A Three-Dimensional Thermal-Mechanical Asperity Contact Model for Two Nominally Flat Surfaces in Contact

2000 ◽  
Vol 123 (3) ◽  
pp. 595-602 ◽  
Author(s):  
Geng Liu ◽  
Qian Wang ◽  
Shuangbiao Liu
Keyword(s):  
Frictional Heating ◽  
Three Dimensional ◽  
Contact Model ◽  
Asperity Contact ◽  
The Finite Element Method ◽  
Flat Surfaces ◽  
Solution Methods ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Rough Surface Contact

The rough surface contact in a tribological process involves frictional heating and thermoelastic deformations. A three-dimensional thermal-mechanical asperity contact model has been developed, which takes into account steady-state heat transfer, asperity distortion due to thermal and elastic deformations, and material yield. The finite-element method (FEM), fast Fourier transform (FFT), and conjugate gradient method (CGM) are employed as the solution methods. The model is used to analyze the thermal-mechanical contact of typical rough surfaces and investigate the importance of thermal effects on the contact performance of surface asperities.

A Two-Dimensional Thermoelastic Rough Surface Contact Model

2004 ◽  
Vol 126 (3) ◽  
pp. 430-435 ◽  
Author(s):  
Yuan Lin ◽  
Timothy C. Ovaert
Keyword(s):  
Rough Surface ◽  
Thermal Deformation ◽  
Frictional Heating ◽  
Asperity Contact ◽  
Two Dimensional ◽  
Elastic Deformations ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Thermal Influence ◽  
Rough Surface Contact

By taking into account steady-state heat transfer, and surface distortion due to thermal and elastic deformations, a two-dimensional thermoelastic model is developed for rough surface asperity contact, where the thermal influence function connecting the thermal deformation and the contact pressure is derived based on the Dundurs’ theorem. The model has been shown to be accurate at low as well as high frictional heating conditions by comparison with published results. As an application of this model, the contact problem of a cylinder on a random rough surface is studied in detail.

Transient Thermoelastic Stress Fields in a Half-Space

2002 ◽  
Vol 125 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Shuangbiao Liu ◽  
Qian Wang
Keyword(s):  
Stress Field ◽  
Half Space ◽  
Frictional Heating ◽  
Three Dimensional ◽  
Thermoelastic Stress ◽  
Parabolic Type ◽  
Elastic Half Space ◽  
Transform Method ◽  
Rough Surface Contact ◽  
Thermoelastic Stress Field

Computing the thermoelastic stress field of a material subjected to frictional heating is essential for component failure prevention and life prediction. However, the analysis for three-dimensional thermoelastic stress field for tribological problems is not well developed. Furthermore, the pressure distribution due to rough surface contact is irregular; hence the frictional heating can hardly be described by an analytical expression. This paper presents a novel set of frequency-domain expressions (frequency response functions) of the thermoelastic stress field of a uniformly moving three-dimensional elastic half-space subjected to arbitrary transient frictional heating, where the velocity of the half-space, its magnitude and direction, can be an arbitrary function of time. General formulas are expressed in the form of time integrals, and important expressions for constant velocities are given for the transient-instantaneous, transient-continuous, and steady-state cases. The thermoelastic stress field inside a translating half-space with constant velocities are illustrated and discussed by using the discrete convolution and fast Fourier transform method when a parabolic type or an irregularly distributed heat source is applied.

Thermal Elasto-Plastic Asperity Contacts of Layered Media

2006 ◽  
Vol 532-533 ◽  
pp. 721-724
Author(s):  
Rui Ting Tong ◽  
Geng Liu ◽  
Quan Ren Zeng ◽  
Tian Xiang Liu
Keyword(s):  
Stress Distribution ◽  
Contact Pressure ◽  
Coating Thickness ◽  
Frictional Coefficient ◽  
Hard Coating ◽  
Asperity Contact ◽  
Asperity Contacts ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Contact Stress Distribution

A thermal elasto-plastic asperity contact model is investigated in this paper, which takes into account the steady-state heat transfer and the asperity distortion due to thermal elasto-plastic deformations. A hard coating and a soft coating are applied to study the correlations between contact area and contact pressure, average gap and contact pressure, coating thickness and contours of the contact stress distribution et al. The effects of material properties, the coating thickness, frictional coefficient, and the heat input combinations on the stress distribution are investigated and discussed. The results may help to make an appropriate choice of the hard coating thickness.

