Numerical Analysis of Bonded Composite T Joint Subjected to Hydrodynamic Ram Pressures

Abstract

When a high-velocity projectile impacts a fluid-filled structure, hydrodynamic ram occurs from the overpressure caused by the transfer of energy and momentum from the projectile to the fluid, often with catastrophic effects. The critical damage is usually located at the seams/joints of said enclosure. A RamGun can be used as a less expensive alternative for assessing joint resistance to hydrodynamic ram. Numerical techniques are regularly used to supplement testing and to predict hydrodynamic ram damage in structures. This study was used to evaluate the viability of using a coarse mesh cohesive zone modeling technique to model a bonded joint in concert with LS-DYNA arbitrary Lagrangian–Euler fluid structure interaction algorithm to ascertain the joint resistance to hydrodynamic ram pressures generated in a RamGun. The ballistic testing approach was used to determine the failure pressure range for a joint that was used to calibrate the numerical model. The calibrated coarse mesh was able to predict joint failure in line with the test pressure values and also captured failure modes for various coupons of varying skin thicknesses. This will serve as a baseline for modeling and assessing joint failure in larger structures like fuel tanks and storage containers subjected to hydrodynamic ram.