Irregular reflection of spark-generated shock pulses from a rigid surface: Mach-Zehnder interferometry measurements in air

2019 ◽  
Vol 145 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Maria M. Karzova ◽  
Thomas Lechat ◽  
Sébastien Ollivier ◽  
Didier Dragna ◽  
Petr V. Yuldashev ◽  
...  
Keyword(s):  
Rigid Surface ◽  
Irregular Reflection ◽  
Shock Pulses

The use of optical methods for measuring irregular reflection of weak acoustic shock pulses from a solid surface in air

2017 ◽  
Vol 141 (5) ◽  
pp. 3730-3730
Author(s):  
Maria M. Karzova ◽  
Petr V. Yuldashev ◽  
Didier Dragna ◽  
Sébastien Ollivier ◽  
Vera Khokhlova ◽  
...  
Keyword(s):  
Solid Surface ◽  
Optical Methods ◽  
Irregular Reflection ◽  
Shock Pulses

Irregular reflection of weak acoustic shock pulses on rigid boundaries

2016 ◽  
Vol 139 (4) ◽  
pp. 2207-2207
Author(s):  
Desjouy Cyril ◽  
Sébastien Ollivier ◽  
Olivier Marsden ◽  
Didier Dragna ◽  
Maria Karzova ◽  
...  
Keyword(s):  
Irregular Reflection ◽  
Shock Pulses

scholarly journals Irregular reflection of weak acoustic shock pulses on rigid boundaries : Schlieren experiments and direct numerical simulation based on a Navier-Stokes solver

2016 ◽  
Vol 28 (2) ◽  
pp. 027102 ◽  
Author(s):  
Cyril Desjouy ◽  
Sébastien Ollivier ◽  
Olivier Marsden ◽  
Maria Karzova ◽  
Philippe Blanc-Benon
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Navier Stokes ◽  
Simulation Based ◽  
Irregular Reflection ◽  
Shock Pulses

scholarly journals Shock Pulse Shaping in a Small-Form Factor Velocity Amplifier

2010 ◽  
Vol 17 (6) ◽  
pp. 787-802 ◽  
Author(s):  
Gerard Kelly ◽  
Jeff Punch ◽  
Suresh Goyal ◽  
Michael Sheehy
Keyword(s):  
Pulse Shaping ◽  
Vertical Axis ◽  
Mechanical Shock ◽  
Practical Applications ◽  
Shock Testing ◽  
Acceleration Signal ◽  
High Acceleration ◽  
Component Assembly ◽  
Small Form Factor ◽  
Shock Pulses

This theme of this paper is the design and characterisation of a velocity amplifier (VAMP) machine for high-acceleration shock testing of micro-scale devices. The VAMP applies multiple sequential impacts to amplify velocity through a system of three progressively smaller masses constrained to move in the vertical axis. Repeatable, controlled, mechanical shock pulses are created through the metal-on-metal impact between pulse shaping test rods, which form part of the penultimate and ultimate masses. The objectives are to investigate the controllable parameters that affect the shock pulses induced on collision, namely; striker and incident test rod material; test rod length; pulse shaping mechanisms; and impact velocity. The optimum VAMP configuration was established as a 60 mm long titanium striker test rod and a 120 mm long titanium incident rod. This configuration exhibited an acceleration magnitude and a primary pulse duration range of 5,800–23,400 g and 28.0–44.0μs respectively. It was illustrated that the acceleration spectral content can be manipulated through control of the test rod material and length. This is critical in the context of practical applications, where it is postulated that the acceleration signal can be controlled to effectively excite specific components in a multi-component assembly affixed to the VAMP incident test rod.

Analysis of the Real Area of Contact Between a Polymeric Magnetic Medium and a Rigid Surface

1984 ◽  
Vol 106 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Complex Modulus ◽  
Critical Value ◽  
Computer Applications ◽  
Hard Material ◽  
Rigid Surface ◽  
Magnetic Medium ◽  
The Real ◽  
Real Area Of Contact ◽  
The Mean ◽  
Real Area

The statistical analysis of the real area of contact proposed by Greenwood and Williamson is revisited. General and simplified equations for the mean asperity real area of contact, number of contacts, total real area of contact, and mean real pressure as a function of apparent pressure for the case of elastic junctions are presented. The critical value of the mean asperity pressure at which plastic flow starts when a polymer contacts a hard material is derived. Based on this, conditions of elastic and plastic junctions for polymers are defined by a “polymer” plasticity index, Ψp which depends on the complex modulus, Poisson’s ratio, yield strength, and surface topography. Calculations show that most dynamic contacts that occur in a computer-magnetic tape are elastic, and the predictions are supported by experimental evidence. Tape wear in computer applications is small and decreases Ψp by less than 10 percent. The theory presented here can also be applied to rigid and floppy disks.

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