Frequency response computation of structures including non-proportional damping in a shared memory environment

Author(s):  
TG Jeong ◽  
SS Lee ◽  
Chang-Wan Kim

With the increased size of the finite element model for improved accuracy, the modal frequency response analysis has been one of the common practices of evaluating the performance of vehicle dynamics. However, there is difficulty in predicting the vehicle dynamics response with non-proportional damping regarding performance. The fast frequency response analysis algorithm (FFRA) has been proved to be very effective for partially damped structural system in the modal frequency response analysis. In the fast frequency response analysis algorithm, performance depends mainly on the complex symmetric matrix eigenvalue problem. Therefore, an efficient complex symmetric matrix eigenvalue problem solver is developed in this article. This approach also uses parallel processing in a shared memory machine for more efficient analysis. Numerical examples show that the new complex symmetric matrix eigensolver provides good accuracy and high performance. Then, the fast frequency response analysis algorithm is applied to a full scale vehicle system that includes only a few viscous damping finite elements. The fast frequency response analysis algorithm significantly improves the performance of the modal frequency response analysis compared to conventional method. In addition, parallel processing improves the efficiency of the overall simulation.

2018 ◽  
Vol 11 (5) ◽  
Author(s):  
Sahil Savara ◽  
Ishbir Singh ◽  
Sachin Kalsi

Author(s):  
C-W Kim

A new algorithm, fast frequency response analysis (FFRA), for the modal frequency response analysis (FRA) with gyroscopic effects is presented for a large and complex structural system. Because the modal gyroscopic matrix is low rank matrix compared to other modal matrices, the FFRA algorithm uses the Sherman-Morrison-Woodbury formula for computing the inverse of coefficient matrix efficiently. The new method, FFRA algorithm, dramatically improve the performance of the modal frequency response analysis with gyroscopic matrix compared to conventional methods in industry with the same accuracy.


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