• Project 1: Peregrino Phase II FEED SURF
• Project 2 Johan Sverdrup Infield Pipeline Concept Study
• Project 3: GRD Project FEED Study & Kvitebjørn Flow Study

IKM Ocean design AS, 2013.08 - 2014.07

• Contribute in pipeline snaking route design and solved the post-buckling deformation controlled in an acceptable range.

• Contribute in investigating the ocean current effect on the lateral displacement and lateral buckling of the steel pipe on bottom.

• Contribute in establishing the complex full-scale trawling model
• Comprehensively investigate the impact and pull-over phase effect on the global response of pipeline

Project: Dynamic umbilical JIP

NTNU,SINTEF Ocean, 2014.08 - 2018.07

• Practical skills of performing full scale test of umbilical under combined tension and bending loads.
• Contribute in programming to deal with test measurement for understanding the dynamic stress behavior of helical components and speed up the workflow.
• Develop new numerical modeling methodology of umbilical’s cross section and improve the dynamic stress accuracy.
• Present latest numerical analysis results and improvements in developing FE software (Bflex and Uflex) in important JIP meetings and software user meetings.

During working in Huazhong university of science and technology, 6 projects have been granted as follows:

1. Nonbonded flexible riser’s structural failure analysis (industrial sponsored, China) (2025-2026)
2. Light dynamic power cable design (research concil, China) oil and gas field (Ministryo f Natural Resources of the People’s Republic of China) (2025-2027)
3. Fatigue mechanism study of dynamic umbilical applied in oil & gas industry (National Natural Science Foundation of China (NSFC), 2021-2023)
   • Responsible to develop a new method to consider fretting fatigue in the conventional fatigue life.
4. Structural analysis of flexible pipes applied in oil & gas industry (Fundamental Research Funds for the Central Universities, HUST, 2019-2021)
   • Responsible to develop a new method to consider fretting fatigue in the conventional fatigue life.
5. Dynamic response analysis of subsea power cable applied in oil & gas and wind turbine industry (Ministry of Science and Technology of the People’s republic of China, 2021-2022)
   • Solve the power cable response under current load in a stochastic way.
   • Propose a new global configuration design for reducing the power cable response in shallow water.
6. Fatigue life prediction of nonbonded flexible pipe applied in Xijiang (CNOOC, China) oil and gas field (industry sponsored) (2021-2022)
   • Perform global response analysis of flexible pipe under dynamic motion of FPSO and combined wave and current load conditions.
   • Develop a new method for the pipe fatigue life assessment when the annulus layer is wet or fully fulfilled with fluid, resulting in significant numerical analysis computation time saving.

Application of a data-driven approach for maximum fatigue damage prediction of an unbonded flexible riser

Tianjiao Dai, Jiaxuan Zhang, Chao Ren*, Yihan Xing, Svein Sævik, Naiquan Ye, Xing Jin, Jun Wu

Ocean Engineering, 2024

• The AK-MDAmax approach efficiently predicts long-term fatigue damage of unbonded flexible risers with sufficient accuracy while accounting for all 400 sea states.

• The approach accurately identifies the maximum fatigue damage location across different assessment scales, with errors in long-term fatigue damage predictions ranging from 0.35% to 0.89%.

• Compared to traditional numerical analysis, the AK-MDAmax approach significantly improves computational efficiency by reducing the required sea states from 400 to 15, achieving a 27-fold enhancement in fatigue assessment efficiency.

Energy efficient design of an SST-flowline system using a coupled dynamic analysis approach

Tianjiao Dai,Jiaxuan Zhang,Yucong Ma,Xing Yihan*

Ocean Engineering, 2024

• The proposed offloading control model integrates SST maneuvering with flowline dynamics, significantly improving motion stability and energy efficiency.

• Flowline tension enhances SST hovering stability but increases energy consumption, with optimized ballast weight reducing energy usage by up to 98%.

