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1.
In this paper, three different modeling ranges were selected in the structural analysis for a hydropower house. The analysis
was carried out using ABAQUS 6.6. The modeling range has a remarkable effect on finite element method (FEM) calculation result
at the middle position of typical cross-sections where the concrete is relatively thin, and at the region close to turbine
floor. If the ventilation barrel, floor slabs and columns above turbine floor are excluded from FEM model, the maximum rise
difference of pedestal structure increases by about 24% compared with that of the whole model. It is indicated that different
modeling ranges indeed affect FEM calculation result, and the structure above turbine floor in the FEM model should be included. 相似文献
2.
A new method was worked out to improve the precision of springback prediction in sheet metal forming by combining the finite element method (FEM) with the data mining (DM) technique. First the genetic algorithm (GA) was adopted for recognizing the material parameters. Then according to the even design idea, the suitable calculation scheme was confirmed, and FEM was used for calculating the springback. The computation results were compared with experiment data, the difference between them was taken as source data, and a new pattern recognition method of DM called hierarchical optimal map recognition method (HOMR) is applied for summarizing the calculation regulation in FEM. At the end, the mathematics model of the springback simulation was established.Based on the model, the calculation errors of springback can be controlled within 10 % compared with the experimental results. 相似文献
3.
ZHONG Yi-feng WANG Rui YING Xue-gan CHEN Huai 《重庆大学学报(英文版)》2006,5(4):218-222
1 Introduction When librating with small amplitude, the discrete linearization freedom vibration equation of a structure is [1]: [m ] {x } [k ]{ x } = {0 } (1) The relevant vibration characteristic question is ([ k ] ? p 2[ m] ){φ } = {0} (2) where [m]… 相似文献
4.
针对复杂结构仿真中有限元仿真精度及效率不高的问题,提出采用高阶响应面方法进行建模及优化,并用桥梁模型来验证。选取合适参数,采用试验设计获取响应样本点,基于数理统计的逐步回归法对各自变量进行显著性分析,筛选对目标响应函数显著度高的自变量,再应用最小二乘法拟合各自变量的系数,得到三阶多项式响应面模型,用多目标优化算法进行优化。对比修正前后模态频率,结果表明应用响应面方法能得到简单而高精度的结构模型,从而验证了高阶响应面方法在建模及模型优化中的有效性。 相似文献
5.
刘成武 《福建工程学院学报》2008,6(Z1)
车身结构模态分析是车身NVH特性研究的重要内容,识别车身系统模态对避免车身结构与声腔共振、降低车内噪声有着重要的意义.文章以某轿车车身为例,利用有限元法建立车身结构模型,进行模态分析计算,从而获得车身结构的模态频率和变形部位. 相似文献
6.
采用参考面单元技术并引入虚拟杆单元,建立筋条局部脱胶开裂复合材料梁／板结构后屈曲分析的有限元简化模型。着重研究不同开裂尺寸和位SLM置对复合材料层合加筋板后屈曲承载能力的影响。计算表明：开裂位置相同,开裂尺寸增加会导致后屈曲承载能力降低;开裂尺寸相同,随着其位置由筋条中心向端部移动,加筋板的后屈曲承载能力逐渐上升;值得注意的是,筋条端部开裂使加筋板的后屈曲承栽能力显著降低,其影响远大于筋条中心位置开裂。 相似文献
7.
为了深入研究路面养护中抗滑界限与公路设计中制动距离限值间的关系,提出了考虑路面摩擦特性时确定制动距离的方法.基于理论流体动力学和基本力学原理,考虑轮胎类型、水膜厚度、路表特性、行车速度等因素,建立了稳态滚动轮胎的有限元模型;运用该模型计算了不同运行条件下的制动距离;通过比较分别满足养护和设计界限的制动距离,确定了路表允... 相似文献
8.
A study of the behaviour of constructional cold-formed stainless steel beams at elevated temperatures was conducted in this paper. An accurate finite element model （FEM） for stainless steel beams was developed using the finite element program ABAQUS. Stainless steel beams having different cross-sections were simulated in this study. The nonlinear FEM was verified against the experimental results. Generally, the developed FEM could accurately simulate the stainless steel beams. Based on the high temperature stainless steel material test results, a parametric study was carried out on stainless steel beams at elevated temperatures using the verified FEM. Both high strength stainless steel EN 1.4462 and normal strength stainless steel EN 1.4301 were considered. A total of 42 stainless steel beams were simulated in the parametric study. The effect of temperatures on the behaviour of stainless steel beams was investigated. In addition, a limiting temperature for stainless steel beams was also proposed. 相似文献
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基于ANSYS的高速包装机的椭圆齿轮模态分析 总被引：1，自引：1，他引：0
采用有限元法,建立了椭圆齿轮的动力学模型,通过有限元分析软件ANSYS对椭圆齿轮进行模态分析,得到了椭圆齿轮的前六阶固有频率和对应振型。该方法和所得结果为动态设计提供了参考,同时也为椭圆齿轮系统的动态响应计算和分析奠定了基础。 相似文献
11.
本文基于电磁场仿真软件Ansoft建立了一种三相四极同步电动机的几何模型,并建立了相应的数学模型,利用该软件对模型进行有限元仿真与分析。通过运用麦克斯韦方程组和虚功原理,得到了该电动机在指定电流下磁力线及磁通密度分布图,并计算在不同电流下的自感、互感及转矩的大小及关系,这些数据为下一步的动态分析和控制设计打下基础。 相似文献
12.
