Search results for " internal friction."

showing 2 items of 2 documents

A frictional interface model for the propagation of cohesive fracture under cyclic loading

2013

The paper presents an extension of a recent presented mechanical interface model, [1-2], for the description of the smooth cohesive/frictional transition along potentially active cohesive fracture surfaces. The model presented includes the description of internal frictional dissipative mechanisms which are active under combined compressive/sliding loading in either the cohesive process zone, or in the fully fractured interface portion. Moreover, always under compressive/sliding loading conditions, frictional dissipation mechanisms can also develop in the undamaged (or sound) portion of the interface, justified by the circumstance that also at the virgin state in the bonding surface are pres…

Interface cohesive fracture internal friction.
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Non-Linear Hysteretic Instability in Rotating Machinery

2013

The destabilizing influence of the shaft hysteresis on the supercritical whirl of rotating machines can be efficiently counterbalanced by proper external dissipative sources in the supports and/or anisotropic suspension systems. The hysteretic effect may be treated either by dry or viscous models obtaining different but somehow similar results in the hypothesis of small dissipation levels. Thus the linear viscous assumption is often accepted as a crude approximation for a straightforward analysis of the whirling instability. Nevertheless the internal friction should be regarded most likely as non-linear and could be approximated for example by Coulombian models taking thus into account also the releasing effect of some shrink-fit coupling present in the mechanical assembly.
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