On this page, you can find links to our internal MSDL report publications, as well as abstracts and bibliographic information for publications in peer-reviewed journal articles and conferences. Older publications by Dr. Collette before he founded the MSDL are also included. Where allowed by copyright, full text downloaded or pre-prints of articles are also provided. Papers where source code and data is provided for provenance will have a link below the abstract to access the code or data. Zotero metadata is also provided for the publications.
Department of Naval Architecture
and Marine Engineering
210 Naval Architecture and Marine Engineering
2600 Draper Dr., Ann Arbor MI 48109
Zhu, J., and M. Collette. 2011. "Lifecycle Fatigue Management for High-Speed Vessels Using Local Approaches." In Proceedings of FAST 2011, 532-539. Honolulu, Hawaii: ASNE.
Structural fatigue cracking in lightweight high-speed vessel structures is a central maintenance and lifecycle costing concern. While existing pass-fail fatigue approaches provide a simple design-oriented metric to limit the amount of fatigue cracking observed in service, these approaches struggle to make accurate mid-life prediction of future fatigue performance and associated structural risks and costs. This paper outlines an inspection updating approach for such predictions. By using local fatigue approaches, which can collapse the fatigue lives of different structural details onto a common S-N curve, the service experience with the vessel is treated as an ongoing fatigue experiment which determines the as-built fatigue properties of the vessel. Different analysis techniques including Bayesian Belief Networks and Markov Chain Monte Carlo analysis are proposed to interpret the service life experience with the vessel and estimate the fatigue properties. Using a hypothetical design for a large, high-speed cargo vessel, the through-life fatigue cracking of the vessel is simulated and three updating techniques are applied to the simulated inspection history to try to determine the as-built fatigue parameters. All methods are able to make some improvements over design-stage fatigue estimates, although the power of the methods varies.
Collette, Matthew. 2011. "Hull Structures as a System: Supporting Lifecycle Analysis." Naval Engineers Journal 123 (3): 45-55.
As modular weapon systems allow cost-effective upgrades of a vessel's war-fighting capability, the degradation of the difficult-to-upgrade structure of the vessel may soon become one of the key drivers of vessel retirement and lifecycle maintenance costing. Existing structural design approaches are reviewed, along with recent developments in this field. It is argued that recent research has produced a number of ad-hoc metrics for structural design, such as producability; however, to truly address the needs of future ship design teams it is necessary to integrate several such metrics in a systems-engineering view to evaluate how the structural system contributes to the overall capabilities and costs of a proposed vessel. Potential architectures for this approach are discussed, along with key shortcomings. A comparative example is given for structural fatigue of a strength deck under global bending loading, comparing the traditional design approach with a systems-oriented view.
Collette, M. "Rapid analysis techniques for ultimate strength predictions of aluminum structures." In Advances in Marine Structures, 109-117. Hamburg, Germany: CRC
A series of rapid semi-analytical methods for predicting the collapse of aluminum structures is presented, including methods for tensile and compressive limit states. The methods presented have been designed to be extensible to a wide range of structural topologies, including both conventional stiffened-panel topologies and more advanced extrusion topologies. Unlike existing steel ultimate strength methodologies, particular attention is paid to capturing aluminum-specific response features, such as alloy-dependent material stress-strain curve shapes and the weakening effect of fusion welds. The methods are validated against finite element analysis and previously published experimental results.
Sensharma, P., Collette, M. & Harrington, J., 2011. Effect of Welded Properties on Aluminum Structures, SSC-460, Washington, DC, USA: Ship Structure Committee.
The 5xxx-series and 6xxx-series aluminum alloys are extensively used for marine structures. Generally, 5xxx-series alloys possess excellent corrosion resistance when immersed in seawater whereas 6xxx-series are inferior. Traditionally, 5xxx-series alloys are used in deck and hull plating whereas 6xxx-series alloys are used as structural reinforcements, bulkheads, and stiffeners that do not come in direct contact with seawater. Welding aluminum results in significant modifications to the material properties in the area around the weld. The 5xxx-series and the 6xxx-series alloys obtain a significant portion of their strength either from cold working or thermal processing, processes that are impacted by the heat input from welding. The area impacted by the heat input from the welding process is termed as heat-affected zone or HAZ. For high-strength 5xxx and 6xxx-series alloys joined by fusion welding, the HAZ is typically 30%- 50% weaker than the base material. Friction stir welding typically has a smaller HAZ with higher strengths. As the underlying metallurgy of the 5xxx and 6xxx-series alloys are significantly different, the HAZ for these two alloys behave in different ways. Additionally, for high-Mg 5xxx-series alloys, the heat input near the weld may cause portions of the HAZ to become susceptible to inter-granular corrosion. The 30 to 50 percent decrease in the strength of the HAZ in aluminum has not been investigated sufficiently. Current design methods assume that all metal will have this reduced strength, whereas the localized weakening has been shown to have less effect on overall strength in compression and in tension. This approach may seriously underestimate the strength of welded structure and it may impose a significant weight penalty on the final vessel design. Alternative approaches to design are possible. For example Paik et al. (2005) proposed equivalent yield strength based on the plate volume. Although the concept of equivalent yield strength has been used in research reports, the full implications for design standards have not been investigated. This research study intends to provide a basis for modification to design standards by analyzing the impact of the HAZ on the strength of aluminum stiffened panels under compressive, tensile, and bending loads.
Knight, J.T., F.T. Zahradka, D.J. Singer, and M.D. Collette. 2011. “Multi-Objective Particle Swarm Optimization of a Planing Craft with Uncertainty.” In Proceedings of FAST 2011, 532–539. Honolulu, Hawaii: ASNE.
Uncertainty exists in many of the design variables and system parameters for planing craft. This is especially true in the early stages of design. For this reason, and others, optimization of a craft’s performance characteristics is often delayed until later in the design process, after uncertainties have been at least partially resolved. However, delaying optimization can also limit its potential, because freedom to make changes to a design is also highly limited in the later stages. This paper demonstrates how uncertainty can be directly incorporated into optimization using particle swarm. A simple synthesis model for a planing craft is built, and a deterministic Pareto front of optimal solutions is found, minimizing two objectives; drag and vertical acceleration at the center of gravity. The craft’s weight is then modelled as a normally distributed random variable and sampling methods are used to quantify the uncertainty in the estimated drag for points along the Pareto front. Preliminary results reveal that drag uncertainty is not constant along the Pareto front, presenting useful trade-off information for designers and decisions makers.