Study On Dynamic Characteristics Of Deferred Insurance Mechanism Of Magnetorheological Fluid

Magneto-rheological fluid delay arming device has advantages such as high accurate arming delay time, high safety and simple structure. Aiming at small caliber fuze magneto-rheological fluid safe and arming device, the research was about the mechanism, in zero magnet field and in unsaturated magnet field.and the researches had great value.The main research work is as follows:(1)The centrifugal environment simulation test was designed. The laboratory equipment was made. The time data of MRF safe and arming device was got through test, and after studying on the rule of discharge time of MRF, the time model was revised.(2)A time model of small caliber fuze magneto-rheological fluid safe and arming device was built. According to knowledge of fluid mechanics, this paper Analyzed on Bernoulli equation of the total flow viscous. It researched on energy loss of the mechanism, and a time model of the device was built. It revised the parameters about local resistance coefficient in the time mode, and by using revised local resistance coefficient the accuracy increased by 9.85% than using experience local resistance coefficient.(3)The multi-body dynamics model of small caliber fuze MRF safe and arming device was established. Studying on the test results of centrifugal environment simulation test, the model was modeling by use of damping-spring elements instead of MRF, and the model of small-caliber fuze MRF machine was established. The delay arming time was got from multi-body dynamics simulation. Simulation time compared with the experimental values, the maximum error was 13.14%.(4)The magnetic circuit of small caliber fuze MRF safe and arming device was designed. When in the service process, the magnet field in the flow field area of MR was large enough to ensure that the device would be not arming. When the projectile was launching, it controlled the falling distance of the permanent magnet, and it affected the fluid flow by magnetic field, then the viscosity increased, and the delay arming time increased. When the permanent magnet fell down 2.86mm, and the viscosity of MRF was 0.09Pa-s in zero magnet field, delay arming time of the mechanism in unsaturated magnet field, compared with the time of the mechanism in zero magnet field, was at least an increase of 65.8%.