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无损检测信号快速三维有限元模拟的组合方法 总被引:1,自引:0,他引:1
提出了一种基于三维有限元的电磁无损检测缺损响应快速模拟的组合方法, 该方法由三项技术构成, 分别是局部计算技术、差场技术和迭代解技术. 采用局部计算技术, 可以将三维计算区域限制在缺损附近的一个较小范围; 使用差场技术, 无缺损情形下的轴对称解可以用来简化三维网格生成以及快速获得三维解答; 而应用迭代解技术, 可以加速无损探头信号有限元模拟的矩阵方程求解. 实例计算表明本文方法是正确有效的, 可以节省大量的计算机资源. 相似文献
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提出了一种不修改通用有限元程序建立的随机有限元方法,即计算机随机产生多组零件尺寸,用通用有限元软件对每组数据进行计算,求出零件危险截面应力等。对应力数据进行检验,若应力服从正态分布、指教分布、威布尔分布、对教正态分布中任一种,强度可靠度可通过公式或数值积分得到。若应力分布不确定,则可靠度用Monte Carlo法求出。变形的可靠度用同样方法解决。用该方法编写的计算机程序,使形状复杂零件的可靠度计算成为可能。 相似文献
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In this paper the residual stresses in a butt-welded plate of2.25Cr 1Mo has been analyzed using a 3D and transient finite element (FE) model. Also the effect of the welding-electrode speed has been studied using death and birth of FEs. For this purpose, a coupled thermo-mechanical FE solution has been used to obtain the temperature distribution and the resulting residual stresses. Also, the variations of the physical properties of the material with temperature have been taken into account. Results show that the residual stresses in the heat affected zone (HAZ) are maximum and change along the weld and also in the plate-thickness. It has been shown that use of the 3D and transient model will lead to more accurate and realistic results which are well compared with the experimental test data. 相似文献
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为了减轻有限元前期数据整理工作,正确划分有限元网格,提出了三维有限元模型的网格图形显示算法及程序的实现. 相似文献
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INTRODUCTION An Artificial Neural Network (ANN) is an in-formation-processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information. It is composed of a large number of highly interconnected processing elements (neu-rons) working in unison to solve specific problems. In recent years, neural network has been widely applied in the field of engineering construction as a large dimensional nonlinear dynamic system, because of its support for … 相似文献
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成思源 《重庆大学学报(英文版)》2003,2(1)
1. Introduction The active contour model (also called snake) was first proposed by Kass [1] and can be used in many image analysis and computer vision applications such as edge detection, motion tracking, image matching, and 3-D reconstruction. A snake is a energy-minimizing curve controlled by internal and external forces. Internal forces act as a smoothness constraint, and external forces guide the snake toward image features that are of interest. B-spline representation of active contour c… 相似文献
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《黑龙江大学工程学报》2017,(1)
在水电站厂房结构中,板壳是最基本的构件。为了更好地运用ANSYS软件模拟水电站厂房结构,首先应研究如何准确地模拟板壳结构。探究了实体单元与板壳单元在模拟板梁结构时的相同和区别之处,并对薄板结构进行了研究。结论表明由于剪切闭锁的现象存在,实体单元并不能准确模拟薄板结构的静动力行为,而板壳单元也只能在模拟特定的某种结构时能够保证准确度。对如何运用ANSYS更加准确地模拟水电站厂房构件静动力行为进行了初步的探索。 相似文献
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对一类抛物型积分一微分方程提出了一种全离散交替方向有限元格式,分析了该格式的收敛性,得到了最佳H^1模误差估计。 相似文献
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A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities 总被引:1,自引:0,他引:1
Dynamic responses of track structure and wave propagation in nearby ground vibration become significant when train operates
on high speeds. A train-track-ground dynamic interaction analysis model based on the 2.5D finite element method is developed
for the prediction of ground vibrations due to vertical track irregularities. The one-quarter car model is used to represent
the train as lumped masses connected by springs. The embankment and the underlying ground are modeled by the 2.5D finite element
approach to improve the computation efficiency. The Fourier transform is applied in the direction of train’s movement to express
the wave motion with a wave-number. The one-quarter car model is coupled into the global stiffness matrix describing the track-ground
dynamic system with the displacement compatibility condition at the wheel-rail interface, including the irregularities on
the track surface. Dynamic responses of the track and ground due to train’s moving loads are obtained in the wave-number domain
by solving the governing equation, using a conventional finite element procedure. The amplitude and wavelength are identified
as two major parameters describing track irregularities. The irregularity amplitude has a direct impact on the vertical response
for low-speed trains, both for short wavelength and long wavelength irregularities. Track irregularity with shorter wavelength
can generate stronger track vibration both for low-speed and high-speed cases. For low-speed case, vibrations induced by track
irregularities dominate far field responses. For high-speed case, the wavelength of track irregularities has very little effect
on ground vibration at distances far from track center, and train’s wheel axle weights becomes dominant. 相似文献
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张敬芝 《佳木斯教育学院学报》2012,(4):351+353
差速器壳设计是汽车设计环节的关键,尤其差速器壳的强度分析是设计的重点之一。本文通过运用PROE软件进行三维设计,运用ANSYS软件对差速器壳进行强度分析,通过对差速器壳模型进行网格划分、差速器壳负载及边界条件的设定,计算求解得出差速器壳应力分布图,从而找出差速器壳易破坏部位,寻找到提高差速器壳强度的措施。 相似文献
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In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BReP hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect. 相似文献
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The Wilson and Taylor elements Q6 and QM6, the representative nonconforming finite element method (FEM), have been successfully
developed and implemented in the finite element code SAP for improved displacement and stress analysis. This paper formulates
an improved convergent nonconforming axisymmetric element AQM6 over the corresponding axisymmetric Q6 and QM6 elements. The
proposed modified nonconforming axisymmetric element AQM6 satisfies the engineering patch test condition for convergence,
and also meets the condition for suppression of spurious shear stress by using a special remedying procedure. The numerical
test results are in agreement with the element performance.
