Разработка методов тепловой дефектоскопии и дефектометрии авиационных композитов

Диссертация посвящена разработке методов дефектометрии в рамках импульсного теплового контроля авиационных композитов. Проведён сравнительный анализ существующих термографических методов количественной оценки глубины дефектов. Выявлены их преимущества и недостатки и обозначены существующие проблемы в этой сфере. Представлен термографический метод количественной оценки глубины дефектов в материалах, обладающих свойством оптической полупрозрачности. Разработан метод количественной оценки глубины дефектов, характеризующихся малым отношением поперечных размеров к глубине. Разработан метод оценки толщины тонких покрытий основанный на пороговой отсечке кажущейся тепловой инерции.This study is focused on quantitative estimation of defect depth by applying pulsed thermal nondestructive testing. A novel method for estimating defect depth is proposed by taking into account the phenomenon of 3D heat diffusion finite lateral size of defects and thermal reflection coefficient at the boundary between a host material and defects. The method is based on the combination of a known analytical model and non-linear fitting (NLF) procedure. The apparent effusivity method for the quantitative evaluation of coating thickness in a one-sided thermal NDT procedure is presented. And the depth prediction method based on neural networks is presented

Microprocessor based system for the development of control and protection of HVDC convertors.

This project investigates aspects of microprocessor based control and protection schemes for high voltage direct current convertors. To enable this investigation to be carried out, a multiple microprocessor HVDC development system has been assembled. This provides the necessary hardware resources, as well as providing the software development facilities necessary for the implementation of real time control and protection tasks. In order to assess and optimise the performance of the various control and protection systems, considerable interactive monitoring facilities are provided as part of the HVDC development system's software. The development system is used to implement real time control of a small scale convertor model. It is also used to implement a new form of convertor fault detection, which is in turn used as the basis for an implementation of convertor fault development control techniques for the first time on an operating convertor. The operation of the fault development control scheme is examined in some detail, and results are presented showing its operation over a wide variety of fault types and system conditions