scholarly journals Fretting Wear Mechanical Analysis of Double Rough Surfaces Based on Energy Method

Author(s):  
Ling Li ◽  
Ganghua Li ◽  
JingJjing Wang ◽  
Xiaohui Shi ◽  
Anjiang Cai

Abstract A fretting wear model of rough surface that conforms to the actual situation is established to accurately reveal the wear mechanism of the connection structure. In the ABAQUS software, the UMESHMOTION subroutine and the energy dissipation model are used to simulate the fretting wear of double rough surfaces. The new model, a single rough surface model, and a smooth model are compared to analyze the differences between them. In addition, the influence of surface roughness, material, and friction coefficient on the fretting wear of rough surfaces is systematically explored through finite element simulation. The results show that the reliability of the model has been verified through Hertz’s theory and experiments. The stress and wear of the contact surface are more realistically reflected by the double roughness model. Besides, with the increase of surface roughness and material rigidity and the decrease of friction coefficient, the wear of the double rough surface model becomes more severe. The research work provides a theoretical basis for the design and performance prediction of the connection structure.

1970 ◽  
Vol 185 (1) ◽  
pp. 625-633 ◽  
Author(s):  
J. A. Greenwood ◽  
J. H. Tripp

Most models of surface contact consider the surface roughness to be on one of the contacting surfaces only. The authors give a general theory of contact between two rough plane surfaces. They show that the important results of the previous models are unaffected: in particular, the load and the area of contact remain almost proportional, independently of the detailed mechanical and geometrical properties of the asperities. Further, a single-rough-surface model can always be found which will predict the same laws as a given two-rough-surface model, although the required model may be unrealistic. It does not seem possible to deduce the asperity shape or deformation mode from the load-compliance curve.


1989 ◽  
Vol 111 (2) ◽  
pp. 260-264 ◽  
Author(s):  
P. Lacey ◽  
A. A. Torrance ◽  
J. A. Fitzpatrick

Most previous studies of boundary lubrication have ignored the contribution of surface roughness to friction. However, recent work by Moalic et al. (1987) has shown that when asperity contacts can be modelled by a slip line field, there is a precise relation between the friction coefficient and the asperity slope. Here, it is shown that there is also a relation between the friction coefficient and the normal pressure for rough surfaces which can be predicted from a development of the slip line field model.


2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Ashutosh Roy ◽  
Bhargava Sista ◽  
Kumar Vemaganti

Abstract The complexity of modeling friction between rough surfaces has prompted many researchers to use Greenwood and Tripp’s sum surface assumption to simplify the analysis. This assumption approximates the contact between two rough surfaces as contact between their equivalent sum surface and a rigid plane. In this work, we develop detailed finite element models to test the sum surface assumption for surfaces with Gaussian and exponential autocorrelation functions. We consider surfaces with differing surface roughness and correlation length values. For each case, we conduct simulations of two rough surfaces interacting in compression followed by shear, and a corresponding equivalent surface model based on the sum surface assumption. Multiple realizations of each parameter combination are simulated to obtain a statistical picture of the responses. We find that (a) the sum surface assumption consistently under-predicts the static coefficient of friction and (b) the equivalent surface model is less accurate for surfaces with differing correlation length-to-surface roughness ratios.


Author(s):  
M. Izadi ◽  
D. K. Aidun ◽  
P. Marzocca ◽  
H. Lee

The effect of surface roughness on the fouling behavior of calcium carbonate is experimentally investigated. The real operating conditions of a tubular heat exchanger are simulated by performing prolonged experiments with duration of 3 to 7 days. The solution used is a mixture of sodium bicarbonate and calcium chloride in de-ionized water with the concentration of 0.4 g/l of each. An on-line fouling evaluation system was developed such that the fouling resistance for a selected solution could be measured in real time. The experiments are repeated with the same procedure for 90/10 Cu/Ni tubes with different internal surface roughness. After the experiment the surface is analyzed by analytical microscopy to investigate the morphology of the deposit layer. Comparison of the experimental results of smooth and rough surfaces shows that a combination of aragonite and calcite polymorphs are formed on rough surface while only dendritic porous aragonite crystals are formed on smooth surface. Accordingly, the deposit layer formed on rough surface is denser and has a higher thermal resistance comparing to that formed on smooth surface. The fouling factor-time curves of smooth and rough surfaces obtained by the current experimental study agree with the results found by the analytical microscopy of the surface and show higher fouling resistances for rough surface. Experimental data is significantly important for the design, and formulating operating, and cleaning schedules of the equipment.


1985 ◽  
Vol 54 ◽  
Author(s):  
J. R. Blanco ◽  
K. Vedam ◽  
P. J. McMarr ◽  
J. M. Bennett

ABSTRACTWell characterized rough surfaces of aluminum films have been studied by the nondestructive technique of Spectroscopie Ellipsometry (SE). The roughness of the aluminum specimens had been characterized earlier by Total Integrated Scattering and Stylus Profilometry techniques to obtain numerical estimates of ras roughness and autocovariance lengths. The present SE measurements on these specimens were carried out at a number of angles of incidence in the range 30–80° and at a number of discrete wavelengths in the spectral range 300–650nm. The SE results were then analyzed by the scalar theory of diffraction from random rough surfaces by treating the surface as a simple random rough surface. The results of such analyses of the SE measurements are compared with the results of the earlier characterization techniques.


