Influence of equipment excitation on flexible carbody vibration of EMU

To study the vibration transmission character istics of a flexible carbody and its suspended equipment, a vertical mathematical model of highspeed electric multiple unit was established with equipment excitation considered. And the dynamic unbalance and impact turbulence excita tion from equipment were taken into account in a single stage and twostage vibration isolation system, respectively. Results show that the excitation transferred to carbody increases with suspension stiffness but decreases with the equipment mass increasing; the vibration transmission can be reduced by increasing the equipment mass or reduce the suspension stiffness. To avoid vibration resonance, the dynamic unbalance frequency of equipment should be out of the possible range of the carbody flexible modes, and a small stiffness should be applied to reduce the impact tur bulence. A small stiffness, however, would result in a large movement of the equipment which is limited by the static deflection requirement, while a great stiffness will transfer high frequency vibration. Therefore, a preferred stiffness should make the suspension frequency of equipment a bit greater than the first bending mode of carbody. Additionally, a 3D rigidflexible coupled dynamics model was built to verify the mathematical analysis, and they show good agreements. Results show that a twostage isolation could reduce the excitation transmission and make the vibration of carbody and equipment acceptable.

Cost Estimation of Voltage Dips in Small Industries Based on Equipment Sensitivity Analysis

Voltage dip is one of the detrimental power quality problems that can lead to huge financial losses in industries. Its economic impact is not only associated with the quality of the supply but also with sensitivity of electronic controls and equipment of the industry which are susceptible to voltage dips. Mitigating solutions are available but the choice depends on the careful assessment of the economic impact of voltage dips and economic gains of solutions. This paper presents an approach for estimating the economic cost of voltage dips based on sensitivity analysis. The voltage-tolerance curves of the sensitive equipment are obtained from experimental tests under different conditions. From the behavior and interaction of process equipment, different failure modes and economic sensitivity density are determined for different types of voltage dips. Voltage events monitored in the MV-network for several years are assessed to determine the frequency and severity of voltage dips at the customer terminal. The economic values of equipment and processes are assessed to get insight into alternative solutions with more rewarding measures. Then, cost-benefit analysis is performed to compare the economic gains of solutions protecting equipment or processes showing more rewarding economic values.

Simulation on the impact pneumatic cylinder with a reservoir

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.

Effect of Pneumatic Boxing Gloves on Impact Kinematics and Their Relationship to Impact Forces

This study was aimed at improved understanding of the mechanisms of previously reported protective effects of a pneumatic boxing glove. A Motion Capture System was used to obtain velocity data from four different boxing gloves dropped on to a force plate from nine heights ranging from 1 to 5 metres. Two gloves were of the conventional type but differed in mass. The other two were prototype pneumatic gloves. One of these (SBLI) had a sealed bladder while the other (ARLI) incorporated a port allowing air exchange with the external environment. The pneumatic gloves decelerated more slowly than the conventional gloves following impact and compressed through a greater absolute distance. Consequently, they took longer to reach zero velocity. As drop height increased, these trends became more pronounced for the ARLI glove than the SBLI glove. Increase in velocity during rebound was also slower for the pneumatic gloves. The ARLI glove had a lower coefficient of restitution than any of the other gloves at low to moderate drop heights but not at high drop heights. The SBLI glove had a higher coefficient of restitution than the other gloves at all drop heights from 2 metres upwards. This indicated that, overall, the ARLI glove was the most effective, and the SBLI glove the least effective, in dissipating the kinetic energy of impact through conversion to other energy forms. For all gloves at all drop heights, peak positive acceleration at the beginning of rebound was of lower absolute magnitude than peak negative acceleration at the end of compression. The influence of drop height on an index characterising this relationship differed between the conventional and pneumatic gloves, possibly reflecting structural changes to gloves as impact energy increased. The conventional and pneumatic gloves differed regarding temporal alignment between key kinematic and kinetic events, and there were some differences between the two pneumatic gloves in this respect. Nevertheless, peak glove deceleration correlated highly with peak impact force, not only for each glove individually but also when data for all gloves were combined. The findings confirmed the potential practical utility of the ARLI glove and identified air cushion thickness, glove compressibility and capacity for air release and subsequent reuptake as critical aspects of its design.

