Investigations of Axially Compressed Tubular Structures Subjected to Lateral Indentations

Tubular structures serve as fundamental designs in the offshore industry, indented to support dead weights and endure additional environmental loads. When such structures face potential lateral loads from events like ship collisions or falling objects, alongside working and environmental loadings, their unstable response in the post-buckling stage can lead to catastrophic consequences. It has been observed that existing compressive loads significantly degrade the energy absorption capacity of these structures. Investigations into axially compressed members subjected to lateral indentations are still necessary. In this study, nonlinear finite element methods were employed to explore the responses of typical offshore tubular structures, including a leg of jacket platforms and a monopile of offshore wind turbines. Scaled models were built to maintain consistent diameter/thickness and length/diameter ratios as practical structure. Initial imperfections were introduced in line with offshore standards. Uniaxial compression tests, and lateral indentation tests with varying levels of pre-compression were conducted. Numerical results were compared to predictions based on design rules and previous research. The findings were summarized and discussed.