The Design Of The Two-stage Speed Reduction Device For The Submunition

Under the background that maritime wars have gradually been taken seriously by various countries,strengthening defense in the maritime field has become the top priority of national defense research.There are more and more new modes of combat in water,and the water blockade-type submunitions appear in this context.After the submunitions are launched with rockets or shots,the flying speed is very fast.Ammunition entering the water at high speed will greatly overload the ammunition,which can easily damage the shape of the ammunition and internal parts and control system.Therefore,it is necessary to slow down before entering the water.In this paper,the underwater blockade submunitions are the object of study.In order to decelerate it to the desired splashing speed before entering the water,the flight attitude is adjusted from horizontal to vertical.This article designed the air secondary deceleration device,which provided a theoretical basis and design reference for the development of the submunitions.Firstly,under the condition of the known initial speed and splashing speed,the appropriate umbrella type and drag coefficient are selected to calculate the drag coefficient of the missile itself,and the area of the secondary umbrella and the appropriate height of the open umbrella are calculated by the parachute design criteria.Then the secondary trajectory of the above design is calculated.In the calculation process,the motion of the parachute is divided into a straightening stage,an inflating stage,and a steady descent stage.The equations of motion of the parachute are established in each stage.Using Matlab software to solve the equations,the trajectory of parachute operation and the maximum open umbrella overload in each phase were obtained.Finally,the structure and components of the parachute are simply designed.Finally,the structure and components of the parachute are simply designed.The parachute is designed as a 0.65 square meter conical umbrella and the main umbrella is an8.5 square meter parasailing.According to the trajectory calculation,the main umbrella opens at a height of 1300 meters and when the speed is 237 m/s,and the parachute is thrown away at the same time.Finally,the submunition enters the water at a speed of 49.3 m/s and a trajectory angle of 89.53°,and the overload of the parachute does not exceed the established overload requirement at all stages of the deceleration process.The entire design has good feasibility and provides a good theoretical basis for the design of the submunitions.