Additively manufactured load and health sensing structures with embedded transducers
Abstract
Nondestructive Testing (NDT), Structural Health Monitoring (SHM) and load sensing systems have been developed separately. Each of these systems use different types of transducers and electronics. Recently commercialized metal additive manufacturing (AM) equipment which use bound metal powder filaments are capable to create regularly distributed closed cells (infill). Infills reduce weight, material cost and manufacturing time. AuthorÕs group has been planning a series of studies to create coil like hidden geometries in addition to the infills inside the parts while it is built by using the AM process. These coil-like hidden geometries will work as embedded transducers. The same embedded transducers will be used for sensing, SHM and NDT. Purchase of Innerspec VOLTA kit and a digital oscilloscope are requested. The Innerspec VOLTA kit includes coils and magnets. Defect and load estimation capability of the VOLTA kit will be evaluated for additively manufactured metal parts. Based on this experience, coil like hidden geometries will be designed and additively manufactured inside the part. These hidden coils will be located precisely at the best places for different type of inspections. Manufacture of these embedded transducers will not increase the cost and they will be protected from environmental elements. The authorÕs group recently developed a new excitation method for polymer parts, used infills to simplify location estimation when surface response to excitation (SuRE) method was used. The new multi-width pulse excitation (MWPE) applies pulses with 20 different durations. Separate piezoelectric elements were used to excite the part with MWPE signal and to measure the created ultrasonic waves. Short time Fourier Transformation (STFT) was used to calculate the 2D time-frequency plots of monitored signals with overlap (spectrogram). Spectrograms were classified by using deep learning Convolutional Neural Networks (CNN). MWPE-STFT-CNN could detect load application and its location when the part was made with infills and different skin thicknesses were used at various sections of the part. Sweep-sine wave excitation (SSWE) was used to create ultrasonic waves on additively and conventionally manufactured steel bars. For data process and classification, SSWE-STFT-CNN combination was used successfully to identify the manufacturing method of the bar (conventional and additively manufactured at two different orientations) and to estimate the applied loads from 0 to 200N by using single CNN simultaneously. The developed SSWE-STFTÐCNN combination will be used with the embedded transducers of additively manufactured metal parts with infills while the critical parts are operations. Applied loads and structural health will be evaluated. Electromagnetic acoustic transducer (EMAT) type NDT systems will be connected through a terminal to these embedded transducers (coils) inside the part for in depth inspection of the integrity of the structures during the scheduled maintenance of the machine. The proposed studies will make important contributions to the design and additive manufacturing of smart structures with sensing and diagnosis capabilities. Four Mechanical Engineering courses will use the Innerspec VOLTA kit as an NDT tool. High schools and industry will be able to use the system when they need it with the help of our support staff and trained FIU students. Over 200 students will use the kit every year with multiple purposes such as training, inspection of parts and research.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 26, 2023
- Source ID
- W911NF2310080
Entities
People
- Ibrahim Tansel
Organizations
- Army Contracting Command
- Florida International University
- United States Army