Session: 01-05-01: Congress-Wide Symposium on NDE & SHM: Computational Nondestructive Evaluation and Structural Health Monitoring

Paper Number: 147424

147424 - Multi-Directional Mechanical Property Characterization of Additively Manufactured Metal Utilizing Wavefield Analysis 

The evolution of additive manufacturing (also known as 3D printing) has catalyzed a transformative shift in the production of metal-based components, heralding a new era of efficiency and precision in the creation of high-strength metallic structures. This progress underscores a movement towards materials and methods that excel in performance, durability, and design flexibility, thereby streamlining the complexities inherent in traditional manufacturing paradigms. The emergence of such techniques has underscored the critical importance of accurately assessing the mechanical properties of additively manufactured metals to meet rigorous industry standards. However, conventional testing methodologies often fall short of providing precise characterizations of additively manufactured metals. The root of this discrepancy lies in the unique challenges presented by layer-wise manufacturing, including inconsistencies in microstructure, the presence of porosity, and variations in material properties due to thermal gradients and cooling rates during the manufacturing process. Moreover, there is a risk of compromising the integrity of the material during the testing phase, further complicating the assessment of these advanced metallic composites.

This paper presents an innovative approach that combines nondestructive ultrasound wave sensing and optimization algorithm enhanced frequency-wavenumber analysis for characterizing multi-directional mechanical properties of 3d printed metal panels. To develop this method, we established a Lamb wave sensing system, which utilized a piezoelectric actuator (PZT actuator) to generate Lamb waves in the metal panel. A laser Doppler vibrometer (LDV) integrated into a 3D robotic stage acquired Lamb waves in a non-contact manner. By automatically moving the laser focus point and collecting Lamb wave signals through 2D grid scanning, our system was able to acquire multiple time-space wavefields. The anisotropic behavior of the 3d printed structure means the scanned time-space wavefield contains a wealth of information about Lamb waves propagating in all directions and layers. To analyze the acquired wavefield and determine the material properties in different directions or layers, we established a novel inverse method combining multi-directional frequency-wavenumber analysis and a fast dispersion curve regression method based on an optimization algorithm. After applying our curve regression method to the experimental dispersion curves, the material's mechanical properties in each direction were obtained. For proof of concept, we conducted an experiment to measure the mechanical properties of a 180mm x 150mm x 5mm 3D-printed steel panel. From the experiment result, we demonstrated that our system could successfully generate Lamb waves in a testing plate using a PZT actuator with a wideband (100kHz – 1MHz) chirp excitation signal modulated by a Hanning window. Meanwhile, the LDV, integrated with the 3D robotic stage, could acquire time-space wavefields of Lamb waves in our testing sample. Furthermore, our wavefield analysis method successfully determined multi-directional material properties (e.g., Poisson ratio and shear wave velocity). This experimental study proves the feasibility of our Lamb wave sensing system for characterizing the mechanical properties of additive-manufactured metal panels. We anticipate this study will advance nondestructive and streamlined techniques for evaluating a variety of AM metals and tracking their properties transformations throughout the additive manufacturing process.
 

Presenting Author: Bowen Cai Mississippi State University

Presenting Author Biography: Bowen Cai is a Ph.D. Candidate in Aerospace Engineering at Mississippi State University studying under Dr. Rani Sullivan and Dr. Zhenhua Tian. He is also a research assistant who works for the Advanced Composite Institute of MSU. His main research direction is acoustic nondestructive testing. He also explores the application of ultrasound and vibration technologies in various fields, including composites and biomaterials. Before pursuing his doctorate, Bowen conducted research in vibration control and finite element analysis of materials. He holds an M.S. in Mechanical Engineering from the University of Dayton and a B.S. in Mechanical Engineering from Tianjin University of Technology.

Authors:

Bowen Cai Mississippi State University
Chuangchuang Sun Mississippi State University
Rani Sullivan Mississippi State University
Zhenhua Tian Virginia Tech