1. Inicio
  2. Atrás
Título: High strain rate deformation and fracture of engineering materials
Autores: Dabboussi, Wael
Fecha: 2003
Publicador: McGill University - MCGILL
Fuente:
Tipo: Electronic Thesis or Dissertation
Tema: Engineering, Aerospace.
Engineering, Mechanical.
Descripción: Containment structures for aircraft engines must withstand impacts of failed engine components, which may be traveling at extremely high velocities. Therefore, the design of such structures requires a thorough knowledge of material behaviour at high rates of deformation. It is well known that at strain rates above 102 s-1, the yield stress of metals may be significantly different than at quasi-static rates. In addition, material fracture under dynamic loading can also differ from that at slower rates due to manifestation of different failure mechanisms. The purpose of this study was to gain an understanding and determine the constitutive behaviour and failure criteria for several metals used in the aerospace industry; specifically Aluminium (6061-T6), Titanium (Ti-6Al-4V) and Stainless Steel (Nitronic 33). An extensive procedure for determining the constitutive response and ductility limits of those materials, at quasi-static and dynamic strain rates, was developed relying on laboratory experiments and computational simulations. The Johnson-Cook constitutive model coupled with a critical equivalent plastic strain failure criterion was used in simulating the material. Results of the different tests and simulations indicated the success of the modeling process for the 6061-T6 and Ti-6Al-4V, however considerable discrepancies were observed when simulating the behaviour of Nitronic 33 using the Johnson-Cook model. The multiplicative nature of the model, and the high strain hardening of this material were among the reasons the Johnson-Cook is unable to represent the material when simulating events with high strain and high strain rates such as punching.
Idioma: en