共查询到19条相似文献，搜索用时 359 毫秒
1.
四边形有限元网格生成方法关键技术 总被引：2，自引：0，他引：2
本对四边形网格生成法中的边界偏移、最优分割线确定等关键技术作了改进。在该方法中，用户只需指定区域的边界以及边界上的单元尺寸，就可以生成疏密自然过渡的四边形网格。它可与二维刚塑性有限元程序集成为具有网格自动重分功能的有限元模拟系统。利用系统对火车车轮预成形过程进行了模拟，结果表明该网格生成法通用性强，自动化程度高。 相似文献
2.
精冲过程的数值模拟及工艺参数优化 总被引：1，自引：0，他引：1
精冲过程是典型的局部塑形大变形过程，基于其成形特点建立有限元数值仿真模型，对精冲工艺进行弹塑形大变形有限元仿真．模型采用网格重划分方法解决网格畸变情况严重时造成计算终止以及计算结果不收敛的问题，同时引入McClintock韧性断裂准则来预测裂纹出现和扩展的时间及位置．在此基础上，给出了剪切区内应力、应变的分布以及发展趋势，同时针对精冲过程中的工艺参数，如凸凹模间隙、刃口圆角、压边力、反顶力等，对精冲成形面质量的影响加以了分析，给出了工艺参数的影响规律，模拟结果与实际生产情况基本符合，可用于指导工艺参数优化． 相似文献
3.
铁楔是防风制动器的关键部件,应具有足够的强度和刚度。文章首先在Pro／E中建立了该铁楔的几何模型,然后导入到ANSYS有限元分析软件中进行网格划分、加载和约束,对该铁楔进行了有限元分析,并提出了改进方案,也为制动器上的其它零件的设计提供了先进的技术和方法。 相似文献
4.
基于CT图像的人工膝关节三维有限元模型构建 总被引：1，自引：0，他引：1
张建宏 《扬州职业大学学报》2008,12(3)
通过CT扫描获得患者膝关节二维图像,利用图像处理技术和逆向工程技术实现膝关节曲面的三维重建,然后在CAD软件中对该重构的模型进行二次设计,形成人工膝关节CAD模型,最后将该CAD模型导入到有限元分析软件ANSYS中,采用自动网格划分工具Smartsize和自由网格划分方式进行网格划分,建立人工膝关节三维有限元模型。 相似文献
5.
《武汉职业技术学院学报》2016,(5):92-94
在参照焊接螺钉焊接强度实验的基础上,提出了一种基于Patran有限元法的焊接螺钉强度分析方法。首先建立焊接螺钉的三维模型,并通过属性选择、网格划分建立有限元分析模型,通过对边界条件和载荷的设置完成强度求解,然后将有限元分析结果和实验结果进行了对比。同时也分析了气孔缺陷对焊接螺钉强度的影响,该方法对焊接螺钉的设计以及焊接缺陷风险评估具有重要指导意义。 相似文献
6.
本描述了对有需要看重分析的局部区域的电磁场进行有限元分析的复合网格法．这种方法基于通常的有限元方法，有总体分析，局部分析和修正后的总体分析3个基本步骤．在前2步中，利用较粗的网格进行总体分析，得到节点的电势，将其作为后续进一步分析的局部区域的人工边界条件．将这些有了边界条件的局部区域用更精细的网格进行分析，得到更为精确的电势与密度分布．在第3步中，进行修正后的总体分析，通过迭代不断改进结果，直到满足给定的求解精度，得到更好的电势与密度分布的结果．数值实验表明，与通常的有限元方法相比，复合网格法在得到同样求解精度的结果时所耗的计算时间要少得多． 相似文献
7.
设计了一种三维有限元网格自适应局部细分的算法及数据管理系统,利用较简单的有限元误差估计方法对计算结果进行分析,建立了空间8节点等参单元网格自适应局部细分程序,通过对典型算例的计算表明,本方法可有效提高计算精度和计算效率。 相似文献
8.
采用具有小支集的奇异基函数的有限元方法求解奇异两点边值问题的奇异解．这种方法既保持了有限元刚度矩阵的带状性质，又能获得最佳的逼近精度 相似文献
9.
