1616. An Evaulation of Improved Analytically Based Weight

Paper

Abstract

Recent government initiated studies have shown that the configurations for aircraft in the future will be significantly different from those designed in the past. The new configurations will be difficult to accurately model in many of the present synthesis programs.
The requirements for the synthesis programs are that they provide a quick turn around and that they consistently give reasonably good estimates. However, in many synthesis programs their weight estimation methodology is based upon designs developed during the fifties, sixties, and seventies and the configurations coming out of our studies show that we need to update these mathematical models to take into account configuration characteristics considerably different from the past. Our intention is to update the Vought Aircraft Synthesis Analysis program (ASAP) to include many of these new methods, to enhance our capability to study the newer configurations with analytically correct methodologies. We can do it now, but it takes a great deal of adjusting the ASAP to develop correct estimates. Our intention is to update ASAP, and to model the new configurations correctly from the start as opposed to forcing the present methods to handle configurations outside of their original database. One of the new methods we will develop is a new geometry characterization routine. This routine will have a CADAM interface as well as an interface for the infrared and radar cross-section characterizations studies and routines which will require the spatial coordinates of the aircraft’s external and internal envelope. Other methods we are considering include modeling additional structural concepts such as blended bodies, and engines buried in the wing. We have performed feasibility studies on methods to assess the impact of crack growth criteria. We will develop methods that break out the weight estimate for portions of a fuselage as opposed to the whole fuselage and methods to model and estimate composite construction as composite in lieu of applying an increment to aluminum structure. We will also include two more wing construction techniques. There will be catalog procedures to enhance ASAP’S productivity and we have investigated a new approach to structural analysis that is close to a finite element type methodology. It is an energy solution methodology but it does not require the same degree of nodal point data and interfacing that NASTRAN does.