Thermomechanical Analysis of Elastoplastic Bodies in a Sliding Spherical Contact and the Effects of Sliding Speed, Heat Partition, and Thermal Softening

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
W. Wayne Chen ◽  
Q. Jane Wang
Keyword(s):  
Half Space ◽  
Frictional Heating ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Thermomechanical Analysis ◽  
Thermal Softening ◽  
Sliding Speed ◽  
Dependent Strain ◽  
Steady State Heat ◽  
Strain Hardening Behavior

A thermomechanical analysis of elasto-plastic bodies is a necessary step toward the understanding of tribological behaviors of machine components subjected to both mechanical loading and frictional heating. A three-dimensional thermoelastoplastic contact model for counterformal bodies has been developed, which takes into account steady state heat flux, temperature-dependent strain hardening behavior, and interaction of mechanical and thermal loads. The fast Fourier transform and conjugate gradient method are the underlying numerical algorithms used in this model. Sliding of a half-space over a stationary sphere is simulated with this model. The friction-induced heat is partitioned into two bodies based on surface temperature distributions. In the simulation, the sphere is considered to be fully thermoelastoplastic, while the half-space is treated to be thermoelastic. Simulation results include surface pressure, temperature rise, and subsurface stress and plastic strain fields. The paper also studies the influences of sliding speed and thermal softening on contact behaviors for sliding speed ranging three orders of magnitude.

scholarly journals Load carrying capacity of partially encased columns for different fire ratings

Fire Research ◽  
2016 ◽  
Author(s):  
Abdelkadir Fellouh ◽  
Nourredine Benlakehal ◽  
Paulo Piloto ◽  
Ana Ramos ◽  
Luís Mesquita
Keyword(s):  
Fire Resistance ◽  
Carrying Capacity ◽  
Three Dimensional ◽  
Thermal Inertia ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Three Dimensional Model ◽  
Load Carrying ◽  
Solution Methods ◽  
Two Parameters

Partially encased columns have significant fire resistance in comparison with steel bare columns. However, it is not possible to assess the fire resistance of such members simply by considering the temperature of the steel. The presence of concrete increases the mass and thermal inertia of the member and the variation of temperature within the cross section, in both the steel and concrete components. The annex G of EN1994-1-2:20051 allows to calculate the load carrying capacity of partially encased columns, for a specific fire rating time, considering the balanced summation model. New formulas will be proposed to calculate the plastic resistance to axial compression and the effective flexural stiffness. These two parameters are used to determine the buckling resistance. The finite element method is used to compare the results for the elastic critical load and the load carrying capacity of partially encased columns for different fire ratings of 30 and 60 min. This work compares the results from both solution methods, provides the validation of the three-dimensional model and demonstrates that a new design curve should be used for the buckling analysis of partially encased columns.

scholarly journals Steady-State Three - Dimensional Numerical Simulation of Heat Transfer for Thermal Bridges Assessment

2016 ◽  
Vol 6 (1) ◽  
pp. 17-22
Author(s):  
Silviana Brata ◽  
Carmen Maduta ◽  
S. Pescari
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Flow ◽  
Three Dimensional ◽  
Outer Wall ◽  
Thermal Transmittance ◽  
State Heat ◽  
Thermal Bridges ◽  
Steady State Heat ◽  
Steady State Heat Transfer

Abstract This paper presents a study on using the steady-state three-dimensional heat transfer software HEAT3 for evaluating the heat flow of heat transfer through different elements of the building envelope in order to establish the linear thermal transmittance of the linear thermal bridge. The linear thermal transmittance is obtained according to the one-dimensional steady-state heat transfer calculation formula for the plane walls using the heat flow values obtained through the method specified above. The results presented in this paper are part of a wider study on evaluating the heat transfer through building’s envelope elements by evaluating as accurate as possible the thermal bridges effect of the most common building structures. As a case study, it was considered the steady-state heat transfer through an opaque outer wall of a building considering the thermal bridges for the following elements: outer walls intersection, inner and outer wall intersection and outer wall with intermediate floor intersection.

Sign in / Sign up

Export Citation Format

Share Document