内压和弯曲联合作用下钢丝缠绕增强塑料复合管力学性能研究

发布时间：2018-01-04 06:35

本文关键词：内压和弯曲联合作用下钢丝缠绕增强塑料复合管力学性能研究　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：钢丝缠绕增强塑料复合管(简称PSP)是一种新型的复合管道。它是以高密度聚乙烯(简称HDPE)为基体材料,以高强度的钢丝左右缠绕成网状骨架为增强体,用高性能的热熔胶将钢丝和HDPE紧密地粘结在一起。PSP结合了钢丝的高强度和HDPE耐腐蚀的特性,被广泛地应用在海洋、石油、化工和市政等领域。PSP应用在海洋条件时将受到复杂载荷的作用,除了受内压作用,还会受到坠落物撞击、船只拖网、抛锚拖曳和波浪冲击等弯曲载荷作用,并受温度等因素的影响。因此内压和弯曲是海洋工况中典型的组合载荷,当组合载荷超过PSP的承载能力时,PSP将发生失效,并造成经济损失和生态破坏。而过往研究中仅分别对PSP承载内压和弯曲进行了相关研究,没有考虑到PSP承受两者联合作用的情况,且尚无复杂载荷条件的试验装备。因此内压和弯曲联合作用下PSP的力学性能研究很有必要,对PSP的安全应用和工程设计具有十分重要的意义。本文在国家自然基金"基于粘弹性损伤模型的聚乙烯管材慢速裂纹扩展机理研究"(项目编号:51575480)和"聚乙烯管道电熔焊接接头超声检测特征线的形成机理研究"(项目编号:51305394)的支持下，，对内压和弯曲联合作用下PSP的力学性能进行试验和有限元研究,主要完成的工作如下:(1)针对海洋复杂载荷条件和聚乙烯温度相关、率相关的材料特性,提出试验装备的功能:装备可对试样管施加内压和弯曲载荷,并能控制温度和弯曲速率;根据功能要求设计装备的结构,分别从机械结构、液压回路和测试系统方面进行设计;机械结构方面,实现将试样管自动移到水箱内的过程;液压回路方面,分别设计液压回路以实现多功能弯曲加载;测试系统方面,通过估算确定加载油缸的最大载荷等参数;根据设计方案组装和搭建试验装备;装备的设计方案获国家发明专利授权。(2)开展室温下(20℃)PSP的内压和弯曲组合载荷试验,试样管失效前发出密集钢丝断裂声,最后试样管破裂并喷射出大量水;将破口处的外层HDPE剖开,可看到10根钢丝发生了断裂,将钢丝断裂作为PSP的失效判据;根据弯矩-位移曲线图可知弯矩呈先增大后减小的趋势,得出极限弯矩和失效位移;通过计算内压降低率以表征PSP在弯曲过程中体积增大的程度;开展其他不同温度下(40℃和60℃)PSP的内压和弯曲组合载荷试验,得到不同温度下PSP的极限弯矩、失效位移和内压降低率,结果显示:温度越高,则极限弯矩越低、失效位移越小,而内压降低率基本不变。(3)根据试验加载和接触条件建立PSP有限元模型;比较试验和有限元的弯矩-位移曲线,两者平均相对误差为4.4%,从而验证有限元模型;计算不同加载位移下的抗弯刚度,结合弯矩-位移曲线,分析PSP在不同阶段下的弯曲过程,得出极限弯矩;根据HDPE和钢丝的应力云图并结合试验结论,将钢丝断裂作为PSP模型的失效判据,计算PSP失效时的曲率;分别计算仅受内压作用、仅受弯曲作用和内压弯曲联合作用下钢丝的应变,分析组合载荷之间的关系;分别计算不同温度和内压下的极限弯矩,拟合二元线性回归方程;讨论钢丝根数和缠绕角度对极限弯矩的影响;分别建立不同工作压力规格和不同管径的X70钢管、X80钢管和PSP有限元模型,讨论不同类型管道的抗弯能力。PSP抗弯能力的分析和影响因素的讨论对管道参数设计和工程应用有指导意义。
[Abstract]:Plastic pipe reinforced by winding steel wire (PSP) is a new composite pipe. It is based on high density polyethylene (HDPE) as the base material, with high strength steel wire wound around into mesh skeleton for reinforcement, hot melt adhesive of high performance steel and HDPE tightly bonded together.PSP characteristics a combination of high strength and corrosion resistance of HDPE steel, widely used in petroleum chemical industry, marine,.PSP application and municipal areas will be subject to complex loads in marine conditions, in addition to the role of inner pressure, but also by the impact of falling objects, boats trawl, drag anchor role and wave impact bending load. And under the influence of temperature and other factors. Therefore, internal pressure and bending load is a combination of typical marine conditions, when the bearing capacity of the combined load of more than PSP, PSP will fail, and cause economic loss and ecological damage. While in the past the study Only for PSP bearing internal pressure and bending are studied, without taking into account the PSP under the combined action of both conditions, test equipment and no complex load conditions. So the research on the combined effect of internal pressure and bending mechanical properties of PSP is necessary and has very important significance for engineering and design of PSP safety. Based on the National Natural Science Foundation "research based on slow propagation mechanism of polyethylene pipe crack of viscoelastic damage model" (project number: 51575480) and polyethylene pipe electric fusion welded joint ultrasonic detection feature line formation mechanism research "(project number: 51305394) under the support of the test and finite element mechanics the performance of internal pressure and bending under the joint action of PSP, the main work is as