Assessment of adhesive bond strength from ultrasonic tone-bursts.

A model for the amplitude and phase of ultrasonic tone-bursts incident on adherend-adhesive interfaces is developed for both reflected and transmitted waves. The model parameters include the interfacial stiffness constants, which characterize the elastic properties of idealized adherend-adhesive interfaces having a continuum of bonds. The ultrasonic model is linked to the more realistic physico-chemical model of adhesive bonding via a scaling equation that establishes the relationship between the interfacial stiffness constants of the ultrasonic model and the fraction of actual bonds in the physico-chemical model.

Subharmonic generation, chaos, and subharmonic resurrection in an acoustically driven fluid-filled cavity.

Traveling wave solutions of the nonlinear acoustic wave equation are obtained for the fundamental and second harmonic resonances of a fluid-filled cavity. The solutions lead to the development of a non-autonomous toy model for cavity oscillations. Application of the Melnikov method to the model equation predicts homoclinic bifurcation of the Smale horseshoe type leading to a cascade of period doublings with increasing drive displacement amplitude culminating in chaos.

Elastic constants of solids and fluids with initial pressure via a unified approach based on equations-of-state.

The second and third-order Brugger elastic constants are obtained for liquids and ideal gases having an initial hydrostatic pressure p1. For liquids the second-order elastic constants are C₁₁=A+p₁, C₁₂=A-p₁, and the third-order constants are C₁₁₁=-(B+5A+3p₁), C₁₁₂=-(B+A-p₁), and C₁₂₃=A-B-p₁, where A and B are the Beyer expansion coefficients in the liquid equation of state. For ideal gases the second-order constants are C₁₁=p₁γ+p₁, C₁₂=p₁γ-p₁, and the third-order constants are C₁₁₁=-p₁(γ(2)+4γ+3), C₁₁₂=-p₁(γ(2)-1), and C₁₂₃=-p₁ (γ(2)-2γ+1), where γ is the ratio of specific heats.

Envelope solitons in acoustically dispersive vitreous silica.

Acoustic radiation-induced static strains, displacements, and stresses are manifested as rectified or 'dc' waveforms linked to the energy density of an acoustic wave or vibrational mode via the mode nonlinearity parameter of the material. An analytical model is developed for acoustically dispersive media that predicts the evolution of the energy density of an initial waveform into a series of energy solitons that generates a corresponding series of radiation-induced static strains (envelope solitons). The evolutionary characteristics of the envelope solitons are confirmed experimentally in Suprasil W1 vitreous silica.