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Thornton, H. R.

Publications and source records attributed to Thornton, H. R..

Mechanical properties of brittle materials

Brittle materials are difficult to tensile test because of gripping problems. They either crack in conventional grips or they are crushed. Furthermore, they may be difficult to make into tensile specimens having, for example, threated ends or donut shapes. To overcome the problem, simple rectangular shapes can be used in bending (i.e., a simple beam) in order to obtain the modulus of rupture and the elastic modulus. The equipment necessary consists of a fixture for supporting the specimens horizontally at two points, these points contact points being rollers which are free to rotate. The force necessary to bend the specimen is produced by a tup attached to the crosshead of an Instron machine. Here, the experimental procedure is explained.

Cornwell, L. R.↗

Investigation of fatigue strength of multilayer advanced fiber composites

The analytical characterization of a multilayer fiber composite plate (without hole) was accomplished for both static and dynamic loading conditions using the finite difference technique. Thornel 300/5208 composites with and without holes were subjected to static and tensile fatigue testing. Five (5) fiber orientations were submitted to test. Tensile fatigue testing also included three (3) loading conditions and two (2) frequencies. The low-cycle test specimens demonstrated a shorter tensile fatigue life than the high-cycle test specimens. Failure surfaces demonstrated effect of testing conditions. Secondary failure mechanisms, such as: delamination, fiber breakage, and edge fiber delamination were present. Longitudinal delamination between plies also occurred in these specimens.

Thornton, H. R.↗