Predictive modeling of space structures for SHM with PWAS transducers

This paper presents an investigation of predictive modeling of space structures for structural health monitoring (SHM) with piezoelectric wafer active sensors (PWAS) transducers. The development of a suitable SHM system for complex space structure is not trivial; creating a robust SHM capability requires at least: (a) flexible accommodation of numerous configurations; (b) detection of damage in complex multifunctional structures; (c) identification if mechanical interfaces are properly connected. To realize this, we propose a predictive modeling approach using both analytical tools and finite element method (FEM) to study the health status of the structure, the power and energy transduction between the structure and the PWAS. After a review of PWAS principles, the paper discusses the modeling and the power and energy transduction between structurally guided waves and PWAS. The use of guided wave (GW) and the capability of embedded PWAS to perform in situ nondestructive evaluation (NDE) are explored. FEM codes are used to simulate GW of 2D and 3D space structure using the commercials software ABAQUS. PWAS transducers placement at different location on a flat plate and on an isogrid panel was simulated. The signal scattered by a crack emerging from the hole is simulated. Predictive modeling of power and energy transduction is discussed using an analytical approach. This model of 2-D power and energy transduction of PWAS attached to structure allows examination of power and energy flow for a circular crested wave pattern. Wave propagation method for an infinite boundary plate, electromechanical energy transformation of PWAS and structure, and wave propagation energy spread out in 2-D plate are considered. The parametric study of PWAS size, impedance match gives the PWAS design guideline for PWAS sensing and power harvesting applications.