Experimental fatigue crack growth analysis of the aircraft structural component subjected to different cycling loading has been presented. The purpose of the experimental test was to evaluates the fatigue behavior of the real aircraft spar, made in aluminum 2024-T3. In-house laboratory fatigue test installation is described in the paper. The spar-test specimen has been manufactured specifically for the cycling damage testing. Test results were obtained with most modern equipment for data acquisition. Applied loads and obtained spar fatigue results are described in detail. Conclusions have been made with reference to the previous work on the duraluminum spar fatigue testing. As it is presented in the previous work with advanced numerical methods for fatigue analysis, in this paper is given an opinion on the same. At the end, possible directions of the further experimental spar fatigue testing is given and shows us that it makes sense to make the comparison between real and numerical results only in situations where cracks behave similarly and the numbers of required cycles are about the same.

Designing the motion platform for the flight simulator is closely coupled with the particular aircraft’s flight envelope. While in training, the pilot on the motion platform has to experience the same feeling as in the aircraft. That means that flight simulators need to simulate all flight cases and forces acting upon the pilot during flight. Among many existing mechanisms, parallel mechanisms based on the Stewart platform are suitable because they have six degrees of freedom. In this paper, a real coded mixed integer genetic algorithm (RCMIGA) is applied for geometry optimization of the Stewart platform with rotary actuators (6-RUS) to design a mechanism with appropriate physical limitations of workspace and motion performances. The chosen algorithm proved that it can find the best global solution with all imposed constraints. At the same time, the obtained geometry can be manufactured because integer solutions can be mapped to available discrete values. Geometry is defined with a minimum number of parameters that fully define the mechanism with all constraints. These geometric parameters are then optimized to obtain custom-tailored geometry for aircraft flight simulation.

The assessment of the service durability of aerospace components and assemblies has become an important segment of design. In order to meet strict safety requirements, a number of complex and long experiments are carried out. The use of finite element method (FEM) and extended finite element method (XFEM) for the estimation of fatigue life and fatigue crack growth predictions has been proved as a good alternative to the expensive experimental methods.In this paper, both experimental and numerical analyses of 2024-T3 aluminum spar of a light aircraft under variable amplitude loading are presented. FEM has been used for estimation of the spar life to crack initiation, whereas XFEM has been used for fatigue crack growth predictions and fatigue life estimation of damaged spar. The values of stress intensity factors were extracted from the XFEM solution in MorfeoCrack for Abaqus software. Numerical results (i.e. number of cycles to failure) have corresponded well with the experimental values obtained for the spar made of 2024-T3 aluminum alloy.The investigations have shown that it's possible, using XFEM, to obtain not only the good estimation of fatigue life of the assembly such as the spar of the light aircraft, but also a good prediction of a number of load cycles which will propagate a crack to a certain length. On the basis of these results, it is possible to determine the proper inspections intervals which could prevent the catastrophic failure of the aircraft structure under variable amplitude loading.

This paper presents the application of the extended finite element method (XFEM) in crack propagation simulation on the integral wing spar that should replace existing differential spar of the light aircraft UTVA 75. Numerical model of...