【作者】 张进；

【导师】 安晨； 段梦兰；

【作者基本信息】 中国石油大学(北京) ， 机械工程， 2021， 硕士

【摘要】 LNG低温复合软管具有柔软性好、重量轻、两船间运动补偿高等优点,可以满足恶劣海况下LNG的输送需求。目前国内外仅有几家公司具备生产LNG低温复合软管的能力,且没有具体的结构设计规范可以参考,该软管的学术研究也基本处于空白状态。LNG低温复合软管截面形式非常复杂,且承受风、浪、流等多种载荷作用,其在超低温环境下的结构性能直接关系到其安全运行,因此本文基于理论、有限元模拟以及试验相结合的方式对LNG低温复合软管的力学性能展开深入研究,进而为LNG复合软管的结构设计提供有益指导。本文主要研究内容如下:(1)针对LNG低温复合软管的结构,给出了各层材料的选型依据以及强度校核准则。不考虑螺旋钢丝的影响,基于三维各向异性弹性力学,在平面应变条件和轴对称条件下建立了LNG低温复合软管力学响应的理论分析模型,给出了管体位移、应变和应力的解析解,并且利用ANSYS里复合材料专用模块ACP建立了相应的有限元分析模型,对LNG低温复合软管在内压载荷作用下的力学响应进行了理论计算与数值模拟,并对比了两种不同分析方法得到的管体轴向应力、环向应力与径向应力,验证了理论模型的正确性。(2)考虑螺旋钢丝的影响,建立了LNG低温复合软管精细化有限元模型,考察了软管在内压载荷作用下的力学响应,并与江苏某软管有限公司进行的LNG低温复合软管静水压试验进行对比,验证了考虑螺旋钢丝影响时LNG低温复合软管有限元模型的准确性,并基于此模型研究了LNG低温复合软管在拉伸、弯曲、以及扭转载荷作用下的力学响应,对各层的应力分布和承载情况进行了研究,重点考察了芳纶布铺层在材料主方向1以及材料主方向2上的应力分布,并研究了温度对LNG低温复合软管力学性能的影响规律。(3)研究了芳纶布铺设角度、芳纶布铺设层数、钢丝螺距以及钢丝直径分别对LNG低温复合软管拉伸刚度、扭转刚度以及弯曲刚度的影响规律,相应地提出了一些结构设计优化的建议,相关研究成果可以为LNG低温复合软管的结构设计提供参考。更多还原

【Abstract】 LNG cryogenic composite hose can meet the needs of LNG transportation under severe sea conditions because of many advantages such as good flexibility,light weight and high motion compensation between two ships.At present,there are only a few companies with the ability to produce LNG cryogenic composite hoses in the word and there are no specific structural design standards to refer to.Also,the academic research on LNG cryogenic composite hoses is almost in a blank state.The cross-section of LNG cryogenic composite hose is very complicated and the hose bears various loads such as wind,waves and currents.The structural behavior of LNG cryogenic composite hose under ultra-low temperature environment is closely related to its safe operation.In this work,the mechanical properties of LNG cryogenic composite hose are studied by means of theory,finite element model and experiments,which can provide useful guidance for the structural design of LNG cryogenic composite hose.The main research work of this paper is summarized as follows:(1)According to the structure of LNG cryogenic composite hose,the reason for the selection of material for each layer and the strength check criteria for each material are given.Based on three-dimensional anisotropic elastic mechanics,a theoretical model for mechanical properties of LNG cryogenic composite hose without spiral steel wires is established under conditions of plane strain and axisymmetric.Analytical solutions of displacement,strain and stress of LNG cryogenic composite hose are given.A finite element model for LNG cryogenic composite hose without spiral steel wires is established with ACP technique,a special module for composite materials in ANSYS.Theoretical calculation and numerical simulation of the mechanical response of LNG cryogenic composite hose under internal pressure are carried out and the theoretical model is verified by comparing the axial stress,hoop stress and radial stress by two different analysis methods.(2)A detailed finite element model for LNG cryogenic composite hose with spiral steel wires is established and the mechanical response of LNG cryogenic composite hose under internal pressure is calculated by the finite element model.The finite element model for LNG cryogenic composite hose with spiral steel wires is validated by the hydrostatic pressure test data conducted by a hose company in Jiangsu Province.Then,the mechanical response of LNG cryogenic composite hose under tension,bending and torsion is studied by the finite element model.The stress distribution of each layer is investigated,especially the stress of PA fabric in the main direction 1 and 2.Also,the influence of temperature on the mechanical properties of LNG cryogenic composite hose is studied.(3)The influences of the laying angles of PA fabric,the number of layers of PA fabric,the wire pitches and the wire diameters on the tensile stiffness,torsional stiffness and bending stiffness of LNG cryogenic composite hose are investigated and some suggestions on structural design optimization are put forward.The research work of this paper can provide useful guidance for the structural design of LNG cryogenic composite hose.更多还原