Author(s):  
Anahita Emami ◽  
Seyedmeysam Khaleghian ◽  
Chuang Su ◽  
Saied Taheri

Friction and wear of viscoelastic materials like rubbers are topics of extreme practical importance such as the construction of tires, shoe heels and soles, rubber O-ring seals, and wiper blades. Friction of viscoelastic materials differs from the frictional properties of the elastic solids as friction is directly related to energy dissipation via the internal damping of such materials while purely elastic materials do not dissipate energy. Based on hysteresis properties of viscoelastic materials, physics based multiscale models were developed by Persson for fiction [1, 2] and powdery wear [3] of rubbers sliding on rough surfaces. In this research, these theories were studied and the theoretical results were compared with experimental results obtained from a dynamic friction/wear tester. The inputs to the theoretical models were the fractal properties of the rough surface, the dynamic modulus, and the fatigue behavior of the viscoelastic material. The fractal properties of the rough surface was obtained from the 3D profile of the surface measured using an optical profilometer. The dynamic modulus of the rubber samples was characterized via dynamic mechanical analysis at different frequencies and temperatures. The fatigue crack growth behavior of the samples were found from experimental results of crack propagation versus tearing energy obtained from the fatigue test. Then, the friction coefficient between different rubber samples and rough surfaces was calculated as a function of sliding velocity using both analytical model and experimental approach. In the dynamic friction/wear tester, normal force was adjusted and measured accurately, in addition, the frictional force was measured using a load cell in longitudinal direction along the sliding axis. The experimental sliding friction coefficient was calculated as the ratio of longitudinal force at a constant velocity to the normal force. The mass loss of rubber sample was measured by weighting the sample before and after each test to obtain the wear rate. The comparison between experimental and analytical results showed that the friction model could predict the friction coefficient accurately while the theory of powdery wear is unable to capture all the physics involved in rubber wear on rough surfaces.


2021 ◽  
Vol 11 (17) ◽  
pp. 8048
Author(s):  
Qiuping Yu ◽  
Jianjun Sun ◽  
Zhengbo Ji

Proper methods and models for mechanical analysis of rough surface can improve the theory of surface contact. When the topography parameters of two rough surfaces are similar, the contact should be considered shoulder-shoulder rather than top-top. Based on shoulder-shoulder contact and fractal characteristics, the geometric model for asperity and contact mechanics model for rough surfaces are established, and the deformation of asperity, the real contact area and contact load of sealing surface are discussed. The effects of contact pressure p and topography parameters (fractal dimension D and fractal roughness G) on the variation of porosity and contact area ratio Ar/A0 are achieved. Results show that with the increase of p, larger D and smaller G corresponds to larger initial porosity but faster and larger decrease of porosity; with the increment of D, porosity increases first and then decreases, and smaller G corresponds to larger porosity reduction; as G becomes bigger, porosity increases, and larger D corresponds to larger porosity difference and change. With the addition of p, Ar/A0 increases, and the variation of Ar/A0 is closer to linearity and less at smaller D and larger G; with the increase of D, Ar/A0 increases gradually, and the growth rate is bigger at smaller G and bigger p; as G becomes bigger, Ar/A0 declines, and it declines more gently at smaller D and p. The influence of D on Ar/A0 is greater than that of G. The results can provide the theoretical basis for the design of sealing surfaces and the research of sealing or lubrication technologies of rough surfaces.


2008 ◽  
Vol 130 (3) ◽  
Author(s):  
D. Cohen ◽  
Y. Kligerman ◽  
I. Etsion

A model for elastic-plastic nominally flat contacting rough surfaces under combined normal and tangential loading with full stick contact condition is presented. The model incorporates an accurate finite element analysis for contact and sliding inception of a single elastic-plastic asperity in a statistical representation of surface roughness. It includes the effect of junction growth and treats the sliding inception as a failure mechanism, which is characterized by loss of tangential stiffness. A comparison between the present model and a previously published friction model shows that the latter severely underestimates the maximum friction force by up to three orders of magnitude. Strong effects of the normal load, nominal contact area, mechanical properties, and surface roughness on the static friction coefficient are found, in breach of the classical laws of friction. Empirical equations for the maximum friction force, static friction coefficient, real contact area due to the normal load alone and at sliding inception as functions of the normal load, material properties, and surface roughness are presented and compared with some limited available experimental results.


2016 ◽  
Vol 721 ◽  
pp. 373-377
Author(s):  
Armands Leitans ◽  
Oskars Linins ◽  
Irina Boiko

This work is devoted to the elaboration of the new methodology for the wear parts contact estimation using 3D surface roughness parameters defined in the standard ISO 25178-2:2012 for friction and wear rate determination. In our research the random surface model was used, where the height of surface asperities h (x,y) has a normal probability distribution. As a result of research the equations for estimation of the elastic contact area and friction coefficient were derived. The existence of the correlation between friction coefficient and 3D surface roughness parameters was proven as well. The results of this work could have wide practical application, for example in design, for the texture specification on drawings, calculation of load, etc.


2007 ◽  
Vol 124-126 ◽  
pp. 1337-1340 ◽  
Author(s):  
Ju Young Kim ◽  
Jung Jun Lee ◽  
Yun Hee Lee ◽  
Jae Il Jang ◽  
Dong Il Kwon

Surface roughness is main source of error in instrumented microindentation when it is not negligible relative to the indentation depth. The effect of a rough surface on the results of instrumented microindentation testing using spherical indenter was analyzed by applying the contact depth model, which takes surface roughness into account. Improved variations in hardness and Young’s modulus were shown for W and Ni when the results were analyzed by this rough-surface model, while these values were underestimated with increasing surface roughness when analyzed by the flat-surface model. The deformation state of asperities underneath spherical indenter was also discussed.


Sign in / Sign up

Export Citation Format

Share Document