Selection of damage parameter – Art or science?

Experimental methodology for high strain-rates tensile behaviour analysis of polymer matrix composites

“…Specimen cartography is achieved using image-analysis. These contribute to characterizing the bundles degradation, in terms of matrix micro-cracks and fibrematrix debonding which are the predominant microscopic damage mechanisms for composite material [15][16][17][18]. This investigation results in a quantitative damage evaluation by estimating defects effects.…”

Multi-scales modelling of dynamic behaviour for discontinuous fibre SMC composites

“…This damage mechanism is then experimentally quantified by micrographic analysis and correlated to a macroscopic damage parameter D macro , (Figure 4-b) through the developed micromechanical model. The D macro is defined using the well-known damage mechanics theory [16,17] and expressed such as (Eq. 5):…”

A rate-dependent damage model for brittle materials based on the dominant crack

“…The requirements for a material volume to be statistically homogenous are those discussed by Krajcinovic (1998). That is, the number of defects (cracks) and heterogeneities within the material volume must be large and their locations and orientations must be random (uncorrelated) and their size small compared to separation.…”

“…The phenomenological approach, which has been increasingly used in constructing damage models, typically starts by postulating thermodynamic potentials and uses irreversible-thermodynamics arguments to derive evolution equations for the damage variables (e.g., Ju, 1987, 1989;Lemaitre and Chaboche, 1990;Krajcinovic, 1984Krajcinovic, , 1989Krajcinovic, , 1996Krajcinovic, , 1998Schreyer, 1994, 1995). The micromechanical approach typically starts with the behavior of a single defect (crack or void) and the continuum level model is obtained by applying statistical averaging to an ensemble of defects (e.g., Seaman et al, 1976Seaman et al, , 1985Dienes, 1978Dienes, , 1996Dienes and Margolin, 1980;Costin, 1983;Grady and Kipp, 1985;Taylor et al, 1986;Rajendran and Kroupa, 1989;Rajendran, 1994;Rajendran and Grove, 1996;Addessio and Johnson, 1990;Gambarotta and Lagomarsino, 1993;Lewis and Schreyer, 1996;Bennett et al, 1998;Hackett and Bennett, 2000;Krajcinovic, 1998;Lee et al, 2004).…”