Dynamic design of a nonlinear energy sink with NiTiNOL-steel wire ropes based on nonlinear output frequency response functions

A novel vibration isolation device called the nonlinear energy sink(NES)with NiTiNOL-steel wire ropes(NiTi-ST)is applied to a whole-spacecraft system.The NiTi-ST is used to describe the damping of the NES,which is coupled with the modified Bouc-Wen model of hysteresis.The NES with NiTi-ST vibration reduction principle uses the irreversibility of targeted energy transfer(TET)to concentrate the energy locally on the nonlinear oscillator,and then dissipates it through damping in the NES with NiTi-ST.The generalized vibration transmissibility,obtained by the root mean square treatment of the harmonic response of the nonlinear output frequency response functions(NOFRFs),is first used as the evaluation index to analyze the whole-spacecraft system in the future.An optimization analysis of the impact of system responses is performed using different parameters of NES with NiTi-ST based on the transmissibility of NOFRFs.Finally,the effects of vibration suppression by varying the parameters of NiTi-ST are analyzed from the perspective of energy absorption.The results indicate that NES with NiTi-ST can reduce excessive vibration of the whole-spacecraft system,without changing its natural frequency.Moreover,the NES with NiTi-ST can be directly used in practical engineering applications.

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.

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.

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.

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 stud-ied 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 rota-tion and the axial force of the lining resulting from the torque of the wire rope was analyzed. Theoretical formulas re-lating 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 fric-tion 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 proves the validity of the theoretical model.

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.

Principles of X-Ray Non-Destructive Testing for Steel Wire Ropes in Conveyer Belt

The principles of X-ray Non-destructive testing (NDT) for steel wire ropes buried in conveyer belt is described in the paper. The mathematical model for calculating the effective cross section of wire ropes has been developed. The test data on steel wire rope samples of various types are presented,which have been compared with the National Standard. And this calculation model for the effective cross section is very important to the prediction system for transverse failure of conveyer belt.

A Methodology for Identifying Defects in Wire Rope Based on Permanent Magnet Excitation

A wire rope defects detection method based on permanent magnet excitation is proposed.A detection system,mainly composed of permanent magnet excitation,distance detection,multi-sensor magnetic flux leakage signal acquisition and data analysis device,is set up.According to the different characteristics of the multi-sensor magnetic flux leakage signal,the localized fault(LF)and loss of metallic cross-sectional area(LMA)signal is separated,and then the two defects can be detected.The experiments show that the method can effectively detect the two defects when they appear simultaneously on the wire rope.

Investigation into Failure in Mining Wire Ropes—Effect of Crystallinity

A range of blends of polypropylene-polyethylene are investigated for their mechanical performances. These speciality polymer blends are chemically designed to suit high modulus/high load bearing mining wire rope applications subjected to continued bending and tensile stresses and fluctuating loads and are exposed to extreme weather conditions. In this paper we study the influence of different parameters on the performance of the wire ropes: chemistry of polymer, crystallinity of the polymer matrix, and the morphology. The FTIR and SEM studies revealed that the high fraction of polypropylene in polypropylene-polyethylene matrix lead to early failure as a result of incompatibility and phase segregation and high spherulite sizes of the polymer matrix.

卫星运输T型钢丝绳隔振器刚度及阻尼研究

钢丝绳隔振器可以缓解卫星运输过程中振动产生的危害,但其缺少试验基础研究,无法提供仿真输入,难以准确实现卫星损伤仿真。针对此问题,对T型钢丝绳隔振器刚度及阻尼特性进行了理论分析和试验研究。首先,对钢丝绳隔振器系统的力学特性进行了理论分析,建立了理想的迟滞回环曲线;其次,建立了钢丝绳隔振器静刚度和动刚度力学测试系统;最后,通过准静态加载以构建静刚度条件下压缩、横滚、剪切状态力和位移的关系。在预承载力为5 kN、振幅为1 mm条件下,分别测试了激振频率5~8 Hz条件下的动刚度性能。结果表明:准静态加载条件下,钢丝绳隔振器的力和位移关系较为稳定;动刚度条件下,在5~8 Hz频率之间,动刚度变化较为稳定;等效阻尼随着激振频率的增加而增加。

