基于OWAS方法的选煤厂工人肌肉骨骼损伤分析

探讨选煤厂拣矸作业中危险姿势对工人肌肉骨骼损伤的影响。通过问卷调查和工作姿势分析系统（OWAS）对工人不良作业姿势重复出现的比例以及身体损伤状况进行评估与分析。结果显示工人背部和颈部出现不良作业姿势的比例、危害和损伤程度较高。这与疲劳自觉症状调查和OWAS系统分析所得出的结果基本一致。采取恰当的轮岗方式,增加座椅以及防护装备可有效降低工人肌肉骨骼的损伤程度,同时会更好的提高工作表现并减少工伤事故的发生。     

基于OWAS和RULA法对电商物流自提点手工作业的风险分析

目的分析电商物流自提点内的人工作业风险,改善工人工作条件。方法应用工作姿势分析(Ovako Working Posture Analysis System,OWAS)和快速上肢评估(Rapid Upper Limb Assessment,RLILA)法对自提点内的分拣和上架作业做动作分析,识别不自然姿势并评估其风险等级。结果分拣作业和上架作业中均存在不自然姿势动作,尤其在上架作业中向手推车抓取包裹和给货架最高层或最底层上架包裹的动作均属于非常有害动作且需立马改进。采取有针对性的改善方案,人工作业风险都能降低。结论 OWAS和RULA法都能在自提点人工作业的研究与改善中得到有效运用,自提点人工作业风险亟需关注。     

工作姿势分析法在汽车零部件工位器具改善中的应用

目的为减少因工位器具设计不当对作业人员带来的工伤。方法本文从人因工程的视角出发,以滤清器总成器具为例,运用工作姿势分析系统(OWAS,Ovako Working posture Analysis System)对汽车厂工位器具进行改善研究。结果研究表明应用工作姿势分析系统(OWAS)改善后的工位器具可以在满足零部件配送要求的前提下,最大程度减少作业人员在这一作业过程中的不合理姿势,能够有效保护作业人员。结论工作姿势分析系统(OWAS)用于工位器具的改善具有良好的效果,且操作简单,具有很高的应用价值和推广意义。     

基于OWAS的人工破拆作业肌肉疲劳骨骼风险分析

目的 探究不良工作姿势对人工破拆作业人员肌肉骨骼损伤(MSDs,Musculoskeletal Disorders)的影响.方法 本文采用工作姿势分析系统(OWAS,Ovako Working Posture Analysis System)对作业人员的不良姿势出现的百分比和负重情况进行分析与评估.结果 数据显示作业人...     

浅谈电磁法铁屑吸屑收集装置研制及应用

电机机座在车削加工后留下的加工毛刺和尖锐棱角需打磨处理，由于打磨部位的不规则性，会导致打磨过程中铁屑的不规则飞溅，严重影响作业人员安全和作业环境卫生。在打磨作业中设计专用的电磁吸屑收集装置，通过电磁吸盘吸附有效收集打磨过程中飞溅的铁屑，达到改善作业环境的目的。     

肌肉骨骼疾患风险评估方法趋势研究

目的肌肉骨骼疾患是与工作姿势有关的主要职业病,不仅影响工人的健康,而且对经济造成巨大的损失。而不良的工作姿势是引发肌肉骨骼疾患的主要原因。因此评估工作姿势所造成的肌肉骨骼疾患并采取科学的纠正措施逐渐成为相应领域研究的热点问题。基于现有对肌肉骨骼疾患风险评估方法的研究现状和未来趋势进行分析与展望。方法通过对肌肉骨骼疾患、人因风险评估、人体姿态识别等核心概念的相关文献进行梳理和归纳,论述了肌肉骨骼疾患风险评估的主要方法,并重点分析了图像识别技术在肌肉骨骼疾患风险评估中的应用,结合人体骨架与神经网络算法模型对作业姿势进行识别,探讨了人工智能环境下,基于图像识别的评估方法中待解决的难点问题,对未来可能发展趋势进行预测。结论将肌肉骨骼风险评估方法总结为三大类,并分析其在现场评估应用过程中的优缺点;结合图像识别技术的发展,对肌肉骨骼风险评估提出了展望,即智能化自动化评估、多评估方法融合、多通道特征识别。     

