Impulse Based Substructuring: Theory, Improvement, and its Implementation on Real Problems

Impulse Based Substructuring: Theory, Improvement, and its Implementation on Real Problems

Haghighat, N.

Rixen, D.J. (mentor)

Mechanical, Maritime and Materials Engineering

Precision and Microsystems Engineering

2011-11-29

Dynamic substructuring as a method to solve complex systems is becoming very important. Dynamic substructuring techniques are based on assembling the dynamic models of some simpler structures in order to generate the dynamic model of a complex structure. Impulse Based Substructuring (IBS) as a time domain substructuring technique computes dynamic response of linear structures by applying convolution product on the impulse responses of the subsystems. The IBS method can be explained in 2 main steps; 1: Computing the Impulse Response Functions (IRFs) of the substructures due to a unit impact (by applying numerical time integration), 2: Assembling procedure and computing the dynamic response of the total system by applying the convolution product between the IRFs and the applied forces. The applied forces consist of both external and unknown internal forces which are made at the interfaces due to substructuring and will be found during the assembling procedure in a way to satisfy the compatibility conditions at the interface. The IBS formulations have been developed based on the 3 different impact models. Afterwards in order to reduce the computation costs for long simulations, truncation and windowing have been applied on the IRFs. In this thesis, the 3 different formulations of the IBS method will be presented and application of the IBS method (using both normal and truncated IRFs) is illustrated by a 1D example. Finally in order to show the validity of the IBS method in real problems, a real 3D example related to an offshore wind turbine has been analyzed by IBS.

substructuring

http://resolver.tudelft.nl/uuid:d1143b64-43fd-4dca-b5ce-7e9ea77260ea

2011-12-29

Student theses

master thesis

(c) 2011 Haghighat, N.