Low cycle fatigue (LCF) life plays an important role in the design of aircraft engine components, especially that of bolted joints. Bolted joints are of critical importance in aircraft engines as they connect parts and transfer loads. In gas turbine engines, most of the bolted flanges experience high pressure loads & high thermal gradients. LCF life/stress is very sensitive to the thermal gradients encountered in flight cycle (from idle to takeoff & takeoff to landing). Accurate flange leakage modeling & accurate boundary condition estimation are critical to design.
This paper emphasizes on thermal analysis of bolted flange using the finite element method. Thermal analysis results show that, during flight cycle (Accel/Decel), flange leakage is a key contributor to thermal gradients. The flange leakage is majorly influenced by the gap between the flanges. Parametric studies have been carried out to understand the impact of gap between the flanges, flange thickness and flange height on the flange thermal gradients. The results presented in this paper will be helpful to the designer in designing better bolted flange joints with improved LCF life.
