Development of a comprehensive process model for accurate prediction of quench induced distortion in a large size aircraft landing gear

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The manufacture of a landing gear requires special attention because it is the most mechanically solicited component of an aircraft with very tight geometric tolerances. SAFRAN Landing Systems, a world leader in landing systems, wants to increase its productivity in order to be more competitive. The process of manufacturing a landing gear made of high strength steel includes many machining steps to give the produce the desired geometry and a heat treatment to attain the required mechanical properties. However, the heat treatment process is accompanied by a change in geometry leading to possible part non-conformance thus resulting in an expensive concessions process sometimes ending with part rejection. To avoid this, a predictive model is needed to quantify this change. Improvement by trial and error is very expensive and non-viable. The use of numerical simulation is an interesting choice; however, the heat treatment process involves interactions of different physical domains such as the thermal, metallurgical and mechanical domains, making the problem very complex. Existing simulation models are unable to provide the required accuracy due to over-simplification of the physical models. As a result, the project will aim to deepen knowledge about the thermo-metallo-mechanical interactions involved in the heat treatment process to eventually have a more robust predictive model.