共查询到19条相似文献,搜索用时 250 毫秒
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本文在疲劳累积损伤模型和刚度降模型的基础上,根据疲劳损伤的两阶段理论,将复合材料的疲劳损伤划分为两个阶段,并用两种不同的函数分段描述疲劳损伤的过程,建立了疲劳损伤演化两阶段模型。利用试验数据,运用多元函数的最小二乘法,得到了模型中的各个参数的拟合值和层合板的S-N曲线。疲劳损伤演化两阶段模型计算数据与试验结果吻合较好。 相似文献
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研究了低速非达西试井解释模型,并利用Laplace变换求得了该模型在Laplace空间下的解析解,对低速非达西模型的求解过程和结果做了进一步的完善。通过对第二类虚宗量贝塞尔函数的积分算法的研究,给出了其在大自变量和小自变量俩种不同情况下的积分算法,分析了两种不同算法在不同情况下的适应程度,结合大量的计算和比较对两种算法的实用范围进行了结合统一,给出了能够精确计算任意自变量的方法,完善了在低速非达西模型中长期存在的一个因计算精度不够而导致典型曲线振荡的问题。最后利用数值反演算法绘制了典型曲线,并和以前算法所得到的典型曲线进行了对比,验证了本文的正确性。 相似文献
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为达到精细注水的注采要求,利用两种不同隐层门控循环单元(GRU)神经网络模型的注水流量预测方法,同时借助国内某油田注水井的历史数据对两种不同隐层模型的预测结果进行了对比.结果表明:与传统的循环神经网络(RNN)和长短期记忆(LSTM)神经网络相比,GRU不仅拥有较好的预测性能,模型训练效率也更高;且双隐层结构较单隐层在... 相似文献
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袁冠威 《化工自动化及仪表》2013,(10):1288-1291
以系统阶跃响应测试数据为依据,针对存在滞后对象的传递函数模型,在开环状态下引入两种使用最小二乘法实现的辨识方法。同时,利用两种算法对不同的控制对象进行模型辨识,验证了两种辨识方法具有较高的辨识精度及方法的可行性,为工业应用提供了有力的理论依据。 相似文献
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1H NMR化学位移被广泛用于研究缔合体系溶液微观结构和溶液热力学性质.本文基于局部组成思想和双液理论,提出了一个半经验的缔合体系核磁共振化学位移关联模型,模型中含有两个代表分子间相互作用力的待定参数.利用新提出的模型,对不同的缔合体系进行了关联,包括自缔、交叉缔等缔合体系.关联的结果表明,该模型能很好地描述各种不同缔合形式的缔合体系1H NMR化学位移随浓度的变化关系.同时利用模型参数中含有的温度关系,预测了同一体系在不同温度时的核磁共振化学位移,预测偏差和模型自身关联偏差基本在同一数量级上. 相似文献
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对工业乙烯氧氯化挡板流化床反应器建立了以两相理论为基础的多釜串联反应器模型,利用大量工业数据求解模型参数并检验模型,计算结果表明模拟值与工业值基本吻合.在此基础上,对反应器操作条件进行优化,得到不同生产负荷下的最优操作条件. 相似文献
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考虑不同尺寸的晶体为不同的分散相,通过有限体积法差分不同尺寸组的晶体求解粒数衡算方程,建立了质量衡算与粒数衡算之间的联系,在考虑晶体成核和生长的条件下,建立了稳态结晶过程的粒数衡算方程与多相流方程的耦合求解方法,得到了工业结晶过程的计算流体力学模拟模型。使用商业软件ANSYS CFD,采用该模型对DTB 型工业结晶器中氯化钾-水体系的结晶过程进行了模拟,最终获得不同尺寸晶体的流场和固体含量的分布信息,从而实现结晶过程的仿真模拟。对部分模拟结果与实验值进行了比较,结果表明模拟结果与实验结果吻合较好。 相似文献
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This paper presents a group of dimensionless parameters which are useful in scaling-up the material hold-up in cylindrical drums of different geometry. These parameters include feed rate, drum rotational speed and discharge opening diameter. It also presents a semi-empirical model which can be used to predict the material hold-up in rotating drums for a wide range of operating and design variables. The values of hold-up predicted with this model are slightly lower than the corresponding experimental values, possibly due to end effects. 相似文献
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橡胶缓冲器有限元分析 总被引:5,自引:0,他引:5
笔者详细描述了橡胶变形的非线性特点和几种应变能函数,用有限元方法对橡胶缓冲器进行建模分析,得到了在不同条件下的载荷.位移曲线。分析结果与试验结果能很好的吻合,因此有限元方法可以用来指导橡胶缓冲器的优化设计。 相似文献
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Qingshan Huang Tianzhong Liu Jing Yang Lishan Yao Lili Gao 《Chemical engineering science》2011,(17):3930
