Development and applications of a new non-contact method for mapping of elastic anisotropy using air-coupled plate and surface waves

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The majority of current and newly developed materials (polymers, composites, ceramics, nano-structures, etc.) exhibit an evident elastic anisotropy which provides anomalous physical properties and a wide range of applications. Mapping of elastic anisotropy is a sensitive tool for testing material structure and strength, monitoring of product quality and its degradation caused by environmental factors or deviations in manufacturing process, progression of damage, etc. A flexible and reliable engineering technology capable of providing such measurements on-line in industrial environment is not available at present. The project represents an application-oriented fundamental research in the field of aircoupled ultrasound and elastic wave propagation in solids which is aimed at development of a new robust method for depth-resolved mapping and imaging of anisotropy of material stiffness using an efficient conversion of air-coupled ultrasound into plate and surface waves. The method enables automated measurements and imaging of in-plane stiffness anisotropy by remote monitoring of wave propagation characteristics in a wide angular range of directions. As a result of the project, a new engineering methodology is established and tested which is capable for on-line non-contact assessment of reinforcement directions in fibrous materials and multi-ply composites, local anisotropy induced by mechanical stresses, fatigue and damage.