Since the events of September 11, 2001, the possibility of an intentional act targeting the chemical process industry has become realistic. It is, therefore, a great concern to be able to predict the immediate consequences of such an act. This study is intended to improve our knowledge about the sequence of events that occurs when a high-speed bullet (>1000 m s−1) penetrates a vessel filled with toxic liquid. We find that, prior to liquid ejection, several well-defined phases occur, including the phenomenon known as the “hydraulic ram.” This paper focuses on projectile–target interactions and explains how the decay of projectile velocity is related to the initial conditions of the target.
"Recently, some authors analysed the HRAM phenomenon through the results of intrumented experimental tests. Lecysyn et al.    studied the drag and cavitation phases of the hydraulic ram, reporting measurements of the movement and deceleration of a projectile after it impacts a fluid-filled vessel results. Disimile et al.    applied a large-scale shadowgraph technique to a fuel tank simulator in order to visualize the pressure waves generated by hydrodynamic ram, and the results were compared to pressure transducer signals; special attention was given to the effect of the succesive cavity implosions. "
[Show abstract][Hide abstract] ABSTRACT: Hydrodynamic ram (H RAM) is a phenomenon that occurs when a high-energetic object penetrates a fluid-filled container. The projectile transfers its momentum and kinetic energy through the fluid to the surrounding structure, increasing the risk of catastrophic failure and excessive structural damage on adjacent components. It is of particular concern in the design of wing fuel tanks for aircraft because it has been identified as one of the important factors in aircraft vulnerability. To study the aforementioned phenomenon, water-filled aluminum tubes (to different volume percentages) were subjected to impact of spherical projectiles. This work is focused on the analysis of energies, momenta, and pressure contours obtained by means of a previously developed and validated numerical model to achieve a better understanding of the fluid/structure interaction problem that takes place during the HRAM phenomenon.
"In the last few years, there have been new advances in development and use of computational methods for fluid–structure interactions due to the interest of reach more effective computational techniques       and solve more difficult problems motivated by different industries, such as aeronautics, naval or more recently biomedical sciences. As an example of the increasing interest on solving industrial fluid–structure problems, it is worth to mention the recent works of Petitpas et al.  and Lecysyn et al.   in which a ballistic impact on an industrial tank, filled with a toxic fluid and made of steel, is studied. The authors propose an analytical model to reproduce the behaviour of the projectile on the fluid and study its influence on the toxic liquid ejection and the droplets generated. "
[Show abstract][Hide abstract] ABSTRACT: Hydrodynamic Ram (HRAM) is a phenomenon that occurs when a high-kinetic energy object penetrates a fluid-filled container. The projectile transfers its momentum and kinetic energy through the fluid to the surrounding structure, increasing the risk of catastrophic failure and excessive structural damage. This is of particular concern in the design of wing fuel tanks for aircraft since it has been identified as one of the important factors in aircraft vulnerability. Usually the HRAM phenomenon is analyzed considering completely filled tanks, but its effect on partially filled containers should also be taken into account due to the fact that tanks use to be impacted under these conditions. In the present paper, the commercial finite element code LS-DYNA has been used to simulate an HRAM event created by a steel spherical projectile impacting a partially water-filled aluminium square tube. The ALE formulation is employed to reproduce the event. Experimental tests which indicate the pressure at different points of the fluid, displacement of the walls and cavity evolution for different impact velocities, are compared with the numerical results in order to assess the validity and accuracy of the ALE technique in reproducing such a complex phenomenon.
[Show abstract][Hide abstract] ABSTRACT: We present the plan for an extended expert-system “front end” or design advisor for implementing systems (DAIS) for use in conjunction with a commercial digital control system environment, e.g., the Elsag Bailey INFI 90 System. The objective of DAIS is to make it substantially easier for applications engineers to make effective use of the broad spectrum of capabilities of this and similar hardware and software systems for industrial controls implementation. This concept is of quite general applicability for industrial controls environments. The extensions are primarily focused on handling multi-input/multi-output (MIMO) systems. This should greatly enhance the value of DAIS in modern process control applications
Proceedings of the American Control Conference, San Diego, CA; 06/1999
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