电机有限元分析的网格生成 总被引：2，自引：0，他引：2
该描述了电机有限元分析中的2种修正的三角形和四边形网格的生成方法，一种是结合经典的Delaunary方法和波前波产生优化的三角形网格，另一种是结俣传统的铺砖法Delaunary三角形方法来生成优化的四边形网络，这2种网格生成方法已成功地用于多种电机模型的网格划分，证实了该方法的可靠性与有效性。 相似文献
10.
基于Ansys的齿轮仿真分析 总被引：2，自引：0，他引：2
文章利用Ansys软件对齿轮齿根弯曲应力进行有限元仿真分析,与理论结果做比较,从网格类型、网格精度、加载方式等方面寻求最佳模型,为齿轮的优化设计和可靠性设计奠定了坚实的基础。 相似文献
11.
Iona Burnell 《Journal of Further & Higher Education》2017,41(2):227-237
The further education (FE) sector in the UK, or post-compulsory education as it is often referred to, has undergone some radical changes in recent years. Historically, FE is synonymous with vocational education and training, providing communities with courses that tended to be in practical, non-academic subjects. Many FE lecturers came from industries such as construction and engineering and were vital in providing the subject knowledge needed by colleges to enable them to offer a wide provision of courses. However, FE had not undergone the regime of teacher qualifications, regulation and inspection to the extent experienced by schools. In 2001, the New Labour government began a series of reforms that would overhaul post-compulsory education with the objective of making the sector more effective, and thereby meeting the wider objective of creating a more productive workforce. One of the many reforms was to introduce a system of inspection by placing FE into Ofsted’s remit. The new reform prompted FE colleges, for the first time, to implement their own institutional policies of observing teaching and learning (OTL) in order to prepare for impending inspection by Ofsted. This article examines the implementation of the policy of OTL, with a focus on one college of FE, and scrutinises its effects on the sector. 相似文献
12.
Using FEM to predict tree motion in a wind field 总被引：1，自引：0，他引：1
In this paper we propose a finite element （FE） simulation method to predict tree motion in a wind field, Two FE tree models were investigated： One model was generated based on a realistic nature-looking geometric tree model, and the other was a symmetric model to investigate the influence of asymmetric material properties on tree motion. The vortex-induced vibration （VIV） theory is introduced to estimate the fluctuating wind force being exerted on tree stems and the fluid-structure interaction （FSI） analysis is also included in the simulation. The results indicate that asymmetric material properties result in the crosswind displacement of the investigated node and the main swaying direction deviation. The simulation reveals that under wind loading, a tree with leaves has much larger swaying amplitude along the wind direction and longer swaying period than a tree without leaves. However, the crosswind swaying amplitude is mainly due to branch interaction. The numerical simulation proved that the interaction of tree branches can prevent dangerous swaying motion developing. 相似文献
13.
一种实时模拟血管中引导线变形的有限元模型 总被引：1，自引：0，他引：1
为了实时仿真微创介入手术过程中引导线在外力作用下的变形,提出了一种适合于描述纤细物体力学特性的模型.通过对引导线的仿真,医生可以在术前预演手术,并选择最佳的手术方案.模型采用多体结构离散化引导线,根据弹性理论推导出引导线的弹性能是节点位移的多项式函数,病人的血管四面体网格模型可从血管的三角面网格模型拓广得到,并将共轭梯度法能量下降的过程应用于引导线变形过程的模拟.实验结果表明:由于模型的弹性能和节点位移呈多项式函数关系,共轭梯度法的求解得到了有效的简化,模型的效率有显著提高.与目前广泛采用的显式计算模型相比不仅稳定且更快速.模型可应用于血管中引导线变形的实时仿真. 相似文献
14.