球型钢丝绳隔振器非对称迟滞模型

针对球型钢丝绳隔振器的非线性刚度和阻尼特性导致迟滞模型表征困难的问题,提出了非线性弹性因子和修正因子改进的归一化Bouc-Wen迟滞模型,结合Simulink仿真完善改进的迟滞模型,采用最小二乘法和遗传算法相结合的方法对改进模型进行参数识别。通过数值仿真绘制GGQ25-62L型球型钢丝绳隔振器在不同工况的迟滞环,并和实验数据进行对比。结果表明,参数识别方法准确可靠,实验数据和理论计算曲线具有较强的一致性,该模型能够有效地描述隔振器的动态特性。

基于磁场模型的矿用钢丝绳检测信号特性试验研究

电磁检测是矿用钢丝绳缺陷可靠的检测手段之一。基于电磁法的矿用钢丝绳缺陷检测,目前存在缺陷与信号特性表征规律不明确的问题,定量识别时存在无关信号特性,影响识别准确性。采用三维磁偶极子理论计算、Maxwell模拟仿真与试验相互验证的方法,总结漏磁信号特性与缺陷变化之间的表征关系。首先建立磁场环境下的钢丝绳三维磁偶极子理论模型,应用模型对标准缺陷处进行磁场理论计算并进行Maxwell模拟仿真;分别提取理论值与仿真值的峰/谷绝对值、波宽、峰谷差值、峰谷值宽度四项信号特性,进行缺陷与信号的表征分析;最后设计缺陷进行试验验证,得到试验数值的斯皮尔曼相关系数。试验结果表明:缺陷的宽度、深度与峰/谷绝对值、波宽、峰谷差值3个信号特征值呈正相关,与峰谷值宽度无明显相关性;缺陷长度与峰/谷绝对值呈先上升后下降的趋势,与波宽、峰谷差值、峰谷值宽度呈正相关。并且发现宽度缺陷信号幅值最强,长度缺陷信号幅值最弱,深度信号幅值居中,峰谷差值和峰谷绝对值与缺陷相关性最高。该研究具有一定的工程指导价值。

新型双质量飞轮弹性元件动态特性建模研究

为解决现有双质量飞轮存在的刚度跃变、离心力影响扭振特性和阻尼特性无法满足多工况需求等问题,提出了一种采用钢丝绳环作为弹性元件的新型双质量飞轮;对飞轮的重要弹性元件钢丝绳环开展了试验研究,获得不同频率和振幅下绳环的动态迟滞特性试验曲线;建立了钢丝绳环的多项式迟滞模型并基于试验数据进行模型参数识别,获得钢丝绳环动态迟滞模型通用公式并通过试验验证模型有效性。结果表明:所建立的模型能够很好的描述钢丝绳环非线性迟滞特性,方便计算弹性元件的动刚度和阻尼特性,为厘清钢丝绳环非线性迟滞特性规律提供了新的分析方法,为进一步研究新型钢丝绳环双质量飞轮的扭振特性奠定了基础。

一种基于单轴向充磁永磁环励磁的钢丝绳无损检测方法

为提高钢丝绳缺陷检测能力,简化励磁结构,提出一种基于单个轴向充磁永磁环励磁的钢丝绳无损检测方法。通过分析钢丝绳缺陷在单个轴向充磁永磁环励磁方法下产生的漏磁场,得到该方法能通过漏磁场感知缺陷运动方向的结论。在此基础上,利用COMSOL软件对该励磁方式进行有限元建模,通过仿真计算缺陷处漏磁的分布,验证了结论的正确性,分析了影响漏磁场的因素,并结合霍尔元件性能参数,给出了传感器的最佳布置位置。最后,通过设计信号调理电路,结合3D打印实现传感器结构,完成了实验平台搭建。仿真结果表明,对于同一缺陷,基于该励磁方式产生的最大漏磁场明显大于传统方式。实验结果表明,对于10 mm粗的钢丝绳,当霍尔元件布置的提离值为3 mm和8 mm时,均能够通过缺陷处漏磁信号感知钢丝绳运动方向。

一起电梯安装事故原因分析与预防措施

本文以一起电梯安装过程中吊装钢丝绳断裂引发事故为案例,通过现场勘察、吊装钢丝绳受力分析、断口失效分析以及电梯安装工艺分析等,查明了导致事故的直接原因是电梯安装作业人员违反电梯制造单位的安装工艺,在轿厢内和轿顶采用手拉葫芦进行提升作业时的受力引起悬挂轿厢的钢丝绳发生过载性断裂。基于此,从电梯安装和使用管理方面提出相应预防对策。

