海洋钻井绞车水冷盘式制动器.doc
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海洋钻井绞车水冷盘式制动器,摘要盘式制动器是海洋钻井绞车制动系统的核心部件，其在制动工作时由于热疲劳而出现裂纹甚至断裂，因此开展海洋钻井绞车盘式制动器热疲劳失效机理研究，对确保钻井作业人员和设备的安全具有重要的意义。本文以水冷盘式制动器为研究对象，运用有限元的方法研究了水冷盘式制动器的热-机耦合特性，并以此为基础分析了制动盘热疲劳裂纹形成机理。论...
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摘 要
盘式制动器是海洋钻井绞车制动系统的核心部件，其在制动工作时由于热疲劳而出现裂纹甚至断裂，因此开展海洋钻井绞车盘式制动器热疲劳失效机理研究，对确保钻井作业人员和设备的安全具有重要的意义。本文以水冷盘式制动器为研究对象，运用有限元的方法研究了水冷盘式制动器的热-机耦合特性，并以此为基础分析了制动盘热疲劳裂纹形成机理。论文的主要研究内容及创新工作如下：
(1) 阐述了论文研究的基础理论，包括摩擦生热理论、热传导理论和热-机耦合分析理论，给出了温度场热传导的有限元求解方法和热-机耦合条件下温度场与应力场的有限元描述。
(2) 根据水冷盘式制动器结构特点，建立了制动系统的热-机耦合理论分析模型，并确定了其热分析的初始条件和边界条件。利用Pro/E软件建立了制动系统实际尺寸三维建模，利用有限元前处理软件Hypermesh对其进行网格划分，并运用非线性有限元分析软件ABAQUS建立了制动器的热-机耦合分析模型。
(3) 根据海洋钻井绞车的紧急制动工况和连续制动工况各自的特点，运用ABAQUS软件，分别对两种工况进行了数值模拟，得到了制动盘温度场和应力场的分布特性和变化规律，并通过改变工况参数和材料参数等方式，研究了温度场和应力场的影响因素。
(4) 基于制动过程的热-机耦合分析结果，分析了水冷式制动盘的失效机理，并确定了制动盘的危险部位和载荷谱，应用局部应力应变法建立制动盘热疲劳寿命预测模型，分析了不同制动形式下制动盘热疲劳寿命和影响因素。
研究表明：在制动过程中，制动盘的温度场与应力场是相互耦合的，较大的制动盘比热容、导热系数大和较低的热膨胀系数、弹性模量有利于降低制动盘温度极值和应力极值；冷却水速度越大对制动盘的冷却效果越明显，但当速度达到一定数值时，冷却效果就不再非常明显；在节点的三向应力中，周向应力是产生表面裂纹的主要分量；下钻速度是影响制动盘热疲劳寿命的主要因素。
关键词 水冷盘式制动器；热-机耦合；数值模拟；失效机理；寿命预测
Abstract
The disc brake is one core component in the ocean drilling equipments. The practical results show that the crack or fracture induced by thermal fatigue is the main failure mode of the brake. Therefore, to carry out the failure mechanism research of the disc brake has a very important significance in safeguarding the safety of drilling workers and equipments. Aiming at a water-cooling disc brake of offshore drilling drawworks, the thermo-mechanical coupling characteristics of the water-cooling disc brake were simulated by the method FEM. Based on the above results, the formation mechanism of thermal fatigue cracks of the brake disc was analyzed. The main research and innovation work include:
(1) The basic theory used in this thesis was elaborated, including friction heat theory, thermal conduction theory, and thermo-mechanical coupling analysis theory. The finite element solution method of heat transfer and the finite element description of temperature field and stress field under thermo-mechanical coupling conditions were also given in the thesis.
(2) Thermo-mechanical coupling theoretical analysis model of the brake system was established according to the structural features of water-cooling disc brake, then the initial and boundary conditions of thermal analysis were determined. Three dimension modeling software Pro/E was used to build the real dimension brake disc system. The software Hypermesh was applied to mesh the brake system. And the FEA software ABAQUS was adopted to build up the thermo-mechanical coupling model.
(3) According to the characteristics of emergency braking and repeated braking, the two braking conditions were simulated respectively by using software ABAQUS, and the distribution characteristics and variation disciplinarian of temperature field and stress field of the brake disc were obtained. The factors of temperature field and stress field were discussed through changing the working parameters and material parameters, etc.
(4) Based on the results of thermo-mechanical coupling analysis during braking, the failure mechanism of water-cooling brake disc was analyzed. Then dangerous parts and load spectrum of the brake disc were determined. Thermal fatigue life prediction model of the disc was established by the local stress and strain law. The thermal fatigue life of the brake disc and its factors in different braking forms were also analyzed.
The research showed that temperature field and stress field during braking were coupled. The higher specific heat, thermal conductivity and the lower thermal expansion coefficient, elasticity modulus could help decrease the maximum values of the temperature and stress of the brake disc. The greater the rate of cooling water was, the more obvious the cooling effect of the brake disc was, but when the rate of cooling water reached a certain value, and the cooling effect was unobvious. In the three-dimensional stress, circumferential stress was the main reason for causing the initial cracks on the surface of brake disc. The velocity of round trip was a major factor in influencing thermal fatigue life of the brake disc.
