基于SQL Server和Abaqus的关节轴承数据查询与性能分析系统

该系统的研制是为方便轴承使用人员对关节轴承进行选型、数据查询和受力变形分析。简述了系统的功能特点、功能模块划分和包括关节轴承数据库的建立、多种查询方式界面的设计和通过脚本接口实现与Abaqus有限元软件集成的系统研制过程。该系统基于Visual Studio+SQL Server+Abaqus平台开发,可以实现关节轴承数据多方式查询,以及经简单的参数数据输入从而获取基于Abaqus有限元仿真分析后的关节轴承的应力分布和位移分布图。该系统具有极高的实用性,可推广运用到其他机械领域的研究开发。     

基于Abaqus的预制混凝土装配结构干式节点参数化建模分析插件二次开发

为提高预制混凝土(precast concrete, PC)装配结构干式节点建模分析速度并简练输出显示分析结果，通过Python语言编制参数化建模和图像数据可视化分析内核脚本，基于Abaqus提供的图形用户界面与内核脚本之间的人机交互原理，创建专用GUI界面插件。结果表明：二次开发的前处理GUI界面可显著提升节点建模的效率；后处理开发能根据用户的不同需求选择特定的数据图像，并以图片的形式便捷呈现。     

基于Python的复合材料船体梁极限强度分析

为在复合材料船体结构数值仿真分析中进行快速建模和分析,采用Python脚本语言和Abaqus前处理模块,开发出针对复合材料船体梁极限强度计算的通用模块.该模块考虑复合材料的各向异性、失效准则及铺层方式等因素.实例表明：所开发的程序界面友好、可操作性强,能有效提高复合材料船体梁极限分析的效率.     

基于HyperMesh的工程爆破模拟前处理优化

为提高工程爆破模拟前处理工作的效率、改善爆破设置方法，基于HyperMesh二次开发技术，结合爆破工程学专业知识，利用TCL/TK语言编写爆破前处理工作插件。该插件支持用户根据爆破工程实际情况设置炸药起爆位置、炸药种类和炸药当量，融合LS DYNA多物质流固耦合技术，使传递冲击波的介质与爆破物体间能够在单元非共节点状态下传力。该插件使用图形化界面进行多起爆点设置和起爆点参数修改，采用介质有限元网格自动划分技术优化HyperMesh的爆破边界条件设置。应用该插件优化HyperMesh工程爆破的前处理工作，既能保证结果的准确性，又能减少爆破前处理设置的复杂操作、提高工作效率。     

基于Abaqus的湿陷性黄土地区复合桩基承载性能分析

湿陷性黄土在我国西部地区分布广泛,伴随着西部大开发战略的实施和重要基础设施的不断兴建,长短复合桩基在该地区得到广泛应用.用Abaqus分析一种长短复合桩基的承载性能.在桩基所承受的竖向载荷不变的情况下,逐步加大桩基所承受的横向载荷,得到承台的横向位移变化情况.分别改变桩长、桩径、桩距和桩-土弹性模量比等参数,进行多工况分析.最后给出Abaqus针对该问题的加速性能测试结果.     

样条曲线的参数化变形方法

提出一种曲线在几何约束下发生整体变形,且约束能够被精确满足的计算曲线变形的方法,该方法被称为参数化变形,位移曲线被定义为变形后曲线的表达式与变形前曲线的表达式之差所表示的曲线,对传统能量法进行改进,提出对位移曲线的能量在线性约束下求最小的方法,得到了精确的变形计算公式,以此公式为基础,提出在非线性约束情况下曲线变形的计算方法,文中提出的参数化变形的计算方法可用于二维参数化设计模型中。     

某型航空发动机叶盘数控喷丸"脱机编程"实施应用

本文详细地分析了五坐标数控喷丸机的结构特点及其运动形式,利用NX CAM设计符合喷丸加工的编程策略,利用坐标变换原理,推导出符合该喷丸机的后置处理算法,设计相应的后置处理程序,自动生成整体叶盘喷丸加工的数控程序,实现某型机整体叶盘的喷丸加工. 一、现状分析 整体叶盘是典型的整体、薄壁、难加工材料和复杂结构件,目前国内对整体叶盘的喷丸加工仍采用在机手工编程的方法.在机编程不仅具有加工效率低、产品一致性难以保证、生产人员工作环境恶劣等弊端,而且在机编程对加工人员有较高的技能要求,一旦操作失误,可能导致整个零件报废.因此,研究整体叶盘喷丸离线编程新方法非常必要.     