Pneumatic Boxing Glove Reduces Upward Drift in Peak Force and Loading Rate over a Long Series of Impacts

A conventional boxing glove and a prototype pneumatic glove were each fitted to a mechanical fist and dropped 253 times from a height of 3 metres on to a force plate covered by an ethylene vinyl acetate (EVA) mat. Impact dynamics were measured and modelled. From the outset, peak impact force and peak rate of force development (loading rate) were lower for the pneumatic glove. For both gloves, these variables displayed upward drift during the drop series, but the drift was smaller for the pneumatic glove. Consequently, the magnitude of the protective effect provided by the pneumatic glove increased with the number of impacts. For the conventional glove, change in peak force showed a close inverse relationship to force plate contact time (R2?>?0.96) and the time from first contact of the glove with the force plate to attainment of peak force (R2?=?0.85). These relationships were much weaker for the pneumatic glove (R2?=?0.09 and 0.59 respectively), suggesting the possibility of a more complex impact damping mechanism. Following the 253 drops of the pneumatic glove, the EVA mat covering the force plate was replaced, and another 10 drops then performed. Peak force readings were immediately reduced to an extent suggesting that 26%?-?34% of the increase that had occurred over the 253 drops was attributable to impact-induced change in mat properties. This has implications for future experimental designs. Overall, the findings provided further evidence of the potential of pneumatic gloves to enable safer boxing.

某型舰船设备大负载复合材料支承冲击强度试验方法研究

舰船设备支承件的冲击特性研究受到各国海军的重视,然而超过常规冲击机能力范围的冲击载荷等要求,使得开展大负载支承件冲击强度试验成为难题。以某型动力设备的大负载复合材料支承为对象,采用水下非接触爆炸的方式,以标准浮动冲击平台冲击环境为输入参数设计其冲击强度试验方法:在低速冲击条件下,通过保证冲击载荷、降低试验负载质量、提高系统安装频率的途径来设计试验装置,依据冲击谱和冲击载荷计算对应的试验冲击因子来设计强度试验工况,并得出了实际试验与设计参数之间因试验系统多个结合面对冲击载荷传递影响的折减系数。试验结果表明,复合材料支承承受的冲击载荷与要求值之间的偏差在5%以内,为今后开展类似试验提供了参考。

山区涉河桥梁墩柱冲磨破坏机理及防护措施

近年来自然灾害频发,山区桥梁水毁事故时有发生,针对山区涉河桥梁墩柱冲磨性能的提升正逐渐成为研究热点。该文综述山区涉河桥梁墩柱冲磨破坏机理及防护措施研究现状,并针对一种新型防护措施的防护效果进行数值模拟分析,以期为应对桥梁结构冲磨破坏问题提供参考。

考虑环境影响的城轨多设备维修策略研究

针对城轨设备欠维修和过维修等问题,提出考虑环境影响的城轨多设备维修策略。考虑到外部环境因素对城轨设备运行状态的影响,构建一种考虑环境影响的可靠性评估模型;以单个城轨设备为对象,以设备维修成本最小化为目标构建城轨单设备维修模型;以多个同类型城轨设备为研究对象,引入机会维修以考虑各设备之间的维修时间相关性,以设备平均维修成本最小化为目标构建城轨多设备维修模型;以某地铁换乘车站4台自动检票机实际故障数据为例,研究结果表明,多设备维修策略能有效降低设备维修成本,在730d内可以为每台自动检票机在单设备维修策略的基础上进一步节约维修成本约3921元,维修成本减少约10.74%。考虑环境影响的城轨多设备维修策略能够使设备维修维护更加合理,为城轨设备维修决策提供理论依据。

