O FECHO DE FENDA COMO CAUSA PRINCIPAL PARA AS INFLuENCIAS DA TENSÁO MÉDIA E DA ESPESSURA NA VELOCIDADE DE PROPAGAÇÁO DE FENDAS POR FADIGA NO AÇO CK45

Luis M. P. Abreu  José D. Costa  J. M. Ferreira      

Anales de la Mecánica de la Fractura, nº 13 . 1996 . Pág. 351 -356
Ver (.pdf): Anales13-059

Resumen: In this work the influence of the stress ratio on the crack closure propagation rate was analysed for R=O, 0.2 and 0.4. The material used in this study was the steel CK 45 DIN 17200. Also, the influence of thickness on the crack propagation rate was analysed for B=6, 12 and 24 mm. Crack length was monitored by the optical method and by the direct current potential drop (DCPD) technique. The crack closure measures were obtained by the compliance technique, using a gauge similar to the Elber type. From the load versus displacement plots, the crack opening loads P ab were obtained and used in the calculation of the effective range of the stress intensity factor, t:.Ker. The plots da/dN -t:.Ker show that the closure phenomenon seams to be the main cause to explain both intluences of the mean stress and t11e thickness on the crack propagation rate in the París regime.

LocalizaciónLuso, Portugal

Departamento de Engenharia Mecanica/ FCT. Universidade de Coimbra, Polo ll, Pinbal de Marrocos 3030 Coimbra, Portugal
Departamento de Engenharia Mecanica/ FCT. Universidade de Coimbra, Polo ll, Pinbal de Marrocos 3030 Coimbra, Portugal
Departamento de Engenharia Mecanica/ FCT. Universidade de Coimbra, Polo ll, Pinbal de Marrocos 3030 Coimbra, Portugal