Experimental Modal Analysis of an Additively Manufactured Model

Abstract

Additive manufacturing methods have advanced a lot in the past year. Methods like Fused Deposition Modeling (FDM) have gained popularity due to their versatility in material and minimal limitation on the geometry. Structural modeling of additively manufactured parts can, however, be complicated. This is primarily due to the dependence of material stiffness on print settings such as layer height, infill density, and infill pattern. In addition, the material can exhibit anisotropic characteristics due to parameters like the adhesiveness of layers, the orientation of the raft, and the layer deposition speed. This study conducts an experimental modal analysis on a 40% scaled model whose geometry is based on the aircraft Initial Concept 3.X (IC3X). The test article was manufactured using FDM, and ABS was chosen as the material. Fiber-optical strain sensors were attached to the test article and were used to record the response to structural excitation. Static tests were performed in addition to dynamic testing to further evaluate the test article’s stiffness. The static test cases were used to update a finite element model of the test article and to obtain precise values of the Young’s modulus, which is dependent on printer settings. The natural frequencies obtained from both the numerical model and dynamic testing showed good agreement.