框架塔动力特性的有限单元法研究

利用大型有限单元程序ANSYS对框架塔的自振频率进行了模拟计算 ,并将计算值与试验值进行了对比。在此基础上 ,对框架塔的参数 ,即刚度比与相对高度对自振频率与位移响应的影响进行了探讨 ,并给出了在设计框架塔时适宜的框架高度。     

有限元法在卧螺离心机转鼓强度分析上的应用

有限元法作为离心机强度计算的数值分析方法,相对于传统的强度计算方法有着显著的优越性。对有限元法在卧螺离心机转鼓强度分析上的应用进行了总结,对用有限元法分析转鼓强度时应重点考虑的问题进行了讨论,并对其在卧螺离心机设计中的更多应用进行了展望。     

带加强箍离心机转鼓应力的有限元分析

用有限元法对具有不同过盈量的加强箍对离心机转鼓内应力的影响进行了分析比较。结果表明有过盈量的加强箍不仅为转鼓筒体承担部分载荷,而且因过盈在转鼓内产生预应力,在工作条件下可大幅度降低转鼓内的应力;对离心机转鼓合理设置加强箍、选择加强箍与筒体间的过盈量具有参考价值。     

高速釜用磁力传动器隔离套的设计与有限元计算

提出了迷宫式的冷却通道结构,并基于有限元法对具有冷却通道结构的两种方案进行计算和分析,通过与隔离套原始结构的对比和评估,进而指导产品具体工程化设计。     

复杂管系气柱固有频率的有限元法计算

采用有限元分析方法 ,对简单管道气柱的固有频率进行求解 ,其结果与用传递矩阵法求得的结果是一致的。对实验室复杂管系气柱的固有频率进行计算 ,分析了管道振动的主要原因     

内伸入式接管焊接接头应力的有限元分析

本文应用Ansys有限元应力分析软件,根据钢制化工容器结构设计规定(HG20583-1998),分别建立内部施焊和外部施焊的内伸入式接管与壳体间焊接接头的模型,分析焊接接头处应力分布的情况,并对焊接接头处的应力进行对比。对比结果表明:a类焊接接头所受应力最大;c类焊接接头应力相对较小;b类焊接接头受力效果最好。若可以对焊缝的坡口连接拐点附近进行优化,可以大大的减小应力水平,改善焊缝的受力情况。     

有限元方法在离心机转鼓强度分析中的应用

在回顾以往转鼓强度分析的基础上 ,指出了目前转鼓有限元应力分析所存在的问题 ,给出了提高计算精度和保证模拟有效性的注意事项 ,并探讨了转鼓强度评定准则     

回转窑托轮与轴过盈配合的接触有限元数值仿真

根据回转窑托轮与托轮轴的结构特点及现场运行的实际情况 ,用接触有限元法建立了托轮与托轮轴过盈配合的有限元力学模型。针对托轮和托轮轴的 3种不同配合状态 (H8/s7,H8/t7和H8/r7) ,用ANSYS6 .1进行了接触有限元数值仿真 ,得出了托轮与托轮轴在这 3种不同配合状态下的应力分布规律及变形情况 ,找到了托轮轴断裂的主要原因 ,确定了托轮和托轮轴最佳的过盈配合形式 ,为托轮和托轮轴的优化设计提供了依据     

加气站用储气钢瓶的有限元分析

运用有限元分析方法对CNGPR27.5/25-1300-610-HXS型加气站用储气瓶钢进行了力学分析,得到了气瓶的应力分布规律,并按照分析设计原则进行了强度评定。分析结果表明,该规格气瓶有较大的使用安全系数,完全满足强度使用要求。     

保温层对废热锅炉温度及温差应力影响的有限元分析

对壳体外部设有保温层及未设保温层的两台废热锅炉用ANSYS进行了数值模拟,分析了该废热锅炉的温度场分布情况,计算出由温度梯度产生的温差热应力。并将两台废热锅炉的温度和温差热应力情况进行对比,得出保温层可以降低外壁面温度和温差热应力的结论。     

Experimental Investigation on High Strain Rate Tensile Behaviors of HTPB Propellant at Low Temperatures

To study the high strain rate tensile behaviors of hydroxyl‐terminated polybutadiene (HTPB) propellant at low temperatures, uniaxial tensile tests were conducted at different strain rates (0.4–42.86 s⁻¹) and temperatures (233–298 K) using an INSTRON testing machine. Scanning electron microscopy (SEM) was employed to observe the tensile fracture surfaces. Experimental results indicate that strain rate, temperature and test environment remarkably influence the tensile behaviors of HTPB propellant. The stress‐strain curves exhibit three different shapes. The elastic modulus and maximum tensile stress increase with decreasing temperature and increasing strain rate. However, the strain at maximum tensile stress decreases with increasing strain rate at low temperatures and there is a maximal value at 298 K and 14.29 s⁻¹. The effects of strain rate, temperature and test environment on the tensile behaviors are closely related to the changes of properties and fracture mechanisms of HTPB propellant. The dominating fracture mechanism depends on not only temperature but also strain rate, and it changes from the dewetting and matrix tearing at room temperature and lower strain rate to the particle brittle fracture at low temperatures. Based on the time‐temperature superposition principle (TTSP), the master curves of mechanical parameters for HTPB propellant were obtained.     

