezoelectric actuator was proposed, taking into account the microscopic characteristics of the contact surfaces and using GM theory to describe them. The model provides insight into the influence of microscopic, macroscopic, and material properties on the actuator's output performance, guiding its design. Simulations and experiments were conducted to analyze and validate the effects of factors such as material type, surface roughness, initial distance, and preload on contact performance.
Article
Materials Science, Multidisciplinary
R. L. Jackson, T. D. B. Jacobs
Summary: The true contact area between two surfaces is only a small fraction of the apparent macroscopic contact area. This study investigates the influence of roughness at different size scales on the true contact area using a multiscale framework and a statistical roughness model. The results show that even the smallest scales can have a significant influence on the contact area, and scale-dependent strength can improve the accuracy of rough-surface contact modeling.
MECHANICS OF MATERIALS
(2023)
Article
Mechanics
T. Silva Sabino, A. M. Couto Carneiro, R. Pinto Carvalho, F. M. Andrade Pires
Summary: The impact of non-Gaussian height distribution on the real contact area evolution is investigated for elastic, frictionless, and non-adhesive contact. The Weibull probability function is used to accurately model the practical surfaces. The shape parameter of the height distribution, wavelength ratio, and Hurst exponent are discussed as important variables for the problem parameterization. The study reveals deviations from the Gaussian case as the topographies become more non-Gaussian, and the spectral properties exhibit distinct effects on different non-Gaussian surfaces.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Mechanical
R. Pinto Carvalho, A. M. Couto Carneiro, F. M. Andrade Pires, T. Doca
Summary: The proposed multiscale strategy efficiently models rough contact and predicts the evolution of contact area. By incorporating statistical information into scale transitions, the contact area fraction is evaluated effectively.
TRIBOLOGY INTERNATIONAL
(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
Engineering, Mechanical
S. Sklenak, D. Mevissen, J. Brimmers, C. Brecher
Summary: Surface roughness significantly affects the tribological properties in rolling contact, including friction, wear, and fatigue. The initial load causes major changes in the tribological properties. This study presents an elastic-plastic contact algorithm for calculating plastic deformation of rough surfaces in dry contact, taking into account residual stresses and interactions of microscopic peaks.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
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, Mechanical
G. Violano, L. Afferrante
Summary: In this study, an efficient multi-asperity model considering contact coupling and coalescence is proposed for modeling the elasto-plastic contact between rough interfaces. The results show that the contact area increases linearly with the applied load, and this relationship is affected by the yield strength and roughness amplitude. Additionally, the contact area is found to be independent of the high-frequency cut-off of the roughness spectrum due to plastic deformations.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(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
Engineering, Mechanical
Lei-Tao Li, Xuan-Ming Liang, Yu-Zhe Xing, Duo Yan, Gang-Feng Wang
Summary: This study presents a new apparatus for measuring the real contact area of metallic samples and identifies the mechanisms of elasticity and plasticity in contact. A quantitative parameter is introduced to indicate the contribution of plasticity. This work provides insight into how elastic and plastic deformation work in contact with rough surfaces.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Materials Science, Multidisciplinary
L. Afferrante, G. Violano, D. Dini
Summary: This study contributes to the debate by numerical simulations and experimental observations, revealing the crucial role of long-wavelength roughness and the influence of short-wavelength roughness on adhesion.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Mechanics
Cheng-Ya Li, Gang-Feng Wang
Summary: The study adopts a constant mean contact radius from the original Greenwood-Williamson model and deals with asperity interactions by arranging random distributed contact spots into a hexagonal distribution. Finite element simulation is used to determine the load-area relation up to almost complete contact in a representative unit with symmetrical boundary conditions. Compared to the GW model without asperity interactions, interactions induce larger loads for a given contact fraction. The obtained load-area relation is extended to a general formulation, showing good agreement with direct finite element simulations and being applicable for a large range of contact fraction. This model provides an efficient method to predict the overall contact response of rough surfaces and reduces computational burden greatly.
Article
Engineering, Mechanical
Anahita Emami, Seyedmeysam Khaleghian, Saied Taheri
Summary: Modeling the real contact area is crucial in various tribological processes, and the accuracy of predicting friction, adhesion, and wear depends on it. Consideration of physical parameters such as surface roughness characteristics, material properties, sliding velocity, and normal load can lead to a more precise estimation of the friction coefficient.
Article
Materials Science, Multidisciplinary
Tevis D. B. Jacobs, Lars Pastewka
Summary: Materials science studies the relationship between a material's structure and its properties, including elastic modulus, yield strength, and other bulk properties in the sphere of mechanical behavior. This article shows that a material's surface structure governs its surface properties, such as adhesion, friction, and surface stiffness. The articles in this issue provide the latest understanding of the structure-property connections for surfaces, including the theoretical basis for topography-dependent properties and the engineering of surfaces to improve performance.
