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A numerical study was conducted to simulate and predict damage initiation and growth around the crack tip in particulate composite specimens made of hard particles embedded in a soft rubber-like matrix material. Therefore, damage evolution in the matrix material around crack tips was investigated. The progressive damage was modelded using a micro/macro-approach which combined two levels of analyses like the micro-level and the macro-level analyses. Damage description was undertaken at the microlevel using a simplified three-dimensional unit-cell model and an isotropic continuum damage theory. The numerical study examined both thin and thick specimens with a short or long edge crack to understand the effects of specimen thickness and crack size on the damage initiation, growth, and saturation. Some numerical results were validated by experimental data.

We studied the chronology of galactic bulge and disc formation by analysing the relative contributions of these components to the B-band rest-frame luminosity density at different epochs. We present the first estimate of the evolution of the fraction of rest-frame B-band light in galactic bulges and discs since redshift z~0.8. We performed a bulge-to-disc decomposition of HST/ACS images of 3266 galaxies in the zCOSMOS-bright survey with spectroscopic redshifts in the range 0.7 < z < 0.9. We find that the fraction of B-band light in bulges and discs is $(26 \pm 4)%$ and $(74 \pm 4)%$, respectively. When compared with rest-frame B-band measurements of galaxies in the local Universe in the same mass range ($10^{9} M_{\odot}\lessapprox M \lessapprox 10^{11.5} M_{\odot}$), we find that the B-band light in discs decreases by ~30% from z~0.7-0.9 to z~0, while the light from the bulge increases by ~30% over the same period of time. We interpret this evolution as the consequence of star formation and mass assembly processes, as well as morphological transformation, which gradually shift stars formed at half the age of the Universe from star-forming late-type/irregular galaxies toearlier types and ultimately into spheroids., Letter to the Editor, 4 pages, 2 figures, accepted for publication in Astronomy and Astrophysics