共查询到19条相似文献,搜索用时 250 毫秒
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通过介绍离心机用橡胶弹簧的工作特点,以及橡胶弹簧本身材料特性,设计橡胶弹簧的动刚度试验,得出其动刚度在不同条件下的变化情况,为今后离心机用橡胶弹簧的设计研发提供参考。 相似文献
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为寻求提高反共振离心机工作性能的途径,建立了离心机的动力学模型,给出了对应的幅频特性曲线。通过对离心机橡胶弹簧进行动态特性测试,研究了橡胶弹簧的静刚度特性和动刚度特性。结果表明:随着切向位移增大,橡胶弹簧刚度下降;不同温度下橡胶弹簧的刚度随着压缩量的增加而明显增大;橡胶弹簧预压缩量为3和2 mm情况下,刚度变化规律基本一致;在25、32、34、37和40 ℃等不同温度条件下,橡胶弹簧的平均刚度变化不显著;在激振力频率不变的情况下,随着作用力的减小,橡胶弹簧的动刚度增大;在位移不变的情况下,随着频率减小,橡胶弹簧的动刚度减小。 相似文献
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充填采矿法在两步骤回采方式中广泛应用,胶结充填体作为人工矿柱,其稳定性至关重要;而胶结充填体力学特性及本构模型是进行稳定性分析与评价的重要内容,因此,亟需开展胶结充填体力学特性及本构模型研究。通过对不同灰砂比的胶结充填体进行单轴压缩试验,试验结果表明:在初始压密阶段因空隙存在而表现出非线性变形特征;在塑性屈服阶段及破坏后阶段刚度和强度均表现出软化特性;破坏后阶段存在较强的承载特性。针对试验结果,采用宏观和细观相结合的方法,将胶结充填体抽象成空隙和细观单元2部分,并引入胶结充填体有效损伤因子,结合统计损伤理论,分别构建空隙本构方程和细观单元损伤软化本构方程,进而得到胶结充填体损伤软化本构模型。最后将本研究理论模型曲线与试验曲线、现有理论基于试验数据和其他学者试验数据得到的曲线进行对比分析,分析结果表明本研究得到的理论曲线与试验曲线有较高的匹配度,各阶段曲线拟合相关系数都达到95%以上,更好地表征了胶结充填体空隙非线性变形特征及软化特性。研究结果可为胶结充填体稳定性分析提供理论依据。 相似文献
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充填采矿法在两步骤回采方式中广泛应用,胶结充填体作为人工矿柱,其稳定性至关重要;而胶结充填体力学特性及本构模型是进行稳定性分析与评价的重要内容,因此,亟需开展胶结充填体力学特性及本构模型研究。通过对不同灰砂比的胶结充填体进行单轴压缩试验,试验结果表明:在初始压密阶段因空隙存在而表现出非线性变形特征;在塑性屈服阶段及破坏后阶段刚度和强度均表现出软化特性;破坏后阶段存在较强的承载特性。针对试验结果,采用宏观和细观相结合的方法,将胶结充填体抽象成空隙和细观单元2部分,并引入胶结充填体有效损伤因子,结合统计损伤理论,分别构建空隙本构方程和细观单元损伤软化本构方程,进而得到胶结充填体损伤软化本构模型。最后将本研究理论模型曲线与试验曲线、现有理论基于试验数据和其他学者试验数据得到的曲线进行对比分析,分析结果表明本研究得到的理论曲线与试验曲线有较高的匹配度,各阶段曲线拟合相关系数都达到95%以上,更好地表征了胶结充填体空隙非线性变形特征及软化特性。研究结果可为胶结充填体稳定性分析提供理论依据。 相似文献
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为深入了解振动筛橡胶弹簧的力学性能,采用试验方法对振动筛橡胶弹簧的刚度、阻尼系数、阻尼比等力学参数进行测定,测定结果表明:橡胶弹簧的线性与非线性刚度的区分点为其10%变形量;不同的加载速度对橡胶弹簧线性阶段刚度影响较小,对非线性刚度影响较大,且呈线性增长的趋势;橡胶弹簧刚度越大,其阻尼系数及动态阻尼比越小,试验测定橡胶弹簧阻尼系数为0.031132~0.036892,动态阻尼比为0.046 833~0.062062. 相似文献
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通过分析液压支架轴用动密封蕾形复合密封圈的密封原理、有限元的非线性问题、接触问题,阐述了橡胶、聚氨酯的材料特性、橡胶类超弹性体的基本理论和本构模型,并用不同常数的Mooney-Rivlin模型来表征橡胶和聚氨酯的材料特性。通过橡胶、聚氨酯的单轴拉伸和单轴压缩实验,得到两种材料的Mooney-Rivlin模型参数。依据实验参数对蕾形复合密封圈进行有限元分析,发现蕾形复合密封圈适合动密封,且随着载荷增大密封效果下降。本研究对密封件的设计具有参考意义。 相似文献
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基于导向臂用52CrMoV4弹簧钢的热轧及热压变形工艺研究,采用Gleeble-3500型热模拟试验机,在变形温度(1173-1373 K)和应变速率(0.01-10 s-1)下对52CrMoV4弹簧钢进行等温热压缩实验。基于实验所得真应力-真应变曲线,分析了热变形参数与流变应力之间的关系,建立了修正的Johnson-Cook本构模型和基于应变补偿的Arrhenius本构模型,并对两种本构模型的准确性和有效性进行了比较。结果表明,52CrMOV4弹簧钢的流变应力随着温度的升高和应变速率的降低而降低。通过精度分析可知,修正Johnson-Cook模型的相关系数为0.98955,平均绝对相对误差为5.4625%,均方根误差为6.87029 MPa,计算较为简单却具有较高的准确性。而应变补偿的Arrhenius模型的相关系数为0.99023,平均绝对相对误差为4.4319%,均方根误差为6.22664 MPa,其精度较修正Johnson-Cook模型更高,可以更好地预测52CrMoV4弹簧钢的流变应力行为并作为热变形工艺及有限元模拟参数选择的依据。 相似文献
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By ANSYS, dynamic simulation analysis of rubber spring supporting equipment used in vibrating screen was made. The modal frequency,
mode, and harmonic displacement under working frequency were obtained. Variation of rubber spring supporting equipment’s dynamic
performance was discussed first, which is under the condition of existing spring stiffness difference and exciting force bias.
