U形波纹管膨胀节的强度分析

本文利用钱伟长教授的细环壳理论,获得了在压力或轴向位移载荷作用下U形波纹管弹性解析解,其结果与作为EJMA标准理论式的Anderson解或作为JISB 2352—1977理论式的浜田——竹圆解极为一致,并且与U形波纹管膨胀节的应力电测实验结果相符合.     

离散粒子群算法的波纹管优化设计研究

为了解决波纹管所涉及的非线性约束离散变量的优化设计问题,文中尝试将粒子群算法与惩罚函数法相结合,建立新型离散粒子群算法,实现离散变量与连续变量之间的转化。提出了一种新的离散惩罚因子更新策略,以保证离散解的精度及算法的收敛性。通过著名的容器设计算例验证,文中方法优于文献方法。用该方法对波纹管工程实例进行优化设计,优化目标值比在用产品提高了79.96%,且与理论值接近,离散解的精度满足要求,进一步证明了该方法在求解波纹管工程非线性约束离散变量优化设计问题时的有效性。     

基于有限元的内肋增强聚乙烯螺旋波纹管结构优化

为减小聚乙烯(polythene以下简称PE)的用料,同时保证环刚度基本不变,对内肋增强PE螺旋波纹管进行了结构优化。利用Solidworks和ANSYS workbench进行联合仿真,建立了内肋增强PE螺旋波纹管环刚度仿真测试的有限元模型,并通过环刚度理论计算模型对其进行了验证。将波纹管内肋截面的结构高度、圆弧半径、圆角半径和内肋角度作为设计变量,以单位长度波纹管PE的用料体积作为结构优化目标,以波纹管的环刚度作为约束条件。利用ANSYS workbench中的Design Exploration模块,求得设计变量对优化目标和约束条件的影响,及优化目标和约束条件对各设计变量的敏感度,从而得到设计变量的优化解。结构优化后的内肋增强PE波纹管,在环刚度基本保持不变的情况下,单位长度波纹管的PE用料体积减少了7.72%,能有效降低用料成本。     

机械密封用挤压成型金属波纹管应力及轴向刚度的有限元分析

研究挤压成型波纹管机械密封中波纹管的轴向刚度及应力状态,将有限元计算与采用工程实际经验公式的计算结果和该波纹管的试验结果进行了比较。同时通过建立的波纹管有限元模型,分析了外压作用下波纹管结构对波纹管的应力状态的影响。     

基于场协同理论的波纹管强化换热的数值模拟研究

应用Fluent软件对5种结构的波纹管内的传热与流动进行了数值模拟,并与相同当量直径的圆管进行了对比,结果表明,波纹管周期对Nu数的影响较大,且周期与幅值比S/a为8.17时,波纹管换热效果最好。基于场协同理论分析了波纹管的局部换热效果,研究表明,波纹管波峰处可获得较好的场协同性,换热效果最好,波谷处协同作用最差。     

预应力塑料波纹管的应用前景

青岛科创塑料机械有限公司成功开发的预应力塑料波纹管生产线。采用齿条传动，稳定可靠。该生产线所生产的塑料波纹管在代替金属波纹管成为桥梁建筑的首选材料上。也有其特殊的优势。本文着重通过介绍预应力技术及HDPE塑料波纹管与金属波纹管的比较分析，阐述了预应力塑料波纹管的发展前景。     

波纹管式换热器的综合性能分析

分析波纹管式换热器的强化传热理论机理和换热特性;试验研究了波纹管的强度与刚度;对比分析了波纹管换热器所具有的经济性。     

高模量聚丙烯双壁波纹管的制备及其应用优势研究

主要制备了与聚乙烯双壁波纹管相同结构的高模量聚丙烯双壁波纹管,分析了其质量、环刚度、冲击性能等。结果表明:与高密度聚乙烯双壁波纹管相比,高模量聚丙烯双壁波纹管的环刚度较高;在相同环刚度下单位长度质量轻,可以节省原料;在0℃时保持较高的冲击性能,在应用上具有较大的优势。     

