Showing papers on "Sandwich panel published in 1977"
TL;DR: In this article, a parametric cubic modeling system for lines, surfaces, volumes, and physical data that uses construction-in-context to generate numerical data is presented with applications to structures of composite material.
Abstract: A new approach to modelling solids that are anisotropic and heterogeneous is presented with applications to structures of composite material. A parametric cubic modelling system is presented for lines, surfaces, volumes, and physical data that uses construction-in-context to generate numerical data. This system automates the construction of discrete element models and can reduce input data requirements by more than an order of magnitude. A tricubic isoparametric discrete element is presented that does not require displacement derivatives to define connectivity. This element is capable of exact displacement and strain continuity over a surface while permitting strain discontinuities at heterogeneous material interfaces. The shape of an element can be any hexahedron, pentahedron, or tetrahedron and the material properties are allowed to vary over the volume. Evaluation of modelling error with respect to closed-form solutions for curved geometries indicate a single element can model up to 90-degree segments with stresses accurate to 1 per cent. Applications of the system to composite structures are presented for interlaminar edge effects and attachment stresses in a sandwich panel.
48 citations
Patent•
02 May 1977
TL;DR: A structural panel material of the sandwich-type construction includes inner and outer facings and a core bonded between the facings as discussed by the authors, which has the highly desirable characteristics of being flexible enough to conform to a mold shape under gravity and with the application of little or no external pressure so that special jigs are not required.
Abstract: A structural panel material of the sandwich-type construction includes inner and outer facings and a core bonded between the facings. The core includes a plurality of blocks of lightweight core material, such as rigid or semi-rigid plastic foam, balsa wood, or a combination of plastic foam. These blocks are arranged in strips. The strips are joined together by corrugated sheet material. In a preferred embodiment, double-sided corrugated paperboard is used to join the lightweight structural strips. The resulting core material has the highly desirable characteristics of being flexible enough to conform to a mold shape under gravity and with the application of little or no external pressure so that special jigs are not required.
20 citations
01 Sep 1977
TL;DR: In this article, the fatigue characteristics of an actively cooled structural panel for a hypersonic aircraft have been investigated for fatigue characteristics, which involved a bonded honeycomb sandwich panel with d-shaped coolant tubes embedded in the honeycomb, and the flat portion was either soldered to the inner surface of the outer skin.
Abstract: Elements of an actively cooled structural panel for a hypersonic aircraft have been investigated for fatigue characteristics. The study involved a bonded honeycomb sandwich panel with d-shaped coolant tubes. The curved portion of these tubes was embedded in the honeycomb, and the flat portion was bonded or soldered to the inner surface of the outer skin. The elements examined were two plain skin specimens (aluminum alloy); two specimens with skins attached to manifolds and tubes (one specimen was bonded, the other soldered); and a specimen representative of a corner section of the complete cooled sandwich. Sinusoidal loads were applied to all specimens. The honeycomb sandwich specimen was loaded in both tension and compression; the other specimens were loaded in tension only. The cooling tubes were pressurized with oil throughout the fatigue tests. The most significant results of these tests follow: All specimens exceeded their design life of 20,000 cycles without damage. Crack growth rates obtained in the plain skin specimens were used to determine the crack growth characteristics of aluminum alloy. Cracks in skins either bonded or soldered to cooling tubes propagated past the tubes without penetration. The coolant tubes served as crack arresters and temporarily stopped crack growth when a crack reached a tube-skin interface. The honeycomb core demonstrated that it could contain leakage from a tube.
1 citations