Transmission Loss Optimization of a Helmholtz Resonator by Design Exploration

This presentation was made at the NAFEMS European Conference on Simulation-Based Optimisation held on the 15th of October in London.

Optimisation has become a key ingredient in many engineering disciplines and has experienced rapid growth in recent years due to innovations in optimisation algorithms and techniques, coupled with developments in computer hardware and software capabilities. The growing popularity of optimisation in engineering applications is driven by ever-increasing competition pressure, where optimised products and processes can offer improved performance and cost-effectiveness which would not be possible using traditional design approaches. However, there are still many hurdles to be overcome before optimisation is used routinely for engineering applications.

The NAFEMS European Conference on Simulation-Based Optimisation brings together practitioners and academics from all relevant disciplines to share their knowledge and experience, and discuss problems and challenges, in order to facilitate further improvements in optimisation techniques.

Resource Abstract

The early design phase of technical products is marked by many inherent uncertainties such as loads, geometric parameters and material properties. For a better classification of the influence of the input parameters on the system response behavior, numerical experiments can be used to find a more convenient design. This is particularly important in the case of a non-linear relationship between input and output variables. PERMAS [3] offers a so-called SAMPLING procedure (i.e. DOE process) for this purpose. It is a repeated analysis in sequential form with modified discrete values for all design variables. One possible application of SAMPLING is the improvement and validation of parts and assemblies by targeted parameter variation. If gradient information is unavailable, unreliable or difficult to compute, one might use a design exploration instead of a direct optimization. This approach is pursued here.

The reduction of noise emissions is an important factor in the design of duct systems (Fig. 1). The influence of the cylindrical shape parameters (radius and length) of a Helmholtz resonator (HR) on the transmission loss will be analyzed in this paper. A mesh morphing approach [4] is used for this purpose. This has the advantage that only a single finite element mesh is needed and therefore no remeshing is necessary. The underlying example is taken from the literature [1] and shows only a single maximum in the examined frequency range as opposed to more complex muffler systems [2]. However, the geometric variations lead to a large number of local optima (Fig. 2) and to a frequency shift of the maximum transmission loss in the examined frequency range. With this prior knowledge, a detailed analysis of the local maxima can then be carried out. That helps us to find suitable geometries in a design-driven development process at an early stage.

Document Details

AuthorWagner. N
Date 15th October 2019
OrganisationINTES GmbH


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