皂化废液换热器用光滑管和波纹管传热与结垢性能试验研究

对光滑管与波纹管的传热与阻垢性能进行了对比试验研究。结果表明,试验介质为清水时,波纹管的传热系数约为光滑管的1．25—1．31倍;试验介质为皂化废液时,波纹管传热与阻垢性能均不如光滑管;试验介质为皂化废液清液和CaCO3过饱和溶液时,波纹管的传热与阻垢性能均优于光滑管,波纹管传热系数为光滑管的1．1～1．2倍,污垢热阻为光滑管的0．5倍左右。     

波纹管的极限载荷分析

采用极限载荷分析法对单层和多层波纹管进行极限载荷分析,不仅研究了波纹管拉伸位移及相关参数对波纹管极限承载能力的影响,也研究了同等厚度单层波纹管和多层波纹管极限载荷之间的关系。结果表明:波纹管极限载荷不随拉伸位移和层间接触状态的变化而变化,但随着波纹管波形参数增大而减小;多层波纹管极限载荷小于同等厚度的单层波纹管。     

局部应力-应变法预测大型波纹管的疲劳寿命

鉴于大型波纹管膨胀节全尺寸疲劳寿命试验在工程上实现的困难性,研究了基于局部应力－应变法预测大型波纹管的疲劳寿命。应用非线性有限元获取波纹管的最大局部应力应变,并据此局部应变设计简化的试板。当弯曲试板上的最大应变等于波纹管的最大局部应变时,板的弯曲疲劳试验寿命即可代替波纹管的试验寿命。本方法在工程设计中被证明是实用且可靠的,它也适用于低压工况下通用尺寸波纹管的疲劳寿命的预测。     

波纹管疲劳寿命可靠性分析

波纹管是典型的低周疲劳部件,用局部应力应变法预测其疲劳萌生寿命可行且精确,考虑到影响疲劳寿命的诸多因素的随机性,将应变寿命曲线表示为概率曲线,并考虑累积损伤的随机性,通过建立近似拟合多项式方法求得各设计寿命下的波纹管的可靠度曲线,该方法是简单有效的波纹管疲劳寿命可靠度计算方法。     

Incone l625合金波纹管失效分析

用化学分析、透射电子显微镜(TEM)、X射线光电子能谱仪(XPS)和扫描电子显微镜(SEM)等微观测试分析技术对失效波纹管的化学成分、力学性能、断口腐蚀产物及断口微观形貌进行综合分析。结果表明,波纹管的失效原因是材料处于腐蚀环境,在局部高应力处发生高温硫化及氧化,诱发疲劳裂纹源,在交变应力的作用下发生腐蚀疲劳开裂。     

Evaluation of fatigue performance of filled and unfilled natural rubber/styrene-butadiene rubber composites

This paper deals with the fatigue life analysis of a blend of natural rubber (NR) and styrene-butadiene rubber (SBR) with and without nanoclay particles. Various damage parameters based on strain are investigated. A nonlinear finite element analysis is carried out by using ABAQUS. To formulate the life prediction models, the measured fatigue life is used together with various damage parameters. It is shown that all the damage parameters can estimate the fatigue lives effectively with correlation coefficients greater than 0.9. There is a good agreement between the obtained fatigue live predictions and the measured fatigue results. The effect of various parameters such as true strain and nanoparticles' loading is also investigated. The results of sensitivity analysis show that the strain has a greater effect on the variation of the rubber compounds' fatigue life. The test samples' fracture surface is assessed via scanning electron microscopy (SEM). SEM results show that as the strain increases, the test samples softly fail while the fracture surface of the nanocomposite is roughened by the addition of nanoclay.     

三坐标检测技术在金属波纹管膨胀节型式试验中的应用

波纹变形量是膨胀节型式试验合格判定的重要参数。针对波纹变形量检测,使用了基于三坐标技术的检测方法。利用三坐标设备对金属波纹管膨胀节进行特征提取和点云采集。利用三坐标软件的分析比较功能,对波纹管特征数据和点云数据进行分析,并将检测的结果以图文方式直观显示出来。该方法的应用为波纹管膨胀节波纹变形量检测提供了方便、快捷、准确的技术手段。     

