In earth penetration events the projectile generally strikes the target at an oblique angle. As a result, the projectile is subjected to a multi-axial force and acceleration history through impact. The effectiveness of an earth penetration system is enhanced by the ability to withstand severe
The Dynamic Design Analysis Method (DDAM) is a U.S. Navy methodology for qualifying shipboard equipment and supporting structures for survival of shock loading due to
underwater explosions (UNDEX). The DDAM is a regimented collection of procedures that utilize estimates of the peak linear dynamic response of ship equipment and structures
Accurate numerical modeling of the shock response of marine structures is of considerable importance in their design since the cost associated with physical testing is often prohibitive. Along with the shock response calibra-tion, designers often have to grapple with opposing fac-tors while trying to optimize performance during operating conditions. Abaqus allows for the analysis of both the structural integrity and acoustic radiation in such cases.
The Extended Finite Element Method (XFEM) capabilities of Abaqus V6.9-EF1 could have a significant impact on finite element modeling of failure for the U. S. Army. The Army has many areas where fracture is important from failure of components, to penetration, to warhead development. To assess the value of XFEM under static loading, comparisons were made with experimental data of notched panels. The panels had different angles of notches. The crack growth direction and applied forces for crack growth were compared to experiments using ABAQUS.
In developing weapon systems for the warfighter, the US Army uses modeling and simulation tools to support the design, test and manufacturing of these systems. One of these tools is Abaqus/Explicit, including the coupled Eulerian-Lagrangian capability CEL. The addition of CEL in version 6.7EF-1 opened the door to a new realm of problems that could not be previously be modeled. With the addition of this new capability came the need for internal validation to establish a level of confidence for the class of problems of interest to the U.S. Army.
Monte Carlo reliability calculations for high-reliability systems are very computationally expensive. Variance reduction techniques optimize this process greatly and directional simulation is one such technique. Directional simulation is particularly valuable for high reliability systems where the failure surface is highly curved or dislocated.
A new method is introduced for conducting blast load analyses using the new Coupled-Eulerian-Lagrangian (CEL) capability of Abaqus/Explicit. In the past, either a 1-D blast code or tabular data was used to determine a pressure vs. time curve that would be applied to the exterior surfaces that were assumed to interact with the blast wave. These pressure curves were generated using knowledge of the amount/type of explosive and line-of-sight distance away from the explosion.
A finite element model is developed to investigate the instantaneous as well as long-term (time-dependant) structural response of a pre-loaded torsional spring. Torsional springs belong to a class of spiral springs that are commonly made out of Elgiloy - an alloy of Cobalt, Chromium, Nickel and Iron. Elgiloy has very high yield strength, and is commonly used as a spring material in clocks.
The U.S. Army Armament Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal, NJ is developing an inert 40mm sensor grenade which houses an array of sensors and electronic components. This grenade is intended to be fired from a hand held launcher and relay sensory information back to the user. To accomplish this task, the internal electronic components must be structurally housed and guarded from impact induced g-levels.
The Army is developing new grenades with sensors instead of explosives. A grid of 40-mm grenades will be fired from conventional M16 rifles. The projectiles must survive gun launch and impact. After impact, soldiers will get a real-time ‘picture’ of a local area. Signals from the onboard sensors will be processed on a hand-held computer that captures the activity within the
