预应力钢丝缠绕超高压液压缸的结构设计

【作者】 叶涛；

【导师】 吴志学；

【作者基本信息】 扬州大学 ， 机械制造及其自动化， 2017， 硕士

【摘要】 近年来,随着全球工业化进程的加速,液压机的应用越来越广泛,逐渐从传统的机械领域向国防工业、航空航天、核工业等领域扩展。与此同时,液压机也呈现重载化、小型化趋势,其锻造速度、压下精度也随之提高,这就对其核心部件液压缸提出了更高要求。作为液压机的核心部件,液压缸直接决定了液压机的承载能力、工作精度和锻造速度,液压机的重载化、小型化也促使液压缸往超高压化、小尺寸化的方向发展,传统的液压缸设计方法显然已经无法满足要求。预应力钢丝缠绕超高压液压缸具有高承压、高疲劳寿命、小尺寸、安全性好等优点,已经成为制造超高压液压缸的最佳选择。目前,对于预应力钢丝缠绕超高压缸已经进行了大量的研究,但大都是将钢丝层简化为当量外压,并未考虑钢丝层间的摩擦,也就无法准确反映芯筒和钢丝层的应力和应变的变化规律;对于缠绕过程中钢丝分层数对缠绕缸的影响也没有进行具体研究。因此,本文采用预应力钢丝缠绕技术设计80MPa超高压液压缸,在对其进行ANSYS仿真分析时考虑钢丝层间摩擦力、分层降温加压,研究结果能够准确反映芯筒和钢丝层应力应变的变化规律;对缠绕过程中的钢丝分两层、五层和十层缠绕进行分析,得出钢丝分层数对缠绕缸的影响。具体研究内容如下:首先,介绍预应力钢丝缠绕液压缸的结构形式、工作原理、优势和设计缠绕缸所遵循的原则,并根据弹塑性力学的相关知识推导出缠绕缸的相关计算公式,计算出80MPa缠绕缸的芯筒和钢丝层的尺寸。将缠绕过程分为五层计算,得出缠绕时每层施加的初张力和每层缠绕完毕后芯筒内壁的应力分布、半径收缩量。然后,借助有限元分析软件ANSYS的参数化设计语言APDL建立80MPa缠绕缸的有限元模型,模拟预应力钢丝缠绕过程和缠绕缸的合成状态。针对缠绕缸的结构,将预应力钢丝缠绕过程分为五层分析,得出每层缠绕完毕后芯筒和钢丝层的应力分布、芯筒内壁的切向应力和半径收缩量;缠绕完毕后芯筒内壁加压,模拟缠绕缸的合成状态,分析芯筒和钢丝层的应力分布。将钢丝分为十层和两层缠绕,研究钢丝分层数对缠绕缸的影响。分析结果表明:有限元仿真值和理论计算值高度吻合,并且符合设计缠绕缸所遵循的原则;钢丝分层数越多,有限元仿真值越接近理论计算值,预紧效果越好。最后,介绍缠绕过程中的工艺要求并对80MPa超高压液压缸进行五层缠绕施工。对每层缠绕完毕后芯筒内壁的应变进行测试,计算得出内壁切向应力;对每层缠绕完毕后的芯筒内径进行测量,得出芯筒内壁的半径收缩量。将测试结果同理论计算值和有限元模拟值进行比较,结果表明:三者吻合度较高,从而验证理论计算和有限元分析的正确性。本文采用预应力钢丝缠绕技术设计80MPa超高压液压缸,能够有效减小超高压液压缸的尺寸,显著降低生产制造成本,对超高压类容器的设计具有重要的指导意义。更多还原

【Abstract】 In recent years,with the rapid development of global industrialization,The application of hydraulic press has been more and more extensive,its application fields have gradually expanded from the traditional mechanical industry to the defense industry,aerospace,nuclear industry and other fields.Meanwhile,hydraulic press show the trend of miniaturization and heavy-load,its forging speed and working precision have also improved.This put forward higher requirements for the hydraulic cylinder of the core part of hydraulic press.As the core part of the hydraulic press,the hydraulic cylinder directly determines the bearing capacity,working precision and forging speed of the hydraulic press,it has show the trend of ultrahigh pressure and small size because of miniaturization and heavy-load of the hydraulic press.Obviously,the traditional design method of hydraulic cylinder is unable to meet the requirements.Prestressed steel wire wound hydraulic cylinder has already become the best choice for the manufacture of ultrahigh pressure hydraulic cylinder,which has the advantages of high pressure,high fatigue life,small size,good safety performance.At present,a lot of achievements have been made in the study of the prestressed steel wire wound hydraulic cylinder.However,the steel wire layers are simplified to equivalent external pressure and the friction between the layers are not considered in the course of the study,it is difficult to accurately reflect the stress and strain of the inner cylinder and the steel wire layer.The influence of the number of steel wires on the wound cylinder has not been researched in the process of winding.Consequently,the 80MPa ultrahigh pressure hydraulic cylinder is designed by the prestressed wire winding technology.The friction between the layers are considered and pressures are exerted by every layer in the process of analysis using ANSYS.The steel wires is divided into ten layers,five layers and two layers,and the influence of the number of steel wires on the wound cylinder is researched The results show that the stress and strain of the inner cylinder and the steel wire layer can be accurately reflected.The main contents fall into such parts as follows:In the first place,the structure,working principles,advantages and design principles of prestressed steel wire wound hydraulic cylinder have been introduced.The relative calculation formula is deduced according to the knowledge of elastic-plastic mechanics.The size of the 80MPa wound cylinder is calculated.The winding process is divided into five layers,then the initial tension exerted on each layer and the stress distribution of the inner wall of inner cylinder in the winding process are obtained.Then the finite element model of 80MPa ultrahigh pressure hydraulic cylinder is created by using ANSYS program’s APDL,which is used to simulate the process of the prestressed steel wire winding and the working status of wound cylinder.The winding process is also divided into five layers,then the stress distribution of the inner cylinder and steel wire layer in the winding process is obtained,the tangential stress and radial shrinkage of the inner wall of the cylinder are also given.The stress distribution is analyzed in detail in the working status of wound cylinder.The steel wires is divided into ten layers and two layers,and the influence of the number of steel wires on the wound cylinder is researched.The results show that the FEM results are consistent with the theoretical values,and they all meet design principles of prestressed steel wire wound hydraulic cylinder.The more the number of steel wires,the better the pre-tighten purpose.The value of finite element simulation is closer to the theoretical value.In the end,the technological requirements of 80MPa ultrahigh pressure hydraulic cylinder is introduced and hydraulic cylinder is winded.The winding process is also divided into five layers,the strain on the inner wall of the cylinder is tested in the winding process,the tangential stress of the inner wall is obtained.The radial shrinkage of the inner wall of the cylinder is measured.The test results are compared with the theoretical calculation values and the FEM results.Research results show that they have similar values.The test of wound cylinder is carried out to verify the correctness and reliability of the simulation analysis and theoretical analysis.This paper adopts prestressed wire winding technology to design 80MPa ultrahigh pressure hydraulic cylinder.The size of hydraulic cylinder is decreased obviously and the the production cost is also reduced significantly.It has an important practical significance for the design of ultrahigh pressure containers.更多还原