New Achievements in the Field of Impulse Processing Technologies

The outcomes of research in the field of application of high pressure in a process engineering are stated. The high pressure is created by impulsive sources of energy, such as explosion of condensed explosive substances and gaseous detonatable mixtures. Application of high pressure created by explosion for technological processes of sheet forming parts from metal and non-metal materials is considered. In the latter case, the mechanical properties in the process polymerisation of composite materials in the outcome of the impulsive loading significantly rise. The impulsive high pressure has a significant impact on handling - compressing of powder materials, on manufacture of special products, foundry forms and ont destruction of rods in molten products

Mathematical Modeling of Impulsive Forming Processes Using Various Energy Sources and Transmitting Medium

High-speed forming uses high explosives, gun powder, combustible gas mixes and compressed gases as sources of energy. Special mathematical models are used to take into account specific dynamic properties. Different technological processes of forming have been modeled in the work. They use liquid (water), elastic (polyurethane), and gaseous transmitting medium. The difference between impulse energy transference, load distribution on a blank and tool surface, and also wave propagation is shown for used transmitting medium. The developed procedures allow taking account significant thermal effects at adiabatic compression of the material and heat transference directly from products of explosion. Specially developed modules and mathematical models have allowed the application of standard software products for modeling high-speed forming and sheet metal punching processes

Mechanical behavior of a notched oxide/oxide ceramic matrix composite in combustion environment: Experiments and simulations

This paper is focused on understanding the role of combustive environment on thermal fatigue of Nextel™ 720/alumina CMCs. The role of pre-existing flaws in thermal monotonic and fatigue failure of the CMCs is also computationally and experimentally investigated. A notch (hole) was fabricated on the samples to study the effect of defects on the mechanical behavior of CMCs in combustion environment. Fatigue life in the combustion condition for notched samples was lower by an order of magnitude in comparison to the unnotched samples in combustion environment and notched samples in isothermal furnace results across the range of applied stress. The different fatigue performance is attributed to the thermal gradient stresses and increased rate of oxidation due to a high moisture level in the combustion rig test condition. The former will be further verified using finite element analysis and the latter from finite element analysis and microscopic analysis of the fracture surfaces