Research on the cutting thermodynamic behavior of high-strength large-thickness offshore jack-up platform leg rack

The cutting of offshore jack-up platform leg rack is highly nonlinear and complex thermal processing process.The residual stress influences the following welding quality and cause crack growth.Therefore,research on the cutting practice of jack-up platform leg rack is significant to improve the safety and reliability of the offshore platform.A heating source model that is applicable to the cutting and emulation of high-strength thick plates han been presented.Then,the thermo-physical characteristic parameters of NV E690 leg plate was calculated by JMATPRO,and is revised according to the theory of metallographic.Furthermore,the numerical simulation of the linear cutting of leg plate was conducted,and the reliability of the heating source model and the thermo-physical characteristic parameters of material were proved by comparing them with the experimental data.Based on the former study,the optimal parameter（heating source,cutting speed and radius of the heating source model） which ensured that the gear plate was cut through without edge collapses during cutting was calculated.The optimized process parameters can be used to study the distribution of residual stress in gear plate during cutting which provides theoretical guideline for improving the construction technology of offshore platform legs.