کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
797598 | 1467484 | 2013 | 15 صفحه PDF | دانلود رایگان |
The growth of 3D star-like cracks in a porous borosilicate glass was induced by “cold-to-hot” thermal shocks inducing triaxial tension in cylindrical specimens. As a consequence of the dynamic character of their propagation, the cracks had a “mirror-mist-hackle” aspect. Damage in unbroken specimens was characterized either by a modification of their vibration modes or by direct observations of sections. Pores were identified as the crack initiation sites. Thermo-mechanical simulations were done to analyze the stress field and its consequences, using either linear thermo-elasticity or an anisotropic continuum damage mechanics approach. Crack initiation was predicted at mid-height, at the center of the specimens, in accordance with the observations. The pore-induced stress concentration was shown to depend on the local stress triaxiality, as well as the stress intensity factor for an annular crack initiated from a pore. The capacity of the anisotropic continuum damage approach to predict qualitatively the influence of the shape of the specimen, as well as damage-induced modifications of vibration modes and the total fracture surface was demonstrated.
► Glass specimens were broken in triaxial tension induced by cold-to-hot thermal shock.
► Cracks initiated from pores propagated dynamically with a “mirror-mist-hackle” aspect.
► Damage in unbroken specimens was detected by a change of their vibration modes.
► An anisotropic continuum damage mechanics model was used for numerical simulations.
► The model predicts well the increase in fracture surface with the thermal amplitude.
Journal: Mechanics of Materials - Volume 57, February 2013, Pages 15–29