面向输电线路铁塔组立施工承力系统安全检测的力传感器设计

现阶段,输电线路铁塔组立工艺在承力系统吊装施工过程中,安全措施主要依赖施工人员的施工经验、人工监测以及视频监控等方式,严重缺乏直观可视的保障手段;在针对施工过程受力检测方案中,缺少适配范围广,安装简便,与现有工艺结合性强的设备。为解决上述问题,在铁塔组立吊装过程中,选择抱杆、钢丝绳和卸扣主要承力部件作为检测对象,检测包括抱杆姿态、钢丝绳张力和姿态、卸扣所受拉力和姿态等数据;与传统串联型力传感器相比,该文在不改变钢丝绳外在结构的情况下,依靠绳索端固定的卸扣实现准确的力感知;针对D型卸扣设计可包覆、可拆卸专用的触感单元支架,然后通过受力分析与仿真,得到施力下的力敏感区域,并将应变片贴置于力敏感区域。最后通过仿真与实验,证明该文设计的力传感器能够实现输电线路铁塔组立施工承力检测。

基于磁敏调向的钢丝绳漏磁检测绳股信号抑制方法

分析钢丝绳漏磁检测方法中绳股信号的形成原因,提出了基于磁敏调向的钢丝绳漏磁检测绳股信号抑制方法,且搭建了消除绳股信号特征的磁敏调向试验装置,通过试验对比分析了不同磁敏方向的绳股信号特征,最终确定了抑制绳股信号的最佳磁敏调向。结果表明,该方法极大地抑制了绳股噪声信号,提高了钢丝绳损伤信号信噪比。

高速重载大行程运动升降平台设计及实现

[目的]为满足恶劣海况下舰船的大幅运动模拟需求,开展高速、重载、大行程运动升降平台的研发工作。[方法]针对运动平台的重载、高速及变参数特点,基于Adams仿真平台对采用重量平衡、4钢缆同步伺服驱动的高速升降平台进行动力学仿真分析,提出一种基于模糊PID控制的多电机同步驱动控制系统,并基于控制特性相似原理研制了1∶14的缩比高速升降平台。[结果]通过平台的响应特性试验,验证了控制系统具有同步性强、控制精度高的优点,运动平台可以良好地模拟恶劣海况下舰船的升沉运动。[结论]所设计的重量平衡、4钢缆同步伺服驱动的高速升降平台可填补舰船大幅升沉运动模拟领域的空白,并对类似运动模拟器的研发具有参考意义。

强噪声与非周期脉冲激励下单稳系统的随机共振及应用

随机共振是噪声背景下非线性系统对微弱特征信号的最优响应,能够对微弱特征信号进行增强。偏置单稳态系统相较于传统的双稳态系统,对非周期脉冲激励具有良好的共振特性。然而,非线性系统的参数影响系统的最优输出,对不同的非周期脉冲激励,系统难以自适应调节。针对上述问题,该研究强噪声与非周期脉冲激励下偏置单稳态自适应随机共振。首先,基于优化算法实现不同非周期脉冲激励下的自适应随机共振。然后,以强噪声背景下钢丝绳漏磁检测信号为应用对象,经偏置单稳态系统自适应随机共振输出后,以峰峰值作为损伤特征演化评价指标,评估不同微弱损伤特征间的差异。同时,应用偏置单稳态自适应随机共振法和自适应移位平均法对强噪声背景下钢丝绳漏磁信号进行对比分析,以峰峰值增益和信噪比增益为指标,结果表明偏置单稳态自适应随机共振法效果优于自适应移位平均法。最后,讨论了噪声强度对单稳态自适应随机共振的影响,发现偏置单稳态自适应随机共振具有较强的抗噪能力。

钢丝绳远程监测系统的设计与实现

针对现有的工业钢丝绳损伤监测系统的局限性,设计并实现了一款基于LabVIEW、Flask和Vue.js的钢丝绳远程智慧监测系统。该系统兼具传感器数据采集、信号处理、可视化展示、远程检测、数据分析等多项功能,以满足钢丝绳检测的全面需求。系统使用LabVIEW进行传感器数据采集和实时处理,Flask用于构建后端服务器以及数据处理,Vue.js负责前端的可视化展示和用户界面,使工程师和操作人员能够远程监测钢丝绳状态并及时作出反应。试验结果表明,采用的综合性系统设计不仅提升了工业生产中钢丝绳的质量控制水平,也大幅提高了远程监测能力,为工程人员提供了全方位的实时监测和管理工具。