Static and Vibration Analysis of Glare Hybrid Composite

Abstract

Hybrid composite, also known as fiber metal laminate (FML)composite materials have been subject of permanent interest of aerospace, military, aeronautics and mechanical specialists due to its low weight and high stiffness to weight ratio. Along with this is has good moisture resistance, corrosion resistance, fire resistance, fatigue insensitivity. It consists of alternating layers of metal sheets and fibre-reinforced composites. It has advantages of both metal as well as of composites. For any structure, natural frequency and damping behaviour is of very much importance as at this frequency the structure behaves in an uncontrolled manner. This study concerns fabrication and determination of natural frequencies, damping behaviour, mode shapes and elastic behaviour of GLARE hybrid composite rectangular panel (GHCRP). GLARE stands for Glass laminated aluminium reinforced epoxy. In first phase Glass reinforced composites are prepared using hand layup method and bonded to aluminium sheets using viscoelastic silicon glue to get the final hybrid material. Then Finite element software ANSYS is used to find out the mode shapes and natural frequencies for GLARE plate at various boundary conditions. A series of experimental investigations are conducted using a GHCRP in order to determine vibrational properties. Free vibration tests are conducted multiple times to find out damping factor of the glare material and forced vibration is carried out to find first two natural frequency of the same. The results from the experiments are compared with results obtained through FEA software. Further UTM is used to find out young’s modulus of the glass reinforced epoxy composite. From the UTM result, the fiber volume fraction is obtained and theoretical elastic modulus are calculated for verification. Finally the variation of natural frequency for various boundary condition as well as variation with aspect ratio are analysed. From the comparison, it can be inferred that due to minor errors associated with hand layup method like air traps,improper bonding, the experimental value of results are less than that obtained through computational work. Further the values of natural frequencies are higher in case of fully clamped plate and lower in case of two opposite sides simply supported plate case and with increase in aspect ratio the value of natural frequencies decreases.From the fabrication experience it is suggested to follow hand layup method with proper procedures and precautions to get smooth fine texture and accurate results.