基于SiPESC平台用户材料子程序的UMAT实现

针对复杂环境和加载条件下的材料本构模型,参照Abaqus所提供的用户材料子程序UMAT接口,实现基于SiPESC平台弹塑性分析功能的UMAT本构模型插件封装及调用.采用Ｃ++面向对象程序设计方法编制inp文件读取功能插件,实现Abaqus计算模型向SiPESC平台数据库的导入.将不同UMAT单独编译成动态库,同时利用工厂设计模式,实现不同材料本构模型的动态替换和调用.该设计模式可方便添加本构模型,具有一定的通用性、开放性和可扩展性.数值算例的验证表明基于SiPESC平台的UMAT的有效性.     

飞机结构件动态变形测量技术研究

针对飞行试验中飞机结构件的动态变形测量问题,提出了一种基于图像的测量方法,对其中涉及的关键技术进行了研究;采用10参数模型非线性成像模型补偿摄像机系统误差,引入摄像机动态校准算法,使摄像机标校重投影误差小于0.03 pixel;采用编码标志作为测量标志,提高了图像自动识别和匹配效率;采用双像机交会测量计算测量标志位移变形量可达到0.15 mm/m;实验证明,该方法满足飞行试验中飞机结构件动态变形要求。     

基于Abaqus二次开发插件的汽油机气门座圈和导管变形分析

应用Abaqus对某汽油机气门座圈及导管变形进行温度场分布计算,在此基础上计算气门座圈和导管在冷装配及热装配工况下的变形情况.采用傅里叶展开法通过Abaqus柱面零件变形分析插件得到气门座圈和导管各阶次变形;通过阶次变形评价气门座圈和导管变形,并将计算结果与试验结果进行对比.     

基于Python的Abaqus二次开发在空间可展单簧片结构仿真分析中的应用

针对不同型号簧片结构分析需重复进行建模和网格划分等工作的问题,基于Python对Abaqus的前后处理模块进行二次开发.通过增设特定的窗口和命令,形成专门针对空间可展单簧片结构分析的仿真模块和后处理程序.建立一套由几何参数和材料参数直接生成模型,可进行空间可展单簧片结构弯曲过程力学性能分析的系统.该系统为用户提供简单、快速的建模途径和自动化的后处理功能,使得空间可展单簧片结构的力学性能分析变得更加高效.     

Numerical simulation of the stress peen forming process and experimental validation

Stress peening forming is widely used in the aeronautics industry to induce curvatures in wing skins. Most of the investigations of stress peen forming are empirical and experimental. In this paper, a three step numerical model that can simulate this process was developed. First, an implicit Finite Element Analysis (FEA) with ANSYS where a prebending moment along the spanwise direction of the component was performed. Then, an explicit FEA with LS-DYNA simulating shot impacts on the pre-stressed component was executed in order to obtain the resulting stresses inside the component. Finally, an implicit FEA with ANSYS was performed for calculating the arc heights and the curvature radii of the component in chordwise and spanwise directions. Numerical analysis of the process shows that the prebending moments have an influence not only on the residual stress profiles but also on the curvatures of the deformed component in chordwise and spanwise directions. This model was used to establish a relationship between the prebending moment and the resulting arc heights and residual stress profiles. The numerical strategies developed in this paper supply a useful tool for studying and optimizing the stress peening process.     

On the potential applications of a 3D random finite element model for the simulation of shot peening

Shot peening is a cold-working process that is used mainly to improve the fatigue life of metallic components. Experimental investigation of the mechanisms involved in shot peening is very expensive and complicated. Therefore, the Finite Element (FE) method has been recognized as an effective mean for characterizing the shot peening process and several types of FE models have been developed to evaluate the effects of shot peening parameters. However, in most of the existing FE models, the shot peening sequence and impact location were defined a priori. It is therefore the purpose of this study to consider the random property of the shot peening process. A novel 3D FE model with multiple randomly distributed shots was developed combining a Matlab program with the ANSYS preprocessor. The explicit solver LS-DYNA has been used to simulate the dynamic impingement process. Several potential applications of this novel model such as: the quantitative relationship of the peening intensity, coverage and roughness with respect to the number of shots have been presented. Moreover, simulations with multiple oblique impacts have been carried out in order to compare with results from normal impingements. Our work shows that such a computing strategy can help understanding and predicting the shot peening results better than conventional FE simulations.     

