Numerical Simulation And Analysis On The Open Packet Of Spherical Shell

The shell of fireworks were prepared under the laboratory conditions. The numericalsimulation model of the open spherical shell process was built and optimized by numericalsimulation software. The open shell initial velocity was simulated under different pressureand different thickness of shell. The main contents are followed:The fireworks shell was prepared according to the actual production process, and thedensity and mechanical performance parameters were measured. The density is0.706g/cm3,the elastic modulus is2.16GPa, the shear modulus is0.87GPa, the Poisson’s ratio is0.241GPa, and the tensile strength14.72MPa.The numerical simulation model of the openspherical shell process was built by the numerical simulation software named AUTODYN.The model was built on the basis of ignoring the influence of air resistance and internalobjects, and the internal pressure was assumed for a certain value. The open shell initialvelocity was simulated under different pressure. When the medicine to open the shell isblack powder, the initial velocity is about127.43m·s-1; when the medicine to open the shellis potassium perchlorate, the initial velocity is about313.92m·s-1. To optimize theestablished shell model,82stars were added in the original model, assuming these stars asrigid material, ignoring the deformation. The open shell initial velocity was simulated underdifferent thickness of shell. When the thickness of the fireworks shell is4mm, the initialvelocity is about114m·s-1; when the thickness of the fireworks shell is10mm, the initialvelocity is about46m·s-1.In order to verify the accuracy of the optimized model, the openfireworks shell process was observed by the high speed photography. The results show thatthe initial velocity is about101.33m·s-1, slightly less than the numerical results, but theerror is in the allowable range.This paper takes the spherical shell as the research object. Analyzed how the openpressure and thickness of shell influence the open shell initial velocity. The numericalsimulation model of the open spherical shell process was built and optimized, which laid afoundation for building up the fireworks tripping type design model.