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Experimental Study of Dynamic Frictional Sliding Modes along Incoherent Interfaces


Lykotrafitis, Georgios C. (2006) Experimental Study of Dynamic Frictional Sliding Modes along Incoherent Interfaces. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0CCJ-5S66.


Dynamic sliding along incoherent (frictional) interfaces is investigated experimentally in a microsecond time scale. A bimaterial system comprised of Homalite and steel plates and a homogeneous system consisting of two Homalite plates are considered. The plates are held together by a uniform compressive stress while dynamic sliding is initiated by an impact-induced shear loading. The evolution of maximum shear stress contours is recorded by high-speed photography in conjunction with dynamic photoelasticity. Simultaneously with photoelasticity, a newly-developed technique based on laser interferometry is employed to locally measure the sliding speed at the interface.

The response of the Homalite-steel bimaterial system differs according to whether the impact loading is applied to the Homalite plate or to the steel plate. In the first case, a disturbance traveling along the interface at a constant speed close to the Rayleigh wave speed of steel generates a shear Mach line crossing the P-wave front. Sliding initiates behind the P-wave front in the Homalite plate and it propagates at a supershear speed with respect to the shear wave speed of Homalite. A disturbance, traveling at constant speeds between the shear wave speed and the longitudinal wave speed of Homalite, appears behind the sliding tip. Wrinkle-like opening pulses, propagating along the bimaterial interface at a constant speed between the Rayleigh wave and the shear wave speed of Homalite, are also observed. When the impact loading is applied to the steel plate, sliding at a given point initiates with the arrival of the P-wave front there, so that the rupture is sonic with respect to steel and supersonic with respect to Homalite.

In all the experiments performed on the bimaterial structure (Homalite-steel), sliding always occurred in a crack-like mode. In the case of a homogeneous system of Homalite plates however, direct physical evidence of different modes of sliding is recorded. Crack-like sliding, pulse-like sliding and mixed mode sliding in the form of pulses followed by a crack are discovered. Supersonic trailing pulses are also recorded. Behind the sliding tip, wrinkle-like opening pulses are developed for a wide range of impact speeds and confining stresses.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:bimaterial structure; crack-like rupture; Dynamic frictional sliding; homogeneous system; incoherent interface; photoelasticity; pulse-like rupture; subshear wrinkle-like pulse; supershear rupture; velocimetry
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Awards:Charles D. Babcock Award, 2004.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Rosakis, Ares J.
Thesis Committee:
  • Rosakis, Ares J. (chair)
  • Ravichandran, Guruswami
  • Knowles, James K.
  • Tromp, Jeroen
  • Lapusta, Nadia
  • Huang, Yonggang
Defense Date:21 November 2005
Non-Caltech Author Email:gelyko (AT)
Record Number:CaltechETD:etd-01162006-005552
Persistent URL:
Lykotrafitis, Georgios C.0000-0003-2088-5478
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:196
Deposited By: Imported from ETD-db
Deposited On:24 Jan 2006
Last Modified:18 Dec 2020 18:53

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