Abstract: Having lower area density and high specific energy absorption(SEA),fiber-reinforced composites are widely used in the area of personal armor.And the breakage of fibers in composites is the main mode of energy absorption.Previous researches were focused on the observing of the damage mode after a ballistic test.This paper simulated Twaron~D○R fiber struck by the steel projectile with finite element analysis(FEA).The result is compared with that of previous experiment and found that they are quite similar.In addition,fiber energy absorption principle was further explained.This research result may serve as a guide in the design of personal armors.