This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Fabrication and Analysis of Tetra-Core: A Layered Anisotropic Fiber Composite
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1972 by SAE International in United States
Annotation ability available
Tetra-Core is the name given to a fiber composite-material developed by the U.S. Army Aviation Materiel Laboratory, Fort Eustis, Va. This report discloses the initial studies conducted at the University of Kansas on Tetra-Core, including fabrication methods, analytical strength analyses, and experimental test results.
The Tetra-Core composite is formed by stacking oriented, spaced-fiber lamina in a repeating -60, 0, +60 deg pattern. Layers are offset slightly as the stacking occurs to produce a tetrahedrally shaped element.
An improved fabrication loom was conceived and tested. The loom concept is predicated on the fact that the intersection of two planes is a straight line. In the case of Tetra-Core, planes are formed by the buildup of lamina, intersecting to produce tetrahedrally shaped elements. The straight lines formed at these intersections are at an angle of 35 deg 15 min from the vertical. This sloped-wall loom concept provides for more positive fiber placement, higher fiber density, and greater flexibility than afforded by the first methods of Tetra-Core fabrication. This loom concept can be automated to produce either individual panels or a continuous sheet of Tetra-Core. Patent applications have been filed.
Tetra-Core is an orthotropic material that falls into the special category of quasi-isotropic fiber composites. Three strength analyses, based on the macroscopic properties have been conducted: netting analysis, layered anisotropic stringer analysis, and layered anisotropic lamina analysis. Results of all three analyses compare favorably.
An experimental test program was conducted to determine the coefficients of the compliance and stiffness matrices. Four elastic properties were measured: Young's modulus in the 1 and 2 directions, in-plane shear modulus in the 1-2 direction, and Poisson's ratio in the 1-2 direction.
|Technical Paper||Advanced Composite Manufacturing Methods|
|Technical Paper||Design & Analysis of Composite Impact Structures for Formula One Using Explicit FEA Techniques|
|Technical Paper||3D Woven Composites for Energy Absorption Applications|
CitationGordon, F., Forman, G., and Reese, C., "Fabrication and Analysis of Tetra-Core: A Layered Anisotropic Fiber Composite," SAE Technical Paper 720343, 1972, https://doi.org/10.4271/720343.
- Gordon J. E. “The New Science of Strong Materials.” Harmondsworth, Middlesex, England Penguin Books Ltd. 1968 162 168
- Tsai Stephen W. “Experimental Determination of the Elastic Behavior of Orthotropic Plates.” ASME Transactions 87 1965 315 318
- Gordon Frank E. “Fabrication and Analysis of Tetra-Core: A Layered Anisotropic Fiber Composite.” University of Kansas Lawrence 1971