Steel components absorb impact energy by plastic deformation whilst composi
te materials absorbing it by damage mechanisms such as fiber debonding, fib
er fracture, and matrix cracking. Therefore, in order to properly substitut
e metal components with composite ones in industrial applications, the impa
ct property of composite materials must be well known. In this study, the i
mpact behavior of sheet molding compounds (SMC), which is widely used in au
tomobile industry due to its relatively low cost and high productivity, was
examined both experimentally and numerically. In order to investigate the
impact behavior of SMC, an experimental study was carried out by setting up
a drop weight impact test system. Using this system, the dissipated impact
energies of SMC flat plates were measured to investigate the influence of
the mass and shape of impactor, initial velocity, and specimen thickness on
the impact behavior.
For numerical predictions, a modified damage model for SMC was developed an
d adopted in the user defined material subroutine of the commercial simulat
ion program LS-DYNA3D. For the sake of improving efficiency of impact simul
ations, the SMC material property was determined in consideration of the lo
cal differences of the fiber volume fractions. The dissipated impact energi
es under various conditions and the reliability of the developed impact sim
ulation process were examined through comparisons of the predicted data wit
h the experimental results.
From this comparison, it was found that, in the scope of current study, the
specimen thickness is the most important parameter that should be consider
ed in the design of SMC components for the aspect of impact behavior. (C) 2
000 Published by Elsevier Science Ltd.