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Results
Diagnosis And Health Monitoring For Free Spanning Submarine Pipelines
Feng, Xin (School of Civil and Hydraulic Engineering, Dalian University of Technology) | Zhou, Jing (School of Civil and Hydraulic Engineering, Dalian University of Technology) | Yuan, Yongbo (School of Civil and Hydraulic Engineering, Dalian University of Technology) | Zhang, Jun (School of Civil and Hydraulic Engineering, Dalian University of Technology)
ABSTRACT The environment conditions for free spanning submarine pipelines are serious. The different types of loadings including wave, current, landslide and earthquake make the pipelines oscillate and damage. Normally, the damage in the structures is the local phenomenon, and the response signals of the submarine pipeline are with the non-stationarity. Therefore, the conventional Fourier-based approach is not able to extract the damage sensitive features. In this paper, a wavelet packet analysis-based approach is adopted to diagnose anomalous structural condition for free spanning submarine pipeline. The measured vibration signals of healthy structural condition are decomposed by wavelet packet analysis, and the component energies are calculated as condition-sensitive features. The corresponding condition-sensitive features of an unknown structural condition are calculated in the same method. Anomalous structural condition is detected by the changes in the condition-sensitive features. The model experiments of free spanning submarine pipelines on the shaking table and wave tank are carried out to investigate the feasibility of the proposed approach method and to simulate the health monitoring system. The results show that the proposed method is effective to extract the damage sensitive features and to diagnose the anomalous structural condition of free spanning submarine pipeline. The health situation of the structure is predicated. INTRODUCTION The environment conditions of the free spanning submarine pipelines are serious. The different types of loadings including wave, current, landslide and earthquake make the pipelines oscillate and damage. The importance of maintaining the health of submarine pipeline has been recognized. Though the present health monitoring techniques provide a useful platform for the submarine pipeline, the drawbacks of these method is also evident. Most currently inspection techniques of submarine pipeline are based on the detection of the oil leakage instead of the damnification of the pipeline.
- Health & Medicine > Consumer Health (1.00)
- Energy > Oil & Gas > Midstream (1.00)
Numerical Simulation Of The Truss Spar ‘Horn Mountain’
Theckumpurath, Basil (Ocean Engineering program, Department of Civil Engineering, Texas A&M University College Station) | Ding, Yu (Ocean Engineering program, Department of Civil Engineering, Texas A&M University College Station) | Zhang, Jun (Ocean Engineering program, Department of Civil Engineering, Texas A&M University College Station)
ABSTRACT A truss spar, named as Horn Mountain, was deployed in the Gulf of Mexico in 1,650 m of water, approximately 150 km southeast of New Orleans in 2002. Extensive field measurements were made using an integrated marine monitoring system attached to the truss spar. In this study, dynamic analysis of the truss spar interacting with its mooring and riser system was performed using a time-domain numerical code, known as ‘COUPLE’. The simulated results were then compared with the corresponding field measurements made during Hurricane Isidore. Satisfactory agreement between the simulation and corresponding measurements was in general reached, indicating that the numerical code can be used to conduct the time-domain analysis of a truss spar interacting with its mooing and riser system under severe storm impact. INTRODUCTION Considering the truss spar, Horn Mountain, deployed in relatively deep water (1,650 m), coupled analysis should be made to account for the dynamic interaction between its hull and mooring and riser system. A numerical code, known as COUPLE, was used in this study. Initially, it was developed for computing the 3-DOF (Degree- Of-Freedom) motions of a spar positioned by taut mooring lines using a quasi-static (quasi coupled) analysis (Cao and Zhang 1997) and later extended to allow for dynamical interaction between a spar and its mooring system to quantify the damping effects of a mooring system on the slow-drift motion of a spar (Chen et. al. 2001). More recently, it was extended to allow for 6-DOF motions of a moored floater (Chen 2002, Ding et al 2003, Chen et al. 2006). It consists of two basic computational parts: one for computing the dynamics of a mooring/tendon/riser system and the other for the wave/current/wind loads on a moored floater (hull).
- North America > United States > California (0.28)
- North America > United States > Louisiana > Orleans Parish > New Orleans (0.24)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Risers (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Mooring systems (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Floating production systems (1.00)