# A Case Study of Floating Offshore Super-Long Steel Pipeline Combing with Field Monitoring
## 1 Introduction
The unmanned aerial vehicles technology is suitable for the overall monitoring of long and large pipelines, but it is not mature yet. Furthermore, besides the monitoring method, the mechanical and deformation characteristics of the pipeline body are also worthy to attend. Many efforts focused on the material characteristics and deformation mechanism of the pipe body. [PERSON] et al. [27] investigate the transverse impact response for ultra-lightweight cement composite (ULCC) filled pipe-in-pipe structures through a parametric study using both a validated finite element procedure and a validated theoretical model. [PERSON] et al. [28] have determined through mechanical tests, metallographic analysis, and morphological studies that the degree of discoloration of the HAZ is directly affected by the atmospheric oxygen content during purging, and it has been proven to have a good electrical resistance in welded joints. [PERSON] et al. [29] measured the characteristics of stainless steel during large plastic deformation through a hot torsion test, and obtained the best heating temperature range for the studied steel deformation. Offshore pipeline monitoring is a challenging task. The main concerns are pipeline stress and strain, pipeline leakage and vibration. Relevant scholars have conducted a large number of studies on the offshore pipeline. They focused on a single fixed pipeline joint and ignored the deformation of the pipeline itself. For ultra-long pipelines, there will inevitably be an error in the calculation of force exerted on them by these methods. [PERSON] et al. [30] analyzed stress states of pipelines upon floating by using the Finite Element Calculation method. [PERSON] et al. [31] presented a probabilistic methodology for monitoring the condition of offshore pipelines and predicting the reliability considering stress observation and structural deterioration. There were many ways to monitor pipeline corrosion and leakage. [PERSON] et al. [32] described the application of the finite element method (FEM) and the development of equations to predict the failure pressure of single corrosion affected pipelines subjected to internal pressure and axial compressive stress. [PERSON] et al. [33] introduced the application of the boundary element method in the calculation of a closed cylindrical shell of stepped thickness, and compared it with two numerical methods: boundary and finite element. Negative pressure wave [34] and dynamic modelling [35; 36] methods were used to monitor pipeline leaks. [PERSON] et al. [37] presented a scalable design and simulation of a water pipeline leakage monitoring system using Radio Frequency Identification and Wireless Sensor Network technology. The study on the vibration of the pipeline is mostly about the vibration characteristics of the submarine pipeline during the period of use, while the study on the vibration of the floating pipeline is less. [PERSON] and [PERSON] [38] presented numerical simulations and experimental verification of a vibration-based damage detection technique. [PERSON] et al. [39] suggested that fatigue could be calculated based on the modal shape of response and amplitudes from the monitoring data. [PERSON] et al. [40] investigated the transverse vortex-induced vibrations (VIVs) of a submarine pipeline near an erodible sandy seabed under the influence of ocean currents by a series of experiments. Considering the function of inertia and dampness, under the optimal span, a frequency response analysis was carried out. [PERSON] et al. [41] proved that resonance did not happen between the pipeline and wave. One marine riser fatigue acoustic telemetry scheme was proposed by [PERSON] et al. [42] to monitor deep and ultra-deepwater risers' vibration fatigue. [PERSON] et al. [43] studied the dynamic response of multiple ocean pipelines. A semi-analytical method for the multi-spans offshore pipeline was developed by them, which provided a fast and accurate alternative to finite element modeling of potentially interacting spans. Also, [PERSON] et al.