Distribution of wire deformation within strands of wire ropes

Using ANSYS software, we developed a modeling program for several kinds of wire ropes with metal cores and built a geometric model for the 6×19 IWS wire rope. Through proper grid partitioning, a finite element model for calculating the deforma-tion of wire rope was obtained. Completely constraining one end of the wire rope and applying an axial force to the other end, we established the boundary conditions for solving the model. In addition, we numerically simulated the stress and deformation of the wire, obtaining the deformation distribution of each wire within the wire rope under different laying directions. At the end, a tensile test of the 6×19 IWS wire rope was carried out and the results of simulation and experiment compared.

Numerical investigation of the seismic response of a UHV composite bypass switch retrofitted with wire rope isolators

An ultra-high voltage(UHV)composite bypass switch(BPS)faces increasing seismic challenges when UHV projects extend to high seismic intensity areas.The UHV composite BPS still generates excessive stress at the bottom section although hollow composite insulators with high flexural strength are adopted.Since the standard retrofitting strategy by using stiffer supports cannot reduce stress responses,wire rope isolation is introduced.The optimal design of isolation considers both stress and displacement responses since the slenderness and composite material of insulators contribute to significant displacement.The results show that properly designed isolation can significantly reduce stress without excessive displacement responses.A larger radius configuration helps to improve the applicability of small stiffness isolators under high winds.When the isolation still cannot satisfy the requirement,smaller stiffness isolators with a larger radius,or isolators with increased loops and smaller radius,can be introduced to gain better energy dissipation capacity and effectiveness in response mitigation.Accordingly,a three-step design procedure is proposed to increase the damping force but fix the rotational stiffness of isolation.Hence,the application of wire rope isolation can be extended to UHV composite BPS with a low natural frequency,but conductors with enough redundancy should be used.

Effect of Tension on Friction Coefficient Between Lining and Wire Rope with Low Speed Sliding

In order to obtain the exact friction coefficient between lining and wire rope, the tension of wire rope is studied as a factor which affects this coefficient. A mechanical model of a wire rope subjected to axial load was established to determine the torque of the wire rope. The contact motion between lining and wire rope was regarded as a screw rotation and the axial force of the lining resulting from the torque of the wire rope was analyzed. Theoretical formulas relating tension of the wire rope and the friction coefficient was obtained. Experiments between lining and wire rope with low sliding speed were carried out with friction tester made by us. Experimental results show that increment of the friction coefficient is proportional to that of the tension of the wire rope with a low sliding speed. The experimental results agree with the theoretical calculation; the errors are less than 6%, which oroves the validity of the theoretical model.

Dynamic behavior of bridge-erecting machine subjected to moving mass suspended by wire ropes

The dynamic behavior of a bridge-erecting machine, carrying a moving mass suspended by a wire rope, is investigated. The bridge-erecting machine is modelled by a simply supported uniform beam, and a massless equivalent ＂spring-damper＂ system with an effective spring constant and an effective damping coefficient is used to model the moving mass suspended by the wire rope. The suddenly applied load is represented by a unitary Dirac Delta function. With the expansion method, a simple closed-form solution for the equation of motion with the replaced spring-damper-mass system is formulated. The characters of the rope are included in the derivation of the differential equation of motion for the system. The numerical examples show that the effects of the damping coefficient and the spring constant of the rope on the deflection have significant variations with the loading frequency. The effects of the damping coefficient and the spring constant under different beam lengths are also examined. The obtained results validate the presented approach, and provide significant references in the design process of bridgeerecting machines.

Key technique of a detection sensor for coal mine wire ropes

Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.

盘扣式钢管脚手架施工技术研究

研究主要分析了盘扣式外架与定型化金属网片组合使用的应用现场。针对传统钢管脚手架与密目式安全网组合方法存在的弊端进行探究,研究结合具体项目的实际情况,采用了这种新的组合方法,做出了新的临时拉结与卸荷方式,达到了提高效率,保证质量,提升外立面形象,减少风险的目的,研究旨在为同类工程提供借鉴经验。

钢丝绳网三维细观几何与参数化实体建模

为建立钢丝绳网的细观三维实体模型并实现模型的参数化.以钢丝绳网中的单根钢丝绳作为基本单元,采用坐标变换理论首先建立了包含钢丝绳芯丝和侧丝的三维几何参数模型;再根据各钢丝绳间的编织关系,建立了钢丝绳网的几何参数模型;最后,以所建立的几何参数模型为基础,采用Pro/E完成了钢丝绳网的三维造型设计.研究结果为可为钢丝绳网的力学特性分析及强度、结构参数优化的前期基础工作提供参考.

