Dependence of the Coefficient of Friction on the Sliding Conditions in the High Velocity Range

1999 ◽  
Vol 121 (1) ◽  
pp. 35-41 ◽  
Author(s):  
A. Molinari ◽  
Y. Estrin ◽  
S. Mercier
Keyword(s):  
Coefficient Of Friction ◽  
High Velocity ◽  
Numerical Solutions ◽  
Constitutive Relations ◽  
Shear Banding ◽  
Normal Pressure ◽  
Adiabatic Shear ◽  
Velocity Range ◽  
Adiabatic Shear Banding ◽  
The Coefficient Of Friction

The velocity, normal pressure, and slider size dependence of the coefficient of dry friction of metals in the range of high sliding velocities (V ≥ 1 m/s) is investigated theoretically. Failure of the adhesive junctions by adiabatic shear banding is considered as the underlying process. The concept of asperity shearing by the adiabatic shear banding mechanism represents a new approach to unlubricated high velocity friction. Analytical solutions of a coupled thermomechanical problem are given for two constitutive relations. Numerical solutions for steel-on-steel friction showing a decrease of the coefficient of friction with the sliding velocity for different normal pressures are presented. The model is considered to be adequate in the velocity range of 1–10 m/s where friction enhanced oxidation or surface melting are believed not to interfere with the asperity shearing process.

Investigation on Micro-Structure Evolution of Mg-12Gd-3Y-0.5Zr Magnesium Alloy under High Velocity Impact

2014 ◽  
Vol 997 ◽  
pp. 325-331
Author(s):  
Xiao Ming Yang
Keyword(s):  
Magnesium Alloy ◽  
High Velocity ◽  
Shear Bands ◽  
Initial Strain Rate ◽  
Adiabatic Shear ◽  
Structure Evolution ◽  
High Velocity Impact ◽  
Adiabatic Shear Bands ◽  
Micro Structure ◽  
Velocity Impact

Cubic-shaped specimens and hat-shaped specimens were used to investigate ASBs formed in Mg-12Gd-3Y-0.5Zr magnesium alloy under different initial strain rate impact. It shows that no adiabatic shear bands (ASBs) is observed in micro-structure of cubic-shaped specimens by scanning electron microscope (SEM) , but obvious ASBs can be observed in hat-shaped specimens. Johnson-Cook model based on thermoviscoplasticity constitutive relation was used to simulate internal stress distribution and fracture mode, and it indicated that the result of failure analysis from specimens under high velocity impact tests was the same as that obtained by computer simulation.

Effect of strain rate, off-axis loading and high-velocity impact damage on the compressive strength of C/SiC composite

2018 ◽  
Vol 53 (4) ◽  
pp. 535-546 ◽  
Author(s):  
M Altaf ◽  
S Singh ◽  
VV Bhanu Prasad ◽  
Manish Patel
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
High Velocity ◽  
Impact Damage ◽  
The Other ◽  
High Velocity Impact ◽  
Fibre Bundles ◽  
Velocity Impact ◽  
Kink Bands ◽  
Other Hand

The compressive strength of C/SiC composite at different strain rates, off-axis orientations and after high-velocity impact was studied. The compressive strength was found to be 137 ± 23, 130 ± 46 and 162 ± 33 MPa at a strain rate of 3.3 × 10−5, 3.3 × 10−3, 3.3 × 10−3 s−1, respectively. On the other hand, the compressive strength was found to be 130 ± 46, 99 ± 23 and 87 ± 9 MPa for 0°/90°, 30°/60° and 45°/45° fibre orientations to loading direction, respectively. After high-velocity impact, the residual compressive strength of C/SiC composite was found to be 58 ± 26, 44 ± 18 and 36 ± 3.5 MPa after impact with 100, 150 and 190 m/s, respectively. The formation of kink bands in fibre bundles was found to be dominant micro-mechanism for compressive failure of C/SiC composite for 0°/90° orientation. On the other hand, delamination and the fibre bundles rotation were found to be the dominant mechanism for off-axis failure of composite.

scholarly journals Analysis of High Velocity Impact on Hybrid Composite Fan Blades

1980 ◽  
Vol 17 (10) ◽  
pp. 763-766 ◽  
Author(s):  
C. C. Chamis ◽  
J. H. Sinclair
Keyword(s):  
Hybrid Composite ◽  
High Velocity ◽  
High Velocity Impact ◽  
Velocity Impact

Apparatus for investigating the effects of high-velocity impact on polymers

1972 ◽  
Vol 5 (5) ◽  
pp. 812-813
Author(s):  
V. V. Kovriga ◽  
V. N. Chalidze
Keyword(s):  
High Velocity ◽  
High Velocity Impact ◽  
Velocity Impact

Shape optimization of bumper beams under high-velocity impact loads

2015 ◽  
Vol 95 ◽  
pp. 49-60 ◽  
Author(s):  
Niyazi Tanlak ◽  
Fazil O. Sonmez ◽  
Mahmut Senaltun
Keyword(s):  
Shape Optimization ◽  
High Velocity ◽  
Impact Loads ◽  
High Velocity Impact ◽  
Velocity Impact

Crack Propagation and Local Failure Simulation of Reinforced Concrete Subjected to Projectile Impact Using RBSM

2016 ◽  
Author(s):  
Yoshihito Yamamoto ◽  
Soichiro Okazaki ◽  
Hikaru Nakamura ◽  
Masuhiro Beppu ◽  
Taiki Shibata
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
High Velocity ◽  
Failure Modes ◽  
Concrete Structures ◽  
Constitutive Models ◽  
Local Failure ◽  
High Velocity Impact ◽  
Velocity Impact ◽  
Projectile Impact

In this paper, numerical simulations of reinforced mortar beams subjected to projectile impact are conducted by using the proposed 3-D Rigid-Body-Spring Model (RBSM) in order to investigate mechanisms of crack propagation and scabbing mode of concrete members under high-velocity impact. The RBSM is one of the discrete-type numerical methods, which represents a continuum material as an assemblage of rigid particle interconnected by springs. The RBSM have advantages in modeling localized and oriented phenomena, such as cracking, its propagation, frictional slip and so on, in concrete structures. The authors have already developed constitutive models for the 3D RBSM with random geometry generated Voronoi diagram in order to quantitatively evaluate the mechanical responses of concrete including softening and localization fractures, and have shown that the model can simulate cracking and various failure modes of reinforced concrete structures. In the target tests, projectile velocity is set 200m/s. The reinforced mortar beams with or without the shear reinforcing steel plates were used to investigate the effects of shear reinforcement on the crack propagation and the local failure modes. By comparing the numerical results with the test results, it is confirmed that the proposed model can reproduce well the crack propagation and the local failure behaviors. In addition, effects of the reinforcing plates on the stress wave and the crack propagation behaviors are discussed from the observation of the numerical simulation results. As a result, it was found that scabbing of reinforced mortar beams subjected to high velocity impact which is in the range of the tests is caused by mainly shear deformation of a beam.

The failed strength of ceramics subjected to high-velocity impact

2008 ◽  
Vol 104 (1) ◽  
pp. 013533 ◽  
Author(s):  
Timothy J. Holmquist ◽  
Gordon R. Johnson
Keyword(s):  
High Velocity ◽  
High Velocity Impact ◽  
Velocity Impact
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