Condition Monitoring (CM) : Concept selection of sensors for monitoring of mechanical wear

Sammanfattning: This bachelor thesis has been executed with the product development process double diamond. The thesis has been performed at Karlstad University in cooperation with Kongsberg Maritime in Sweden AB. The objective of the thesis has been to develop a condition monitoring system for Kongsberg’s waterjet department. Substantially it has to do with finding a system which could monitor wear and problematic trends  in  the hydraulic oil and oil lubricated bearings. The wear is to be translated to an electrical signal which could be used to alert and visualize the wear to the end user. The literature study was divided into two parts. The first part of the literature study consisted of analyzing and understanding wear and condition monitoring systems. The second part of the literature study instead consisted of analyzing different kind of measurement methods which could be suitable for so-called online measurements. The used references come from scientific articles and documents publicized by various classification societies. The final solution consists of a system of different sensors and measurement methods. Due to the fact that the system is to be  installed on ships, the system needed to be considered with rules from various classification societies. The rules which are relevant for the project was placed in an elimination matrix where concepts that didn’t live up to the rules were scrapped. Further on, the sub concepts were evaluated  and selected  with a relative matrix and a weighted Kesselring matrix, which gave the most suitable sub concepts. The sub concepts were merged into a complete condition monitoring system at concept level. The final system solution could measure solid particles in oil, humidity in oil, oil flow, torque, rotational speed of the shaft and vibrations. The selected sensors also enabled the system to measure shaft power, oil conductivity and oil permittivity which were not included in the task.