A Numerical Investigation of Loading Rate Effects on Pre-Cracked Charpy V-Notch Specimens

176 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.To quantify the effects of loading rate on ductile crack growth in CVN specimens, plane strain, finite element analyses are used to model ductile crack extension in specimens subjected to quasi-static and impact loading. The Gurson-Tvergaard dilatant plasticity model for voided materials describes the degradation of material stress capacity. Fixed-size, computational cell elements defined over a thing layer along the crack plane provide an explicit length scale for the continuum damage process. Parametric studies focusing on numerically generated R-curves quantify the relative influence of impact velocity, material strain rate sensitivity, and properties of the computational cells (thickness and initial cell porosity). In all cases, impact loading elevates significantly the R-curve by increasing the amount of background plasticity. Validation of the computational cell approach to predict loading rate effects on R-curves is accomplished by comparison to quasi-static and impact experimental sets of R-curves for three different steels.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD