A note on the Hertz contact model with nonlinear damping for pounding simulation

2009 ◽  
Vol 38 (9) ◽  
pp. 1135-1142 ◽  
Author(s):  
Kun Ye ◽  
Li Li ◽  
Hongping Zhu
Keyword(s):  
Nonlinear Damping ◽  
Contact Model ◽  
Hertz Contact ◽  
Hertz Contact Model

Modified Analytical Expression of Damping Constant in the Hertz Contact Model with Non-Linear Damping for Structural Pounding

2010 ◽  
Vol 29-32 ◽  
pp. 220-225 ◽  
Author(s):  
Kun Ye ◽  
Rong Fu ◽  
Sha Qi Ma
Keyword(s):  
Impact Force ◽  
Analytical Formula ◽  
Nonlinear Damping ◽  
Coefficient Of Restitution ◽  
Contact Model ◽  
Spring Stiffness ◽  
Hertz Contact ◽  
Structural Pounding ◽  
Linear Damping ◽  
Hertz Contact Model

Structural pounding under earthquakes has been recently extensively investigated by using different models of impact force. In this paper, reexamination into the Hertz contact model with nonlinear damping is made. Based upon this reexamination, the formula used to determine the damping constant in terms of the spring stiffness, the coefficient of restitution and relative approaching velocity of two colliding bodies is found to be wrong. In order to correct this error, a more accurate approximating formula for the damping constant is theoretically derived. The correctness of the derived analytical formula has been confirmed through numerical simulations.

Dynamic Interaction of Vehicle and Discontinuous Slab Track Considering Nonlinear Hertz Contact Model

2016 ◽  
Vol 142 (4) ◽  
pp. 04016011 ◽  
Author(s):  
Javad Sadeghi ◽  
Amin Khajehdezfuly ◽  
Morteza Esmaeili ◽  
Davood Poorveis
Keyword(s):  
Dynamic Interaction ◽  
Contact Model ◽  
Hertz Contact ◽  
Slab Track ◽  
Hertz Contact Model

scholarly journals A cell-based mechanical model of coronary artery tunica media

2017 ◽  
Vol 14 (132) ◽  
pp. 20170028 ◽  
Author(s):  
N. B. Melnikova ◽  
A. I. Svitenkov ◽  
D. R. Hose ◽  
A. G. Hoekstra
Keyword(s):  
Coronary Artery ◽  
Mechanical Model ◽  
Adhesive Contact ◽  
Contact Model ◽  
Chain Model ◽  
Hertz Contact ◽  
Wormlike Chain ◽  
Tunica Media ◽  
Hertz Contact Model

A three-dimensional cell-based mechanical model of coronary artery tunica media is proposed. The model is composed of spherical cells forming a hexagonal close-packed lattice. Tissue anisotropy is taken into account by varying interaction forces with the direction of intercellular connection. Several cell-centre interaction potentials for repulsion and attraction are considered, including the Hertz contact model and its neo-Hookean extension, the Johnson–Kendall–Roberts model of adhesive contact, and a wormlike chain model. The model is validated against data from in vitro uni-axial tension tests performed on dissected strips of tunica media. The wormlike chain potential in combination with the neo-Hookean Hertz contact model produces stress–stretch curves which represent the experimental data very well.

ANALYSIS OF HIGH-SPEED RAIL ACCOUNTING FOR JUMPING WHEEL PHENOMENON

2014 ◽  
Vol 11 (03) ◽  
pp. 1343007 ◽  
Author(s):  
KOK KENG ANG ◽  
JIAN DAI ◽  
MINH THI TRAN ◽  
VAN HAI LUONG
Keyword(s):  
High Speed ◽  
Computational Study ◽  
Dynamic Responses ◽  
Contact Model ◽  
High Speed Train ◽  
Train Track ◽  
Hertz Contact ◽  
High Speed Rail ◽  
Track System ◽  
Hertz Contact Model

In this paper, a computational study using the moving element method (MEM) was carried out to investigate the dynamic response of a high-speed train–track system. Results obtained using Hertz contact model and linearized Hertz contact model are compared and discussed. The dynamic responses of a train travelling across a uniform foundation and a transition region are also investigated. Parametric study is performed to understand the effect of various factors on the occurrence and patterns of the jumping wheel phenomenon such as the variation of foundation stiffness, travelling speed of the train and the severity of railhead roughness.

scholarly journals Axisymmetric Contact Problem for a Flattened Cell: Contributions of Substrate Effect and Cell Thickness to the Determination of Viscoelastic Properties by Using AFM Indentation

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Xinyao Zhu ◽  
Lanjiao Liu ◽  
Zuobin Wang ◽  
X. Liu
Keyword(s):  
Mechanical Properties ◽  
Linear Elasticity ◽  
Viscoelastic Properties ◽  
Present Model ◽  
Finite Thickness ◽  
Contact Model ◽  
Substrate Effect ◽  
Biological Cells ◽  
Hertz Contact ◽  
Hertz Contact Model

Nanoindentation technology has proven to be an effective method to investigate the viscoelastic properties of biological cells. The experimental data obtained by nanoindentation are frequently interpreted by Hertz contact model. However, in order to validate Hertz contact model, some studies assume that cells have infinite thickness which does not necessarily represent the real situation. In this study, a rigorous contact model based upon linear elasticity is developed for the interpretation of indentation tests of flattened cells. The cell, normally bonded to the Petri dish, is initially treated as an elastic layer of finite thickness perfectly fixed to a rigid substrate. The theory of linear elasticity is utilized to solve this contact issue and then the solutions are extended to viscoelastic situation which is regarded as a good indicator for mechanical properties of biological cells. To test the present model, AFM-based creep test has been conducted on living human hepatocellular carcinoma cell (SMMC-7721 cell) and its fullerenol-treated counterpart. The results indicate that the present model could not only describe very well the creep behavior of SMMC-7721 cells, but also curb overestimation of the mechanical properties due to substrate effect.

