An Approach to Use the Structural Intensity for Acoustical Topology Optimization

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Abstract

The aim of vibroacoustic engineering is to find a design of a part which is optimal in strength, weight and acoustics. To find the optimal construction shape in early design stages, topology optimization is the most widely used tool. Based on numerically calculated local mechanical values, the optimization method considered in this contribution decides to delete or add material in the region concerned, based on one value, e.g. stress. The aim is to find the best possible utilization of the material’s mechanical strength, regarding the component weight. This approach works very well for static problems.

It is desirable to reduce all mechanical information to a single mean value, comparable to von Mises stress in case of static problems, to make a decision on structural changes. However, in acoustics, a dynamic system has to be solved. It is important to take the mechanical behavior of the adjacent regions of the focused area into account. The whole system together provides the specific acoustic characteristics. In addition, a frequency dependency exists. A reliable value to assess local areas of a construction, regarding the relevance for the overall acoustical behavior, is still missing.

The idea of this paper is to use the structural intensity (STI) as a basic value for an acoustic assessment of finite elements. It combines two essential mechanical properties: the stress-tensor and the acoustically important velocity-vector. The STI represents the structure-borne sound energy flow and its direction at each point. These information could be used to lead the optimization algorithm to build up a component topology with improved acoustical properties. The approach presented shows how the structural intensity could be used to assess and evaluate each voxel concerning its acoustical impact.

Keywords

Topology optimization Acoustic Structural intensity Assessment criteria Evaluation 
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Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  1. 1.Technische Universität BraunschweigBraunschweigGermany

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