Calculated and Measured Strength of a Composite Aircraft Undercarriage Spar

The main aircraft undercarriage spar was designed using various criteria for laminate strength. The calculated stress-strain status was evaluated simultaneously with the use of basic phenomenological and mechanistic criteria for the set operating modes and the requested safety factors. Subsequently, prototypes of the spar were manufactured and subjected to structural tests. The obtained results provide important information concerning the reliability of the employed criteria in terms of prediction of the point of critical damage and the level of the corresponding load when applied on an actual aircraft component featuring a general reinforcement structure.