Photoreactors are of great importance and their design is very difficult because of the multiphysics nature and the nonuniformity of light intensity inside it. The radiative transfer in the participating media is performed using the finite volume method (FVM) and the models of radiation are verified and discussed for a wide range of optical thickness in the absorption and scattering medium. An iterative method of solving the radiation transport equation, which is the same as the method of solving flow, heat and momentum transfer is presented. A revised model for the lamp and the quartz sleeve, which is simplified to be a boundary wall with reflection, is proposed. The predicted profiles of light intensity agree well with the experimental data in the photoreactors. The model and methods verified in this contribution can be used as a tool for the design and scaling-up of photoreactors. 相似文献
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Based on the previous work of the hydraulic, axial mixing, and mass-transfer performance of an annular pulsed disc-and-doughnut column (APDDC), the effects of scaling-up on its performance were studied in APDDCs with different annular space widths. The effect of scaling-up on holdup was discussed, and a more universal correlation was established. The effect of scaling-up on the Sauter drop diameter could be expressed by the previous obtained correlation. The effects of scaling-up on both the flooding holdup and throughput were mainly reflected in the correlation of the Sauter drop diameter. The equations of operating regimes were also independent of the scaling-up effect as demonstrated by experimental data. The scaling-up effects on the axial-dispersion coefficient of the continuous phase, the mass-transfer coefficient, and the height of a transfer unit were also discussed. 相似文献
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A. Audzijonis G. Gaigalas L.
igas A. Pauliukas R.
altauskas A. er kus J. Naru is 《Ferroelectrics Letters Section》2005,32(5):111-118
This paper presents the theoretical investigation of energy of core levels (CL) of the ferroelectric SbSBr single crystals in paraelectric and ferroelectric phases. Since the best approximation for the CL levels is a calculation by the Hartree-Fock method, the molecular model of SbSI crystal was used for calculations. It was found that CL of this semiconductor ferroelectric are sensitive to the small lattice distortion at phase transition, and on ion charges. The experimental splitting of CL obtained by XPS was compared with theoretically calculated one by two different methods. The cluster model calculations showed that the splitting of the CL in SbSBr might be caused by photoelectron emission from the atoms, which have different ion charges at the surface. 相似文献
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汽液两相流动的CHF(临界热流密度)和Tmin(最小膜态沸腾起始点)等特性点附近曲线存在转折,即在此点附近曲线的梯度要发生变化,从数学角度看这些点必然具备一定的奇异性.目前对于函数(信号)奇异性的检测方法主要是用小波变换实现的,由于小波分解具有良好的空间域和频率域的局部化特性,小波变换可以刻画出信号的变化规律以及对信号内奇异点的各种奇异性质进行检测和分析.对汽液两相流动中各传热特性点也可以用边缘检测小波变换去进行分析,并实现对它们的检测、定位和定量分析.通过对具体试验数据的边缘算子的检测证明了边缘检测小波完全可以用于对汽液两相流动的CHF和Tmin等特性点进行检测,并开创了一类新的汽液两相流动的试验研究方法. 相似文献