Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics
| Main Author: | |
|---|---|
| Language: | English |
| Published: |
University of Cincinnati / OhioLINK
2017
|
| Subjects: | |
| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511800640467908 |
| id |
ndltd-OhioLink-oai-etd.ohiolink.edu-ucin1511800640467908 |
|---|---|
| record_format |
oai_dc |
| spelling |
ndltd-OhioLink-oai-etd.ohiolink.edu-ucin15118006404679082021-08-03T07:04:45Z Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics Quintero Badillo, Jorge R. Aerospace Materials Laser ultrasonics phased array CMC Ceramic matrix composites (CMCs) are poised to revolutionize jet engine technologyby enabling operation temperatures well beyond those possible with current superalloys,while reducing active cooling requirements and engine weight. Manufacturing of partsformed by silicon-carbide (SiC) fibers in a SiC matrix is now well advanced, with the firstnon-structural static components already in service in the CFM Leap engine. In order toexpand the scope of application of CMCs to rotating parts, it is necessary to characterizethe modes of failure of these materials at temperatures beyond 1100 C. In this context, theability of nondestructively monitoring the formation and progression of damage in CMCsspecimens during high-temperature mechanical testing is critical.Due to its excellent sensitivity and low cost, ultrasonic inspection is a well developedtechnique which allows to create accurate two and three-dimensional images of specimensby either mechanically scanning them or using phased array probes. However, the elevatedtemperature precludes use of traditional actuation techniques. In this context, thegeneration and detection of elastic waves using laser beams is an attractive possibility tocharacterize CMCs in a hostile environment with high sensitivity.In this work, the first experimental assessment of the feasibility of noncontact laser ultrasonicinspection of SiC/SiC flat coupons is presented. An Nd:Yag laser is used to exciteultrasonic waves on one side of the specimen while a Michelson interferometer detects thesignals emerging on the other side at the epicenter position. The lasers are mounted onsynchronized linear stages to form C-scans as in conventional immersion ultrasonics whileablation damage to the surface of the specimen is prevented by operating the lasers at low power density. It is shown that it is possible to image interlaminar defects caused by impactsand monitor crack opening under tensile load. Finally, very good signal stability isobserved when temperature is increased from 25 C to1250 C, confirming the feasibility oflaser monitoring at high temperature.To advance the technique further by achieving resolution in the thickness direction,an experimental assessment of the performance of a non-contact laser phased array in athrough transmission configuration is also presented. Full Matrix Capture (FMC) data setsare obtained by mechanically scanning the Nd:Yag laser across all the positions formingthe aperture of an array using linear stages. At each source point, a scanning vibrometeruses electronically actuated mirrors to inspect the same aperture. The performance of thetechnique is evaluated by processing FMC data sets acquired from aluminum samples usingthe Total Focusing Method (TFM) algorithm. The resulting image resolution was lowerthan expected based on the performance of piezoelectric phased array imaging. Finite ElementMethod (FEM) simulations revealed the scattering to be more complex than assumedby the acoustic model used in TFM imaging, which leads to image artifacts that precludethe possibility of sizing defects accurately. On the other hand, the image contrast resultingfrom the presence of defects is sufficient to achieve damage detection and location withhigh sensitivity. 2017 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511800640467908 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511800640467908 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Aerospace Materials Laser ultrasonics phased array CMC |
| spellingShingle |
Aerospace Materials Laser ultrasonics phased array CMC Quintero Badillo, Jorge R. Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| author |
Quintero Badillo, Jorge R. |
| author_facet |
Quintero Badillo, Jorge R. |
| author_sort |
Quintero Badillo, Jorge R. |
| title |
Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| title_short |
Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| title_full |
Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| title_fullStr |
Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| title_full_unstemmed |
Non-destructive Evaluation of Ceramic Matrix Composites at High Temperature using Laser Ultrasonics |
| title_sort |
non-destructive evaluation of ceramic matrix composites at high temperature using laser ultrasonics |
| publisher |
University of Cincinnati / OhioLINK |
| publishDate |
2017 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511800640467908 |
| work_keys_str_mv |
AT quinterobadillojorger nondestructiveevaluationofceramicmatrixcompositesathightemperatureusinglaserultrasonics |
| _version_ |
1719453211685814272 |