Linear focusing fragment warhead makes the fragments disperse at an equal velocity and focus linearly by taking advantage of the design of charge generatrix and fragment arrangement, which can exert structural cutting damage to a target. In order to study the influence of structural parameters of linear focusing fragment warhead on the dispersion characteristics of fragments, the fluid-structure interaction (FSI) algorithm is used to numerically simulated the focusing process of fragments. The numerically simulated results reveal the linear focusing mechanism of linear focusing fragment warhead. The typical linear focusing process includes fragment driving stage, fragment focusing stage, focusing completion stage and fragment dispersion stage. The effects of warhead size, fragment arrangement, fragment mass and intersection velocity on the dispersion and spatial distribution characteristics of fragments are further obtained by numerical simulation. The results show that, with the increase in charge length from 0.3m to 0.5m, the standard deviation of fragment velocity increases from 125m/s to 147m/s, the focusing completion time is 490μs, 585μs and 590μs, respectively, and the width of perforation dense distribution increases from 135mm to 234mm. When the fragment arrangement increases from 15 columns to 18 columns, the standard deviation of fragment velocity increases from 117m/s to 125m/s, the focusing completion time is 470μs and 490μs, respectively, and the width of perforation dense distribution increases from 235mm and 135mm respectively. When the fragment mass increases from 4.08g to 9.21g, the standard deviation of fragment velocity decreases from 137m/s to 125m/s, the focusing completion time is 380μs and 490μs, and the width of perforation dense distribution is 156mm and 135mm, respectively. When the interaction speed increases from 0m/s to 1000m/s, the focusing completion time is 490μs, 480μs and 469μs, respectively, the width of perforation dense distribution increases from 135mm to 138mm, and the density of fragment distribution decreases from 640/m2 to 630/m2 with a rate of about 2%. The research results can provide guidance and reference for the design of focusing warhead.
