Resolution of indeterminate landing gear structure design
thesisposted on 23.05.2021, 18:14 by Bradley James Greenland
Aircraft landing gear structural designs involves a balance of weight, cost and robustness while not compromising on safety. On some large commercial aircraft, the introduction of a second main supporting brace has led to an indeterminate structure in that there is redundancy in the load paths. This introduces two major challenges for structural design. The first challenge involves the introduction of a multiple load path. Understanding load path in the landing gear is critical in order to optimize the structure for weight. This report focuses on analysis techniques geared to resolving this indeterminate load path in order to mitigate this risk and optimize the design. The second major challenge is introduced by a compressive load in one of the braces during an in flight airload condition which impedes the ability for the landing gear to freefall, which is a requirement in aircraft design. Solving this problem involves introducing a pretension in the brace by force shortening the geometry. An indeterminate design introduces increased complexity and requires more simulation and analysis than that of a determinant design in order to accomplish the optimization demanded by the aerospace industry.