基于水下光纤应变监测的导管架结构总冰力测量方法

Ice load measurement based on underwater fiber strain monitoring of jacket structure

基于测量结构水下光纤应变获取冰力的方法首次应用于渤海JZ20-2NW加锥导管架平台,该方法方便进行零点标定,可获取结构总冰力的绝对信息(包括均值和波动值)。首先介绍了JZ20-2NW平台的现场监测系统,主要包括结构水下应变响应记录冰力信息,甲板上部视频记录同步冰情(冰厚、冰速和来冰方向)信息和拾振器记录结构冰振响应;重点分析了由测点应变向结构总冰力的转化方法,并对总冰力进行了初步分析。将无量纲化实测冰力与5种典型冰力计算模型进行了比较,分析结果表明,锥体宽度与海冰厚度比值(简称"宽厚比")对冰力大小及变化起决定作用。

Ice load measurement based on underwater fiber strain is applied in the Bohai Sea JZ20-2NW conical platform for the first time. Zero-point calibration could be easily conducted and absolute data of global ice load were obtained, including averages and fluctuation values. Firstly, the full-scaled monitoring system of JZ20-2NW Platform is introduced. The monitored data include ice loads of underwater strain response records, ice conditions of the recorded videos and structural response of accelerometer sensors on the deck. In the paper, the conversion method from measured strain to global ice load on the structure is focused on. The dimensionless full-scaled ice loads with five classical ice load calculation models are compared . Primary comparison results indicate that the ratio of structural cone width to sea ice thickness determines the value and variations of ice loads.