INVESTIGATING THE INFLUENCE OF CERTAIN PARAMETERS ON THE DYNAMIC CHARACTERISTICS OF A COMPOSITE WING STRUCTURE
Keywords:
KEYWORDS: Stiffnesses; Composite Material; Fibre Orientations; Free Vibration. INTRODUCTIONAbstract
ABSTRACT
This paper discusses the effect of some parameters such as fibre orientations, laminate stacking sequence, aspect ratios and stiffness of the rectangular composite wing box models for the free vibration analysis on two wing configurations, the first one producing a material coupling, bend-twist stiffness and the other without material coupling, bend-twist stiffness vanishes. A computer program within MATLAB language is developed to deal with the calculation of the bending, torsion and bend-twist stiffnesses ( , , and ) for the two wing configurations in order to understand their behaviour. Free vibration analysis is also carried out using the finite element program MSC/PATRAN and MSC/NASTRAN v2004 for the same wing configurations. The maximum bending stiffness, torsion stiffness and bend-twist coupling stiffness are found at 0o, ±30 o and ±20 o fibre orientations respectively for the CAS and with zero coupling for the CUS models. It was found that wing stiffnesses are universally proportional with the aspect ratios. A similar variations of the material stiffnesses, eigenvalues and associated eigenvectors versus fibre angle are observed. The effect of aspect ratio on the fundamental bending frequency is almost negligible compared with the torsional frequency, whereas is more pronounced on the torsional frequency compared with bending frequency.