Identification of material properties from full field measurements of a sound field interacting with a solid

Abstract

The identification of the mechanical material properties of orthotropic and porous materials is of primordial importance in many disciplines. In the medical field the identification of the porosity and stiffness of bone material can help in the diagnosis of bone growth and the early detection of anomalies. In structural engineering material identification is a tool to monitor the presence and the extent of damage. In the last decades ultrasound waves have been used with success for material identification purposes in these various disciplines. For orthotropic or porous materials the interactions of the ultrasound wave with the material should be measured at different angles of incidence. Since usually ultrasound transducers are used in combination with a mechanical traverse system, the measurement time can be quite high when a large number of angles of incidence are to be tested. In this article we present a method to estimate material properties from focused sound fields that contain several incidence angles simultaneously. Furthermore, in order to reduce the measurement time, the (ultra)sound fields are measured using a full field optical measurement technique.