7,293 research outputs found
Evaluation of overload effects on fatigue crack growth and closure
Fatigue crack propagation tests with single tensile peak overloads have been performed in 6082-T6 aluminium alloy at several baseline [Delta]K levels and stress ratios of 0.05 and 0.25. The tests were carried out at constant [Delta]K conditions. Crack closure was monitored in all tests by the compliance technique using a pin microgauge. The observed transient post-overload behaviour is discussed in terms of overload ratio, baseline [Delta]K level and stress ratio. The crack closure parameter U was obtained and compared with the crack growth transients. Experimental support is given for the hypothesis that plasticity-induced closure is the main cause of overload retardation for plane stress conditions. Predictions based on crack closure measurements show good correlation with the observed crack growth rates for all the post-overload transients when discontinuous closure is properly taken into account.http://www.sciencedirect.com/science/article/B6V2R-46WPH0W-3/1/82b49d3e31362370a08505d5d300b60
Preferência de ninfas de Euborellia annulipes (Lucas) (Dermaptera: Carcinophoridae) por ovos de Anagasta Kuehniella (Zeller) (Lepidoptera: Pyralidae) parasitados ou não por Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).
Produtividade e teor foliar de nutrientes no sorgo granífero cultivado na safrinha em solo do cerrado.
Estudo dos solos do município de Santa Vitória do Palmar.
bitstream/item/41413/1/Santa-vitoria-do-palmar.pdf; bitstream/item/41414/1/mapa-capacidade-de-uso.pdf; bitstream/item/41415/1/mapa-geomorfologia-e-solos.pdf; bitstream/item/41416/1/mapa-solos.pd
Desenvolvimento de Euborellia annulipes (Lucas) (Dermaptera: Carcinophoridae) em dietas artificiais com diferentes teores de proteína.
- …