Numerical Simulation of High Speed Impact on a Sandwich Panel
Date Issued
2010
Date
2010
Author(s)
Tsao, Da-Fa
Abstract
Large strains often cause material destructions in industry and applications. In numerical simulations, we have to set up material models suitable for computation problems. This thesis simulated bullet penetration problems by LS-DYNA software with Elastic Plastic Hydro Spall Material Model, Johnson Cook Material Model for metals, Johnson Holmquist Concrete Material Model for concrete, and Johnson Holmquist Ceramics Material Model for ceramic.
Concrete is more complicated than the other materials in penetration simulations due to its inhomogeneous composition, which results in errors and inconsistencies. This thesis validated penetration problems employing four concrete models, namely, Johnson Holmquist Concrete in their original document, WES, Forrestal, and U.S. Army empirical formulae. After verifications, we adapted the modeling parameters to calculate bullet impacts on sandwich composite panels. For 9mm Luger bullets with incident angles, the computing results evidence a pertinent angle about 20within which the bullet could penetrate the panel with larger residual kinetic energy than the normal impact.
To improve the sandwich panel strength, we proposed to add a ceramic layer beneath the front steel. B4C, SiC, AlN, and Al2O3 were tested in this investigation. We found that B4C ceramic is the best among the four ceramics. Subsequently, we studied the effects of thickness of B4C ceramic layer on the impact resistance. Numerical results showed that adding 6mm B4C ceramic layer in between the front steal and inner concrete would efficiently enhance the capability of bullet impacting.
Subjects
impact
material model
empirical formula
sandwich panel
B4C ceramic
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