On the viscoelastic response of laminated composites.

• Main Author: Feng, Jie.
• Other Authors: Haddad, Y.
• Format: Others
• Published: University of Ottawa (Canada) 2009
• Subjects: Applied Mechanics.
• Online Access: http://hdl.handle.net/10393/8593; http://dx.doi.org/10.20381/ruor-15894

This thesis addresses the problem of analytical determination of the response behaviour of fibre reinforced composite materials, under both quasi-static and dynamic loadings. In the first part of the thesis (Chapters 2 and 3), the effects of microstructural parameters, such as fibre aspect ratio, fibre off-axis angle and fibre volume fraction, on the damping and stiffness of a fibre-composite system are examined. Quasi-static models are, then, developed by using a "Forced Balance Approach" to define mechanical response properties of discontinuous fibre reinforced composite materials. Subsequently, simultaneous optimization of damping, stiffness and weight is carried out by using the so-called "Inverted Utility Function Method". The obtained results show that discontinuous fibre-reinforced composites have superior design flexibility and higher damping properties as compared with those pertaining to continuous fibre-reinforced composites of the same material. In the second part of the thesis (Chapters 4 and 5), the determination of the impact response of laminated composite plates is dealt with. In this context, the "First Shear Deformation Theory (FSDT)" is employed to deal with the so called "Transient Wave Propagation Phenomenon". In this, the "Correspondence Principle" is, then, utilized to extend the obtained elastic solutions to corresponding viscoelastic problems. Here, the closed form displacement solutions are obtained first in the frequency-domain, then, the "Fast Fourier Transformation (FFT)" is applied to invert numerically the dealt-with solutions from frequency-domain to time-domain. The obtained results emphasize the importance of including viscoelastic effects in the analysis, for the prediction of the mechanical response of laminated composites under impact loading.