Strategy to Enhance the Collapse Capacity of Composite Cylindrical Tubes: Experiments and Simulations

The effects of adding circumferential groove geometries on the collapse capacity of carbon composite cylindrical tubes were investigated experimentally and numerically. Tubular specimens, both with and without grooves, were imploded hydrostatically in a water-filled pressure vessel facility. High-speed imaging captured the collapse behavior, while dynamic pressure transducers recorded the transient collapse pressure history of the implosion event. The results indicate that the collapse capacity is improved by up to 20% by adding a circumferential groove. A numerical model of the hydrostatic buckling was developed using ABAQUS 2022 software and validated against experimental results. A parametric study was conducted by varying the depth, steepness, and number of grooves. The results showed that deeper grooves tended to partition the tubes into sections that collapsed locally at higher pressures. Additionally, reducing the groove steepness increased the collapse capacity up to a certain threshold, beyond which the capacity decreased. Tubes with more grooves collapsed in higher modes and consequently at higher pressures. This provides a tool by which the groove geometry and pitch distance can be adjusted to achieve the desired collapse mode and capacity.