If the Neumann Theory in its original form is applied on the pseudosteady shock reflection process and compared with experimental data agreement can be found in some limited domains, on the other hand significant disagreements, called the von Neumann Paradoxes, appear. The reasons are discussed in the present paper as well as series of parametric c...
Numerische Simulationen von bruchmechanischen Experimenten mit dem Ziel, aus Messungen der Rißlänge den Spannungsintensitätsfaktor und seine Beziehung zur Bruchgeschwindigkeit zu ermitteln, sind bei der herkömmlichen DCB-Probe mit Belastung durch Keil und Bolzen wegen nicht klar definierbarer Randbedingungen problematisch. Es wurden daher Experimen...
Orbital debris poses a danger for spacecraft in orbit. Protection against this threat is obtained by shielding. One or more sheets placed at some distance from the structure to be protected can minimize the damage inflicted by projectiles at high velocity. The range of velocity between 0 and 8 km/s is well covered by tests. Unfortunately, the avera...
Es wurde eine Übersicht über Arbeiten zur Charakterisierung der Rißzähigkeit eines Reaktordruckbehälterstahles 22 NiMoCr 3 7 im Hochlagenbereich bei erhöhten Belastungsraten gegeben, die über die Anwendungsgrenzen konventioneller Bruchmechanikkonzepte hinausführen. Zunächst wurde über die Ermittlung dynamischer J- Rißwiderstandskurven mit Hilfe von...
The effect of explosive detonation wave shaping on the shape and velocity of EFP's are described in this paper. Hydrocode modeling and range testing of warheads with embedded wave shapers of varying diameter were investigated. The range tests consist of a set of experiments of a Comp-B loaded warhead/liner configuration with imbedded polyvinyl chlo...
Constitutive equations for die pressing and sintering are developed and implemented in the finite-element program ADINA (copyright). As an example, the production of a hard-metal tool is simulated numerically. Due to its wedge-type profile, a gradient in green density develops during pressing. This leads to a severe shape distortion during sinterin...
The process of ductile fracture through void nucleation, growth and coalescence under strain rates in the range 1000 - 10000 1/s is studied. The material considered is UNS C36000 free cutting brass containing spheroidal lead particles which serve as void nucleation sites. Tensile Split Hopkinson Bar and Plate Impact tests have been performed to exa...
Micromechanical models for the pressing and sintering of powders are described and macroscopic constitutive equations are derived from them. The effects of cohesion and friction between powder particles on the macroscopic behaviour during compaction are explored. The micromechanical model for sintering is based on the assumption that the surface of...
The penetration behavior of tungsten-alloy long-rod penetrators into steel and glass targets is investigated and contrasted at two impact velocities, 1.25 km/s and 1.70 km/s. Crater shapes as well as penetration depths and residual rod lengths were measured by means of a 600 kV flash X-ray system at different times during penetration. The wavecode ...
The residual velocity of a tungsten alloy penetrator impacting three laminated steel plates in contact without bonding is considered. The target thickness is kept constant, and various combinations of the individual plate thicknesses are investigated and compared to the monolithic case. At impact velocities near the ballistic limit, the residual ve...
