多荷载耦合作用下近海风机桩基础疲劳分析
发布时间：2019-02-18 22:33
【摘要】：近海风机处于复杂的海洋环境，对地理位置和地质条件都有相当严格的要求。从海上风电场设计、建设、安装、运行、维护等全寿命周期看，风机基础的稳定性、耐久性对风机整个的工作起着至关重要的作用。风机受多种荷载共同作用，且有较为突出的周期性，对风机的耐疲劳设计要求高；在强风浪共同作用下，引起结构自身的振动，容易引发共振等振动破坏。鉴于此，本文以教育部博士点基金项目(20125522110004)和重庆市自然科学基金重点项目(cstc2013jjB3002)为依托，采用理论分析和数值模拟等手段，进行多荷载耦合作用下近海风机基础的疲劳分析。主要研究内容和成果如下： 1)运用随机过程来描述海浪过程，分析对比常用的几种海浪谱，采用P-M谱作为本文的海浪谱，并结合Morison方程计算得到波浪力谱；采用风速谱来对风荷载进行模拟；采用海上风机的制造厂商提供的风机运行荷载。为荷载耦合作用下的近海风机基础的疲劳分析提供荷载数据。 2)从荷载形式、地质条件、入土深度、土变形几个适用条件，对比目前常用的横向荷载作用下的桩-土作用模拟方法，选择P-y曲线法来模拟桩-土相互作用。根据P-y曲线的计算方法，针对本文研究的滨海海域地质条件，计算得到近海风机桩基础周围各土层的P-y曲线图。 3)根据前面计算的P-y曲线的地质资料，建立海上风机基础结构的桩-土作用的力学模型。确定ANSYS有限元软件中模拟近海风机三桩式基础结构的模拟单元，建立近海风机三桩式基础的有限元模型，并进行模态分析，分析得到三桩式基础结构的自振特性。 4)在近海风机三桩式基础有限元模型上，运用热点应力法，，计算关键区域的应力幅。运用线性累积损伤理论的Miner准则和S-N曲线法相结合的方法，分别计算极端工况和正常运行工况下的疲劳损伤； 5)对比分析不同工况下的近海风机三桩基础结构疲劳损伤情况，找到危险工况；对比不同关键点的疲劳损伤值，找到近海风机三桩基础结构疲劳损伤最严重的区域；基于线性疲劳累积损伤理论对近海风机三桩基础进行疲劳寿命预测。
[Abstract]:Offshore fan is in complex marine environment and has strict requirements for geographical location and geological conditions. Judging from the whole life cycle of offshore wind farm design, construction, installation, operation and maintenance, the stability and durability of the fan foundation play an important role in the whole work of the fan. The fan is subjected to various loads and has prominent periodicity, which requires high fatigue resistance design. Under the combined action of strong wind and waves, it causes vibration of the structure itself and easily causes vibration damage such as resonance. In view of this, based on the Ph. D. Program of the Ministry of Education (20125522110004) and the key project of Chongqing Natural Science Foundation (cstc2013jjB3002), this paper adopts theoretical analysis and numerical simulation. Fatigue analysis of offshore fan foundation under multi-load coupling is carried out. The main research contents and results are as follows: 1) the wave force spectrum is obtained by using the stochastic process to describe the wave process, analyzing and contrasting several commonly used wave spectra, using P-M spectrum as the wave spectrum of this paper, and combining with the Morison equation. Wind speed spectrum is used to simulate wind load, and the fan load provided by the manufacturer of offshore fan is used. It provides load data for fatigue analysis of offshore fan foundation under load coupling. 2) according to the applicable conditions of load form, geological condition, soil depth and soil deformation, the pile-soil interaction is simulated by P-y curve method. According to the calculation method of P-y curve, according to the geological conditions of coastal area studied in this paper, the P-y curve of each soil layer around the foundation of offshore fan pile is calculated. 3) according to the geological data of P-y curve, the mechanical model of pile-soil interaction of offshore fan foundation structure is established. The simulation unit of the offshore fan three-pile foundation in ANSYS software is determined, the finite element model of the offshore fan three-pile foundation is established, and the modal analysis is carried out, and the natural vibration characteristics of the three-pile foundation structure are analyzed. 4) based on the finite element model of offshore fan three-pile foundation, the stress amplitude of key area is calculated by using hot spot stress method. The Miner criterion of linear cumulative damage theory and S-N curve method are used to calculate the fatigue damage under extreme and normal operating conditions respectively. 5) comparing and analyzing the fatigue damage of offshore fan three piles foundation structure under different working conditions, finding out the dangerous condition, comparing the fatigue damage value of different key points, finding the area where the fatigue damage of offshore fan three piles foundation structure is the most serious. Based on the theory of linear fatigue cumulative damage, the fatigue life of offshore fan pile foundation is predicted.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU473.1
本文编号：2426280
[Abstract]:Offshore fan is in complex marine environment and has strict requirements for geographical location and geological conditions. Judging from the whole life cycle of offshore wind farm design, construction, installation, operation and maintenance, the stability and durability of the fan foundation play an important role in the whole work of the fan. The fan is subjected to various loads and has prominent periodicity, which requires high fatigue resistance design. Under the combined action of strong wind and waves, it causes vibration of the structure itself and easily causes vibration damage such as resonance. In view of this, based on the Ph. D. Program of the Ministry of Education (20125522110004) and the key project of Chongqing Natural Science Foundation (cstc2013jjB3002), this paper adopts theoretical analysis and numerical simulation. Fatigue analysis of offshore fan foundation under multi-load coupling is carried out. The main research contents and results are as follows: 1) the wave force spectrum is obtained by using the stochastic process to describe the wave process, analyzing and contrasting several commonly used wave spectra, using P-M spectrum as the wave spectrum of this paper, and combining with the Morison equation. Wind speed spectrum is used to simulate wind load, and the fan load provided by the manufacturer of offshore fan is used. It provides load data for fatigue analysis of offshore fan foundation under load coupling. 2) according to the applicable conditions of load form, geological condition, soil depth and soil deformation, the pile-soil interaction is simulated by P-y curve method. According to the calculation method of P-y curve, according to the geological conditions of coastal area studied in this paper, the P-y curve of each soil layer around the foundation of offshore fan pile is calculated. 3) according to the geological data of P-y curve, the mechanical model of pile-soil interaction of offshore fan foundation structure is established. The simulation unit of the offshore fan three-pile foundation in ANSYS software is determined, the finite element model of the offshore fan three-pile foundation is established, and the modal analysis is carried out, and the natural vibration characteristics of the three-pile foundation structure are analyzed. 4) based on the finite element model of offshore fan three-pile foundation, the stress amplitude of key area is calculated by using hot spot stress method. The Miner criterion of linear cumulative damage theory and S-N curve method are used to calculate the fatigue damage under extreme and normal operating conditions respectively. 5) comparing and analyzing the fatigue damage of offshore fan three piles foundation structure under different working conditions, finding out the dangerous condition, comparing the fatigue damage value of different key points, finding the area where the fatigue damage of offshore fan three piles foundation structure is the most serious. Based on the theory of linear fatigue cumulative damage, the fatigue life of offshore fan pile foundation is predicted.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU473.1
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