Simulation of Wing and Nacelle Stall, Juni 2010, Joint Symposium of DFG FOR 1066 and DLR-Airbus C²A²S²E: "Simulation of Wing and Nacelle Stall"

Gust and Turbulence Simulation for Design and Certification of Large Aeroplanes - Industrial Application of Unsteady Aerodynamics for Loads

Wolfgang Weigold, Michael Kruse

Not public. Keywords: Gust and Turbulence Simulation, Industrial Application

Excerpt from: IFASD 2009, Seattle.

Assessment of a non-linear control surface deflection in turbulence using an equal frequency of exceedance approach

Michael G. Kruse

Continuous turbulence analysis for a small sample model with a non-linear control law was carried out using a methodology proposed as accepted means of compliance in AMC 25.341 [1]. A pseudo-random turbulence stream was generated and then used to create the system response using the efficient method to couple open loop frequency domain systems with a non-linear time domain control law presented in [2, abstract 2007 below]. Comparing the non-linear with a linear reference system at equal frequency of exceedances yields non-linear design load levels following the principle of equivalent safety. The valuable applicability of this methodology, its sensitivity to input parameters, the effect of the non-linearity as well as a comparison to the equivalent gain frequency domain approach is shown.
Keywords: Gust Loads Analysis, Continuous Turbulence, Non-Linear Control, Exceedance Counting.

Excerpt from: IFASD 2007, Stockholm.

Efficient method for coupling discrete gust loads analysis in the frequency domain with a fully non-linear flight control system simulation

Patrick Teufel, Michael Kruse

An efficient method to couple frequency domain analysis and time domain simulation for discrete gust loads analysis is presented. This is achieved by solving the convolution integral time step by time step coupled with the flight control system simulation to obtain the time histories of the control surfaces of the aircraft during gust encounter. With control surface histories available time histories of a very large number of output quantities of the aircraft can be generated very efficiently with classical Fast Fourier Transformation (FFT) method of discrete gust analysis. It is shown that the method is robust, furthermore typical issues that occur during FFT analysis of aircraft transfer functions are discussed.
Keywords: Gust Loads Analysis, Non-Linear Control, Fourier Transformation.