Limitations of the describing function for limit cycle prediction

Prediction of Limit Cycle Pressure Oscillations in Gas Turbine Combustion Systems Using the Flame Describing Function

The Performance of Karafillis-Boyce Yield Function on Determination of Forming Limit Diagrams

Forming Limit Diagrams are useful tools for evaluation of formability in the sheet metals. In this paper the effects of yield criteria on predictions of the right and left-hand sides of forming limit diagrams (FLDs) are investigated. In prediction of FLD, Hosford 1979, “Karafillis-Boyce” (K-B) and BBC2000 anisotropy yield functions have been applied. Whereas the prediction of FLD is based on th...

Effect of different yield functions on computations of forming limit curves for aluminum alloy sheets

In this article, the effect of different yield functions on prediction of forming limit curve (FLC) for aluminum sheet is studied. Due to importance of FLC in sheet metal forming, concentration on effective parameters must be considered exactly in order to have better theoretical prediction comparing experimental results. Yield function is one of the factors which are improved by adding new coe...

Limit Cycle Prediction in Multivariable Nonlinear Systems Using Genetic Algorithms

This paper presents an intelligent method based on multiuobjective genetic algorithm (MOGA) for prediction of limit cycle in multivariable nonlinear systems. First we address how such the systems may be investigated using the Single Sinusoidal Input Describing Function (SIDF) philosophy. The extension of the SIDF to multi loop nonlinear systems is presented. For the class of separable nonlinear...

Limit-cycles prevention via multiple H∞ constraints with an application to anti-windup design

Rate and magnitude control limitations are often responsible for the apparition of undesired limit-cycles in the resulting nonlinear closed-loop system. Based on the wellknown describing function approach, it is shown in this paper that such limit cycles can be avoided as soon as H∞ constraints are simultaneously satisfied by appropriately chosen linear interconnections. This result is then use...