The use of dough moulding compound (DMC) as a structura~ material will be feasible as more information on mechanlcal properties becomes available. In this investigation, room temperature tensile and fatigue properties were determined prior to the testing and evaluation of simple joints in DMC. The DMC was supplied in the form of compression moulded sheets. Tensile tests were conducted to British Standards specification to obtain the mechanical properties and to identify possible sources of variability in properties. Differences in tensile strength due to sheet-to-sheet variability and specimen orientation within a sheet were significant but there was no significant variation due to the cross-head speed over the range O.05mm/min to 300mm/min. Tensile fatigue tests were conducted to British Standards specification. The scatter of fatigue lives was found to be greater than that for other reinforced plastics, but was adequately described by both the Log-Normal and Weibull distributions. In tensile and fatigue tests on larger specimens there was no size effect on tensile strength, but the fatigue strength at a given life and probability of failure was reduced ,slightly. When specimens contained bolt holes, the tensile strength decreased marginally, but the fatigue strength was not affected. Transverse compressive stresses due to a bolt load had little effect on the fatigue behaviour and changes in the cyclic-or static stress did not significantly alter the bolt load relaxation. Cyclic stress was found to cause greater bolt load relaxation than the corresponding mean stress. In tensile and fatigue tests on single shear lap joints, benditig wa~ the main cause of failure and the joint efficiency was low, 43% in tension and 51% in fatigue. By loading the specimens through the bolts at one end, bending was eliminated and the joint efficiency increased to 62% in tension and to 78% in fatigue
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:258452 |
| Date | January 1980 |
| Creators | Huston, Robert James |
| Publisher | Kingston University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.kingston.ac.uk/20476/ |
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