• The model achieves a 64% reduction in total energy consumption and offers a comprehensive methodology for SST-flowline system optimization.

Experimental and numerical study on dynamic stress and curvature in the steel tube umbilical

Tianjiao Dai,Sævik, Svein; Ye, Naiquan Marine Structure, 2020

• Elaborate on the world - leading optical fiber measurement experimental method, which is used for stress measurement of internal units in umbilical cables and full - scale experiments.
• Employ a self - developed advanced friction model combined with bflex numerical analysis, showing an extremely high degree of consistency with experimental data.
• The research findings are applicable to cross - sectional analysis and strength checking of flexible risers, umbilical cables, and dynamic cables in both the industrial and academic sectors.

An anisotropic friction model in non-bonded flexible risers

Tianjiao Dai,Sævik, Svein; Ye, Naiquan Marine Structure, 2018

• The study reveals the impact of contact pressure on friction coefficients and proposes an anisotropic friction model, providing a new method for accurately predicting friction forces along the helical path, thereby enhancing the reliability of umbilical structure analysis.

• By introducing the HCONT453 element and the 2D friction model, the study explores the contact and friction mechanisms between tensile armor layers, optimizing mechanical modeling methods and offering significant guidance for umbilical fatigue analysis.

Friction models for evaluating dynamic stresses in non-bonded flexible risers

Tianjiao Dai,Sævik, Svein; Ye, Naiquan Marine Structure, 2017

• Proposed four friction models, implemented continuous update of dynamic contact pressure, integrated into Bflex to boost non - bonded flexible pipe friction modeling accuracy.
• Verified initial strain concept via full - scale tests, emphasized frictional moment’s significance in fatigue calculation.
• Revealed dynamic friction’s greater impact on axial force, proved industry standard conservatism, suggested small - scale tests for shear stiffness validation.

An efficient fatigue analysis for the nonbonded flexible riser

Li Pengjie, Dai Tianjiao, Jin Xing, Dong Leilei, Liu Shuaiqi, Yang Shuo, Xiang Xianbo, Kang Hooi-Siang.

Ship and offshore structures 1-16, 2021.10, Impact factor, 1.977, 2021

Nonlinear Slow-varying Dynamics-assisted Temporal Graph Transformer Network for Remaining Useful Life Prediction

Zhan Gao, Weixiong Jiang, Jun Wu*, Tianjiao Dai

Reliability Engineering & System Safety, 248(5):110162. 2024

The effect of stick stiffness in friction models on the bending behavior in flexible risers

Dai, Tianjiao; Ye, Naiquan.; Sævik, Svein. OMAE, - International Conference on Ocean, Offshore & Arctic Engineering, 2017

Comparison study of umbilicals’ curvature based on full scale tests and numerical models

Dai, Tianjiao; Sævik, Svein; Ye, Naiquan. ISOPE - International Offshore and Polar Engineering Conference, 2016

Effect of Surface Contact Stiffness on Stress Analysis of Umbilicals

Wang, Howard; Ye, Naiquan; Dai, Tianjiao; Sævik, Svein. ISOPE - International Offshore and Polar Engineering Conference, 2015

Multilayer Fused Correntropy Reprsenstation for Fault Diagnosis of Mechanical Equipment

Deng Qi, Guanhui Zhao, Weixiong Jiang, Weixiong Jiang,Jun Wu, Tianjiao Dai

Sensors 24(18):6142, 2024

Multiscale Spatiotemporal Attention Network for Remaining Useful Life Prediction of Mechanical Systems

Zhan Gao; Weixiong Jiang; Jun Wu; Tianjiao Dai

IEEE Sensors Journal Volume:25 Issue:4, 2024

Self-adaptive Single and Simultaneous Fault Diagnosis for Rotating Machinery via Redefined Signal Quality Indicator and Parallel Ensemble Network

Weixiong Jiang, Kaiwei Yu, Jun Wu, Tianjiao Dai, Haiping Zhu

Applied soft computing 170:112737, 2024