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Damping mechanics for predicting the damped dynamic characteristics in specialty composite structures with compliant interlaminar damping layers are presented. Finite-element based mechanics incorporating a discrete layer (or layer-wise) laminate damping theory are utilized to represent general laminate configurations in terms of lay-up and fiber orientation angles, cross-sectional thickness, shape and boundary conditions. Evaluations of the method with exact solutions and experimental data illustrate its accuracy. Additional parametric studies demonstrate the unique capability of angle-ply composite laminates with cocured interlaminar damping layers to significantly enhance structural damping.

Damping mechanics consists of micromechanical, laminate and structural complexity, as well as interlaminar shear effects. This method displays higher damping under increased laminate thickness and elevated temperatures. This method is very accurate and more responsive toward interlaminar shear than toward natural frequencies.

Computational mechanics, used for the analysis of damping and other dynamic features of thick composite structures, reveals the effectiveness of this method in simulating the damping of thick composite structures. A new discrete-layer assumes a discrete yet piecewise continuous displacement field through the laminate, which is the basis for the modeling of damping at the laminate level. The structural composite damping gets affected by the thickness, the mode order and the laminate configuration, and the three are strongly interrelated.

The influence of interplydamping layers on the dynamic stability of composite plates is studied. A newlydeveloped discrete layer laminate damping theory (DLDT), capable of determiningthe strain and dissipative energy in each damping layer, is used in the analysis. To validate its reliability, an experiment involving a specially fabricated composite plate with interlaminar damping is carried out. An excellent agreement is observed between the DLDT and experimental results.

A method for the multiobjective optimal designing of highly reliable and low-cost composite aircraft structures is discussed. The method was developed to incorporate the factors that could lead to the structures' optimal dynamic performance. These factors include the materials weight, cost and damping characteristics. The efficiency of the method was established through laboratory experiments involving a cantilever graphite/epoxy composite beam. Results indicated that the method is more reliable than traditional design techniques in improving the dynamic performance of aircraft structures.