Análise numérica de rigidez e vibrações livres de placas reforçadas: uma comparação entre o alumínio 7075 T-76 e compósito CFRP

Abstract

Composite materials make up more than 50% of the structural weight of modern commer cial aircraft, making it necessary to better understand the unique characteristics of this material in order to prevent accidents and optimize structural design. With this in mind, the aim was to carry out an analysis of the stiffness and vibration behavior of these materials in aerospace applications. Two materials were selected for comparison purposes: 7075 T76 aluminum and CFRP, materials widely used in aircraft structural components due to their high mechanical properties and low density. The analyses were carried out numerically using the finite element method with the software Abaqus. In addition, four stiffener shapes common in aeronautical applications were chosen to provide better component stiffness and relate their efficiency through stiffness-mass parameters. Equivalent stiffness, specific stiffness and vibration frequencies were measured for each stiffener shape using the two materials. Aluminum showed higher stiffness than composite for all the stiffeners applied, but CFRP showed higher stiffness-mass values, proving to be approximately 34% more efficient. The stiffness and efficiency of the reinforcements increased with the addition of elements, with I, L, T and U being ordered in ascending order. During the modal analyses, the vibration frequencies of CFRP were higher than those of aluminum, since its density is reduced and compensates for its lower stiffness. The vibration mode patterns obtained for each stiffener did not differ greatly between the materials.