Implementation of the surface thickness on additively manufactured parts for estimation of the loading location

Additive manufacturing (AM) technology has been used for the creation of complex parts in different industries. The addition of defect detection and load sensing capabilities to these products can highly increase their values. The application of structural health monitoring (SHM) methods on AM parts is proposed in this paper by implementing the internal design capabilities of the AM parts. First, the influence of the internal top surface layers on the surface wave propagation characteristics was studied. A round part with different top skin thicknesses in each quarter (10, 20, 30, and 40 layers) was designed and fabricated of polylactic acid (PLA). The height of each layer was 0.1 mm and different spectral characteristics were observed in each quarter. Then, the location of an external compression loading was estimated with the help of different skin thicknesses on a plate designed with five zones. Although estimation of the defect or loading on the structure has always been a challenge in SHM studies, the use of hidden geometries helps to effectively overcome this challenge. Surface response to excitation method was used in this study to estimate the loading location by using two piezoelectric elements. A simple algorithm was used to estimate the loading zones in all the test cases.