An energy approach to the fatigue life of ship propulsion systems

The conducted research investigations aimed to carry out an identification of the constructional materials fatigue state of the ship propulsions’ rotational mechanical units for diagnostic purposes. The fatigue cracks of the elements transmitting mechanical energy streams from the propulsion engines to the ship propellers or to the generators of the ship’s electric power station stand for a primary reason for the secondary, usually very extensive, damages within the ship’s main or auxiliary propulsion system. It inevitably leads to immobilizing the ship along with further consequences for her stability and unsinkability. The shafts line’s misalignment or bend represent the most frequent reasons of this kind damages. They usually occur as a consequence of the foundations’ static settlement of the shafts line’s main components, alternatively, as a consequence of the ship’s slight but frequent collisions during her handling in harbors. A laboratory test bed of the simple rotational mechanical unit driven by the electric engine has been especially designed and built for a purpose of the research program realization. It stands for, in a smaller scale, a physical model of the real object what makes possible an actual introducing the external inputs which are characteristic to the propulsion shafts line’s misalignment. The test bed was equipped with a measuring set enabling a registration of the course of the multisymptomatic, continuous and irreversible alterations of the shaft section’s fatigue state while it is subject to cyclic torsional-bending loads during the standard fatigue test. The measuring system makes possible a simultaneous observation of the parameters characterizing accumulation and dissipation processes of different energy forms in the slow- changeable, dynamic process of the fatigue test. A patent application regarding the solution related to energy symptoms measurements of the constructional materials’ high-cycle (mechanical) fatigue presented in the paper has been protected by the Patent Office of the Republic of Poland, as a utility pattern, the registration number: 67362 - “Laboratory test bed for energy examinations of the multisymptomatic high- cycle fatigue of the simple mechanical units’ constructional materials”

The Role of Voltage Controls in Modern All-Electric Ships: Toward the all electric ship

Ships have witnessed an astounding evolution in the last 200 years. The introduction of the combustion engine has started an ever-faster change, both in the performance and functionality given by the ships. From the steam-powered ships of the early 1800s to the modern diesel-electric ships, the improvements were significant and increasingly rapid. In particular, in the last 30 years, the design of ships has made a huge leap ahead, both in terms of efficiency of the entire vessel and new functions given to the owners. This is due to the progressive electrification that has occurred

An Autonomous Surface Vehicle for Long Term Operations

Environmental monitoring of marine environments presents several challenges: the harshness of the environment, the often remote location, and most importantly, the vast area it covers. Manual operations are time consuming, often dangerous, and labor intensive. Operations from oceanographic vessels are costly and limited to open seas and generally deeper bodies of water. In addition, with lake, river, and ocean shoreline being a finite resource, waterfront property presents an ever increasing valued commodity, requiring exploration and continued monitoring of remote waterways. In order to efficiently explore and monitor currently known marine environments as well as reach and explore remote areas of interest, we present a design of an autonomous surface vehicle (ASV) with the power to cover large areas, the payload capacity to carry sufficient power and sensor equipment, and enough fuel to remain on task for extended periods. An analysis of the design and a discussion on lessons learned during deployments is presented in this paper.Comment: In proceedings of MTS/IEEE OCEANS, 2018, Charlesto

A new logic for Controllable pitch propeller management

In this study we want to propose an active logic that, continuously, optimizes the configuration of the propeller and motor speed taking into account changes in resistance and wake. The working principle of the control system is based on the measurement of the torque absorbed by the pro-peller and the engine speed, to obtain the actual thrust and advance speed coefficients. Based on these data, the controller identifies the configuration of the propeller for the best performance of the entire propulsion chain, from engine to propeller. Moreover, in addition to torque and speed limits of the en-gine, the control system chooses pitch angle taking into consideration the propeller’s cavitation

Connected and shared X-in-the-loop technologies for electric vehicle design

The presented paper introduces a new methodology of experimental testing procedures required by the complex systems of electric vehicles (EV). This methodology is based on real-time connection of test setups and platforms, which may be situated in different geographical locations, belong to various cyber-physical domains, and are united in a global X-in-the-loop (XIL) experimental environment. The proposed concept, called XILforEV, allows exploring interdependencies between various physical processes that can be identified or investigated in the process of EV development. The paper discusses the following relevant topics: global XILforEV architecture; realization of required high-confidence models using dynamic data driven application systems (DDDAS) and multi fidelity models (MFM) approaches; and formulation of case studies to illustrate XILforEV application