| Conventional cavity expansion analysis for circular cross-section penetrators presents a general framework for characterizing the resistance of target materials. However, penetration by non-circular penetrators induces phenomena that can only be investigated by a multi-dimensional cavity expansion analysis. Such problems motivate the development of both static and dynamic models that can deal with non-circular cross-sectional cavity expansions. This dissertation presents a development of this cavity expansion analysis for non-circular cross-sectional penetration of semi-infinite, ductile targets.; Two-dimensional cavity expansion models for arbitrary cross-sections are developed for plane strain, cylindrical cavity expansion problems. Cavity expansion resistance of target materials, as well as elastic-plastic solutions around non-circular cavities can be directly obtained for given material properties. The results of the static model are found to be in good agreement with one-dimensional closed-form solutions and numerical simulations using the finite difference code, AutoDyn. A two-dimensional, dynamic cavity expansion model is also developed by adding inertia effects in the static model. This dynamic model can be used to study expanding non-circular cavities subjected to arbitrary tractions on the initially circular cavity surface. Performance of archtypical non-circular, eroding penetrators are investigated. Comparisons are made for equal mass and equal kinetic energy penetrators having different cross-sectional geometries. Lastly, a penetration model including closed-form equations that predicts penetration depth and axial forces is developed for elliptic cross-section, rigid, conical nose penetrators. These penetration model results are highly dependent on the shapes and impact velocities for each cross-section of penetrators. Even though circular cross-section results show increases in penetration ability compared to elliptic cross-section penetrators, further investigations are required for this non-circular cavity-expansion. |