Parameter design methodologies for vertical skewed line gears taking lubrication performance into account

2019 ◽  
Vol 233 (10) ◽  
pp. 1496-1507
Author(s):  
Yangzhi Chen ◽  
Anshi Zhu ◽  
Yueling Lyu
Keyword(s):  
Simulation Experiment ◽  
Design Method ◽  
Elastohydrodynamic Lubrication ◽  
Contact Model ◽  
Parameter Design ◽  
Design Parameters ◽  
Hertz Contact ◽  
Design Methodologies ◽  
Lubrication Performance ◽  
Hertz Contact Model

Based on the elastohydrodynamic lubrication (EHL) theory, design methodologies are proposed aiming to improve the EHL state of the vertical skewed line gear (VSLG) in this article. First of all, the parametric equations of the driving and driven VSLG surfaces are established and then converted into equivalent Hertz contact model. Then, the influences of the design parameters of the VSLG on the ellipticity are analyzed by its equivalent Hertz contact model. Finally, the parameter design method for improving the EHL state of VSLG is deduced. The results of optical elastohydrodynamic experiment and simulation experiment indicate that the parameter design method is effective for the formation of EHL film without changing the kinematic characteristics of VSLG. In short, this paper provides reliable and convenient parameter design methods for VSLG in consideration of EHL.

Elastic Contact and Friction Between Sliders and Circumferentially Textured Disks—Part III: Experiments

1998 ◽  
Vol 120 (4) ◽  
pp. 800-807 ◽  
Author(s):  
K. Tanaka ◽  
J. Ishikawa ◽  
A. Shimamoto
Keyword(s):  
Elastic Contact ◽  
High Humidity ◽  
Two Dimensional ◽  
Hertz Contact ◽  
Real Contact ◽  
Flat Edge ◽  
Contact Situation ◽  
Frictional Coefficients ◽  
Hertz Contact Model ◽  
Flat Contact

This three part paper presents the experiment and numerical analysis of the friction of a thin-film rigid disk with circumferential surface texture. In Part III, we examine the friction of a disk on the unworn virgin and worn tracks at various relative humidities. The real contact areas and pressures on both tracks are estimated using the Hertz contact model of two-dimensional asperities in Part I and related to the frictional coefficients on the basis of the meniscus model in Part II. The analysis yields that the effect of meniscus is predominant in the flat contact situation, particularly on the worn track at high humidity, while the effect is negligible in the taper/flat edge contact situation on both the tracks even at high humidity.

Contact Model of Double Circular Arc Gear Based on Fractal Theory

2010 ◽  
Vol 43 ◽  
pp. 414-419
Author(s):  
Kang Huang ◽  
Song Bo Han ◽  
Rong De Yang ◽  
Shun Xu
Keyword(s):  
Fractal Theory ◽  
Strength Calculation ◽  
Contact Model ◽  
Contact Theory ◽  
Contact Strength ◽  
Hertz Contact ◽  
Circular Arc ◽  
Hertz Contact Theory

Aiming at the problem that it is difficult to solve contact strength calculation of double circular arc gear with the method of traditional the Hertz contact theory and FEM, methods of fractal theory had been used to establish the contact model of double arc gear based on fractal theory, and an example of calculation was given away. This article results that it is feasible to calculate contact strength with fractal theory in the driving of concave convex meshing gear and this contact model of double circular arc gear based on fractal theory would provide a new way of the research of contact strength calculation of double circular arc gear.

scholarly journals Experimental and Theoretical Study of Binary Droplet Head-On Collisions in MEMS

2008 ◽  
Author(s):  
Ya-Pu Zhao ◽  
F. C. Wang ◽  
J. T. Feng
Keyword(s):  
Contact Time ◽  
High Speed ◽  
Theoretical Study ◽  
Experimental Result ◽  
Pdms Substrate ◽  
Hertz Contact ◽  
Elastic Bodies ◽  
Theoretical Investigations ◽  
Hertz Contact Model ◽  
Good Agreement

The experimental and theoretical investigations into the head-on collision between a landing droplet with another one resting on the PDMS substrate were addressed in this talk. The colliding process of the two droplets was recorded with high-speed camera. Four different responses after collision were observed in our experiments: complete rebound, coalescence, partial rebound with conglutination, and coalescence accompanied by conglutination. The contact time between the two colliding droplets was found to be in the range of 10–20 milliseconds. For the complete bouncing case, Hertz contact model was applied to estimate the contact time of the binary head-on colliding droplets with both the droplets considered as elastic bodies. The estimated contact time was in good agreement with the experimental result.

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