Article
Automation & Control Systems
Fengyi Guo, Xin Gu, Li Li, Zhiyong Wang, Tunan Wang, Shenli Jia
Summary: This article experimentally and analytically investigated the influence of surface characteristics of sliding electrical contact friction pairs on contact temperature under different conditions, providing important references for further research on the contact temperature characteristics of the friction pair.
IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS
(2022)
Article
Materials Science, Multidisciplinary
T. Guillen-Hernandez, J. Reinoso, M. Paggi
Summary: The phase field approach is a promising modeling tool for fracture, and this paper presents a phase field formulation for triggering brittle fracture in shell structures made of functionally graded materials. The model incorporates a solid shell kinematic description and uses the Enhanced Assumed Strain and Assumed Natural Strain methods to alleviate locking pathologies. The corresponding multi-field variational formalism is derived and discretized within the context of the Finite Element Method.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Mechanics
M. R. Marulli, L. Heepe, S. N. Gorb, M. Paggi
Summary: This paper proposes a novel finite element method for simulating biologically inspired adhesives with mushroom-shaped patterned surfaces. The proposed computational model can capture attachment and detachment mechanisms without detailed modeling of surface microstructures. A data-driven phenomenological interface constitutive law is formulated to assess Mode Mixity effects at a range of relevant peeling angles. The proposed computational model represents a versatile tool for modeling structural problems involving arbitrary shape components, such as bio-inspired adhesives.
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
Engineering, Mechanical
Pietro Lenarda, Jose Reinoso, Marco Paggi
Summary: This study extends the variational approach to brittle fracture to accommodate the simultaneous interplay of two failure mechanisms affecting grained heterogeneous materials in compression. A multi-phase field variational approach with two independent damage variables for each failure mechanism is proposed. The computational method is applied to 2D mesoscale models of concrete specimens in compression using the open source FEniCS finite element software. The predicted trends align with experimental results and commonly observed failure patterns.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Civil
Pavan Kumar Asur Vijaya Kumar, Aamir Dean, Jose Reinoso, Marco Paggi
Summary: This paper proposes a thermodynamically consistent framework for solving the coupled thermo-mechanical phase-field fracture problem in thin-walled structures made of functionally graded materials (FGMs). The computational model combines Enhanced Assumed Strain (EAS) and Assumed Natural Strains (ANS) to alleviate locking pathologies in the solid shell formulation. Benchmark examples are used to assess the model capabilities and demonstrate the importance of functionally graded materials in crack deflection and temperature distributions.
THIN-WALLED STRUCTURES
(2022)
Article
Mechanics
Deison Preve, Pietro Lenarda, Ian Maskery, Marco Paggi
Summary: The main objective of this study is to assess the fracture occurrence in Triply Periodic Minimal Surfaces (TPMS) foams under compressive loading. TPMS, developed by the mathematics community, can be used as a framework for open porous foams in various engineering and biomedical applications. Therefore, it is fundamental to analyze their fracture response comprehensively. In this study, a 3D phase field model is proposed and applied to TPMS foam structures under compression to predict critical points for crack nucleation, potential crack paths, and mechanical properties of the unit cell. The results show that TPMS can outperform standard Aluminium open foams.
ENGINEERING FRACTURE MECHANICS
(2023)
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
Materials Science, Multidisciplinary
Z. Liu, J. Reinoso, M. Paggi
Summary: A three-dimensional hygro-thermo-mechanical computational framework for photovoltaic laminates has been established and successfully implemented in this study. The method takes into account the thermal properties in thin-walled structures and the characteristics of polymeric interfaces, showing efficiency and reliability.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mathematics, Interdisciplinary Applications
A. Valverde-Gonzalez, J. Reinoso, B. Dortdivanlioglu, M. Paggi
Summary: Soft materials with high deformability and susceptibility to damage events are extensively studied for applications in biomechanics. This study proposes gradient-enhanced continuum damage schemes to model the damage evolution processes in these nonlinear materials that are prone to locking issues. The novel formulations of mixed displacement-enhanced assumed strain and mixed displacement-pressure-Jacobian are derived and successfully implemented, providing satisfactory agreement with ABAQUS built-in elements. Multiple numerical applications demonstrate the effectiveness of these formulations in handling shear and volumetric locking and simulating damage phenomena.