An investigation of ultrasonic nanocrystal surface modification machining process by numerical simulation

As a method for surface severe plastic deformation (S²PD), ultrasonic nanocrystal surface modification (UNSM) enhances metal surface properties through striker peening, a metal dimpling process driven by ultrasonic vibration energy. UNSM treatment introduces residual stress, surface hardening, and nano-crystalline structures into metal surfaces which are beneficial for reducing wear, fatigue, and corrosion properties. In this paper, the process of UNSM is described and a simplified physical model created using the equivalent static loading method is presented. Along with the simplified physical model, a finite elements simulation model was developed. Effective plastic strain was considered as a parameter for evaluating the level of work hardening produced in the simulation. The dynamic processes and energy dissipation were also examined, and it was found that different kinds of energy dissipation occur during UNSM treatment. Comparisons between the processing parameters (processing velocity, static load, and feed rate) were performed using a simulated example of UNSM linear processing. The results show that the linear processing produces a uniform region containing identical distributions of residual stress and effective plastic strain. The effects of the parameters on the processing results (residual stress, plastic deformation and work hardening) were likewise studied using UNSM linear processing. Compared to processing velocity, a high static load produced more work hardening and higher compressive residual stress. Surface deformation and residual stress results were also more sensitive to static load than processing velocity. Feed rate was found to be an important parameter as well, greatly influencing both surface deformation and work hardening.     

航空发动机叶片激光冲击强化技术的研究

介绍了激光冲击强化航空发动机风扇叶片的国内外研究进展情况。激光冲击强化处理是近年出现的表面改性新工艺,其效果优于传统表面改性技术(如喷丸)。通过在航空发动机叶片表面引入残余压应力,激光冲击强化可以大幅度提高叶片的疲劳寿命。激光冲击强化近年的研究,形成了多学科并存的制备技术体系,开发了一系列新的设备和技术,并很快进入了实际应用。制定正确的工艺规程、探索精确控制激光冲击强化的方法,以及结合现代高新技术,引进交叉学科,是今后的发展方向。     

Modelling of residual stresses in the shot peened material C-1020 by artificial neural network

This study consists of two cases: (i) The experimental analysis: Shot peening is a method to improve the resistance of metal pieces to fatigue by creating regions of residual stress. In this study, the residual stresses induced in steel specimen type C-1020 by applying various strengths of shot peening, are investigated using the electrochemical layer removal method. The best result is obtained using 0.26 mm A peening strength and the stress encountered in the shot peened material is ?276 MPa, while the maximum residual stress obtained is ?363 MPa at a peening strength of 0.43 mm A. (ii) The mathematical modelling analysis: The use of ANN has been proposed to determine the residual stresses based on various strengths of shot peening using results of experimental analysis. The back-propagation learning algorithm with two different variants and logistic sigmoid transfer function were used in the network. In order to train the neural network, limited experimental measurements were used as training and test data. The best fitting training data set was obtained with four neurons in the hidden layer, which made it possible to predict residual stress with accuracy at least as good as that of the experimental error, over the whole experimental range. After training, it was found the R² values are 0.996112 and 0.99896 for annealed before peening and shot peened only, respectively. Similarly, these values for testing data are 0.995858 and 0.999143, respectively. As seen from the results of mathematical modelling, the calculated residual stresses are obviously within acceptable uncertainties.     

Finite element analysis of residual stress induced by shot peening process

The aircraft industry has only recently begun to explore possible application of welding as an alternative joining method for the design of future large civil airliner wing. One of the main obstacles, encountered in the past years, to welding application within the aircraft industries were due to failure in the weldments, caused by high tensile residual stresses present in the region of the weld, reducing drastically fatigue strength of welded joints. Improvement in the fatigue life of the welded joint can be obtained if compressive residual stresses are introduced at the weld region.Shot peening is a manufacturing process intended to give aircraft structures the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. This paper presents the modeling and simulation of the residual stress field resulting from the shot peening process. The results achieved show that a significant decrease of welding induced tensile residual stress magnitude can be obtained. Good agreement between experimental and numerical results was achieved.