共查询到18条相似文献,搜索用时 125 毫秒
1.
2.
3.
外压容器设计的公式法及其应用 总被引:1,自引:1,他引:0
以外压容器失稳的临界压力公式为基础,得到了外压容器设计的公式法,可用于长、短圆筒弹性失稳的稳定性设计与校核:并对公式的应用条件与适用范围进行了详细分析,给出了弹性失稳条件下厚径比δ/Di与设计外压P应满足的条件。在满足弹性失稳的条件时,公式法的计算结果与图算法的结果相差较小,满足工程设计要求。 相似文献
4.
《现代制造技术与装备》2018,(9)
盾构机是隧道全断面开挖的高效、环保、安全、优质的地下工程施工机械,在国内城市地铁建设中已被广泛应用。盾构选型过程中,推进系统的推力、刀盘驱动扭矩等主要技术参数的计算是盾构隧道施工成功与否的关键。以公司自主研发的XRE6650e复合式土压平衡盾构机为例,运用理论公式、经验方法、施工条件等介绍其推进系统的计算与选型过程,为土压平衡盾构机的设计和应用提供参考。 相似文献
5.
针对现有盾构刀盘轻量化设计计算成本高、多依赖经验的不足,提出一种基于聚合代理模型的土压平衡盾构刀盘轻量化设计方法。通过熵权TOPSIS综合贡献度分析筛选出对刀盘质量、最大变形和最大应力影响显著的结构参数作为设计变量,采用加权径向基函数模型、Kriging模型和支持向量回归模型的聚合代理模型来拟合设计变量与最大变形和最大应力约束响应间的隐式关系。在上述基础上构建了土压平衡盾构刀盘轻量化设计模型,并以序列二次规划算法进行优化求解。有限元仿真实验结果表明,所提出的轻量化设计方法实现土压平衡盾构刀盘减重7.44%,且能满足刀盘应力和变形要求,轻量化效果良好。 相似文献
6.
7.
8.
9.
10.
11.
12.
针对现有盾构施工中盾尾间隙难以实时精确测量的问题,本文提出了一种基于线结构光的盾尾间隙自动测量方法。该方法首先利用线激光器在管片和盾壳之间投射出一道窄线型指示激光并通过工业相机实时采集线激光器投射在盾壳和管片之间的线激光图像,然后通过图像处理对图像目标特征进行识别并根据单目视觉成像原理和线结构光坐标测量算法提取盾尾间隙端点坐标,进而实现盾尾间隙值的精确解算。实验结果表明,本文所提出方法的重复性测量精度优于0.3 mm,绝对测量精度优于1.7 mm。该方法可以实现相机纵深方向0.2~1.9 m范围内盾尾间隙的实时精确测量,满足城市地铁隧道施工应用需求。 相似文献
13.
Liang TANG Xiangxun KONG Xianzhang LING Yize ZHAO Wenchong TANG Yifan ZHANG 《Frontiers of Mechanical Engineering》2022,17(2):20
The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata. 相似文献
14.
盾构机冗余驱动推进系统不同分组策略是其顺应复杂地质环境中掘进时突变载荷的一种重要的手段。以盾构机机械结构和工作载荷为基础,设计变负载下冗余驱动推进系统动力传递特性研究实验台,引入分组矩阵建立冗余驱动推进机构的力传递模型,通过数值仿真与实验数据相比较验证实验台的有效性。针对盾构机中两种典型的分组策略,提出实验台相应等效分组方法,对不同载荷下冗余驱动推进系统的动力传递特性进行研究。实验结果表明,不同变载荷条件下冗余驱动推进系统采用不同的分组策略可以有效降低载荷波动,该结果为面向复杂地质条件的盾构机冗余驱动推进系统分组设计方法的建立提供了依据。 相似文献
15.
16.
M. R. Isvandzibaei H. Jamaluddin R. I. Raja Hamzah 《Journal of Mechanical Science and Technology》2014,28(7):2759-2768
This paper presents the study on vibration behavior of functionally graded material (FGM) cylindrical shell with the effects of internal pressure and ring support. The FGM properties are graded along the thickness direction of the shell. The FGM shell equations with internal pressure and ring support are established based on strain-displacement relationship using Love-Kirchhoff shell theory. The governing equations of motion were solved by using energy functional and by applying Ritz method. The boundary conditions represented by end conditions of the FGM cylindrical shell are simply supported-simply supported (SS-SS), clamped-clamped (C-C), free-free (F-F), clamped-free (C-F), clamped-simply supported (C-SS), free-simply supported (F-SS), free-sliding (F-SL) and clamped-sliding (C-SL). To check the validity and accuracy of the present method, the results obtained are compared with those available in the literature. The influence of internal pressure, ring support position and the effect of the different boundary conditions on natural frequencies characteristics are studied. These results presented can be used as important benchmark for researchers to validate their numerical methods when studying natural frequencies of shells with internal pressure and ring support. 相似文献
17.
The advantages and limitations of a perturbation method of analysis for the creep buckling of shells is explored in this note by examining the particular case of a long cylindrical shell subjected to a uniform external pressure. It turns out that the oval deformation mode is the most critical as assumed in previous theoretical investigations. However, other modes can make important contributions to the deformation of a cylindrical shell and can, in fact, dominate the response if important imperfections are present in these harmonics. 相似文献
18.
针对现有众多盾尾间隙自动测量方法中普遍存在的精度低和可靠性差等问题,提出了一种基于双线激光基准标尺的视觉测量新方法。通过两道平行布设的窄线形激光构建观测基准,利用传统图像处理技术捕获盾壳与管片的关键特征,结合标尺反算误差补偿技术,实现在盾构掘进过程中盾尾间隙测量值的高精度实时解算。现场实验表明,本文所提出的方法的重复性测量精度优于1.2 mm,绝对测量精度优于2 mm,测量误差小于1.5 mm,该方法可以实现盾尾间隙自动化实时精确测量且具备较高的可靠性,现已应用在我国多个地铁隧道施工现场。 相似文献