Modeliranje padavinskih matrik z mešanico Gaussovih funkcij
The modelling of rainflow matrices with a mixture of Gaussian functions

english
slovenian

2001

volume 47, issue 10

Univerza v Ljubljani, Fakulteta za strojništvo

To evaluate the fatique damage of a dynamically loaded structure, a time history of the structure load should be acquired first. This can be done by means of experiments or simulations. When the time history of the loads is known, it should be transformed into a form that is suitable for the prediction of the fatique damage. This fatique damage of the structure depends heavily on the load cycles that are included in the load time history. Load cycles are extracted from the load time history with different counting methods. A rainflow counting method is widely used in the automotive industry. The rainflow counting industry method results in a matrix of the relative frequencies of the load cycles, which are included in the load time history. With an approximation of the rainflow matrix by a continuous probability density function, random fluctuations of the relative frequencies are reduced and an extrapolation of the probability of the load cycles that were not actually recorded is made possible. In our paper a method of modelling the rain flow matrices by means of a mixture of Gaussian functions will be presented. Unknown parameters of the normal mixture will be estimated with a maximum-likelihood method. The effectiveness of this method will be presented and discussed with an example of the load time histories of a real structure.

16.09.2009