A Fully Automatic Structural Optimization Framework to Determine Critical Loads

Critical loads play an essential role in early aircraft design studies. In order to determine a consistent envelope of critical design loads, a framework has to be introduced in which the dynamic models for loads calculation and the static models for aircraft structural design have to be evaluated and analyzed in an iterative manner. In the course of the DLR project Digital-X a process was established that generically builds an initial aircraft structural model and sizes it in a global optimization loop using updated dynamic models for calculating the trim, gust and maneuver loads necessary to ensure structural integrity as prescribed by the Federal Aviation Regulations (FAR). In this paper the fully automated aeroelastic analysis, flight loads prediction and structural sizing process is presented that determines the design loads used in the Digital-X multidisciplinary design optimization (MDO) framework.