Experimental And Simulation Study On The Pharmacological Properties Of Variable Burning Rate Propellant

The mechanical properties and influencing factors of a double-layer propellant were studied by experiment and simulation.Using the universal material testing machine and the drop hammer test instrument testing the double propellant and different formula of single layer propellant of quasi static mechanical properties and dynamic mechanical properties,get the corresponding mechanical parameters,the calculation model of double-layer propellant was established based on ABAQUS,the simulation of double propellant under quasi static load and dynamic load stress response process;The effects of EC and RDX on the mechanical properties of propellants were compared,and the effects of aspect ratio,outer thickness,interface strength and hole number on the stress response process of propellants were compared.The stress response process of single hole,seven hole,nineteen hole and lace seven hole propellant under radial impact load is studied,and its mechanical properties are analyzed.The main conclusions are:(1)Under quasi-static compression,the strength limit of formula 1 increases with the increase of compression rate,and the elastic modulus and yield limit of propellant are improved by the addition of RDX.From the simulation results,it can be seen that the outer stress is always greater than the inner stress,and the stress accumulates and increases in the process of the internal transfer of the drug granule.The stress concentration appears at the end face boundary and extends inward,and the drug granule presents a "drum shape" macroscopically.The elastic modulus of formula 2 and double-layer propellants is less affected by the compression rate,and the yield limit has the strain rate effect,which increases with the increase of the compression rate.The elastic modulus and yield limit of formula 2and double-layer propellants can be increased by EC.(2)In the impact test,the mechanical properties of the propellant are higher than those under quasi-static compression.With the increase of impact rate,the impact resistance of formula 1 increases,and the deformation resistance of formula 2 and the double-layer propellant increases.The mechanical properties of formula 2 are hard and brittle and formula1 is soft and tough under impact and quasi-static loads.From the simulation results,it can be seen that the stress at the end face boundary is close to that in the stress concentration area inside the drug granule.When the drug granule cracks,the crack will expand inward from the boundary.EC and RDX can enhance the mechanical properties of propellant under dynamic load.(3)The impact resistance of propellant can be increased to some extent with the increase of the aspect ratio of propellant;The increase of the outer layer thickness will change the force body and deformation pattern of the double-layer propellant.When the interface strength decreases,the interface will be broken and separated.The increasing number of holes will change the continuity of stress distribution at the end face(4)After radial impact loading of propellant,the hole is extruded to form stress distortion area and stress concentration occurs.After the number of holes increases,the overall force of the propellant is more uniform.When the stress point is different,the stress distribution will change under the influence of the hole.The stress concentration and fracture of the lace-shaped propellant are prone to occur in the lace-convex area in contact with the drop hammer.