COMPUTATIONAL MECHANICS
(2023)
Article
Engineering, Multidisciplinary
Zeng Liu, Pietro Lenarda, Jose Reinoso, Marco Paggi
Summary: A comprehensive coupled thermo-chemo-mechanical modeling framework is proposed to study the reaction-diffusion phenomena in photovoltaics. The model accurately predicts the chemical degradation of ethylene-co-vinyl acetate (EVA) layers under hygrothermal conditions, considering the spatial and temporal variation of diffusivity and chemical kinetic rates. The framework successfully reproduces the evolution of reaction-diffusion species and demonstrates its capability to predict spatio-temporal variation under cyclic temperature boundary conditions.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Z. Liu, M. Marino, J. Reinoso, M. Paggi
Summary: Nowadays, the recycling of photovoltaics (PV) using solvents is a popular topic, with a focus on the nondestructive recovery of precious silicon wafers. However, there is a lack of comprehensive understanding of the polymer-solvent system in the PV recycling process. This study proposes a thermodynamically consistent large-deformation theory to model the coupled behavior of this system.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Margherita Cacaci, Giacomo Biagiotti, Gianluca Toniolo, Martin Albino, Claudio Sangregorio, Mirko Severi, Maura Di Vito, Damiano Squitieri, Luca Contiero, Marco Paggi, Marcello Marelli, Stefano Cicchi, Francesca Bugli, Barbara Richichi
Summary: The worldwide crisis of bacterial resistance to traditional antibiotics has prompted research into the development of silver-based nanomaterials with enhanced antibacterial activity. This study describes the synthesis of three different silver nanoparticle hybrids using organic and inorganic supports. The tuning of the silver nanoparticles' shape and size according to the type of support used was also investigated. The resulting composite materials showed effective antibacterial activity against clinically relevant multi-drug-resistant bacteria and the fungus Candida albicans.
Article
Humanities, Multidisciplinary
Giusi Sorrentino, Laura Longo, Theodor Obada, Alessandro Borghi, Alessandro Re, Marco Paggi, Alessandro Lo Giudice
Summary: This study developed an analytical procedure to replicate, document, and analyze use-wear traces on ground stone tools. The goal was to create a reference collection for wear patterns during the processing of vegetal resources compatible with the MIS 3 period. Riverine slabs and pebbles were used to explore various aspects of their use in transforming plant organs. The study identified and discussed several variables that affect the wear traces.
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)
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
Yankui Song, Ke Xiao, Guo Xiang
Summary: The novelty of this study lies in constructing an Entropy-based wear and fluid-solid-thermal (FST) coupled model for journal bearings, and revealing the transient interaction behavior between wear evolution and FST evolution during repeated starting and stopping. The wear rate is measured experimentally, and the contact temperature, friction coefficient and normal contact force are obtained from the validated FST model. Wear tests and numerical calculations are conducted to validate the predicted wear rate and investigate the time-varying wear and FST evolution of journal bearings.
Article
Engineering, Mechanical
Xin-long Liu, Xin Guan, Yuan Zhong, Qian Xiao, Yong Cao, Wu-lue Zhang, Song Zhang, Yi-ting Zheng, Ming-sheng Gao, Dao-yun Chen, Wen-bin Yang
Summary: Gaps in the conductor rail joints of intercity trains have an impact on current transmission and the wear of carbon skateboards. These gaps decrease the coefficient of friction, increase electrical contact resistance, and affect the wear rate of carbon skateboards.
Article
Engineering, Mechanical
Yuhang Wu, Conglin Dong, Xiuqin Bai, Chengqing Yuan
Summary: The study developed a new composite material by incorporating hexagonal boron nitride (h-BN) particles into a thermoplastic polyurethane (TPU) matrix, which exhibited excellent self-lubricating properties and reduced frictional excitation forces. The addition of h-BN particles effectively reduced the coefficient of friction, decreased fluctuation amplitude, enhanced wear resistance, and attenuated vibration behaviors.
Article
Engineering, Mechanical
Tiancheng Ouyang, Xiuyang Sun, Wentao Tang, Yinxuan Li, Zhi Qun Tian, Yanzhou Li
Summary: By adding nitrogen-doped graphene and C60 nanoparticles to the lubricant, a highly efficient nano-lubricant with vibration and noise reduction properties is synthesized.
Article
Engineering, Mechanical
Xin Zhuo, Jun Cao, Haibo Huang, Li Liu, Xinkun Suo, Peiqing Ye, Zeshan Abbas
Summary: A polymer coating prepared by liquid spraying technology on the surface of 20CrMo steel demonstrates good tribological and anti-cavitation erosive properties. It can effectively replace CuPb24Sn copper alloy in valve plates for pumps under different lubrication conditions. The coating exhibits adhesive wear and reduces frictional loss, and mainly shows abrasive wear under complex working conditions. Its lipophilicity, high hardness to elastic modulus ratio, and corrosion resistance are the main influencing factors for its performance.
