Magistratūros baigiamajame darbe buvo analizuojamas jūrinio transportinio laivo korpuso korozinis dilimas ir jo priežastys, pateikiami defektacijos metodai, vertinami eksperimentinių matavimų metu gauti rezultatai. Baigiamasis darbas susideda iš teorinės, eksperimentinės ir praktinės dalies. Teorinėje dalyje apžvelgtos laivo korpuso nusidėvėjimo problemos, apžvelgti klasifikacinių bendrovių reikalavimai laivo korpuso būklei, išnagrinėtos laivo korpuso remonto technologijos. Eksperimentinėje dalyje pateiktos balkerio ,,LEDI CHRIS“ korpuso konstrukcijų liekamojo storio matavimo ultragarsiniu stormačiu rezultatai, palyginti matavimų duomenys, gauti laivo korpuso defektacijos tyrimo metu 2002, 2007 ir 2012 m., nustatytos labiausiai korozinio proceso paveiktos laivo konstrukcijos. Praktinėje baigiamojo darbo dalyje buvo atlikti skaičiavimai, siekiant nustatyti laivo korpuso lakštu stipruma po korozijos poveikio ir apskaičiuota tikimybes analize. / The master‘s thesis analyses the causes of the corrosive wear in marine transport ships. It is further followed by the examples of the flaw detection methods and the assessment of the results obtained through experimental measurements. The thesis has theoretical, experimental and practical parts to it. The theoretical part entails the review of the issues related to the depreciation of the ship‘s hull. Moreover, the theory includes the overview of the requirements imposed by the classification society in regards to the condition of the ship‘s hull. The thesis also brings forth the examination of the repair technology that is being used in connection to such issues. The experimental section of the thesis entails the residual thickness measurements of the hull structures obtained through the ultrasonic calipers that were applied on the bunker „LEDI CHRIS“. The comparison of the measurements‘results is also provided, based mainly on the data taken from the flaw detection test that was administered in the years 2002, 2007 and 2012. Additionally, the thesis identifies the structures of the ship that were impacted the most by the process of the corrosion. Last but not least, the practical part of the thesis presents calculations that were conducted in order to determine the durability of the ship‘s hull plating that was affected by the corrosion. The thesis concludes with the probability analysis of the corrosion causes.

The employment of real time NDT systems has been spread widely last years. It is very important to control in real-time layer thicknesses of multi-layered materials during manufacturing process. In this work multi-layer thickness measurement digital signal processing methods are evaluated. Presented real-time nondestructive testing system and signal propagation model is a background for measurement algorithm analysis and development. In this work multi-layer thickness measurement problem is addressed with a different approach, by applying correlation functions on parts of the ultrasonic signal, thus reducing the overall computational complexity.