Design aspects of light aircraft wing spar—Differential and integral approach

Three different wing spar designs (differential, equivalent integral, and optimized integral) are analysed, in order to establish the optimum one. Numerical analysis was carried out by extended finite element method (XFEM) and verified using the experimental data for differential wing spar, followed by the analysis of both equivalent and optimized integral wing spar. The optimized spar design regarding fatigue life was obtained by analysing three different cross sections of integral wing spar