Article
Engineering, Mechanical
Md. Aminul Islam, Jiaren (Jimmy) Jiang, Yongsong Xie
Summary: Erosion-corrosion is a major factor in material loss and reduced useful life of hydro-transport equipment. This study evaluates the erosion-corrosion characteristics of different materials and finds that matrix wear affects the degradation of carbides. Sufficient wear and corrosion resistance in the surrounding matrix are important for good erosion-corrosion resistance.
Article
Engineering, Mechanical
Andre Dubois, Oussama Filali, Laurent Dubar
Summary: This study investigates the effect of surface roughness, contact pressure, and lubrication on the onset of galling in aluminum 6082-T6 using a pin-on-plate tribometer. The experimental results show that the roughness and lubricants play a significant role in preventing galling.
Article
Engineering, Mechanical
Jizhan Wu, Peitang Wei, Guoqiang Liu, Difa Chen, Xiuhua Zhang, Taimin Chen, Huaiju Liu
Summary: This study conducted a comprehensive evaluation of the DLC coating treatment on the loading capacity of gears and characterized the surface features and fatigue performance. The results demonstrate that DLC coating significantly improves the hardness and surface residual compressive stress of the gears, as well as enhances their contact fatigue performance.
Article
Engineering, Mechanical
Yangping Liu, Hwaran Lee, Annsley Mace, Jeremy L. Gilbert
Summary: An AFM-based single asperity tribology method was used to investigate the wear performance of carbides and base metal matrix in high carbon CoCrMo alloy. The wear behavior of the two types of carbides was stress-dependent and influenced by chemical composition. Cr-rich carbides exhibited higher wear resistance compared to Mo-rich carbides.
Article
Engineering, Mechanical
Zdenek Riha, Michal Zelenak, Akash Nag, Jakub Poloprudsky, Tomas Kruml, Sergej Hloch
Summary: This study investigates the erosion performances of a high-speed modulated jet (MWJ) and continuous water jet (CWJ). By comparing different nozzles and water jet powers, the effects of modulated and continuous jets on aluminum alloy were studied. The results show that under certain conditions, modulated jet can create deeper and sharper grooves while reducing the impact of lateral flow.
Article
Engineering, Mechanical
Chunyu Yu, Weipu Li, Yang Guo, Xianbin Sun, Fanli Hong, Ning Sun, Qinghai Zhang
Summary: This study explores the relationship between the wear rate of train brake pads and its features, and proposes a method for predicting the wear rate suitable for small sample data. Grey relational analysis and Pearson correlation analysis are used to determine the preferred features that affect the wear rate, and a BOA-BP model is established for prediction. The results show that BOA-BP exhibits better advantages in prediction with small samples.
Article
Engineering, Mechanical
Shan Yin, Xin Zhao, Shuangchao Huang, Zefeng Wen, Xuesong Jin
Summary: This study simulated the rolling contact of a driving wheelset over tangent and curved tracks at a speed up to 500 km/h using an explicit finite element approach to derive creep curves. The comparison between quasi-steady curves and transient curves in the presence of rail corrugation helped to identify cases where traditional theories are inapplicable and where transient effects must be considered. Additionally, the study further analyzed the influence of middle/high-frequency vibrations in the presence of rail corrugation.
Article
Engineering, Mechanical
Jiyao Zhang, Yuanlie Yu, Junlei Tang, Yingying Wang, Honggang Sun, Kaikai Song, Jianhong Gong, Pingping Liu, Xiaoming Liu, Lina Hu, Parthiban Ramasamy, Juergen Eckert
Summary: The influence of high-carbon addition on the microstructure, hardness, and wear behavior of CoCrNi alloy was investigated. It was found that the addition of carbon resulted in the formation of carbide particles, enhancing the hardness and improving the wear resistance. Fracture and detachment of hard carbides during friction introduced additional abrasive particles, transitioning the wear mechanism from adhesive-dominated to abrasive-dominated.
Article
Engineering, Mechanical
Yanfei Liu, Shengtao Yu, Ruize Zhang, Xiangyu Ge, Wenzhong Wang
Summary: This study reports the tribological behavior of nanodiamond plate (NDPL) as a nanoadditive for the first time and compares it with nanodiamond particles (NDPA). The results show that NDPL provides better lubrication performance at higher concentrations, and the sliding between NDPLs and the structural transformation from sp3 to sp2 carbon play a crucial role in lubrication and wear resistance.