Contemporary technologies are employing composite plate materials developed by using various innovative materials (nanostructures, mica structures, etc.). Such materials are being used in the fields of electronics, specifically, in heating, lighting and electricity control devices and mechanics including aerospace industry wherever exceptional physical properties are required, e.g. in compasses, rockets, oxygen breathing equipment, hearing aids. In many cases, the manufacturing technologies do not allow employing contact measurement methods for quality control of the manufactured products. However, ultrasonic methods enable investigation of key properties of materials which cannot be assessed by merely using traditional methods. For this purpose guided waves propagating within the interior of the objects under investigation may be employed. The guided waves are already used for non?destructive testing and evaluation (NDT) of sheet type materials. Usually they are excited when the vibrations of an acoustic transducer are transferred to the investigated item by a direct contact via a narrow gap of liquid. However, contact liquids are impossible to use in many cases as the investigated item may be contaminated, damaged or otherwise negatively affected. This is relevant in the cases of paper, membranes, GLARE, CFRP and composite structures. The objective of the proposed project is to investigate the propagation of higher order modes of Lamb waves in objects of a complex geometry. At higher frequencies, the speed of the ultrasonic guided waves becomes higher than the velocity in the air. Therefore, it is appropriate to develop new non-contact ultrasonic measurement methods based on excitation and reception of guided waves for the study of such objects. Problems arise from the excitation and reception of higher order modes, which require fundamentally new methods of excitation and reception. In order to achieve this target, two main tasks:
1. To develop novel theoretical methods of non?contact excitation and reception of ultrasonic guided waves using new generation piezoelectric materials;
2. To investigate the propagation of higher order modes of Lamb waves in objects of a complex geometry.
Project funding:
This research project is funded by the European Social Fund according to the 2014–2020 Operational Programme for the European Union Funds’ Investments, under measure’s No. 09.3.3-LMT-K-712 activity “Promotion of postdoctoral fellowships studies”.
Project results:
During the entire course of the project, 2 academic articles shall be published, and 1 presentation at international conferences shall be delivered and to go abroad for an internships at Imperial College London and at Bordeaux University in France. The articles shall be published in foreign journals featuring the Impact Factor in the Clarivate Analytics Web of Science database. The objective of the proposed project is to investigate the propagation of higher order modes of Lamb waves in objects of a complex geometry. At the end of the project, a final internship report will be provided. This new method will enable the use of the developed air?coupled ultrasonic methods for the non?destructive testing in objects of a complex geometry. Applicability of measurement methods: aircraft, wind turbines, industrial trucks and other non-destructive, complex geometries and difficult to access measurement objects.
Period of project implementation: 2020-09-01 - 2022-08-31
Project coordinator: Kaunas University of Technology
