大型组管式反应塔的应力分析（一）——有限元应力分析模型

对结构和受载都非常复杂的某大型组合管式反应塔建立了有限元模型。采用壳单元对组合管式反应塔进行网格划分，既降低了建模难度，又减少了有限元模型的节点数，提高了计算速度。分析了组合管式反应塔所承受的各种载荷。采用Lanczos算法对组合管式反应塔进行模态分析，得到其固有频率，从而可以计算反应塔对风栽荷和地震载荷的动态响应。     

大型组合管式反应塔的应力分析(二)--应力分析结果

在第一部分中建立的反应塔有限元模型基础上，依据．JB4732一1995《钢制压力容器-分析设计标准》，并通过合理有效的简化假设，对6种比较危险的组合工况，分别计算了组合管式反应塔中各危险截面的应力强度。对组合管式反应塔进行了强度和稳定性校核，确定了组合管式反应塔的主要强度尺寸，从而奠定了组合管式反应塔的设计基础。     

600t起重船起吊系统强度校核及应力测试分析

采用结构分析软件Ansys,对600t起重船起吊系统的吊杆、千斤柱在各种组合载荷工况下的强度进行了有限元分析,计算出吊杆、千斤柱在组合载荷工况下的应力分布及危险截面的位置,对计算出的危险截面的应力进行了测试,并对起重船这种特殊起重设备起吊系统的安全运行、结构的改进提出了建议。     

新型绕管式多相流冷却器管板及封头组件结构应力特性研究

针对典型新型绕管式多相流冷却器管板及封头组件在使用工况条件下,采用极限载荷与有限元结构应力应变分析计算方法,对其结构应力应变进行分析计算,并依据JB 4732等压力容器设计制造标准规范,对其结构设计安全性和合理性进行评价,为企业完善设计规范、提高产品的设计质量和设计效率、降低设计生产制造成本打下了良好基础。     

汽车钢板弹簧的应力和变形分析

应用有限元法对一种在垂直力作用下的3片式钢板弹簧进行分析,其中应用8节点块单元对板簧进行实体建模,采用接触分析来模拟板簧各片逐渐进入接触的情况。对钢板弹簧的中心螺栓、U型螺栓夹紧和卷耳、吊耳部分的铰链约束进行独特的处理。应用所建立的有限元模型计算板簧的应力分布和载荷-变形曲线。对该板簧进行的实验应力分析表明,应用该有限元模型得到的计算应力和载荷-变形特性与试验结果吻合较好。     

弯曲载荷作用下含错边缺陷管道环焊缝应力计算

滑坡等地质灾害引起的弯曲载荷是导致环焊缝失效的重要因素，管道环焊缝焊接过程中的错边缺陷，容易形成局部应力集中，除设计压力外，环焊缝还能承受的弯曲载荷已成为管道完整性管理中的重点和难点。基于有限元分析数据提出了一种针对弯曲载荷作用下含错边缺陷环焊缝的应力计算方法。首先，给出了管道承受均匀内压和弯曲载荷的近似解析计算公式；然后，针对无错边和含错边缺陷的环焊缝开展有限元计算，采用子模型方法兼顾了大跨度模型的计算效率和环焊缝的计算精度；最后，基于有限元分析数据对经典解析公式进行修正，得到管道环焊缝单点应力的计算公式。经验证，该方法与有限元结果相差1%以内，可适用于弯曲载荷作用下的环焊缝应力计算，是一种可用于工程强度快速评估的精确分析方法。     

大型轮式港口机械钢圈的加载方案分析和强度计算

为了确定港口机械钢圈的有限元分析模型,采用了其它小型钢圈进行相似载荷的有限元分析计算以及应力分布测试实验来进行参照.提出了几种不同的钢圈载荷分布规律,如余弦规律分布、均匀分布等,对不同载荷分布规律及其分布范围作了有限元分析计算,并与实际检测结果进行对比分析.最终确定采用120度范围的余弦规律载荷对港口机械钢圈进行有限元分析,建立了它的力学计算模型,并通过有限元分析法进行了计算,计算结果表明该方法是可行的,计算结果对指导钢圈产品设计具有重要的意义.     

