Modelling of Damage in Laminated Composite Plates and Nonlinear Flutter Analysis

摘要

In this paper a vector of parameters representing distributions of the crack densities is used to model the damage. One can associate a particular damage mode to each linearly independent vector of damage parameters. Defining a damage mode as a specific combination of the damage parameters, the vector is made dependent on a single parameter representing damage. An important aspect is the role of damping in composite panels. The complete damped linear vibration response of cracked or damaged composite panels can also be modelled and related to single parameter in a particular mode of damage. Thus the dynamics of the composite panel may be modelled in terms of single damage parameter, a damage mode and a set of damping parameters. One application of this theory is to a benchmark problem of panel flutter. In this paper, analytical studies of damaged composite panels have been compared with results obtained earlier. The results of the root loci, damped vibration frequencies and mode shapes correspond to the results obtained in earlier studies. The primary aim is to study the influence of the damage dependent parameter vector representing distributions of the crack densities on the vibration characteristics and establish conditions when damage can induce significant changes in the vibration response. Qualitative conditions are established when damage can induce significant changes to the vibration response although the conditions near flutter are not significantly influenced.