Identification of the mechanical moduli of flexible thermoplastic thin films using reflected ultrasonic waves: Inverse problem

Abstract

A method for the identification of the mechanical moduli and density of flexible, supple thermoplastic thin films placed on elastic substrates using ultrasonic waves has been developed. The composite medium immersed in a fluid host medium (water) was excited using a 50MHz transducer operating at normal incidence in reflection mode. Inverse problems involving experimental data pertaining to elastic wave propagation in the thin films on their substrates and theoretical fluid-solid interaction models for stratified media using elasticity theory were solved. Two configurations having different interface boundary conditions (BC) were modeled, transverse slip for the sliding contact interface in the case where the thin films were placed on the substrate without bonding; a bonded interface condition. The inverse problem for the recovery of the mechanical parameters were solved for the thin films under the bonded and slip BCs. Substrates made of different elastic materials having different geometries were also evaluated and their advantages discussed.

Scanning Acoustic Microscopy of Annealing Effects for Aluminium Thin Film Deposited on Silicon Substrate

“…The last generate conical wave fronts that have a single angle of incidence on the specimen [10]. The description, on the other hand, of the mathematical procedure for acoustical lens design is available in the literature [11][12][13][14][15].…”

Simultaneous Measurement of Thickness and Elastic Properties of Thin Plastic Films by Means of Ultrasonic Guided Waves

“…Measurement of elastic properties of thin films by high frequency ultrasonic waves was analyzed by a few authors [ 3 , 4 ]. For example, measurement of elastic properties and density of thermoplastic thin polymer films such as polyethylene terephthalate, polycaprolactone triol, and polyvinyl butyral was discussed in [ 3 ]. The samples of thin films samples were placed on a solid substrate and immersed in water.…”