A new full-ocean-depth macro-organisms pressure-retaining sampler (FMPS) was designed to collect pressure-retaining macro-organisms samples from the abyssal seafloor. A mathematical model for pressure compensation in the FMPS recovery process was developed. The effects of FMPS structural parameters, pressure compensator structural parameters and sampling environment on the pressure retention performance of FMPS were analyzed. Using the developed FMPS engineering prototype, FMPS internal pressure test, high-pressure chamber simulation sampling, and pressure-retaining test was carried out. The test results show that the key components of FMPS can carry 115MPa pressure, FMPS can complete the sampling action in the high-pressure chamber of 115MPa, the pressure is maintained at 105.5MPa, and the pressure drop rate (ratio of pressure drop during FMPS recovery to sampling point pressure) is 9.13%, the experimental results are consistent with the theoretical calculation. The test verified the feasibility of FMPS design and the reliability of pressure retention, providing a theoretical basis and technical support for the design and manufacture of full-ocean-depth sampling devices. A new full-ocean-depth macro-organisms pressure-retaining sampler (FMPS) was designed to collect pressure-retaining macro-organisms samples from the abyssal seafloor. A mathematical model for pressure compensation in the FMPS recovery process was developed. The effects of FMPS structural parameters, pressure compensator structural parameters and sampling environment on the pressure retention performance of FMPS were analyzed. Using the developed FMPS engineering prototype, FMPS internal pressure test, high-pressure chamber simulation sampling, and pressure-retaining test was carried out. The test results show that the key components of FMPS can carry 115MPa pressure, FMPS can complete the sampling action in the high-pressure chamber of 115MPa, the pressure is maintained at 105.5MPa, and the pressure drop rate (ratio of pressure drop during FMPS recovery to sampling point pressure) is 9.13%, the experimental results are consistent with the theoretical calculation. The test verified the feasibility of FMPS design and the reliability of pressure retention, providing a theoretical basis and technical support for the design and manufacture of full-ocean-depth sampling devices.

This study investigates the impact of expanding and reducing deformation ratios on the performance of L360 straight-seam welded pipes formed by the JCO process for offshore oil and gas transportation. The Split Hopkinson Pressure Bar (SHPB) experimental technique was used to examine the stress/strain relationships, yield strength, and compressive strength of the pipe materials subjected to high strain rates. The results indicated that the impact performance of the pipes significantly improves with both expansion and reduction processes, demonstrating an enhancement effect of deformation. The impact of yield strength and compressive strength increases with higher expansion ratios, reaching maximum values of 1009 MPa and 847 MPa, respectively, at an expansion ratio of 1.2%. At a reduction ratio of 0.8%, the impact yield strength increased by 64% and the compressive strength by 14%. These findings not only provide theoretical support for optimizing the expansion and reduction processes and their associated equipment but also have direct and significant practical implications for enhancing the performance and safety of offshore oil and gas transmission pipelines, thereby contributing to the advancement of the field.