Sandwich-structured composite

About: Sandwich-structured composite is a research topic. Over the lifetime, 5853 publications have been published within this topic receiving 101126 citations.

Dynamic failure of honeycomb-core sandwich structures subjected to underwater impulsive loads

Abstract: The aluminum sandwich structures with hexagonal honeycomb cores subjected to water-based impulsive loading are studied experimentally. The blast resistance in terms of dynamic deformation, failure modes and associated mechanisms is evaluated in relation to the load intensity, core relative density under air-backed and water-backed conditions. 3D digital imaging correlation and postmortem analysis are used to investigate the deformation and failure of individual components, focusing on the effects of loading intensities, core relative density and loaded condition. The failure mode maps of sandwich panels are summarized to study the different regimes of deflection resistance in different experimental cases. The results show that the effect of relative core density significantly influences the blast resistance of sandwich panels under the different loaded conditions. The sandwich panels with denser cores perform better blast resistance at high impulsive loads under air-backed condition. Only slight discrepancy of deflection resistance has been observed under the water-backed condition. The honeycomb sandwich panels suffer significantly smaller backface deflections than solid plates of identical mass per area under air-backed condition, while the discrepancy of deflection is negligible under the water-backed condition.

Damage tolerance of a composite sandwich with interleaved foam core

Abstract: A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was doen to prevent core cracking and improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity, drop-weight impacts as well as high-velocity, ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50% of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low velocity and ballistic impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role. The superiority (in damage tolerance) of the composite sandwich with interleaved foam core, as compared with its plain version, is well established. This is attributable to the toughening effect of the interlayers which serve the dual role of crack arrestor and energy absorber of the impact loading.

Improving honeycomb-core sandwich structures for impact resistance

Abstract: An aluminum honeycomb was filled with a rigid foam to improve its mechanical properties. This foam-filled honeycomb was used to construct sandwich panels with graphite/epoxy composite face sheets. The mechanical properties of the foam -filled honeycomb were found to be superior to the unfilled honeycomb. Low velocity impact test results indicated that the sandwich panel containing the new core had much improved impact resistance and that the impact-inflicted core crushing was highly localized.

Efficient structural components using porous metals

Abstract: Porous metals can now be produced by a variety of techniques After reviewing the available processes we describe the potential for their use in efficient structural components, including honeycomb beams, sandwich panels and cylindrical shells with porous cores

Static Analysis of Sandwich Panels with Square Honeycomb Core

Abstract: Static analysis of sandwich panels with a square honeycomb core is performed using the finite element approach applied to the plate theories. The constitutive behavior of an equivalent continuum to the core is obtained using the strain energy approach. The displacement field of the sandwich panel modeled using the equivalent continuum is then compared with results obtained from a highly detailed finite element method created in ABAQUS. The comparison shows the results of the higher-order shear deformation theory in error of 7.6% compared with the detailed model results. An equivalent single layer finite element method for the sandwich panel was then created in ABAQUS and the displacement results of this equivalent single layer model are compared with those obtained from the detailed finite element method. This comparison reveals an error of 6.1% in the results between the two models. A comparison between the equivalent single layer model and the highly detailed model is presented for different core relative densities at two locations of the sandwich panel. A detailed finite element method analysis of the unit cell of the square honeycomb was next performed using ABAQUS and the flexibility approach. Comparison between the equivalent strain energy approach and flexibility approach applied to detailed ABAQUS models of the unit cell proved the equivalent strain energy approach to be efficient.