Simulation of Residual Stress in Welding and its Influence on External Loads in a Structure

Jagadish Ramaiah, Asha Koshy

GKN Aerospace India


Fusion welding of fabricated parts is an important step in the manufacturing and assembly of large aero engine components. In some of the structural components such as Turbine Exhaust Case (TEC), the total length of welds put together could run as long as 30-50 meters. Welding during the manufacturing or repair of an assembled part could induce residual stresses and if sufficient heat treatment cannot be carried out to relieve these stresses, the residual stresses could adversely affect the life and durability of the component under the influence of other external thermal, pressure and mechanical loads. Hence, it becomes important to consider the effect of residual stresses in determining the strength and life of a structure from a flight worthiness requirement. In this paper, a methodology is discussed on how to simulate welding process for residual stress computation and how to include these residual stresses into further structural analysis of a component under other external loads. The final stresses computed could be used for determining the initiation and propagation life of the component or to assess if the structure has enough strength margins from a durability requirement. The case study discussed in this article highlights a generalized approach that can be used for any structural component and the simulation is carried out using LSDYNA.

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