External System Modeling
Abstract
In this thesis a novel design strategy is presented. The key elements of the design strategy comprise the modeling of the physical sources, the separation of the system into the design component and the external system, the characterization of the external system as a complex source, and finally the use of the complex source/design component model to optimize the performance of the design component. The portion of the system that is undergoing design modifications is referred to as the design component. The entire system excluding the design component is referred to as the external system. In the final model only a reduced subset of the external system dynamics are required to make performance predictions of any new design component. The optimally reduced set of external system dynamics is found by treating the external system as a complex source acting on the design component. Because the designer is not interested in the internal dynamics of the external portion of the system, all of the dynamics associated with the external system portion of the entire system are lumped into an effective source model. The external system source model was obtained using component modeling methods combined with source characterization ideas. Once the external system model is reduced to an equivalent source model, the design component performance may be predicted efficiently for any new design component. This formulation is particularly well suited to use of optimal design algorithms to optimize the design component properties with respect to a performance measure. An example of a design optimization study is given that demonstrates the usefulness of the external system modeling approach. Another of the contributions of the present study is an extension to the receptance method. Previously the receptance method has been used to analyze systems of components that are joined through a few point connections. In this thesis, an extension to the receptance method is proposed that makes it possible to handle distributed connections between substructures, thus expanding the types of problems that may be addressed with the receptance method and the external system modeling technique.
 Publication:

Ph.D. Thesis
 Pub Date:
 January 1995
 Bibcode:
 1995PhDT........78G
 Keywords:

 RECEPTANCE;
 DESIGN OPTIMIZATION;
 Engineering: Mechanical; Physics: Acoustics