Woodruff School of Mechanical Engineering


Comparison of Methods for the Simulation of the Vibro-Acoustic Behavior of Ship-Like Structures


Prof. Lothar Gaul


Institute of Applied and Experimental Mechanics, Universitšt Stuttgart


Friday, February 12, 2010 at 11:00:00 AM


MRDC Building, Room 4211


Prof. Larry Jacobs


The vibro-acoustic behavior of ship-like structures is noticeably influenced by the surrounding water and thus represents a multifield problem. In this work, fast boundary element methods are applied for the semi-infinite fluid domain. As an advantage, the Sommerfeld radiation condition is satisfied in an exact way and only the boundary, i.e. the ship hull, has to be discretized. To overcome the drawback of fully populated matrices, fast boundary element methods are applied. The focus is on the comparison of the multipole method with hierarchical matrices, which are set up by adaptive cross approximation. In both cases, a half-space fundamental solution is used to incorporate the water surface, which is treated as pressure-free. The structural domain is discretized with the finite element method. A binary interface to the commercial finite element package ANSYS is used to import the mass and stiffness matrices. The coupled problems are formulated as Schur complements, which are solved by a combination of iterative and direct solvers. Depending on the applied fast boundary element method, different strategies arise for the preconditioning and the overall solution. The applicability of these approaches is demonstrated using a realistic model problem.


Professor Lothar Gaul has been Head of the Institute of Applied and Experimental Mechanics (formerly Institute A for Mechanics) at the University of Stuttgart since 1993. He received his Doctorate (Habilitation) from the University of Hanover in 1980. He has been Dean of Process Engineering and Engineering Cybernetics at the University of Stuttgart, and was formerly Head of Mechanics at the University of the Federal Armed Forces in Hamburg. Professor Gaul has advised or co-advised over 60 doctoral students, has authored three textbooks and over 350 journal and conference papers. Professor Gaulís wide range of research interests include: computational mechanics, smart materials, structural health monitoring, soil-structure interactions, active and passive control of systems, and adaptive structures.


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