follows: (1) according to the marine complex loading condition and polyethylene temperature, ratio of material properties related to the proposed test equipment Function: equipped on the sample tube Shijianei pressure and bending load, and can control the temperature and bending rate; according to the design requirements of equipment structure and function, respectively, from the mechanical structure, hydraulic circuit and test system is designed; the mechanical structure, the sample tube from moving to the water tank; hydraulic loop respectively, the design of hydraulic circuit to realize the multi function loading bending; test system, loading cylinder parameters such as maximum load is determined by estimating the assembly and test equipment; design scheme according to the design scheme of the equipment; won the national invention patents. (2) carried out at room temperature (20 C) PSP internal pressure and bending combined load test specimen tube failure issued before intensive wire breakage, finally the sample tube rupture and ejected a lot of water; will break at the outer HDPE open, can see the 10 wire fracture occurred, the steel wire fracture As the failure criterion of PSP; according to the displacement curve of bending moment increases, the ultimate bending moment and displacement failure; through the calculation of internal pressure to reduce the rate of characterization of PSP in the bending process volume increased; carry out other at different temperatures (40 C and 60 C) and the internal pressure of PSP bending combined load test, ultimate bending moment of PSP under different temperatures, the displacement and internal pressure reducing failure rate, results showed that: the higher the temperature is, the lower limit moment, failure displacement is smaller, and the reduction of the internal pressure ratio basically unchanged. (3) according to the test load and contact conditions to establish finite element model of PSP; displacement curve moment comparison test and the finite element method, the average relative error is 4.4%, so as to verify the finite element model; stiffness calculation of different loading displacement under bending moment, combined with the displacement curve, analysis of the bending process of PSP in different stages, the very The limit bending moment; according to the HDPE steel and the stress nephogram and the test results, the wire breakage as the failure criterion of the PSP model, the calculation of curvature PSP failure; were calculated only by the internal pressure, bending and internal pressure only by the combined action of bending strain of steel wire, analysis of the relationship between the combined load respectively; to calculate the ultimate bending moment of different temperature and pressure, fitting two element linear regression equation; discussing the effect of the number of the steel wire and the winding angle on the ultimate moment; work pressure were built in different specifications and different diameters of the X70 steel, X80 steel and PSP finite element model, and discussed the impact of different types of pipe bending capacity of.PSP bending capacity factor discussion of pipeline parameter design and engineering application significance.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB333

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