To predict the distortion of aerospace monolithic components, a model is established to simulate the numerical control （NC） milling process using 3D finite element method （FEM）. In this model, the cutting layer is simplified firstly. Then, the models of cutting force and cutting temperature are established to gain the cutting loads, which are applied to the mesh model of the part. Finally, a prototype of machining simulation environment is developed to simulate the milling process of a spar. Key factors influencing the distortion, such as initial residual stress, cutting loads, fixture layout, cutting sequence, and tool path are considered all together. The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results. It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%. 相似文献
13.
Aiming at disclosing the quantitative effects of Coulomb forces on the filtration efficiency of aerosol particles, a three-dimensional random fiber model was established to describe the microstructure of fibrous filters. Then, computational models including the flow model, particle model, and electric field model were constructed to estimate the filtration efficiency using the Fluent custom user-defined function program, neglecting the non-uniformity of the fiber potential and the particle charge distribution. The simulation results using the established models agreed with the data in the literature. In particular, the electric field force was found to be one of the important factors required to improve the filtration efficiency estimation accuracy for the ultrafine particles. Moreover, the variation tendencies of the filtration efficiency and the pressure drop of fibrous filters were studied based on the influence factors of the fiber potential, particle charge-to-mass ratio, solid volume fraction, fiber diameter, and face velocity. The established models and estimated results will provide important guidance on the design of high-efficiency particulate air filters for aerosol particles. 相似文献
14.
A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge engines. The model consists of two exponential functions for calculating the fuel burning rate in different charge zones. The model factors are determined by a non-linear curve fitting technique, based on the experimental data obtained from 30 cases in middle and low loads. The results show good agreement between the measured and calculated cylinder pressures, and the deviation between calculated and measured cylinder pressures is less than 5%. The zero-dimensional single-zone double-curve model is successful in the combustion modeling for stratified charge engines. 相似文献
15.
《天津大学学报(英文版)》2017,(6)
Single-grit grinding of a 2.5D woven composite was investigated by the finite-element method(FEM) using a unit-cell model. According to our hypotheses, the axis of the warp yarn was a sinusoidal curve and the cross section of the weft yarn was shaped like a biconvex lens. AVUMAT subroutine was used to construct the constitutive model of the 2.5D woven composite. The grinding process of the composite was analyzed using an FEM simulation with the ABAQUS/Explicit software. A validation experiment was also carried out. The simulation results showed that a grinding crack was well simulated. Furthermore, the junctions between the warp yarn and weft yarn were found to be seriously damaged and cracks were observed to extend outward along the warp fiber during grinding, in good agreement with the experimental results. In addition,the strain of weft yarns was obviously greater than that of warp yarns when the grinding direction was perpendicular to the weft yarns and parallel to the axis of the warp yarns.These results demonstrate that the mesostructure strongly influences the grinding damage inflicted on woven composites. 相似文献
16.
金属粉末轧制工艺能够生产一般工艺难于或无法生产且成分精确、性能优良的板带材,是制取高性能以及特殊用途材料的粉末冶金成形工艺。在粉末轧制工艺的力学行为研究中,传统的数学模型被证明所提供的作用有限,基于有限元方法的数值模拟为此提供了一种灵活高效的途径。基于把粉末体看作是可压缩连续体的假设,根据椭球面屈服准则推导了金属粉末体变形的弹塑性本构关系。采用了合适的本构关系积分算法,并对摩擦模型进行了分析。基于MSC．Marc平台的二次开发工具编制了相关的用户子程序,对铁基粉末的轧制过程进行了三维弹塑性有限元数值模拟。该程序的准确性已在对粉末闭模压制的数值模拟及实验对比中得到了验证。此外,分析了轧制速度、摩擦系数等对轧制力和相对密度分布的影响。 相似文献
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A real case of a steel lattice shell suffering a fire was studied. Based on the theory of field modeling, fire dynamic simulator (FDS) was used to identify the temperature field. The damage mechanism of the structure was determined by FEM analysis. After damage assessment, the shell was repaired with the pipe-encasement method. Finally, field test was employed to check the capacity of the structure after repair. The numerical study results indicate that the damage assessment agrees well with field inspection, verifying the accuracy of fire numerical simulation and FEM analysis. The field test results prove that the pipe-encasement method is secure and reasonable, and the repaired shell is safe. 相似文献
19.
An integrated finite element model(FEM)of offshore wind tower-foundation-soil is established by ABAQUS, where a large-scale composite bucket foundation with seven compartments inside is applied to supporting the upper wind tower. The dynamic response of the structure-foundation system is studied under three seismic waves with the same peak ground acceleration of 0.035g. It can be seen that the dynamic response increases at the beginning with the structure height, then it decreases because the structural damping increases due to the mass effect of the upper wind turbine generator system. It is shown that the anti-liquefaction capacity of the soil inside and underneath the foundation is improved owing to the high overburden pressure of the upper structure and the constraint effect of the bucket skirt and subdivisions. Moreover, the liquefaction resistance of the soil inside the middle compartment is improved to a higher degree than that inside the side compartments. 相似文献
20.
李健 《南宁师范高等专科学校学报》2010,(5):102-104
有限元法已成为工程分析中强有力的数值分析工具。根据有限元理论与技术发展的特点,针对传统有限元课程教学体系中存在的数学、力学理论起点高,学生难于掌握等问题,对建立课程新的内容体系,通用有限元软件应用和与实际工程问题的教学内容、方法以及课程安排进行改革。实践证明,通过教学改革,对学生理论基础与实际操作能力的提高起到了积极的作用。 相似文献