A Granular Dynamic Model for the Degradation of Material

2004 ◽  
Vol 126 (3) ◽  
pp. 606-614 ◽  
Author(s):  
N. Fillot ◽  
I. Iordanoff ◽  
Y. Berthier
Keyword(s):  
Dynamic Model ◽  
Normal Pressure ◽  
Two Dimensional ◽  
Third Body ◽  
Stable Layer ◽  
Sliding Speed ◽  
Particle Detachment ◽  
Physicochemical Interactions

The work presented here is a model of the degradation of a material (by particle detachment), based on a two dimensional granular dynamic model designed to study the flows of third body particles inside a contact. As the detached particles (third body) cannot exit the contact, the detachments stop after a certain time and a stable layer of third body can be seen. It is shown that the thickness of this stable layer depends both on the conditions applied (normal pressure and sliding speed) and the physicochemical interactions between the detached particles. Such investigations provide better understanding of the mechanism leading to the degradation of material.

A biomechanical analysis of switch stand operation using a two-dimensional dynamic model

1991 ◽  
Vol 24 (3-4) ◽  
pp. 257
Author(s):  
Maury Nussbaum ◽  
Don B. Chaffin ◽  
George Page ◽  
James Foulke ◽  
Charles Woolley
Keyword(s):  
Dynamic Model ◽  
Biomechanical Analysis ◽  
Two Dimensional

Two-dimensional dynamic model of a copper sulphide ore bed

2003 ◽  
Vol 71 (1-2) ◽  
pp. 67-74 ◽  
Author(s):  
M Sidborn ◽  
J Casas ◽  
J Martı́nez ◽  
L Moreno
Keyword(s):  
Dynamic Model ◽  
Copper Sulphide ◽  
Two Dimensional ◽  
Sulphide Ore

scholarly journals Development of a two-dimensional dynamic model of the foot-ankle system exposed to vibration

2020 ◽  
Vol 99 ◽  
pp. 109547 ◽  
Author(s):  
D. Chadefaux ◽  
K. Goggins ◽  
C. Cazzaniga ◽  
P. Marzaroli ◽  
S. Marelli ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Two Dimensional

Modeling and Grasp Stability Analysis for Object Manipulation by Soft Rolling Fingertips

2014 ◽  
Vol 11 (03) ◽  
pp. 1450020 ◽  
Author(s):  
John Fasoulas ◽  
Michael Sfakiotakis
Keyword(s):  
Stability Analysis ◽  
Dynamic Model ◽  
Object Manipulation ◽  
Kinematics And Dynamics ◽  
Control Law ◽  
Two Dimensional ◽  
Orientation Control ◽  
Grasp Stability ◽  
Different Types ◽  
General Dynamic

This paper presents a general dynamic model that describes the two-dimensional grasp by two robotic fingers with soft fingertips. We derive the system's kinematics and dynamics by incorporating rolling constraints that depend on the deformation and on the rolling distance characteristics of the fingertips' material. We analyze the grasp stability at equilibrium, and conclude that the rolling properties of the fingertips can play an important role in grasp stability, especially when the width of the grasped object is small compared to the radius of the tips. Subsequently, a controller, which is based on the fingertips' rolling properties, is proposed for stable grasping concurrent with object orientation control. We evaluate the dynamic model under the proposed control law by simulations and experiments that make use of two different types of soft fingertip materials, through which it is confirmed that the dynamic model can successfully capture the effect of the fingertips' deformation and their rolling distance characteristics. Finally, we use the dynamic model to demonstrate by simulations the significance of the fingertips' rolling properties in grasping thin objects.

Ti3AlC2 — A Soft Ceramic Exhibiting Low Friction Coefficient

2005 ◽  
Vol 475-479 ◽  
pp. 1251-1254 ◽  
Author(s):  
Hong Xiang Zhai ◽  
Zhen Ying Huang ◽  
Yang Zhou ◽  
Zhi Li Zhang ◽  
Shi Bo Li ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction Surface ◽  
High Speed ◽  
Low Carbon Steel ◽  
Normal Pressure ◽  
Aluminum Carbide ◽  
Low Carbon ◽  
Friction Behavior ◽  
Sliding Speed ◽  
Al And Fe Oxides

The friction behavior of a high-purity bulk titanium aluminum carbide (Ti3AlC2) material dryly sliding against low carbon steel was investigated. Tests were performed using a block-on-disk type high-speed friction tester under sliding speed of 20 m/s and 60 m/s, several normal pressures from 0.1 to 0.8 MPa. The results showed that the friction coefficient is as low as about 0.18 for sliding speed of 20 m/s and only 0.1 for 60 m/s, and that almost not changes with the normal pressure. The reason could be related with the presence of a surface layer on the friction surface. The layer was analyzed to consist of Ti, Al and Fe oxides, which played a lubricate part inducing the friction coefficient decrease on the friction surface.

