共查询到19条相似文献,搜索用时 171 毫秒
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固定式承载索挠度对弹性模量影响的研究 总被引:1,自引:0,他引:1
假设承载索两端固定装置的弹性变形为零,即两端固定装置为绝对刚性体。考虑承载索挠度弹性变化,从理论上探讨承载索弹性模量的变化规律,推导出承载索弹性模量公式。 相似文献
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单圣涤 《中南林业科技大学学报(自然科学版)》1985,(2)
索道的有效载量,指索道承载索的有效载量,减去索道其它工作索施于承载索的重力和跑车(包括跑车下落的起重索、挂勾及捆挂索等器件)自重所得的结果。本文应用悬索的无量纲计算理论,经过系统的分析验证,推导出了索道的有效载量公式,使其计算结果能适用于多种钢索,便于在生产实际中应用。 相似文献
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该文从实验和理论上探讨了动载荷时承载索受力的变化,分析了影响承载索受力变化的因子.建立了动载荷时承载索受力的变化规律,揭示了承载索能量分析范围.为理论设计和计算承载索受力建立了理论依据. 相似文献
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罗锦光 《林业机械与木工设备》1987,(3)
在架空索道的设计计算中,人们常把确定承载索的中央挠度系数做为主要计算参数,并以此为主要数据对承载索的其他计算项目进行计算和设计。中央挠度系数值在很大程度上左右着承载索的安装张力。承载索的安装张力过大或过小,都将直接影响架空索道的使用效果、钢索寿命和索道运行的安全度。确定适当的中央挠度系数和计算出承载索的安装张力是比较容易的,但要在架设索道的过程中测出钢 相似文献
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跑车和吊钩(以下统称为跑车)绕承载索翻转,是单杆缆索起重机作业中常发生的故障。翻转后的跑车,由于两端的起重索、回空索和牵引索全都缠在承载索上,使跑车无法运行。缆索起重机只好停止工作。二十多年来,使用缆索起重机作业的各个单位,在出现了上述故障时,普遍采用放落承载索,用人力翻转过来,再张紧承载索的老办法。此方法处理过程繁琐,耗时量较多(每处理一次需2——3小时)。近几年我们在排除这一故障中,探索出一种不落承载索、在高空中翻转跑车的新方法。 相似文献
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承载索许用荷重设计法研究 总被引:1,自引:0,他引:1
原传统的许用应力法,在承载索设计计算中运算繁琐,应用不便。本文提出许用荷重设计法,在抛物线理论的基础上推导出一系列计算公式,编制承载索数值表,建立起系统的许用荷重设计方法。 相似文献
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林业索道承载索的优化设计 总被引:5,自引:2,他引:3
本文建立了林业索道承载索优化设计数学模型,并进行了理论推导,编制了BASIC程序,在PC-1500、APPLE-Ⅱ微机上中、英文通过。该程序能进行单跨或多跨索道承载索的优化设计。本软件功效高,操作简便,运行速度快,计算精确,通用性好。 相似文献
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The ability of a newly developed carriage equipped with a remote control lock and self line extraction system manufactured
by Oikawa motors Co., Ltd. was analyzed. The study investigated the reduction of the work load of the choker setter in the
haul line-pulling out process of a cable logging system by a mobile tower yarder. The main objective was to compare the walking
time, pulling out time, and the tension force using the three types of cable setting method, a running skyline with a simple
carriage, a fixed skyline with a simple carriage and a fixed skyline with a newly developed carriage. The measuring of haul
line pulling out was conducted on different slope gradients at different distances from the tower spar by four choker setters.
The study showed that choker setters could reduce the force exerted by about 33%, and a decrease in the heart beat rate of
12%, when using the fixed skyline with the newly developed carriage as opposed to the running skyline with the simple carriage.
The fixed skyline with the newly developed carriage resulted in more pulling speed than the running skyline with the simple
carriage on the slope gradient of over 2° and the fixed skyline with simple carriage on the slope gradient of over 7°. With
the newly developed carriage the pulling tension, time and heart rate are lower, when the haul line is pulled out. Thus it
can be concluded that the new carriage is more productive than the simple carriage in the line pulling out process. 相似文献
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钢丝绳弹性模量的研究 总被引:7,自引:0,他引:7
钢丝绳是不少机械的重要组成部分。钢丝绳属挠性体,负荷时不可避免出现弹性伸长,其关键参数弹性模量的取值问题关系到机械设计的精度与安全性。架空索道、缆索起重机等承载索挠度比较大的设备,弹性伸长更是不可忽视。通过综合考虑挠度引起弹性模量和弹性伸长引起弹性模量推导出等效弹性模量。 相似文献
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本文在半悬空集材索道设计的数学模型及其理论推导的基础上,用高级BASIC语言编程.该系统能对单跨半悬空集材索道的三种类型(两端固定式、松紧式、运行式)分别进行完整的设计计算.并绘制索道纵断面图。 相似文献
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Cable-based technologies have been a backbone for harvesting on steep slopes. The layout of a single cable road is challenging because one must identify intermediate support locations and heights that guarantee structural safety and operational efficiency while minimizing set-up and dismantling costs. Our study objectives were to (1) develop an optimization approach for designing the best possible intermediate support layout for a given ground profile, (2) compare optimization procedures between linearized and nonlinear analyses of a cable structure and (3) investigate the effect of simplifying a multi-span representation. Our results demonstrate that the computational effort is 30–60 times greater for an optimization approach based on nonlinear cable mechanical assumptions than when considering linear assumptions. Those nonlinear assumptions also stipulate lower heights for intermediate supports and a larger span length. Finally, compared with the unloaded case, tensile force in the skyline is increased by as much as 80% under load for a single-span skyline configuration. Our approach provides additional value for cable operations because it ensures greater structural safety at a lower cost for installation. Improvements are still needed in developing a stand-alone application that can be easily distributed. Moreover, our rather simple assumptions regarding set-up and dismantling costs must be refined. 相似文献
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71型索道即承载索松紧式索道,在无荷与有荷状态时,都可以用抛物线法求解,线型同样符合两端固定式索道承载索遵循的定律,设计方法很多,但以钢索最大拉力为依据调整统盘机制动力矩的方法最为简便、安全。 相似文献
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作者从天际轮廓线、视觉通廊、空间格局等方面分析了现代都市建筑对江南园林的影响,并提出了一些合理化建议,以期得到城市规划、园林管理部门以及社会各界的广泛关注。 相似文献
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伐区采集作业方式对森林生态环境的影响分析 总被引:9,自引:0,他引:9
通过分析伐区几种主要的采集作业方式对森林生态环境的影响,结果表明择伐和架空索道集材两种作业方式对森林生态环境的影响最小。 相似文献
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