M. Theiss, T. Wagner, R. Vacchelli, D. Rigamonti

A central issue that has to be considered when thinking of aircraft fatigue, aging aircraft and life extension of aircraft structures, is the information basis used to perform theoretical analysis. To guarantee a safe operation for the helicopter structure, in many repair cases the decisions have to be taken according to the available certification documentation (load analysis, stress reports, etc.), which usually is not as extensive as information created nowadays with FEM and other methods. This means that decisions have to be taken as conservative as the assumptions made during the aircraft design. This can be a very expensive method, considering that the design assumptions were conservative in order to minimize the calculation effort and risk. Taking this theory into account, RUAG Aerospace Services GmbH created a project to reanalyse the structure of the complete UH-1 D helicopter using FEM, regenerate the basic helicopter analysis (calculation tables from the early 60s) with computer programs (Excel) and compare the calculated results with an operational load measurement (OLM) considering one basic design flight manoeuvre defined for this helicopter during its development. The purpose of this project is to gain experience on the conservativeness of the assumptions made during the development of the helicopter by comparing the original approved structural analyses with an operational load measurement (OLM) and a Finite Element Model validated with the OLM data. The research for this paper is done for the load analysis of the airframe structure. It does not contain the load analysis of the dynamic components such as the rotor system, control system, main gear and engine.

23rd ICAF Symposium of the international Committee on Aeronautical Fatique, 2005, Hamburg

Conference Paper

englisch

A5, 18 Seiten

DGLR-Bericht, 2005, 2005-03, 23rd ICAF Symposium of the international Committee on Aeronautical Fatique - Proceedings; S.283-300; 2005; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

certification, analysis methods, design criteria, load analysis

Bestellbar

2005