Aviation Material and Construction Fatigue Damage Assessment on the basis of Acoustic Emission Signals
2015
Jevgēņijs Garbuzs

Defending
13.10.2015. 13:00, Ezermalas ielā 6, 405. auditorijā

Supervisor
Aleksandrs Urbahs

Reviewers
Juris Krizbergs, Valdis Priednieks, Jonas Stankūnas

A machinery (vehicle, including, air ships, space devices and others) resource is usually determined on the basis of the results of the stand fatigue test. “Weakest” design elements limiting the resources of the entire object as a whole are determined during the stand tests; determining cell survivability and viability. Furthermore, one of the most important and most difficult problems is the need to discover defects at an early stage that have emerged during the testing process of the construction material. An important problem is the kinetic control of crack propagation. The following traditional non-destructive test methods are used for control and diagnostics in fatigue test: visual optical, ultrasonic, eddy current, powder magnets as well as capillary method (colour and luminescence). All of these methods have limitations related to the fact that fatigue cracks usually occur in various parts of the joints, which in most cases are difficult or even impossible to access without disrupting the connection. They cannot be used to control defects, which occur within the elements of the object, i.e., traditional method is effective if it is possible to disassemble the construction. In addition, these methods are very time-consuming because of the need to scan virtually the entire surface of the object. One of the methods without most of the drawbacks mentioned herein is the acoustic emission (AE) method. This method is based on the elastic wave (wave voltage) emergence and spread process analysis, which causes changes in the structure of the rigid body at different loads. Since these changes are related mainly to the material decay processes, it is possible to identify both the emergence and development of various defects. Furthermore, the AE method enables the performance of an integrated object damage assessment and determination of defect locations. Aviation construction damage control with the acoustic emission method during the stand testing process will allow discovering dangerous defects in the testing process, such as fatigue fracture at an early stage, evaluating the durability of the construction and predicting its resources during the process of use.


Keywords
Aviācija, diagnostika, akustiskā emisija, pētījumi

Harbuz, Yevhen. Aviation Material and Construction Fatigue Damage Assessment on the basis of Acoustic Emission Signals. PhD Thesis. Rīga: [RTU], 2015. 174 p.

Publication language
Latvian (lv)
The Scientific Library of the Riga Technical University.
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