共查询到18条相似文献，搜索用时 143 毫秒
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韩玺艳 《石家庄铁路职业技术学院学报》2018,(1)
针对弦支网架张拉过程中预应力控制、张拉方案选取的问题,结合北塘游泳馆的弦支网架结构,制定了张拉方案,并利用Ansys有限元软件对网架结构强度、网架挠度、拉索内力进行张拉模拟。研究结果表明:弦支网架撑杆的最大轴拉应力为36.1 MPa,网架中间部位最大挠度为28 mm,拉索最大内力为380 k N,均符合安全设计要求。张拉方案、张拉原则保证了弦支结构体系承载力及整体刚度良好,相对于弦支穹顶、弦支梁等弦支结构,新型弦支结构体系传力效率高、稳定性好,可为其他弦支网架工程的安全性研究提供参考。 相似文献
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在苏丹麦洛维大坝工程溢流坝闸墩预应力钢筋施工中,采用新型螺纹钢筋、新型千斤顶、新型液压油泵、半球形紧固螺母、法国Alstom注浆泵以及国际工程施工常用的伸长值反算实际张拉力、快速注浆阀门等新工艺和新技术,确保了工程施工质量,提高了工作效率。这些新技术可为同类工程借签。 相似文献
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杜文举 《石家庄铁路职业技术学院学报》2011,10(1)
结合成绵乐客运专线700 t预制箱梁预应力的张拉控制过程,根据钢绞线的物理和力学性能指标及预应力施工工艺流程,详细阐述700t箱梁的张拉施工工艺和施工技术要求以及控制要点,对客专700t预制箱梁张拉施工控制技术进行系统的总结. 相似文献
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倪振利 《石家庄铁路工程职业技术学院学报》2014,(2):74-77
盾构机是城市地铁和隧道施工的主要机械装备,盾构机各项参数的设定对于掘进速度和施工质量影响重大。从盾构机刀盘扭矩和转速、千斤顶总推力、推进速度、螺旋输送机转速和压力、注浆流量和压力、加泥加泡沫流量和压力等参数分析入手,详细分析各项参数的设置对掘进性能的影响。并以北京地铁盾构施工为例,设计各项参数优化的具体实现思路,为盾构施工的科学组织和优化管理提供理论指导。 相似文献
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李坤 《石家庄铁路职业技术学院学报》2020,19(2)
随着技术的发展,传统人工张拉、压浆技术越来越显示其局限性,智能张拉、压浆施工技术的推广应用已成为桥梁预应力施工发展的一种趋势。结合延延高速公路预应力预制箱梁施工的实践,系统介绍了智能张拉、压浆施工技术的主要原理、工艺流程及主要操作要点,为智能张拉、压浆施工技术在公路预应力施工中的推广应用提供实践经验。 相似文献
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《中国远程教育(综合版)》1984,(1)
携带式单油路镦切两用机镦切两用机是一种予应力施工中镦切高强度钢丝的专用工具。在镦头锚固法施工中,用此机具锚固的钢丝束,具有锚固性能好、工作能力大、应力损失小、张拉操作方便、可重复张拉等优点。它可广泛地在桥梁、铁道、房屋及水工建筑、予应力电杆、压力管子、高压容器以及予制构件上应用。携带式单油路镦切两用机,体积小、重量轻,能适应地面、高空、固定或移动等各种情况下作业。它 相似文献
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基于多级油泵的现场要求,提出了集多参量检测与控制为一体的多级油泵测控系统。从阐述多级油泵的结构和工作原理入手,确定了以数字信号处理器TMS320LF2812为控制核心的总体方案,设计了流量、压力等参数的检测电路和IGBT的驱动保护电路,给出了相应的软件。结果表明,该测控系统可以以一定的准确度实现压力、瞬时流量、累积流量的测量,也可对三相异步电动机进行变频控制,从而达到调节异步电动机转速、进而调节多级油泵流量和压力的目的。该系统具有结构紧凑、成本低、工作安全可靠、性能优良等特点。 相似文献
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王巍 《浙江工贸职业技术学院学报》2011,11(4)
通过对拉索索力振动法测试计算公式简化分析,引入振动法测试的索力系数,只要在桥梁施工过程中通过压力传感器法或张拉千斤顶法确定各条吊索的索力系数,则振动频率法测试索力的公式变成了仅与拉索振动频率有关,对提高利用振动频率法测索力精度意义很大,尤其是精确测试短索的索力。 相似文献
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范学增 《天津职业院校联合学报》2010,12(5):6-9
轴向柱塞泵在使用中,经常出现配流副的早期磨损和"烧盘"现象,直接导致轴向柱塞泵磨损失效.通过对轴向柱塞泵配流副润滑油膜厚度的实验研究和综合分析,得出配流副磨损失效的主要原因是油液中的污染物造成的,提出改善配流副工作性能、延长轴向柱塞泵使用寿命的有效措施. 相似文献
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By an iteration method, the influence of oil film inertia on piston skirt lubrication in a high speed engine is investigated. By alternately solving the Navier-Stocks equations and the Reynolds equation, the new iteration method can trace the variations of velocity field and pressure field with time. Based on this, the mixed-lubrication model suitable for the piston skirt of high engines is proposed. By introducing the inertia coefficient, the new lubrication model includes the inertia term in oil film. The model can be also used to solve for the lubrication performances of a piston skirt in low or medium speed engines and for lubrication problem in general excluding 相似文献