改良型序批式一体化污水处理设备效能研究

构建基于A^(2)O与SBR串联工艺的改良型序批式一体化设备(MSBR),以实际生活污水为处理对象,考察了该设备在水量波动、间歇断流和水温变化条件下的运行特征与处理效能,并对其运行经济性进行对比分析。结果表明,在间歇和连续进水两种工况下,COD、NH_(4)^(+)-N和TN去除率均达到90%以上,均满足《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准,TP满足一级B标准。当水力停留时间为10.4 h时,COD、NH_(4)^(+)-N、TP和TN去除率达到82.4%、88.3%、97.1%和68.3%,此时COD和NH_(4)^(+)-N满足GB 18918—2002一级A标准。夏季系统出水COD、NH_(4)^(+)-N、TP和TN去除率分别为92.8%、95.7%、93.0%、77.8%,冬季系统出水COD、NH_(4)^(+)-N、TP和TN去除率分别为89.8%、89.3%、91.6%、72.3%,COD、NH_(4)^(+)-N和TN均满足GB 18918—2002一级A标准,TP满足一级B标准。与现有工艺对比分析表明,MSBR的COD和NH_(4)^(+)-N去除负荷明显较高,总运行维护费用为0.67元/t,具有明显的经济优势,可为生活污水处理和生态环境治理提供新技术与新思路。

面向航空装备的物料缺件影响程度自动评价方法

在国资委对军工制造业低成本、低库存的要求下,生产物料缺件不齐套是影响复杂装备产线运行及订单准时交付的非常规问题.针对采购人员无差别跟踪缺件物料进展的现象,本文提出一种面向航空装备的物料缺件影响程度自动评价方法,通过对物料缺件影响程度进行量化,为业务人员提供采购优先级的支持,以实现缺件、欠料问题的敏捷反应,推动物料管控水平转型升级。

供配电设备制造企业设备安全隐患排查治理的研究及应用

设备是制造企业生产的核心,若存在安全隐患,可能导致事故、人员伤亡或财产损失。因此,周期性的设备安全隐患排查至关重要,可防患于未然,保护员工安全和生产顺畅。为保证员工安全、提高生产效率和质量、降低企业风险和成本。本文以叉车设备为例,利用FMEA方法,结合熵权法确定隐患排查的频次,建立针对企业叉车设备的安全隐患排查标准知识库,从而为企业设备提供了一套有效的安全隐患排查和治理标准。此外,本研究还明确了隐患排查的责任分配和治理要求,确保了设备安全管理措施的实施效率和有效性。

锂离子电池撞击测试方法及参数研究

高能量密度的锂离子电池在使用和运输中,碰撞难以避免,品质控制尤为重要。电池受物理撞击后可能有内短路,为检验成品电池综合品质,需在出厂前进行可靠性检测。介绍可靠性检测中,八角转鼓设备的方法及合理的参数设置。借助运动仿真模拟电池在转鼓中的撞击参数,收集测试后电池的数据,以判断品质是否达到六西格玛(6σ)的工程能力。

水下爆炸冲击试验海上测控系统设计与实现

为解决装备水下爆炸冲击毁伤海上试验数据采集与安全风险控制难题,依托试验保障平台构建水下爆炸冲击试验海上测控系统,对应变、加速度、冲击波压力和视频图像等数据采集分系统开展模块化设计,制定相关试验流程、试验安全防护和风险控制方案,码头联调后开展海上实装水下爆炸冲击试验测试,试验后对测控系统可靠性、试验保障平台各设备安全性进行查验,查验结果表明,采取的抗冲击防护措施可行,该测控系统稳定可靠、安全可控,能有效实现单次毁伤试验中多方位多要素数据采集与存储,同时指出了本次测试试验存在的不足以及后续海上实装水下爆炸冲击试验需重点关注的问题,可为后续装备水下爆炸冲击毁伤试验的开展提供有力的经验参考及保障条件支撑。

舰船空调设备抗冲击性能仿真技术

为验证某舰船空调设备的抗冲击性能,根据摆锤式中量级冲击试验台装置的结构和基本原理,应用Ansys软件创建实验台的有限元模型。基于显式动力学和接触碰撞分析基本理论,采用有限元软件LS-DYNA对模型的冲击载荷产生过程进行仿真分析,并与试验测试数据进行对比,验证模型的有效性。采用该冲击试验台有限元模型开展舰船空调换热器设备的抗冲击性能分析,获得设备在中量级冲击载荷作用下的完整响应过程,结果表明舰船空调换热器的整体抗冲击性能有待提高。

