Research On The Molybdenum Material Liner And The Application In Multi-mode Warhead

Aiming at revealing the application advantages of molybdenum in a multi-mode warhead,this paper focuses on the response behavior of molybdenum material under the dynamic impact,the forming and penetration characteristics of molybdenum material under different velocity damage elements,molybdenum liners explosive formed projectile(EFP),and jetting penetrator charge(JPC)dual-mode warhead.Molybdenum liner metal JET(JET)and jetting penetrator charge(JPC)dual-mode warhead are studied,providing a theoretical and technical basis for applying molybdenum material in the charge liner and multi-mode warhead.Firstly,molybdenum materials’ dynamic impact response behavior with different processes under different temperatures and strain rates was studied.Through the evaluation methods of strain rate sensitivity(SRR),strain sensitivity(SHR),and temperature sensitivity(TSR),it was found that the high purity of molybdenum materials was less sensitive to the combined effect of rate and temperature,and the smaller the deformation of materials was,the greater the strain strengthening effect was.A modified-Johnson-Cook constitutive(MJC)was proposed based on the rate-temperature combined effect and the temperature softening effect during the adiabatic impact process.The complex mechanical responses of molybdenum materials with different purity and deformation under dynamic impact were evaluated.A bivariate damage model based on strain and strain rate was established to obtain the damage evolution parameters of molybdenum materials concerning strain and strain rate.The results show that with the increase of strain rate,the failure strain decreases,and the molybdenum material exhibits an impact embrittlement trend,which is consistent with the intergranular fracture characteristics observed at the micro-level.Secondly,the stable forming model of pure molybdenum damage element under large deformation was established.Based on the extended PER jet forming theory and EFP forming model,the response model of material with deformation path after the damage element forming was constructed,and the forming parameters of molybdenum material forming explosive projectile and jet damage element was analyzed theoretically.The results show that the strain strengthening effect and temperature softening effect of molybdenum material damage element is more obvious,and the strain rate effect due to the influence of adiabatic effect,the deformation energy is converted to adiabatic temperature rise,and finally reflected in the temperature softening effect.Under extremely high strain rate deformation,the material failure stress in the damage element mainly comes from the strain hardening effect caused by a highvelocity gradient.Thirdly,the equal mass molybdenum liner and copper liner were designed to form explosively formed projectile(EFP),rod jet(JPC),and metal jet(JET).The numerical simulation and experimental study on the forming and penetration characteristics of molybdenum material damage element at different speeds revealed that under the condition of five times the explosive height of charge diameter,in the medium-low speed and medium-high speed damage elements of molybdenum material,compared with the copper material damage element,the penetration hole diameter increased by 30.43 %,and the hole diameter in the middle part of the channel increased by 28.64 % to 40.1 %,which had a distinct advantage of hole expansion.In the ultra-high-speed jet damage element,compared with the copper material damage element,the penetration depth is increased by 31.42 %,the opening diameter is increased by 31.22 %,the hole diameter is increased by 18.75 %,and the hole diameter in the middle part of the hole is increased to 44.5 %,which has distinct advantages of penetration depth and hole enlargement.Finally,the application of molybdenum materials in EFP and JPC dual-mode warheads,JET and JPC dual-mode warheads is explored.The multi-mode damage element matching design model based on multi-preference physical programming is established to construct Class-3 S type preference function,and the equal mass molybdenum liner dual-mode warhead is designed with the optimal copper liner dual-mode warhead(EFP and JPC).The traditional structural optimization method obtained the optimal molybdenum liner dual-mode warhead(JET and JPC),and the equal mass copper liner dual-mode warhead was designed.By comparing the penetration power of EFP and JPC,JET,and JPC dual-mode warheads,it is found that molybdenum material is particularly suitable for the design of JET and JPC composite dual-mode warheads.The dual-mode warhead achieves high penetration depth by relying on high jet velocity in the JET damage element mode and achieves a large hole expansion damage effect by relying on lateral stress in the JPC damage element mode.In this paper,the application of molybdenum material in shaped charge liner was studied,and the dynamic response mechanism of molybdenum material under a high strain rate is deeply discussed.The multi-mode warhead of the molybdenum liner is designed to explore the forming and penetration properties of the damage element,which is of great significance for the application of molybdenum liner.