Numerical modelling of the hydrodynamic ram phenomenon

• Published in: International journal of impact engineering Vol. 36; no. 3; pp. 363 - 374
• Main Authors: Varas, D., Zaera, R., López-Puente, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-03-2009; Elsevier
• Subjects: Exact sciences and technology; Fluid-filled tank; Fluid–structure interaction; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Hydrodynamic ram; Impact; Physics; Solid mechanics; Structural and continuum mechanics; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Impact; Fluid–structure interaction; Hydrodynamic ram; Fluid-filled tank; Wing; Tube; Vibration; Rupture; Hydrodynamics; Vehicle tank; Fluid displacement; Fluid structure interaction; Metal; Steel; Experimental study; Modeling; Fluid-structure interaction; Penetration ballistics; Finite element method; Motion transfer; Internal fluid; Kinetic energy; Aircraft; Damaging
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2008.07.020

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. 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 water-filled aluminium square tube. Two different formulations (ALE and SPH) are 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 both ALE and SPH techniques in reproducing such a complex phenomenon.