Calculating Inertial Loads of Aeroplanes Using Simulation

Fatigue is one important factor that affects the structure of military and civil aeroplanes. Hence, their life spans and endangers the flight safety. One of the factors that cause fatigue is the change loading on the plane structure. This is why many researches have been done to determine and calculate these loads, especially those applied during the service life. The loads are of two types, namely inertia and aerodynamic. The magnitude of the inertial loads depends on the vertical and angular accelerations that affect the mass distribution of the plane components. Calculation of these accelerations during different air maneuvers is of utmost importance. In this paper, a method has been presented for the calculation of inertia loads applied on aeroplanes during their services life. For this purpose, a training aircraft was selected as a specimen and its fuselage was divided longitudinally in to 100 parts. Then, mass distribution along the plane body was specified and the mass of every part calculated. Finally, to calculate the local shear inertia loads applied on each part, an equation was defined in terms of the linear and angular accelerations affecting the magnitude of the loads using analytical methods.To find the values of the accelerations used in and this equation, the selected training plane was simulated and the results of simulation were validated using the data found from test flights. The inertial loads applied on the fuselage (during a loop maneuver) were calculated using the parameters found from simulation. Obviously, the calculation process can be generalized to wide-body transportation planes too. Results have revealed that the proposed method for the determination of the distribution of the inertial loads applied on the fuselage (during its service life), with low cost and avoidance from real flights risks, is appropriate.