Keywords water-cooling disc brake; thermo-mechanical coupling; numerical simulation; failure mechanism; life prediction
目 录
摘 要 I
Abstract II
第1章 绪论 ..
盘式制动器是海洋钻井绞车制动系统的核心部件，其在制动工作时由于热疲劳而出现裂纹甚至断裂，因此开展海洋钻井绞车盘式制动器热疲劳失效机理研究，对确保钻井作业人员和设备的安全具有重要的意义。本文以水冷盘式制动器为研究对象，运用有限元的方法研究了水冷盘式制动器的热-机耦合特性，并以此为基础分析了制动盘热疲劳裂纹形成机理。论文的主要研究内容及创新工作如下：
(1) 阐述了论文研究的基础理论，包括摩擦生热理论、热传导理论和热-机耦合分析理论，给出了温度场热传导的有限元求解方法和热-机耦合条件下温度场与应力场的有限元描述。
(2) 根据水冷盘式制动器结构特点，建立了制动系统的热-机耦合理论分析模型，并确定了其热分析的初始条件和边界条件。利用Pro/E软件建立了制动系统实际尺寸三维建模，利用有限元前处理软件Hypermesh对其进行网格划分，并运用非线性有限元分析软件ABAQUS建立了制动器的热-机耦合分析模型。
(3) 根据海洋钻井绞车的紧急制动工况和连续制动工况各自的特点，运用ABAQUS软件，分别对两种工况进行了数值模拟，得到了制动盘温度场和应力场的分布特性和变化规律，并通过改变工况参数和材料参数等方式，研究了温度场和应力场的影响因素。
(4) 基于制动过程的热-机耦合分析结果，分析了水冷式制动盘的失效机理，并确定了制动盘的危险部位和载荷谱，应用局部应力应变法建立制动盘热疲劳寿命预测模型，分析了不同制动形式下制动盘热疲劳寿命和影响因素。
研究表明：在制动过程中，制动盘的温度场与应力场是相互耦合的，较大的制动盘比热容、导热系数大和较低的热膨胀系数、弹性模量有利于降低制动盘温度极值和应力极值；冷却水速度越大对制动盘的冷却效果越明显，但当速度达到一定数值时，冷却效果就不再非常明显；在节点的三向应力中，周向应力是产生表面裂纹的主要分量；下钻速度是影响制动盘热疲劳寿命的主要因素。
关键词 水冷盘式制动器；热-机耦合；数值模拟；失效机理；寿命预测
Abstract
The disc brake is one core component in the ocean drilling equipments. The practical results show that the crack or fracture induced by thermal fatigue is the main failure mode of the brake. Therefore, to carry out the failure mechanism research of the disc brake has a very important significance in safeguarding the safety of drilling workers and equipments. Aiming at a water-cooling disc brake of offshore drilling drawworks, the thermo-mechanical coupling characteristics of the water-cooling disc brake were simulated by the method FEM. Based on the above results, the formation mechanism of thermal fatigue cracks of the brake disc was analyzed. The main research and innovation work include:
(1) The basic theory used in this thesis was elaborated, including friction heat theory, thermal conduction theory, and thermo-mechanical coupling analysis theory. The finite element solution method of heat transfer and the finite element description of temperature field and stress field under thermo-mechanical coupling conditions were also given in the thesis.
(2) Thermo-mechanical coupling theoretical analysis model of the brake system was established according to the structural features of water-cooling disc brake, then the initial and boundary conditions of thermal analysis were determined. Three dimension modeling software Pro/E was used to build the real dimension brake disc system. The software Hypermesh was applied to mesh the brake system. And the FEA software ABAQUS was adopted to build up the thermo-mechanical coupling model.
(3) According to the characteristics of emergency braking and repeated braking, the two braking conditions were simulated respectively by using software ABAQUS, and the distribution characteristics and variation disciplinarian of temperature field and stress field of the brake disc were obtained. The factors of temperature field and stress field were discussed through changing the working parameters and material parameters, etc.
(4) Based on the results of thermo-mechanical coupling analysis during braking, the failure mechanism of water-cooling brake disc was analyzed. Then dangerous parts and load spectrum of the brake disc were determined. Thermal fatigue life prediction model of the disc was established by the local stress and strain law. The thermal fatigue life of the brake disc and its factors in different braking forms were also analyzed.
The research showed that temperature field and stress field during braking were coupled. The higher specific heat, thermal conductivity and the lower thermal expansion coefficient, elasticity modulus could help decrease the maximum values of the temperature and stress of the brake disc. The greater the rate of cooling water was, the more obvious the cooling effect of the brake disc was, but when the rate of cooling water reached a certain value, and the cooling effect was unobvious. In the three-dimensional stress, circumferential stress was the main reason for causing the initial cracks on the surface of brake disc. The velocity of round trip was a major factor in influencing thermal fatigue life of the brake disc.
Keywords water-cooling disc brake; thermo-mechanical coupling; numerical simulation; failure mechanism; life prediction
目 录
摘 要 I
Abstract II
第1章 绪论 ..
