The expansion and fracture behavior of titanium coil shell wall is not only influenced by the burst load characteristics, but also related to the material properties, the characteristic size of column shell structure and other factors. This paper mainly focuses on the analysis of TA2 titanium alloy tube with specific structure size under different burst pressures.

Researchers used finite element method and experimental analysis method to study the titanium tube burst expansion failure machine and its influencing factors. By analyzing the law of shock wave propagation, strain and stress state evolution and development in the ideal titanium tube under different charge burst loads. The fragmentation phenomenon of titanium tube was discussed. The results showed as followings:

1. The failure of Gr2 titanium coil under different burst pressures is the shear fracture of 45 or 135 direction with radial direction, but the initiation of crack and failure process are different. At a higher burst pressure. The micrometallograph of the fragment section shows the distribution of holes and microcracks in the middle of the wall thickness and the cracks extend from the middle of the sample section to the inner and outer surfaces. At lower detonation pressure. The crack starts from the inner wall of the sample and extends outward to cause fracture. The fem results are in good agreement with the experimental results.

2. The finite element analysis shows that under the high burst pressure because the shock waves in sample bounces back and forth between internal and external wall form secondary plastic zone in order to make the sample wall thickness in the central area of equivalent plastic strain on interior and exterior, fracture occurred in the shock wave loading stage, crack damage from the first sample wall thickness in the middle of the starting and expand to the internal and external wall lead to fracture. While under the low detonation pressure, the failure occurs in the free expansion stage, when the whole sample enters the state of tensile stress. The larger the equivalent plastic product at the inner wall is the fracture starts from the inner surface and extends to the outer wall shear.

3. Some of the outer wall tensile fracture phenomena in related experiments may be related to the geometry of the sample, material defects and other factors and the influence of defects on the burst failure characteristics of titanium coil deserves further attention.