边坡柔性防护系统的典型工程应用

介绍柔性防护系统在国内边坡防护中的几个典型工程应用实例,包括迄今为止在国内已得到应用的各种柔性防护系统结构形式和柔性网类型,以此说明柔性防护系统的采用原则及其技术经济优势。

预应力钢丝绳-铁丝网聚合物砂浆加固混凝土柱轴压力学性能试验研究

对1个预应力钢丝绳-聚合物砂浆加固试件、3个预应力钢丝绳-铁丝网聚合物砂浆加固试件和1个钢筋混凝土对比试件进行轴压力学性能试验,以研究预应力钢丝绳-铁丝网聚合物砂浆这一加固体系对于方形截面柱的加固效果。主要试验变量为钢丝绳预应力水平以及有无铁丝网。试验结果表明:(1)预应力钢丝绳-聚合物砂浆加固法可在一定程度上提高试件的峰值应力、峰值应变和变形能力,提高幅度依次为15%、6%和31%;(2)钢丝绳预应力的变化对试件轴压力学性能的影响不显著;(3)人工包裹的双层铁丝网未能有效约束混凝土的横向膨胀。

跑车防护装置拦车网冲击载荷的分析与探讨

针对常闭式斜井跑车防护装置中柔性拦车钢丝绳承载终端的强度设计进行了探索,对钢丝绳受到冲击后的冲击力、冲击应力、冲击变形的计算进行了分析和探讨,提出了计算方法,为常闭式跑车防护系统,特别是拦车网及其缓冲装置的设计提供了参考依据。

崩塌落石的SNS柔性拦石网系统

在崩塌落石的栅栏式拦截防护中，以圬工、钢木结构为主的传统结构物，因其体积庞大、材料用量大、施工劳动强度大和缺乏可靠的设计技术保障，已难以适应诸如高等级公路、铁路和其他工程建设等级和技术水平的不断提高。本文在分析评价国内现有崩塌落石防护技术的基础上，介绍了以钢绳网为主要构成材料的岩崩落石ＳＮＳ柔性拦石网系统的功能原理、基本特征、主要构成和主要适用范围，阐明了该项新技术在防护功能、标准化设计与施工作业以及适应性和安全可靠性等方面相对于传统常规手段的技术经济优势。

斜坡坡面地质灾害SNS柔性防护系统概论

在简单分析评价国内现有坡面地质灾害防治现状的基础上 ,介绍了以钢丝绳网为主要构成材料的 SNS( Safty Netting System)主动覆盖和被动拦截柔性防护系统的基本构成和功能特征 ,从而阐明了该项新技术在防护功能、标准化设计与施工作业以及对复杂地形的适应性和安全可靠性等方面的技术经济优势。

Application of Low Temperature Liquid Sulfurization Catalyzed with Rare Earth on Cr12 Impacting Die

One kind of quenched Cr12 steel dies for impacting stainless steel wire rope （SSWR） was treated by low temperature liquid sulfurization catalyzed with rare earths, in order to extend their service life for assuring the continuity of production line, and simultaneously improve the surface quality of SSWR obtained. After immerged into the melting sulphur containing 4 % （mass fraction） of LaF3 and 1% of CeCl3 at 463 K for 4 h, the sulfurized dies were very smooth and black, with little distortion and hardness loss. They exhibited a certain extent of corrosion-resistance in air due to the coexisting rare earths in the sulfurized layer. Optical observations showed that the sulfurized layer was uniform and had scale-like structure. The trail of machined SSWR indicated that the production capacity of sulfurized dies had been doubled and the replacing period on line was postponed. SEM morphology also proved that the wear extent of cavities on sulfurized dies decreased greatly and the surface quality of SSWR obtained was improved markedly.

