A higher order plate theory for dynamic stability analysis of delaminated composite plates

Abstract

A higher order shear deformation theory is used to investigate the instability associated with delaminated composite plates subject to dynamic loads. Both transverse shear and rotary inertia effects are taken into account. The procedure is implemented using the ®nite element method. Delamination is modeled using the penalty parameter approach. The natural frequencies are computed and compared with NASTRAN 3D results and available experimental data. The effect of delamination on the critical buckling load and the ®rst two instability regions is investigated for various loading conditions, plate thickness and boundary conditions. As expected the natural frequencies and the critical buckling load of the delaminated plate are lower than those of the nondelaminated plate. They decrease with increase in delamination length. Increase in delamination length causes instability regions to be shifted to lower parametric resonance frequencies and the normalized width of the instability regions to increase.

Vibration of delaminated multilayer beams

“…They modeled the delaminated region by using additional boundary conditions at the delamination fronts. Chattopadhyay et al [15], Radu and Chattopadhyay [16] and Hu et al [17] presented finite element models using higher-order shear deformation theories.…”

Vibration of composite beams with two overlapping delaminations

“…They modeled the delaminated region by using additional boundary conditions at the delamination fronts. Finite element methods using the higher-order deformation theory were presented by Chattopadhyay et al [13], Radu and Chattopadhyay [14] and Hu et al [15].…”

Load and frequency interaction effects in dynamic buckling of soft core sandwich structures

“…5(a)). In contrast to the situation at the buckling point for the overall instability, the development of the face wrinkling instability does not result in a complete loss of the oscillation capability o the system with a vanishing frequncy f (1) .T hesharpdropinthenaturalf requancyf (1) is followed by a sudden re-increase, however, to a lower level than prior to the drop in the eigenfrequency. The lower values of the first natural frequency f (1) in comparison to the values in the pre-wrinkling state remain present thoughout a further increase of th eapplied load.…”

“…Notice that the boundary condition of simply supported external edges all around the considered structure has already been applied in the definition of the analytical solution procedure in Sec. 2.5. In Figs In Figs.5(a) and (b), the dynamic solution of the problem is presented, considering the two natural frequencies f (1) and f (2) . Starting from an initial value of f (1) = 0.2055 kHz, the first natural frequency decreases monotonously with increasing applied edge deflectionû a 1 and thus increasing resultant edge loadN a 11 .…”

“…Especially in cases, where the static pre-loads are in the vicinity of the respective buckling loads, the natural frequencies might be subject to distinct variations. Whereas Kuznetsov [12] provided criteria for dynamic buckling, Chattopadhyay et al [1] have presented a finite element development and analysis of interactions of the resonance frequencies with external loads and growing delaminations in composite plates. For monolithic plates and shells, the interaction of the natural frequencies with static and thermal pre-loads has been studied, among others, by Librescu et al [13], [14].…”