Research On Response Behaviors Of PBXs Substitute Materials Under Intensive Dynamic Loading

Polymer-bonded explosives(PBXs)are particulate composite materials made of explosive compounds with bonder,plasticizer,and desensitizer.PBXs have many peculiarities,such as high energy-density,low mechanical sensitiveness,good mechanical and processing properties.Therefore,they can be widely applied to military and industrial areas.However,because of inevitable damages and mechanical property changes during the PBXs storage and transportation processes,abnormal explosive consequently occurs.It is well known that the damage evolution depends on strain rate.Therefore,researches on PBXs damages and mechanical property changes with different strain rates are crucial.So far,the expriments under low and medium strain rates have been performed while there are few researches based on intensive dynamic loading(high strain rate).For safety,PBXs substitute materials are used for experiments of PBXs response behaviors.In this study,samples made from white sugar,Epoxy Resin E51,oxalic acid,and plasticizer are used for PBXs response behaviors under intensive dynamic loading.In chapter 1,PBXs mechanical behaviors were theovetically,numerically and experimentally studied.Chapter 2 introduces formulas of common PBXs substitute materials.In addition,substitute sample is made from white sugar,Epoxy Resin E51 and other materials by the universal testing machine.Pressing procedures and matter needing attention are listed.Chapter 3 shows shock tests on PBXs substitute material by one-stage light gas gun,getting a stress-strain curve.In addition,this chapter researches the stress wave propagation property of the substitute material under the circumstance of one-stage light gas gun,which shows that the decay of stress wave complies with the law of exponential decay.Then,PBXs substitute material is turned into the viscoelastic one for studying its relaxation time.Results show there is a negative exponent relation between the relaxation time and strain rate.In chapter 4,the finite element modelly is carried out,and the results show that the modelling data match the test data well.Meanwhile,the damage simulated pictures are given.Chapter 5 builds the exponent relation between the material relaxation time by shocking and strain rates that involve four orders of magnitude through the Maxwell model.Also,the mechanism is explained.Chapter 6 gives a summary and foresight.This research could predict the relation between relaxation time and strain rate,which is important for establishing the constitutive relation of PBXs.