Seminarium Instytutowego Seminarium Mechaniki im. W. Olszaka i A. Sawczuka

The Shock Initiation and High Strain Rate Mechanical Characterization of Explosive Powders and Compositions

dr S. Walley

poniedziałek, 24 maja 2004, godz. 10:00, sala Aula (II p.)

A number of techniques have been developed and applied in our laboratory for the investigation of the properties of energetic materials. One method we have used in a wide range of such studies has been high-speed photography. The advantage is that it is possible to see directly what is going on in, for example, hot spot initiation of energetic materials. In recent years, it has increasingly been desired to model the impact response of structures containing energetic materials using numerical methods. If meaningful numerical results are going to be obtained for, say, munitions or rockets, it is of vital importance that constitutive relations be constructed which describe the mechanical response of unreacted energetic materials over the temperature and strain rate ranges of interest. With this in mind, we have developed a range of techniques for obtaining the mechanical properties of energetic materials over a wide range of strain rates and temperatures. One problem with conventional mechanical testing methods is that they only allow the measurement of the global response of a specimen. Energetic materials usually consist of a viscoelastic binder heavily loaded with explosive crystals. In order to develop realistic and physically-based constitutive models for such unusual composites, it is vital to determine how these materials deform on the mesoscale. To this end, we have developed a range of optical and microscopy techniques. These have been used for both quasistatic and dynamic studies.