基于GAP单元的滚动轴承应力分析

利用有限元分析软件MSC.Marc/Mentat对某一滚动轴承进行有限元分析,采用GAP单元代替滚动体模拟轴承内外圈间的接触,在某组载荷工况下,计算该简化模型的应力结果;在同组工况下,对比实体轴承模型与GAP单元简化模型的有限元分析结果,对比各自的最大应力值;同时用理论计算方法计算轴承在相同工况下的最大应力值,来验证有限元结果的正确性.结果表明:GAP单元可以有效的模拟滚动轴承内外圈之间的接触,从而为滚动轴承建模及与轴承连接的组合件之间的建模提供了一种简便且有效的方法.     

起重机实验台应力计算分析模型

用有限元方法，通过I-DEAS软件建立了某型起重机实验台的模型，以确立其结构在不同载荷条件下所承受的应力状态。同时通过对起重机实验台应力的试验值和有限元方法的计算值进行对比，从而评价了有限元模型及实验台模型的正确性。     

基于ABAQUS的夹钳钳口有限元应力分析

应用ABAQUS有限元分析软件,建立巨型重载锻造操作装备夹持系统中夹钳钳口的有限元分析模型,并对模型在承受最大工作载荷时的应力进行了分析,计算出模型的应力分布和应力集中区域,从而为模型的结构优化提供了充分的理论数据。     

基于有限元法的转炉托圈应力分析研究

转炉托圈是一个重型的复杂空间焊接结构,在使用中承受机械载荷以及长期温度载荷。托圈所承受的机械载荷经由多个复杂的接触面接触传递。为了分析托圈结构的强度和变形,运用有限元数值仿真技术对炼钢转炉托圈及耳轴进行三维应力场分析,转炉按水平状态、垂直状态以及旋转200、500和700状态分别进行应力分析,得到托圈等效应力。分析可知最大应力在上支承结构焊接区。该研究为转炉托圈的设计及结构优化设计与使用提供了可靠依据,具有一定的应用推广价值。     

首都机场AMECO-A380机库动力特性测试与分析

采用环境随机振动法对北京首都国际机场AMECO-A380六机位维修机库大跨空间网架结构进行了现场结构动力特性测试.利用谱分析方法对实测数据进行了参数识别和处理,并进行了振型分析,确定了机库屋架结构的自振频率和振型.并用有限元模型计算了结构自振频率和振型.对测试和计算结果进行的分析比较结果表明,结构基本周期的测试值和计算值接近,各自所对应的第1阶振型吻合较好.     

连续墙抓斗起重机猫头架结构应力计算与有限元分析

以某一特定型号的连续墙抓斗起重机为研究对象,在进行受力计算之后,借助Pro／Mechanica软件对猫头架结构进行有限元计算,获取猫头架在受到外载荷作用后的响应情况,并对得到的结果进行分析,对猫头架的设计提出了改进意见。     

极端服役环境下的风电机组塔架结构参数优化研究

以大型风电机组塔架为对象,开展了极端服役环境下的塔架结构参数优化设计研究。采用壁厚分段式线性变化结构对塔架进行描述,介绍了基于BEM理论的风电机组气动载荷分析方法,运用有限元仿真分析塔架结构参数与极限载荷作用下的应力以及结构参数与固有频率的关联特性,采用支持向量机(SVM)方法分别构建了结构参数与应力、固有频率的快速计算模型。以质量最小为目标,强度、固有频率和边界条件为约束对塔架结构参数进行了设计优化,引入遗传算法(GA)进行优化求解。对某2MW风电机组塔架进行实例设计研究,结果表明优化后的塔架质量减小3.5%。      

套筒活齿的应力数学模型及其计算方法

利用通过有限元方法计算的各种典型工况下的套简活齿内部应力，根据套筒活齿的几何和受力特点以及非线性回归方法，对多点受力套筒活齿的应力分析问题建立了应力计算的经验公式，从而解决了套筒活齿在几何尺寸不同、受力大小不同、力作用的位置不同以及受力个数不同时的应力分析问题。     

Stress analysis and design for a structural fatigue testing machine

A closed loop servo-hydraulic structural fatigue testing machine was developed. It can apply fatigue loads on actual engineering parts or components for their fatigue strength evaluation. The testing machine consists of a structural bending load frame, a structural torsion load frame, a hydraulic system, and a control system. Stress analysis and design for the crosshead, columns and test bed for the structural bending test frame are described. Finite element analysis was performed for the structural torsion load frame. Evaluation of the structural load frames and application of the test machine are briefly given.     

