When Stochastics Matters: New Pathways in Ship Design Using Stochastic Simulation-based Design Optimization
Dr. Matteo Diez, INSEAN-CNR, Rome
Sala Conferenze IMATI-CNR - Tuesday, December 15, 2015 h.15:00
Abstract.
If greenhouse gas emissions will continue to drive global temperatures upward, a more hostile natural environment can be foreseen, with a broad range of consequences, including rising averaged sea states and sea levels, along with increasing frequency of storms and extreme waves events. Ships will always sail under a broad range of aleatoric operating and environmental conditions, whose intrinsic uncertainty cannot be reduced by either the designer or the operator. The large variety and complexity of design conditions and requirements motivated the development of stochastic simulation-based design optimization (SSBDO) methods, which have replaced the traditional build-and-test paradigm (costly and time consuming), providing opportunities for robust design decision, large design space exploration, and unconventional concepts. The confidence of the final solution relies on the use of accurate high-fidelity solvers, which have been constantly developed exploiting the increasing availability of high-performance computing systems. The SSBDO integrates three main elements: (a) geometry modification and automatic meshing, (b) analysis tools including high-fidelity solvers and uncertainty quantification methods, and (c) optimization algorithms. Its implementation represents an algorithmic and technological challenge, facing almost unaffordable computational costs. The seminar will present recent progress in efficient shape optimization for ship design, which includes design space dimensionality reduction techniques based on the Karhunen-Loève Expansion [1], uncertainty quantification methods for the ship performance in waves [2], hybrid global/local derivative-free optimization algorithms [3], and finally metamodels based on adaptive sampling procedures [4]. The applications will cover numerical studies, as well as their final experimental assessment [5].
References
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Diez M., Campana E.F., Stern F., “Design-space dimensionality reduction in shape optimization by Karhunen–Loève expansion,” Computer Methods in Applied Mechanics and Engineering, Vol. 283, pp. 1525-1544, 2015. DOI: 10.1016/j.cma.2014.10.042.
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Diez M., Campana E.F., Stern F., “Development and evaluation of hull-form stochastic optimization methods for resistance and operability,” FAST 2015, 13th International Conference on Fast Sea Transportation, Washington DC, USA, September 2015.
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Serani A., Fasano G., Liuzzi G., Lucidi S., Iemma U., Campana E.F., Diez M., “Derivative-free global design optimization in ship hydrodynamics by local hybridization,” 14th International Conference on Computer Applications and Information Technology in the Maritime Industries, COMPIT 2015, Ulrichshusen, Germany, May 2015.
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Volpi S., Diez M., Gaul N.J., Song H., Iemma U., Choi K.K., Campana E.F., Stern F., “Development and validation of a dynamic metamodel based on stochastic radial basis functions and uncertainty quantification,” Structural and Multidisciplinary Optimization, Vol. 51, No. 2, 2015, pp. 347-368. DOI: 10.1007/s00158-014-1128-5.
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Diez M., Broglia R., Durante D., Campana E.F., Stern F., “Validation of high-fidelity uncertainty quantification of a high-speed catamaran in irregular waves,” FAST 2015, 13th International Conference on Fast Sea Transportation, Washington DC, USA, September 2015.
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