薄壁仿生护具微冲击响应智能预测方法仿真

通过预测可以更好地了解护具的性能和行为特征,优化护具的设计参数和结构,为穿戴者的安全提供更加可靠的保障。在此背景下,进行不同载荷下薄壁仿生护具结构微冲击响应预测研究。研究选择3种不同类型的薄壁仿生护具作为测试样品,以实验测试的方式,通过落锤冲击试验和微冲击后的压缩破坏试验测试得出不同载荷下薄壁仿生护具结构微冲击响应数据,包括应变值和剩余强度值。以多元回归方程为基础,以不同载荷条件参数为自变量,以应变值和剩余强度值为因变量,实现薄壁仿生护具结构微冲击响应预测。测试结果表明:所设计方法的预测误差较小,证明其预测准确性更高。

基于失效模式与影响分析的化工设备安全评估方法研究

化工作为我国工业的重要组成部分,是壮大国家综合实力、提高人民共同利益的重要保障,而化工设备安全工作则是企业进步的重要法宝。为确保化工产品质量,提高化工经济效益,让化工企业在竞争中获得长远发展,就必须加大对化工设备安全的重视程度,在此环境下基于失效模式与影响分析方法应运而生,它是一种常用的化工设备安全评估方法,过分析设备故障的失效模式、评估其对系统性能和安全的影响,并制定相应的预防和纠正措施,以提高设备的安全性和可靠性。对基于失效模式与影响分析的化工设备安全评估方法进行研究,提出提高化工设备安全的改善策略,以期提高化工企业的经济效益。

零地电压对数据中心IT设备运行的影响与优化对策应用研究

零地电压问题一直是数据中心运行课题讨论不可或缺的论题,有论点认为零地电压对数据中心IT设备运行影响很大,甚至会影响IT设备的安全运行,还有论点认为零地电压本身就是数据中心的一种谬论,本文结合设计规范及实际运行经验,分析设计规范对数据中心零地电压的定义,并阐述了零地电压产生的原因及对计算机设备正常运行的影响,提出采用智能配电列头柜、高频UPS、增加隔离变压器、调整接地方案、改变材质、增加高频谐波滤波器等多种解决方案,来降低IT配电系统中的零地电压,消除可能出现的安全隐患。

全自动冲击样制样设备设计及验证

针对传统冲击试样制备效率低下、质量不稳定的问题,提出一种全自动冲击试样制样设备的设计方案。该设备集成了加工中心、清理机、打标机、智能化试样翻转存储机构等,实现制样全过程的自动化。通过正交试验,优化了不同材料的加工参数。结果表明,该设备可加工出尺寸精度高、表面质量好的冲击试样,显著提升了制样效率。断裂韧性测试与扫描电子显微镜分析证实,所制备试样的力学性能和断裂行为与材料本征特性吻合。该设备可为材料断裂研究提供高质量的试验样品。

沥青净味剂对沥青混合料烟气减排效果室内评价方法

沥青净味剂(Bitumen Perfume,BPF)能有效降低沥青混合料在拌和过程中产生的有害气体的排放量,但目前尚缺乏成熟的减排效果室内评价方法。鉴于此,进行了以下研究:首先,基于室内沥青混合料拌和装置研制了一套沥青混合料在拌和过程中排放气体的采集设备,提出了以降解率为指标的BPF减排效果室内评价方法;其次,对四种热拌沥青混合料在不同BPF掺量下拌和产生的有害气体浓度及降解率进行了评价,并提出了以目标降解率为控制指标的最佳BPF掺量确定方法;最后,对净味SBS改性沥青及其混合料的性能进行了检验。室内试验结果表明,四种有害气体的降解效果均随BPF掺量增加而显著增强;在推荐掺量下,净味SBS改性沥青及其混合料的性能与原值差异不明显且均符合相关规范要求。

基于全寿命周期理论的电力电缆环境影响分析和成本计算

文章研究了一种电力设备的全寿命周期环境影响的分析方法,以电力电缆为例,对其进行了全寿命周期的环境影响分析和成本计算,得出了各阶段的主要排放物含量,及不同参数变化时各部分成本的变化趋势。算例分析表明,从电力电缆环境影响角度而言,其生产阶段的环境影响主要在于大量排放的废水,运行阶段的影响主要在于能耗及温室气体的排放,退役回收阶段的影响较小;从电力电缆成本分析角度来看,运行成本的比重随着负荷的增大而提高。