A Physics-based Approach to Assess Critical Load Cases for Landing Gears within Aircraft Conceptual Design

Abstract

The European Union and the United States are proposing to bring in more strict flight vehicle emission criteria in their reports of the high‐level groups on aviation research, i.e. EU Flightpath 2050 and US Destination 2025. More fuel‐efficient aircraft must be developed to achieve this target. Moreover, the increasingly competitive aviation market also expects more fuel‐efficient aircraft to be designed. An efficient and reliable aircraft design with a decreased weight could significantly contribute to the improvement of aircraft economical and environmental performance. Various research studies have highlighted the potential for significant weight savings on the landing gear system. In general, the landing gear accounts for around 5% of aircraft Maximum Landing Weight. In the aircraft conceptual design stage, there are two methods to achieve weight savings on the landing gear system: 1. Investigation of conventional designs 2. Introduction of innovative designs In the use of these two methods, a key step is to verify the design of the landing gear w.r.t certain critical load cases. A landing gear critical load case is defined as a set of combinations of aircraft flight attitudes and motions, control surfaces and engine throttle settings, and environmental conditions that could lead to damage and failure of the landing gear structure. These critical load cases reflect the possible extreme conditions that might occur in operation. These critical load cases are traditionally obtained by utilizing the methods based on statistical data while ignoring specific flight dynamics and landing gear characteristics. These methods could lead to three problems.