| Summary: | Thesis (MEng)--Stellenbosch University, 2017. ENGLISH ABSTRACT: In order to estimate the forces exerted on ship propellers during ice navigation, the rotational dynamics of the propulsion system need to be accurately modelled. The direct measurements of propeller loads of ships during ice navigation is challenged by the harsh operating environment. Indirect measurements are therefore performed on the shaft line of such ships to estimate propeller loads through an inverse problem. Three case studies are presented, namely open water, cavitation and ice navigation. The maximum torque loading on the shaft occurred during ice navigation and the maximum thrust case during cavitation. Ice-induced moments on the SAA II propeller were determined from shaft line measurements using inverse methods, whereby the maximum ice load was found to be 941 kNm. Estimated load profiles for navigation in the Arctic and Antarctica are presented using rainflow counting techniques. The aim of the present research was to perform data-driven modelling of the rotational dynamics of the shaft line to aid future design of ice going vessels. AFRIKAANSE OPSOMMING: Ten einde die kragte op ’n skip se aandrywingstelsel te bepaal, moet die rotasionele dinamika van die stelsel gemodelleer word terwyl die skip vaar. Tydens ysnavigasie is die direkte bepaling van skroeflaste van skepe uitdagend weens die ruwe operasionele omgewing. Om skroeflaste te bepaal word indirekte metings op die dryfaste van sulke skepe uitgevoer. ’n Inverse probleem moet opgelos word om die beraamde skroeflaste te bepaal. Drie gevallestudies word aangebied, naamlik oop water, kavitasie en ysnavigasie. Die maksimum wringkrag is gedurende ysnavigasie en die maksimum stukrag gevalle is gedurende kavitasie gemeet. Die wringkrag weens ysimpakte op die SAA II skroef is bepaal deur dryfas-metings en die daaropvolgende inverse metodes. ’n Maksimum yslading van 941 kNm is bepaal. Geraamde lasprofiele vir navigasie in die Arktiese see en Antarktika word aangebied deur gebruik te ...
|
|---|