Also, the quantitative calculation formulas were given. The results indicate that the performance of vibrating screen is closely
related with rubber spring supporting equipment’s dynamic performance. Differences of springs’ stiffness coefficients reduce
the modal frequency reduced, decrease the dynamic stiffness, and increase vibration displacement. Exciting force bias induces
a larger lateral displacement. When rubber springs’ stiffness coefficients exist, differences and lateral force accounts for
5% in total exciting force; rubber spring supporting equipment’s side swing is larger than 1 mm, exceeding the side swing
limit. 相似文献
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节理峰前剪切应力-位移曲线是研究节理剪切行为的重要内容。然而目前对于节理峰前剪切行为大多以线性描述,不能较好的描述非线性的特点。对于非线性的描述也仅仅是唯象描述剪切应力-位移曲线,未能反映影响模型的参数物理意义及影响因素。以峰前节理刚度软化行为为出发点,采用归一化的思想将节理剪切刚度与位移无量纲化,用双曲线函数表示出剪切刚度与位移之间的关系。提出了考虑刚度软化的峰前剪切本构关系,通过与试验结果对比验证了本构关系的合理性。影响该模型最重要的两个因素是初始剪切刚度与峰值剪切位移。以Greenwood和Williamson模型为基础在细观上探讨了初始剪切刚度的影响因素;抓住法向应力与节理粗糙度主要因素,探讨了影响峰值剪切位移的影响因素。对模型参数的研究有助于进一步阐明节理峰前剪切机理。 相似文献
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《International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts》1993,30(4):351-359
In the present study, a constitutive model of jointed rock masses is presented which reflects the size, density, orientation and connectivity of joints as well as their mechanical properties. Following the continuum approach, the incremental stress-strain relation of the jointed rock mass is formulated by taking the volume average of stress and strain inside a representative volume element where the evaluation of the relative displacement across the joints is required. Employing an elasto-plastic constitutive model of the joint behavior, the relative displacement across the joint can be obtained once the stress acting on the joint is known. The fundamental difficulty in the constitutive modeling of jointed rock masses is due to the fact that the stress acting on a joint is different from the average stress since a joint does not cut through the rock mass but terminates within the rock mass, possibly connecting with other joints. The lower the stiffness of the surrounding matrix is, due to the existence of other joints or the connection of joints, the higher the stress acting on the joint will be. In the present study, the stress concentration tensor, which gives a relation between average stress and the stress acting on the joint, is introduced and a simple method to evaluate it is developed. The interaction effect between joints and the effect of joint connection are properly considered in the model. Some simple examples are solved by the proposed constitutive model. The results are in agreement with experimental data showing the characteristic features of the behavior of jointed rock masses. The proposed constitutive model for jointed rock masses is implemental into a finite element analysis program with a 3-D isoparametric element to analyze actual engineering problems. As an example, the program is used to analyze a plate-loading test problem and the results of the 3-D finite element analysis of the problem are compared with the test data. For highly jointed rock masses, the continuum model offers a powerful analytical method. 相似文献
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构建人工冻土BP神经网络本构模型,利用冻土三轴实验数据对神经网络模型进行训练,并2次开发有限元本构程序。用BP神经网络本构模型能很好的反映人工冻土非线性,人工冻土三轴数值模拟值和实验值误差在2.43%范围内。通过深井冻结工程数值模拟表明:人工冻土BP神经网络本构模型能较好的描述复杂应力路径变形特征,数值结果和现场实测规律一致,且和实测位移误差在5.0%;应用BP神经网络冻土本构模型准确预测预报人工冻土帷幕应力场和变形场,为冻结工程设计与施工提供参考。 相似文献