Transfer Path Analysis - Options

With the LMS Test.Lab Component Editing add-in, users can edit different components of the TPA model (force, FRF), and immediately evaluate the effect of these changes on the path contribution. Graphical editing of the FRF and/or forces is supported; individual path or case contributions can be enabled or disabled. The changes can be saved as a new model, and the different models can be compared against each other.

LMS Test.Lab Virtual Car Sound can be used for general sound design and target setting as well as advanced vibro-acoustic troubleshooting in the vehicle refinement stage. Starting from experimental or CAE data, a sound quality equivalent model (SQE) is generated that decomposes the interior car noise into powertrain, road/tire, and wind noise. The SQE model is equivalent in quality and features to the original sound. For troubleshooting and target setting applications, the model can be refined with a TPA model to study the different structure-borne and airborne path contributions. The LMS Test.Lab Virtual Car Sound solution is mainly applied to vehicles, but can be helpful when analyzing issues found in other rotating machinery products and components.

LMS Test.Lab Principal Component Analysis helps users reduce complex noise and vibration problems to more manageable, independent, and uncorrelated problems with multiple, partially correlated references. These problems range from structure-borne road-noise to the combined effects of air-conditioning compressor and engine noise. By applying singular value decomposition techniques on a multi-reference crosspower matrix, this matrix is decomposed into its principal components, yielding as many single reference sets of crosspowers as there are references. The solution also features other functions such as virtual coherence and virtual spectra. Principle component analysis results can be used for further transfer path analysis.

This add-in provides off-line multi-reference spectral processing on crosspower, FRF, partial coherence and transmissibility. It can be used separately and will then only support stationary averaging. It can also be used together with signature throughput processing to include tracked processing. The calculated transmissibilities can be used in LMS Test.Lab Transfer Path Analysis to perform a response-only operational path analysis. Autopower and crosspower spectra can be used as input for a principal component analysis.

The LMS Test.Lab Time Domain TPA add-in is the ideal solution to decompose transient and semi-stationary responses into path contributions. Starting from a TPA model (direct, mount stiffness, LMS OPAX, single path inversion or matrix inversion), it provides the analysis and auralization of the time domain contributions. The contribution time traces are available for further analysis with for example signature throughput processing or sound diagnosis.

The investigation of the noise contributions of vehicle interior targets has become standard practice for vehicle manufacturers to gain insight in noise contributions, interface forces and system sensitivities. Because new technologies are being implemented and available time for testing time reduces, the need for dedicated testing devices increases. LMS uses its experience in NVH technology to continuously develop new acoustic and structural exciters under the brand name LMS Qsources. >> more information