整体多层包扎式高压容器筒体与球形封头连接区应力状态有限元分析

建立了整体多层包扎式高压容器多层筒体与球形封头连接区有限元接触分析模型,得到了端部阶梯式连接结构的应力分布状况,并与相同尺寸非多层结构的应力分布进行了比较。结果表明,两种结构内外壁应力变化趋势相似,在连接区出现明显的应力集中,连接处轴向应力上升趋势大于周向应力,达到最大应力值后迅速衰减。     

The Effect of Adhesive Thickness on the Mechanical Behavior of a Structural Polyurethane Adhesive

One parameter that influences the adhesively bonded joints performance is the adhesive layer thickness. Hence, its effect has to be investigated experimentally and should be taken into consideration in the design of adhesive joints. Most of the results from literature are for typical structural epoxy adhesives which are generally formulated to perform in thin sections. However, polyurethane adhesives are designed to perform in thicker sections and might have a different behavior as a function of adhesive thickness. In this study, the effect of adhesive thickness on the mechanical behavior of a structural polyurethane adhesive was investigated. The mode I fracture toughness of the adhesive was measured using double-cantilever beam (DCB) tests with various thicknesses of the adhesive layer ranging from 0.2 to 2 mm. In addition, single lap joints (SLJs) were fabricated and tested to assess the influence of adhesive thickness on the lap-shear strength of the adhesive. An increasing fracture toughness with increasing adhesive thickness was found. The lap-shear strength decreases as the adhesive layer gets thicker, but in contrast to joints with brittle adhesives the decrease trend was less pronounced.     

机械密封环热应力的有限元计算及分析

利用ANSYS 8.0有限元程序对密封环稳态温度场进行数值计算,并用热-结构耦合法计算密封环的热应力,获得了密封环的三向应力(径向、轴向、周向)及Mises等效应力,得到其最大值及其位置。     

The Effect of PEEK Fibres and Powder on Joints Made with a High Temperature Adhesive

High temperature adhesives typically exhibit low levels of peel strength since they tend to be more brittle than typical toughened adhesives used for lower temperature applications. It was found that incorporating thermoplastic fibres or powder into the bondline of a joint made with a high temperature epoxy-based adhesive resulted in significant improvements in peel strength. Poly(ether ether ketone) (PEEK) fibres and powder were incorporated into the adhesive resin and used in aluminium joints. These were tested in peel and single lap shear using a range of fibre lengths, orientations and volume fractions. It was seen that large increases in peel strength could be achieved but that lap shear strength was degraded with most types of modification. However, some modifications resulted in significant increases in peel strength with limited decrease in lap shear strength. These improved properties have been achieved using physical modifications rather than chemical alteration of the resin.     

渣油拱顶罐拱顶失稳的有限元分析

为了分析渣油拱顶罐拱顶失稳原因,应用ANSYS软件建立拱顶罐力学模型,进行失稳校核和内压强度分析,模拟储罐的失稳情况,得出储罐的失稳载荷。     

溶液罐封头偏置接管应力有限元分析

为了分析带偏置接管的溶液罐封头局部区域的应力分布,对该特殊结构进行三维有限元分析,并且采用分析设计方法对该封头进行强度评定。计算结果显示,最大应力发生在封头接管的边缘焊缝处,在此基础上分别在不考虑焊缝结构和增大局部载荷的条件下进行计算和分析,并对结果进行比较,得到相应情况下的应力分布,为工程设计和应力分析提供参考。     

小冲杆蠕变试样中心挠度-蠕变应变关系的有限元分析

利用有限元数值方法分析了小冲杆试样中心挠度δ与中心蠕变应变ε之间的关系 ,指出该δ ε关系与蠕变时间、载荷大小和材料性能等条件均无关。计算结果还表明 ,在薄膜变形分析的基础上 ,非蠕变条件下试样中心挠度 中心弹塑性应变函数关系和蠕变状态下试样中心挠度 中心蠕变应变函数关系等价     

基于有限元方法分析不同参量对裂纹漏磁场的影响

用有限元方法研究了裂纹深度、永磁体厚度、极靴间距及气隙等参量值变化对裂纹漏磁场强度和密度的影响,并给出它们的关系曲线。     

Modeling and Parametric Study of a Single Solid Oxide Fuel Cell by Finite Element Method

A 2D isothermal axisymmetric model of an anode‐supported solid oxide fuel cell has been developed. The model, which is based on finite element approach, comprises electronic and ionic charge balance, Butler–Volmer charge transfer kinetic, flow distribution and gas phase mass balance in both channels and porous electrodes. The model has been validated using available experimental data coming from a single anode‐supported cell comprising Ni–YSZ/YSZ/LSM–YSZ as anode, electrolyte and cathode, respectively. Hydrogen and steam were used as fuel inlet and air as an oxidant. The validation has been carried out at 1 atm, 1,500 ml min^–1 air flow rate and three different operating conditions of temperature and fuel flow rate: 1,073 K and 400 ml min^–1, 1,073 K and 500 ml min^–1, and 1,003 K and 400 ml min^–1. The polarization and power density versus current density curves show a good agreement with the experimental data. A parametric analysis has been carried out to highlight which parameters have main effect on the overall cell performance as measured by polarization curve, especially focusing on the influence of two geometrical characteristics, temperature and some effective material properties.