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Air-driven boosters are widely used to obtain high-pressure gas. Through analysis of the boosting process of an air-driven booster, the basic mathematical model of working processes can be set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression. Using MATLAB/Simulink for simulation and studying the booster experimentally, the dimensionless outlet flow characteristics of the booster were obtained and the simulation results agree well with the experimental results. Through analysis, it can be seen that the dimensionless outlet flow of the booster is mainly determined by the dimensionless input pressure of the driving chamber, the dimensionless outlet condition pressure of the booster and the dimensionless area of the piston in the driving chamber. The dimensionless average outlet flow becomes larger with an increasing dimensionless input pressure of the driving chamber, but it becomes smaller with an increase in the dimensionless outlet condition pressure of the booster. Especially when the dimensionless outlet condition pressure is approximately 1.4, the dimensionless average outlet flow reaches zero. With an increase in the dimensionless area of the piston in the driving chamber, the dimensionless average outlet flow increases and peaks at approximately 1.89, and after this peak, it starts to decrease. This research can be referred to in the design of air-driven boosters. 相似文献
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蒋幸幸 《武汉工程职业技术学院学报》2009,21(4):17-19
分析液压轴向柱塞泵产生工作噪声和发热以及影响使用寿命的主要因素,研究液压轴向柱塞泵配流机构在配流过程中产生压力瞬变和流量脉动以及配流噪声的机理,提出采用在高低压腰形槽的始端设置具有两种宽度夹角的双级三角阻尼槽配阻尼孔结构的设计方案,可降低噪声、减少发热,提高使用寿命。 相似文献
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In this paper, dynamic analyses of the swash plate vibration and pressure pulsation of an aircraft piston pump based on fluid-structure interactions (FSIs) are presented. Models of the swash plate piston pumps with three FSIs (named full FSIs and non FSI) are given. The simulation results of the discharge pressures at different rotation speeds in the synthesized pump model and experiments show good agreement. The numerical simulation results of the forces on the swash plate and the flow rate of the outlet chamber are presented and compared. The results of the two models show that the discharge pressure pulsation mostly depends on the kinematic relations of the piston slipper-shoe units (FSI-1), and is almost isolated from the swash plate vibration. The full FSIs simulation shows that the swash plate vibration is strongly influenced by the pressure pulsation through the control actuator mechanism (FSI-2) and the control valve mechanism (FSI-3), but the non FSI model does not show the same result. The full FSIs model is much more accurate in predicting the vibration of the swash plate and the pulsation of the discharge pressure than the non FSI model. 相似文献
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为在船舶柴油机上燃烧动态乳化油,开发了一套基于喷油泵试验台的动态乳化油模拟系统,进行油水比例的精确计量和控制。台架试验结果表明,模拟系统能完整地表现各类船舶柴油机实际喷油过程,并且能实现乳化剂的选择、掺水配比量对乳化油物性的影响分析、乳化剂添加量的确定、乳化油颗粒特性分析以及功能加压试验等功能,操作简单、管理方便,为乳化油试验研究提供了一个可靠的平台。 相似文献
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We proposed a novel impact pneumatic cylinder with a reservoir connected to the inlet chamber so that the pneumatic cylinder can achieve a high speed. A reservoir with high-pressure air enabled the cylirider to achieve considerable＇acceleration when it began to Work. We established a mathematical model to simulate the behaviors of an impact pneumatic cylinder, focusing on the relationships of the maximum piston speed with the air supply pressure and the reservoir volume. The results show that the reservoir .can help significantly enhance the pneumatic system velocity. When the reservoir volume is less than double the cylinder volume, an increase in the reservoir volume is more effective in increasing the maximum piston velocity. 相似文献