Technical Research On Fuze Low-overload Recoil Insurance Mechanism

In order to make the low emission overload fuze better distinguish between launch environment from drop environment,four kinds of low recoil overload insurance mechanisms are studied.In order to solve the problem of fall safety of the double-degree-of-freedom recoil insurance mechanism of a certain fuze,the fall safety design of the mechanism is improved through parameter optimization and structure optimization.Finally,a better mechanism model is obtained and numerical simulation is used.The motion characteristics under the environment of launch,vertical drop and tilt drop of the mechanism are studied.The simulation results show that the mechanism can effectively improve the drop safety on the premise of reliable release of insurance.Finally,the validity of the simulation results is verified by experiments.In order to meet the requirements of small size of some small fuzes,a sequential low-overload insurance mechanism is designed.ADAMS is used to study the ability of the mechanism to distinguish the launching environment from the falling environment,and the validity of the simulation results was verified by experiments.On the basement of above study,optimization of the device was done,and the results show that:variation of friction coefficient has little effect on the arming time,but it is advisable to take a smaller value for the friction coefficient considering the reset performance;by increasing the mass of auxiliary pin 1,the mass of the backup pin and reducing the secondary pin 2 quality will cause the arming time to decrease slightly,and the fall safety of the organization is improved;the proposed mechanism can identify a large range of drop overload,so the drop safety is good;when N=2,the mechanism is safe for the general fall overload,when N=3,the mechainsm has a self-locking effect,and the mechainsm is more secure when it falls toward a very soft target or with a buffer pack.In order to make a quasi-fluid delay arming device suitable for low emission overload environment,a low-overload rigid squat insurance mechanism is designed with the shear pin as the main part.The feasibility of the mechanism is illustrated by force analysis and energy analysis.ADAMS and ANSYS/LS-DYNA are used to verify the feasibility of the mechanism,and the validity of the simulation results was verified by experiments.Finally the influence of the main parameters on the performance of the mechanism is studied,the results show that:the cylinder's speed and the cylinder's mass approximately inversely proportional;with the diameter of the shear pin increased,the kinetic energy needed to shear the shear pin increases significantly;due to the cumulative damage of the shear pin,impact of the upper cylinder and the below cylinder should be avoided when dropping;with the increase of k/m,the displacement of the pressure cylinder decreases,therefore,an appropriate increase in the k/m value is favorable to satisfy the mechanism's miniaturization requirements.In order to provide reference for the design of the fluid recoil insurance mechanism,the finite element method is used to study the motion law of the fluid recoil insurance mechanism.ADAMS and ANSYS/LS-DYNA are used to establish the mechanism model.The mechanism parameters and the structure to influence the mechanism performance are studied.The results show that the damping coefficient is sensitive to the drop displacement,especially when the fuze drops to a hard target,and the spring stiffness is sensitive to the emission displacement;the reset performance of the mechanism is affected by the liquid viscosity,and the greater the viscosity,the worse the reset performance;The bigger the diameter of the orifice and the number of orifices,and the better the damping effect of damping hole.Compared the displacement of the concave model with the convex model,the damping effect of the concave model is better.