炭黑/白炭黑补强硫化胶的疲劳过程及使用寿命预测

应用断裂力学的方法，解析和预测了采用高耐磨炭黑与白炭黑并用补强体系的天然橡胶。在疲劳过程中形变能密度的变化，疲劳破坏寿命和断裂特征，建立了数学模型，预测了胶料动态疲劳破坏寿命。研究结果表明，在天然橡胶中采用高耐磨炭黑与白炭黑并用补强体系，随白炭黑用量的增加。胶料疲劳破坏寿命延长，胶料内部潜在缺陷减小，裂纹扩展速度减慢，形变能密度下降缓慢，建立的数学模型能较好地预测含高耐磨炭黑与白炭黑补强体系的胶料疲劳破坏寿命。     

二次曲线拟合法波纹管管内传热系数研究

针对波纹传热表面结构复杂难以测量管壁温度的特点,提出了二次曲线拟合法测量波纹管传热系数的方法,研究结构参数对波纹管传热特性的影响规律,为开发和设计结构合理的波纹管换热器提供依据。用W illson拟合曲线分离法,对一定的结构参数波纹管经一次拟合建立传热特性与介质物理性质的准数关系式。在此基础上,对不同的结构波纹管进行实验,并对实验结果进行二次拟合确定结构参数的影响。用该方法得到的波纹管对流传热系数准数关联式,在实验范围内计算误差小于15%。减小侍测侧与非侍测侧传热系数的比值,可进一步提高测量精度。     

干气密封焊接金属波纹管的结构动态分析

应用PRO-E软件分别对单圆弧、两圆弧和三圆弧3种结构类型的焊接金属波纹管进行建模,并导入ANSYS软件进行模态分析,分别得到它们的固有频率和振型。通过分析比较得出,在几何参数相同的情况下,单圆弧的固有频率最大,双圆弧的次之,三圆弧的最小;又对3种类型的波纹管进行了谐响应分析,求出了响应值(位移)-频率曲线。通过分析得到,在相同的工况下,三圆弧波纹管的位移最小,是最优选择。     

Uniaxial ratchetting and low-cycle fatigue failure behaviors of adhesively bonded butt-joints under cyclic tension deformation

Ratcheting and low-cycle fatigue failure behaviors of the adhesively bonded hollow cylindrical butt-joints has been experimentally investigated. A series of uniaxial cyclic tension experiments were carried out under stress-controlled mode. The effects of stress amplitude, mean stress and cycle time on the uniaxial ratcheting response, fatigue damage variable evolution and fatigue life of the adhesively bonded butt-joints were analyzed. The results show that the ratcheting strain, ratcheting strain rate and fatigue damage variable all increase with the increase of stress amplitude and mean stress. The shorter cycle time results in the increase of fatigue damage variable and the degradation of the stiffness of the adhesive material. It is also found that the increase of stress amplitude and mean stress can reduce the low-cycle fatigue life. Meanwhile, the fatigue life increases with the increase of cycle time for the adhesively bonded butt-joints.     

Multiaxial ratcheting‐fatigue interaction on acrylonitrile‐butadiene‐styrene terpolymer

A series of multiaxial tests on an industrial acrylonitrile‐butadiene‐styrene (ABS) tube were conducted at room temperature. The ratcheting strain accumulation was found to be closely related to the shear strain amplitude and axial mean stress. The ratcheting strain and its rate increased with increasing shear strain amplitude as well as axial mean stress. At the same time, the ratcheting strain accumulation was retarded with a negative mean stress, and the ratcheting shakedown appeared when the negative mean stress reached ?10 MPa. To understand the influences of loading history on axial ratcheting strain, a series of multistep loading tests under constant symmetrical torsion at different axial mean stresses of 5, 0, and ?5 MPa were performed. The results showed that both the compressive viscous strain and strain relaxation of ABS could lead to the decrease of axial ratcheting strain. Furthermore, the compressive viscous strain and strain relaxation are independent of the loading history. Considering the influence of mean stress, a modified fatigue life model based on the Basquin law was presented to predict the pure torsional fatigue and multiaxial fatigue of ABS. The results of the modified fatigue life model show it can give relatively accurate fatigue life predictions. POLYM. ENG. SCI., 55:664–671, 2015. © 2014 Society of Plastics Engineers