Non-stationary oscillations of sandwich plates under local dynamic loading

The paper addresses the elastic response of composite sandwich panels to local\ud dynamic loading. The plane and axisymmetric formulations are considered; no\ud overall bending is assumed. The governing equations are derived using the static\ud Lamé equations for the core and the plate Kirchoff-Love dynamic theory for the\ud faces. The closed form solutions for the non-stationary excitation are obtained\ud using integral transformations technique. The solutions allow to predict the stressstrain state of the structure and are in good agreement with finite element analysis

Effect of Physical Nonlinearity on Local Buckling in Sandwich Beams

This article deals with experimental, theoretical, and FE characterization of the local buckling in foam-core sandwich beams. In the theoretical approach, this phenomena is considered in a periodic formulation (unbounded wrinkle wave); a nonlinear stress—strain response of the face material is accounted for. In the FE approach, nonlinearity of the core material is also modeled. Full-field strain measurement is employed in the tests showing that the commonly used edgewise compression set-up can cause premature waviness of the faces, and therefore, nonlinear local deformations in the core layer

Stability of the face layer of sandwich beams with sub-interface damage in the foam core

This paper addresses the effect of local indentation/impact damage on the bearing capacity of foam core sandwich beams subjected to edgewise compression. The considered damage is in a form of through-width zone of crushed core accompanied by a residual dent in the face sheet. It is shown that such damage causes a significant reduction of compressive strength and stiffness of sandwich beams. Analytical solutions estimating the Euler’s local buckling load are obtained for two typical modes of damage. These solutions are validated through experimental investigation of three sandwich configurations. The results of the analytical analysis are in agreement with the experimental data

Compression strength of sandwich panels with sub-interface damage in the foam core

This paper addresses the effect of a local quasi-static indentation or a low-velocity impact on the residual strength of foam core sandwich panels subjected to edgewise compression. The damage is characterized by a local zone of crushed core accompanied by a residual dent in the face sheet. Experimental studies show that such damage can significantly alter the compressive strength. Theoretical analysis of the face sheet local bending is performed for two typical damage modes (with or without a face–core debonding). The solutions allow estimation of the onset of (a) an unstable dent growth (local buckling) or (b) a compressive failure in the face sheet. The theoretical results are in agreement with the test data for two considered sandwich configurations

The elastic response of sandwich structures to local loading

The paper addresses the elastic response of sandwich panels to local static and dynamic loading. The bottom face is assumed to be clamped, so that the overall bending is eliminated. The governing equations are derived using the static Lamé equations for the core and the thin plate Kirchoff–Love dynamic theory for the faces. The plane and axisymmetric formulations are considered. The closed-form solutions are obtained using Fourier–Laplace (Hankel–Laplace) integral transformations for the cases of forced excitation and impact by a rigid body. The solutions allow to predict the stress–strain state of the structure. The analytical solutions demonstrate a good agreement with experimental data and finite element analysis