Simulation of the behaviour of a ship operating in pack ice is a computationally intensive process to which General Purpose Computing on Graphical Processing Units (GPGPU) can be applied. GPGPU is the use of a GPU (graphics processing unit) to do general purpose scientific and engineering computing. The model for GPU computing is to use a CPU and GPU together in a heterogeneous co-processing computing platform. The sequential part of the application runs on the CPU and the computationally-intensive part is accelerated by the GPU. From the users perspective, the application just runs faster because it is using the high-performance of the GPU to boost performance. This thesis presents an efficient parallel implementation of such a simulator developed using the NVIDIA Compute Unified Device Architecture (CUDA). This simulator can be used to give users the ability to analyze ice-interactions for design, assessment and training purposes. This thesis also describes the execution of experiments to evaluate the performance of the simulator and to validate the numerical modeling of ship operations in pack ice. It also describes the useful applications that have been done using this simulator in planning ice management activities. i

In the offshore industry, fibre reinforced sliding journal bearings are increasingly used due to their low-maintenance and self-lubricating characteristics. To be able to use the bearings in the rough offshore environment, under heavy loading, full scale tests are essential to assess the friction and wear rate development during use. For this purpose, two full scale wear tests were performed on composite sliding journal bearings of 300 mm in diameter. These tests were performed at the laboratory of TNO Structural Dynamics in Delft, The Netherlands, over a period of eight months. For this purpose, a test rig was designed in which a shaft runs through the journal bearing. The latter is loaded in the range 50 to 700 kN and the shaft is given triangle-like cyclic displacements. To be able to test under realistic conditions, the bearing is constantly submerged in flowing seawater. Forces, displacements and temperatures were constantly monitored to manage the system and determine the parameters. Besides a description of the test rig, a rationale of choices made, observations during testing and detailed cycle-by-cycle friction characteristics are presented, next to generalized trends for the wear and Coefficients of Friction (CoFs) under the various loading conditions.

No abstract

Simulation of failure in thin-walled structures is critical for the correct determination of crash performance of ships and offshore structures. Typically, shell elements are used, but these elements are not able to adequately capture local failure, especially inside of a neck. This paper addresses these gaps by adapting the Bridgman (1952) model of a neck inside of a plate by making it three-dimensional and offering an estimate of the relationship between state parameters of a shell element and the geometry inside of a neck. Finally, recommendations are also made about how to interface this information with the Modified Mohr-Coulomb failure locus to create a practical algorithm for assessing failure in shell elements.