Aeroelastic Properties and Nonlinear Vibration Control of a Simply-Supported Lattice Sandwich Beam Embedded with Nitinol-Steel Wire Ropes

As a novel vibration absorber,Nitinol-steel wire rope(NiTi-ST)has rarely been studied on vibration suppression for lattice sandwich beams in supersonic airflow.In this paper,NiTi-ST with nonlinear stiffness and hysteretic damping is embedded in a lattice sandwich beam to control the beam's vibration.The nonlinear restoring and hysteretic damping force of NiTi-ST are treated as polynomials.The dynamic equation is established based on Hamilton's principle.The amplitude responses of the beam with different NiTi-ST configurations are calculated.The vibration-suppression effects and energy dissipation of lattice sandwich beam with different NiTi-ST configurations under different air velocities are also compared.The frequency-domain and time-domain methods are used to analyze the structural aeroelastic properties.Simulation results show that the use of NiTi-ST can significantly suppress excessive vibration of a lattice sandwich beam in supersonic airflow.

市政砖混箱涵盖板加固设计

通过对某市政工程砖混箱涵盖板的检测,分析了盖板出现病害的原因,提出了三种盖板的加固方案,并作了比较分析,最终选择了钢丝绳网片一聚合物砂浆加固法,介绍了加固设计措施及施工注意事项,以保证工程质量。

ELASTIC DEFORMATION ANALYSIS OF MULTILA YERED STRANDS

This paper describes a general model for the mechanical behavior studying of general wire rope strand. An exact solution of the deformation characteristics was given when the strands is under tensile and torsional loads. The theoretical results are useful in evaluating the extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is establised for the nonrotating ropes.

综采工作面末采撤架过程常见问题及对策应用

对综采工作面末采回撤支架过程中出现的顶板管理不到位、钢丝绳铺设不达标、金属网搭接联接质量不合格、撤架通道支护强度不够、回柱绞车拖拉支架起吊器具不完好等造成顶板冒落伤人、机械伤人一些常见问题进行了分析研究,提出了加强末采回撤支架现场管控,采取了风险评估、隐患治理、重点监督等措施,确保了末采回撤设备期间安全回撤、安全搬家,有效地缩短了回撤设备的工期,提高了搬家倒面的工效,杜绝了各类安全事故的发生,保证了工作面的衔接接替。

沃溪坑口深井开采支护工艺优化与实践

在高地压和开采扰动下,沃溪坑口深部采场支护工艺存在安全隐患。为保障矿区深部开采安全,通过分析现有支护工艺存在的问题,联系矿山深部生产实际情况,提出了钢丝绳锚杆和整体锚网2种支护方案,并分别进行井下试验。结果表明:钢丝绳锚杆支护主要适用于围岩稳固区域,整体锚网支护虽成本较高,但支护效果优异,可满足井下破碎、复杂区域的支护要求,在配合不同锚杆使用时可满足不同的支护条件。

Vibration Control on Roadheader with Horizontal Cutting Head of Electric-Control-Box

Analysis and measurements of the vibration on AM50 horizontal axis roadheader of electric-control-box was carried out, and the vibration characteristics were obtained. Based on the results, a new type of wire rope isolator was designed, whose characteristics were examined by experiments. The tests show that the wire rope isolator achieves satisfied results and can meet the requirements for the vibration control of the roadheader of electric-control-box.

注浆锚杆和柔性防护技术在国家高山滑雪中心项目中的应用

在高陡山区边坡防护工程中,存在着混凝土运输困难、 成本较高等问题.为了既满足边坡防护要求,又能降低施工成本,结合冬奥会国家高山滑雪中心中的高海拔边坡工程,本文提出了一种"注浆锚杆+柔性防护"的边坡防护施工方法.该方法具有自身高柔性、 易伸展性等优势,并兼具了安全防护、 生态建设、 环境保护与经济成本等综合价值.现场实践证明,该方法在高陡山区边坡防护中发挥了重要作用,且能够很好地推广到其他高陡山区边坡防治工程中.