Numerical Investigation of the Three-Dimensional Elastic–Plastic Sloped Contact Between Two Hemispheric Asperities

2016 ◽  
Vol 83 (10) ◽  
Author(s):  
Xi Shi ◽  
Yunwu Zou ◽  
Huibo Fang
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Azimuthal Angle ◽  
Three Dimensional ◽  
Polar Angle ◽  
Load Ratio ◽  
Interfacial Shear ◽  
Initial Contact ◽  
Elastic Plastic ◽  
Elastic Rebound

For real engineering surfaces contact, most asperities come into contact in a configuration of shoulder-to-shoulder instead of aligned head-on. In this work, a three-dimensional (3D) model of two identical elastic–plastic spherical asperities in contact was developed which characterizes the initial contact offset with polar angle α and azimuthal angle β. The simulations with finite-element method (FEM) show that the adhesive coefficient of friction (COF) is only influenced by large initial azimuthal angle thus mainly depends on interfacial shear strength. The plowing COF is determined, however, by effective contact interference, which reflects the combined effects of α and β. Moreover, a detailed parametric study shows that the load ratio is significantly dependent on Young's modulus and interfacial shear strength, while the maximum elastic rebound force during the unloading phase is mainly dependent on polar angle.

A Mathematical Model for Frictional Elastic-Plastic Sphere-on-Flat Contacts at Sliding Incipient

2005 ◽  
Vol 74 (1) ◽  
pp. 100-106 ◽  
Author(s):  
L. Chang ◽  
H. Zhang
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Shear Strength ◽  
Contact Pressure ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Contact Model ◽  
Elastic Plastic ◽  
Plastic Sphere ◽  
Flat Contact

This paper presents a mathematical model for frictional elastic-plastic sphere-on-flat contacts at sliding incipient. The model is developed based on theoretical work on contact mechanics in conjunction with finite-element results. It incorporates the effects of friction loading on the contact pressure, the mode of deformation, and the area of contact. The shear strength of the contact interface is, in this paper, assumed to be proportional to the contact pressure with a limiting value that is below the bulk shear strength of the sphere. Other plausible interfacial-shear-strength characteristics may also be implemented into the contact model in a similar manner. The model is used to analyze the frictional behavior of a sphere-on-flat contact where the experimental data suggest that the interfacial shear strength is similar in nature to the one implemented in the model. The theoretical results are consistent with the experimental data in all key aspects. This sphere-on-flat contact model may be used as a building block to develop an asperity-based contact model of rough surfaces with friction loading. It may also serve in the modeling of boundary-lubricated sliding contacts where the interfacial shear strength in each micro-contact is coupled with its flash temperature and related to the lubricant/surface physical-chemical behavior.

scholarly journals Enhanced Interfacial Shear Strength and Critical Energy Release Rate in Single Glass Fiber-Crosslinked Polypropylene Model Microcomposites

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2552 ◽  
Author(s):  
Uwe Gohs ◽  
Michael Mueller ◽  
Carsten Zschech ◽  
Serge Zhandarov
Keyword(s):  
Shear Strength ◽  
Electron Beam ◽  
Energy Release Rate ◽  
Glass Fiber ◽  
Release Rate ◽  
Interfacial Shear Strength ◽  
Glass Fibers ◽  
Critical Energy ◽  
Interfacial Shear ◽  
Critical Energy Release Rate

Continuous glass fiber-reinforced polypropylene composites produced by using hybrid yarns show reduced fiber-to-matrix adhesion in comparison to their thermosetting counterparts. Their consolidation involves no curing, and the chemical reactions are limited to the glass fiber surface, the silane coupling agent, and the maleic anhydride-grafted polypropylene. This paper investigates the impact of electron beam crosslinkable toughened polypropylene, alkylene-functionalized single glass fibers, and electron-induced grafting and crosslinking on the local interfacial shear strength and critical energy release rate in single glass fiber polypropylene model microcomposites. A systematic comparison of non-, amino-, alkyl-, and alkylene-functionalized single fibers in virgin, crosslinkable toughened and electron beam crosslinked toughened polypropylene was done in order to study their influence on the local interfacial strength parameters. In comparison to amino-functionalized single glass fibers in polypropylene/maleic anhydride-grafted polypropylene, an enhanced local interfacial shear strength (+20%) and critical energy release rate (+80%) were observed for alkylene-functionalized single glass fibers in electron beam crosslinked toughened polypropylene.

scholarly journals Advanced Models for Modulus and Strength of Carbon-Nanotube-Filled Polymer Systems Assuming the Networks of Carbon Nanotubes and Interphase Section

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 990
Author(s):  
Yasser Zare ◽  
Kyongyop Rhee
Keyword(s):  
Carbon Nanotubes ◽  
Shear Strength ◽  
Carbon Nanotube ◽  
Interfacial Shear Strength ◽  
Tensile Modulus ◽  
Interfacial Shear ◽  
Filled Polymer ◽  
Polymer Systems

This study focuses on the simultaneous stiffening and percolating characteristics of the interphase section in polymer carbon nanotubes (CNTs) systems (PCNTs) using two advanced models of tensile modulus and strength. The interphase, as a third part around the nanoparticles, influences the mechanical features of such systems. The forecasts agree well with the tentative results, thus validating the advanced models. A CNT radius of >40 nm and CNT length of <5 μm marginally improve the modulus by 70%, while the highest modulus development of 350% is achieved with the thinnest nanoparticles. Furthermore, the highest improvement in nanocomposite’s strength (350%) is achieved with the CNT length of 12 μm and interfacial shear strength of 8 MPa. Generally, the highest ranges of the CNT length, interphase thickness, interphase modulus and interfacial shear strength lead to the most desirable mechanical features.

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