Stress Analysis of The Vertical Tail Skin Joint and Estimation of Fatigue Life Due to Fluctuating Side Loads

Vertical tail VT is one of the main components of the airframe. VT is attached with a rudder, which is the control surface, which is used for controlling the yawing motion of the aircraft. The deflection of the rudder introduces side load on the VT. Without rudder deflection, the aerodynamic load will not be applied to the VT. The load due to the deflection of the rudder is the major load for the VT. From a design point of view side, gust load is also important in transport aircraft. The present study is on a critical region with a riveted joint in the VT skin. A stiffened panel of the vertical tail with the spliced skin will be considered for the identification of the critical location. FEM will be used for the analysis of the component. In this study, loads of small transport aircraft will be considered. The maximum stress location and distribution of stresses on the stiffened panel are conducted by the FEM method. To obtain the mesh independent magnitude of stress, a refined local analysis is conducted. The tensile stresses on the skin are caused by the side loads of VT on the stiffened panel. Rivet holes are the stress concentration locations. The locations for fatigue crack initiation is the rivet holes. Fatigue damage estimation is calculated by the use of Miner's rule. Fluctuating loads due to rudder deflection will be considered for damage calculation. SN data curve of the aluminium alloy material used for the VT skin will be considered for stress-based damage calculation.