Advanced constitutive relations for modeling thermo-viscoplastic behaviour of metallic alloys subjected to impact loading

• Autores: José Antonio Rodríguez Martínez
• Directores de la Tesis: Ángel Arias Hernández (dir. tes.), Alexis Rusinek (dir. tes.)
• Lectura: En la Universidad Carlos III de Madrid ( España ) en 2010
• Idioma: inglés
• Tribunal Calificador de la Tesis: Alain Molinari (presid.), Ramón Zaera Polo (secret.), Tomasz Lodygowski (voc.), Ryszard Pecherski (voc.), José Fernández Sáez (voc.)
• Materias:
  • Física
    • Mecánica
      • Mecánica de medios continuos
• Enlaces
  • Tesis en acceso abierto en: e-Archivo
• Resumen

  • In this doctoral Thesis the thermo-viscoplastic behaviour of metallic alloys used for structural protection purposes has been analyzed. The study includes the proposition of advanced constitutive relations and their integration into numerical models. These numerical models are validated for impact problems within the low-intermediate range of impact velocities (until 85 m/s). The advanced constitutive relations derived are based on the Rusinek-Klepaczko model whose validity is extended to metallic alloys showing dependence on plastic strain on the volume thermally activated. In addition the constitutive relations developped allow describing macroscopically viscous drag effects at high strain rates, negative strain rate sensitivity and martensitic transformation phenomena. Implementation of previous constitutive relations has been conducted into the FE code ABAQUS/Explicit. Thus, development of numerical models for the simulation of ring expansion test and conventional dynamic tension test has allowed analyzing the formation of plastic instabilities. In this analysis the effects of strain rate sensitivity, strain hardening and plastic wave propagation have been considered. Finally, it has been examined the impact behaviour of metallic alloys widely used for structural protection purposes: the mild steel ES, the aluminium alloy 2024-T3, the steel AISI 304 and the steel TRIP 1000. For that goal conventional characterization tests as well as impact tests have been conducted. Numerical models based on the constitutive relations derived have been developped in order to simulate the impact tests. These numerical models offered a suitable description of the perforation process in terms of ballistic limit and the associated failure mode of the target.-----------------------------------------------------------------