Project supported by CAO Guangbiao High-Tech F. of Zhejiang Univ. (No. U19902), Zhejiang Edu. Committee SRF for Outstanding
Returned Overseas Scholars (No. G59990), US NSF (No. DDM-9313204) and Seiko Epson-Rutgers Univ. Project (No. 4-27365). 相似文献
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高分子材料在不同的结构形态下体现出不同的性能,结合高分子材料的这一特征,采用粘弹性有限元的方法对凝聚态下的高分子材料进行了建模分析与计算,并给出了具体的边界约束条件,分析了高分子材料在凝聚态下的性态特征,对于进一步提高高分子材料凝聚态下性质的研究具有一定的借鉴意义. 相似文献
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钢索起吊重物的摆动角度是影响吊钩结构强度的重要因素。通过有限元软件ANSYS模拟计算,揭示吊钩结构的危险截面及钢索摆动角度对吊钩结构强度的影响规律。计算结果表明:吊钩结构的危险截面分别在A-A、B-B和C-C截面处;随着摆动角度的增大,水平附加分力引起的A-A和C-C截面处的应力值变化极小,而B-B截面呈递增趋势,影响显著。分析结果为吊钩结构的强度设计提供理论依据。 相似文献
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Applying stiffness migration method, a 3D finite element mechanical model is established to simulate the excavation and advance processes. By using 3D nonlinear finite element method, the tunnel boring machine (TBM) excavation process is dynamically simulated to analyze the stress and strain field status of surrounding rock and segment. The maximum tensile stress of segment ring caused by tunnel construction mainly lies in arch bottom and presents zonal distribution. The stress increases slightly and limitedly in the course of excavation. The maxi-mum and minimum displacements of segment, manifesting as zonal distribution, distribute in arch bottom and vault respectively. The displacements slightly increase with the advance of TBM and gradually tend to stability. 相似文献
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黄道业 《河南职业技术师范学院学报》2011,(3):86-89
基于共轭展成法啮合原理和微分几何的理论,推导出了平面产形轮和被加工锥齿轮的齿廓方程,利用Pro-E中参数化建模的方法,在直角坐标系Cartesian中编制齿廓曲线方程,最终生成了整体模型.通过建模的过程证明了建立数学模型的正确性,也进一步拓宽了在应用软件方面建立精确锥齿轮三维模型的途径. 相似文献
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The multi-pass scheduling method is a key issue in die-less spinning for determining the quality of the final products, including their shape deviations and wall thicknesses, and has drawn increasing interest in recent studies devoted to trying to improve the accuracy of the formed parts. In this paper, two main parameters, roller path profiles and deformation allocations in each pass, are considered in newly proposed multi-pass scheduling and optimizing methods in die-less spinning. Four processing methods with different roller path profiles and with three deformation allocation methods are proposed for investigating the influence of scheduling parameters on product qualities. The ‘similar geometry principle for restraining shape deviation’ and the ‘small curvature principle for maintaining wall thickness’ are presented for optimal design of roller path profiles; in addition, the ‘uniform allocation principle for maintaining wall thickness’ and the ‘large deformation principle for restraining shape deviation’ are brought forward as suggestions for deformation allocations. Based on these principles, a scheduling method denoted by RF+(FP & EHS) is presented to improve the comprehensive quality of a product of die-less spinning. 相似文献