Fully automatic finite element （FE） modelling of the fracture process in quasi-brittle materials such as concrete and rocks and ductile materials such as metals and alloys, is of great significance in assessing structural integrity and presents tremendous challenges to the engineering community. One challenge lies in the adoption of an objective and effective crack propagation criterion. This paper proposes a crack propagation criterion based on the principle of energy conservation and the cohesive zone model （CZM）. The virtual crack extension technique is used to calculate the differential terms in the criterion. A fully-automatic discrete crack modelling methodology, integrating the developed criterion, the CZM to model the crack, a simple remeshing procedure to accommodate crack propagation, the J2 flow theory implemented within the incremental plasticity framework to model the ductile materials, and a local arc-length solver to the nonlinear equation system, is developed and implemented in an in-house program. Three examples, i.e., a plain concrete beam with a single shear crack, a reinforced concrete （RC） beam with multiple cracks and a compact-tension steel specimen, are simulated. Good agreement between numerical predictions and experimental data is found, which demonstrates the applicability of the criterion to both quasi-brittle and ductile materials. 相似文献
15.
基于结构健康监测的润扬悬索桥有限元模型修正与验证 总被引：5，自引：0，他引：5
采用大型有限元分析软件ANSYS建立了润扬悬索桥的三维有限元模型并对其进行了自振特性分析,同时计算了各种工况下大桥的应力及位移响应.基于灵敏度的物理意义以及罚函数的思想,提出了一种结构有限元模型修正的新方法.该方法仍以自振特性为目标函数,以结构设计参数为待修正参数,但设计参数的上下限根据测试所得静力响应值和理论值的对比以及工程经验来确定,因此静力响应可用于验证修正后的有限元模型.采用结构健康监测系统数据及提出的方法对大桥有限元模型进行了修正与验证,得到了能够较好地反映大桥整体动静力性能的有限元基准模型,为润扬悬索桥的健康监测和损伤预警提供了研究基础. 相似文献
16.
ABSTRACTOver the last 40 years, the Conceptual Physical Education (CPE) movement has played an important role in the evolution of secondary school physical education (PE). In this article, we trace the history of CPE as well as fitness education (FE) programs that share common objectives with CPE. CPE at the college/university level is almost universal and has been shown to be a longstanding innovation. The information provided here suggests that CPE/FE programs at the secondary level are also an innovation, rather than a passing fad. Among the topics explored include factors precipitating the innovation, the stages of implementation, the current status of the innovation, factors leading to success, barriers to be overcome in program implementation, and suggestions for the future. Finally, evidence is provided to show that CPE, when conducted with fidelity, can be effective in promoting the overarching objective of quality PE programs—promoting lifelong physical activity. 相似文献
17.
赵秀芬 《鞍山师范学院学报》2000,2(3):32-36
通过对平面上网格点阵的讨论,得到平等四边形网格是唯一确定点阵的充分条件,基本网格是国平等于坐标轴的单位正方形网格,以及整点的两点性质,并运用这些性质来解决以矢量p,q作成的平等四边形的面积表达式为│ad-bc│,其值为1的一类问题。 相似文献
18.
Kasthurirangan Gopalakrishnan 《浙江大学学报(A卷英文版)》2008,9(9):1157-1166
Previous research studies have successfully demonstrated the use of artificial neural network （ANN） models for predicting critical structural responses and layer moduli of highway flexible pavements. The primary objective of this study was to develop an ANN-based approach for backcalculation of pavement moduli based on heavy weight deflectometer （HWD） test data, especially in the analysis of airport flexible pavements subjected to new generation aircraft （NGA）. Two medium-strength subgrade flexible test sections, at the National Airport Pavement Test Facility （NAPTF）, were modeled using a finite element （FE） based pavement analysis program, which can consider the non-linear stress-dependent behavior of pavement geomaterials. A multi-layer, feed-forward network which uses an error-backpropagation algorithm was trained to approximate the HWD back- calculation function using the FE program generated synthetic database. At the NAPTF, test sections were subjected to Boeing 777 （B777） trafficking on one lane and Boeing 747 （B747） trafficking on the other lane using a test machine. To monitor the effect of traffic and climatic variations on pavement structural responses, HWD tests were conducted on the trafficked lanes and on the untrafficked centerline of test sections as trafficking progressed. The trained ANN models were successfully applied on the actual HWD test data acquired at the NAPTF to predict the asphalt concrete moduli and non-linear subgrade moduli of the medium-strength subgrade flexible test sections. 相似文献
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