Structural safety assessment of bowstring type RC arch bridges using ambient vibration testing and finite element model calibration

The structural safety evaluation of a bowstring type reinforced concrete (RC) arch bridge was investigated by ambient vibration testing and finite element model calibration in this study. The bridge named as Ali Çetinkaya Bridge in Samsun, Turkey, was selected for this investigation. The bridge constructed in 1937 consists of the seven discrete arches and its total length is approximately 250 m. The bridge damaged by environmental effects and it was closed to the traffic loads. The presented study consists of four main parts: ambient vibration test, initial finite element modeling, finite element model calibration and structural analysis of the calibrated finite element model. The ambient vibration tests were performed using Operational Modal Analysis Method under the wind, human and water flow loads to identify the actual natural dynamic parameters, such as the natural frequencies and mode shapes, modal damping ratios. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods were used to extract the experimental dynamic characteristics. The initial finite element model was developed by including the soil effects in SAP2000 program to obtain the analytical dynamic characteristics. In the initial finite element model, the beam, plane and solid elements were used. After that, the initial finite element model was calibrated according to the ambient vibration test results considering the material properties and boundary sections as variable parameters. The calibrated model assumed to reflect the current state of the bowstring bridge was analyzed under dead, moving, traffic, water and earthquake loads. The maximum displacements, tensile stress, compressive stress and shear stress were attained each case and compared with each other.     

Dynamic and acoustic characteristics of bell type structure using finite element method

Dynamic and acoustic characteristics of the bell type structure were analyzed numerically. The finite element method with 3-D general shell element was used to identify the natural frequencies and mode shapes of the structure. Mode shapes and stress distributions of a transient dynamic analysis were effectively displayed by using computer graphic technique. The results of this numerical study were in good agreement with those obtained from the experimental test of fast Fourier transform analyer. Vibrational modes, which effect the acoustic characteristics of the typical bell-type structure were found to be the first flexural mode (4-0 mode) and the second flexural mode (6-0 mode). Asymmetric effects by Dangjwas and acoustic holes gave rise to beat frequencies, and the Dangjwa was found to be most effective. When the impact load was applied to the bell, the stress concentration occured at the rim part of the bell. It was found that the bell type structure should be designed thickly at the rim part in order to prevent failure from impact loads.     

Vibro-acoustic analysis of free piston engine structure using finite element and boundary element methods

This paper presents the results of vibro-acoustic modeling and simulation using the finite element and the boundary element methods for the free piston engine structure. A model of the engine was constructed through the use of finite element software to perform a normal mode analysis of the engine structure. The objective was to determine the mode shapes and the natural frequency that contribute to engine structure vibration. Theoretical development of the engine balance motion and frequency response was also conducted. From the simulation and finite element analysis, the force response pattern of the engine vibration was determined and then compared with its natural frequency. The vibration data were used as the input data for noise analysis using the boundary element method. The integration of the finite element and the boundary element determined the noise-frequency data of the engine structure toward the occurrence of engine noise. The information can be used by designers to analyze engine specifications and structure, especially at the preliminary design stage.     

超声冲击消除残余应力频率参数的确定

建立模拟焊接过程的三维有限元模型,得到了焊接残余应力的应力场分布,通过对此焊接残余应力场的分布进行研究,可以对焊接结构的质量和使用性能进行预测。应用ANSYS的模态分析功能,得到了模型的固有频率,在固有频率下进行超声冲击消除残余应力会得到较好的效果,并验证了输入频率大于固有频率时,超声冲击消除残余应力的效果与在固有频率下冲击的效果差别不大。