Widening Classical Wear Laws to the Concept of Third Body

2005 ◽  
Author(s):  
N. Fillot ◽  
I. Iordanoff ◽  
Y. Berthier
Keyword(s):  
Twentieth Century ◽  
Wear Rate ◽  
Applied Pressure ◽  
Third Body ◽  
Sliding Speed ◽  
Wear Law

During the second part of the twentieth century, many efforts have been done to model wear. Particularly, Archard proposes in 1953 [1] one of the first wear law, which is often written on the following form: dW/dt=K.P.V(1) with dW/dt the mass of detached particles from the rubbing materials per unit time, P the applied pressure, V the sliding speed and K the “wear rate”.

Numerical Simulations of the Formation of Melting-Layer Cloud

2008 ◽  
Vol 136 (1) ◽  
pp. 223-241 ◽  
Author(s):  
Kazuaki Yasunaga ◽  
Akihiro Hashimoto ◽  
Masanori Yoshizaki
Keyword(s):  
Numerical Simulations ◽  
Temperature Profile ◽  
Initial Temperature ◽  
Critical Role ◽  
Middle Level ◽  
Squall Line ◽  
Two Dimensional ◽  
Stable Layer ◽  
Cloud Coverage ◽  
Thin Cloud

Abstract A number of previously published observational studies have reported the common occurrence of cloudy layers at around 5-km elevation in the tropics. There are two candidate processes that are able to explain the occurrence of cloudy layers in the middle level: cloud detrainment promoted by the stable layer and enhanced condensation to compensate for melting cooling. In the present study, the authors used a cloud-resolving nonhydrostatic model and conducted numerical simulations of a squall line to clarify the process responsible for the formation of midlevel thin cloud, especially the cloud at the 0°C level. In a two-dimensional control experiment thin cloud was simulated in the middle level, and cloud coverage showed a notable peak just below the 0°C level for environments without a stable layer in the initial temperature profile. Enhanced and weakened stability layers simultaneously appeared above and below the peak level of the cloud coverage. The formation of midlevel thin cloud is associated with intensified condensation to compensate for strong cooling due to the melting of ice particles. The enhancement of condensation continues until ice is no longer provided to the cloud at the melting level. This means that the cloud survives for a longer period than cloud at other levels. To investigate the influence of the commonly observed tropical stable layer on the occurrence of midlevel thin cloud, the authors performed three sensitivity tests in which a warm rain microphysics scheme was employed and/or the initial temperature profile had enhanced and weakened stability layers in the middle level. Comparisons among the control and sensitivity experiments revealed that intensified condensation related to melting cooling plays a critical role in the formation of midlevel thin cloud, although the stable layer is associated with the inhibition of convection growth in the middle level. A three-dimensional experiment under more realistic conditions simulated cloud formation at the 0°C level, although the peak of the cloud coverage was less prominent than those in the two-dimensional experiments.

Two-dimensional gas-dynamic model of laser ablation in an ambient gas

2000 ◽  
Vol 154-155 ◽  
pp. 66-72 ◽  
Author(s):  
A.V. Gusarov ◽  
A.G. Gnedovets ◽  
I. Smurov
Keyword(s):  
Laser Ablation ◽  
Dynamic Model ◽  
Two Dimensional ◽  
Gas Dynamic ◽  
Ambient Gas

Wear Characteristics of Bulk Ti3AlC2 under Current-Carrying Conditions

2007 ◽  
Vol 561-565 ◽  
pp. 563-566
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Hua Zhang ◽  
Hong Bing Zhang
Keyword(s):  
Wear Rate ◽  
Low Carbon Steel ◽  
Normal Pressure ◽  
Mechanical Effect ◽  
Low Carbon ◽  
Wear Properties ◽  
Sliding Speed ◽  
Wear Characteristics ◽  
Friction Tester ◽  
Iron Titanate

The current-carrying wear characteristics of Ti3AlC2 sliding against low-carbon steel were investigated. Tests were carried out using a block-on-disk type friction tester, with sliding speeds of 20~60 m/s, normal pressures range in 0.4~ 0.8 MPa, and the current intensity of 0 A, 50 A and 100 A. The Ti3AlC2 showed good current-carrying wear properties. At the sliding speed of 20 m/s, the wear rate of the Ti3AlC2 (× 10-6 mm3/Nm) was varied in the range of (2.05 ~ 2.41), (2.64 ~ 2.39) and (6.26 ~ 3.62), under the current of 0 A, 50 A and 100 A, respectively. Both the surfaces of Ti3AlC2 and the steel were covered by a frictional film, which was consisted of iron titanate (Fe2.25Ti0.75O4) and aluminum iron oxide (AlFeO3). The wear rate of Ti3AlC2 with current was composed of two parts: the interaction of micro-arc ablation and mechanical friction, and the coupled action of thermal and mechanical effect. Which one will be the main mechanism depends on the material parameters of Ti3AlC2 and the mechanical parameters such as the normal pressure or the sliding speed.

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