特定作业环境下作业姿势的研究

针对某厂实际生产过程中的铆接工序,研究了作业环境对作业姿势的限制,提出了考虑人因的作业规划,设计了3种人体作业姿势方案.利用人因工程学原则,分别对每种姿势进行了可行性分析;利用人因软件对各方案进行了视觉分析、手的操作范围分析和人体负荷计算.在对各方案综合分析评价的基础上,结合实际生产过程中的设备情况,确定了该力工环境下最优的作业姿势.     

岔区轨件打磨对高速列车动力特性影响分析

针对福州工务段在杭深客运专线部分岔区采用的轨件打磨方案。在实测岔区轨件打磨前、后关键断面廓形的基础上,基于车辆-道岔动态相互作用,建立了车辆-道岔仿真模型,以列车250 km/h速度直逆向过岔为例,对打磨前、后两种工况的动力响应特征进行了深入对比分析。结果表明:轨件打磨作业后,列车第一轮对右侧脱轨系数幅值降低27.7%、横向轮轨力幅值降低27.4%,车体横向振动加速度和横移量幅值分别降低了56.8%和47.7%,列车过岔安全性及动力特性得到了明显改善;工务段晃车仪、添乘仪以及动检车的检测结果显示,岔区轨件打磨作业后,线路设备质量得到了显著提升,列车过岔时的车体横向加速度明显降低;根据岔区轨件打磨经验表明:钢轨打磨是改善岔区轮轨接触关系、提升动车组运行品质的有效手段;理论研究成果验证了福州工务段为解决管内岔区"晃车"问题所采用的轨件打磨方案的合理性,为高速铁路岔区轨件廓形优化打磨提供了理论支持。     

活性炭逾渗作用对阻燃乙烯-醋酸乙烯酯橡胶硫化、燃烧及力学性能的影响

研究了竹基活性炭(AC)对膨胀阻燃乙烯-醋酸乙烯酯橡胶(EVM)硫化、燃烧及力学性能的影响。硫化性能研究表明,逾渗作用导致AC在阻燃EVM中形成了网络结构,随AC添加量增大,阻燃EVM最大扭矩及黏度随之增大。流变及溶胀测试发现,AC逾渗作用明显提高了阻燃EVM的剪切黏度及交联度,利于改善EVM阻燃及力学性能。微观形貌分析证明了AC网络的形成。燃烧及力学性能研究证实,AC与膨胀阻燃剂(IFR)之间存在协效作用,AC的逾渗作用提高了EVM的阻燃性能。IFR与AC质量比为37∶3时的阻燃性能最佳,添加量为40%(质量分数,下同)及25%的氧指数分别达到33.6%和28.7%;同时,热释放也显著降低。阻燃EVM拉伸强度随AC添加量增加而提高,断裂伸长率有所降低。AC在平衡膨胀阻燃EVM硫化、阻燃及力学性能方面展现出优势,有利于改善阻燃材料的综合性能。     

家具封边作业的人体仿真测量与优化

目的对家具封边岗位的疲劳度进行测试,以人体工程学原理作为参考依据,对单边直线封边岗位工人的作业疲劳度进行深度剖析和优化。方法使用动素分析对封边作业的每一个连续动作进行分解,记录无效动作。再应用人体仿真软件3DSPSS构建虚拟的工厂环境,输入采集到的各种的人体尺寸和典型的作业姿势,并给虚拟的人指派任务,从而输出人体各种姿势下各部位的身体疲劳数据。结果工作岗位上人与人之间作业的不协调会增加无效动素,也增加了身体疲劳度;不断重复的弯腰动作会增加腰椎盘间的压力从而易造成腰椎间盘损伤;正常的直立或者前俯动作的腰椎间盘压力比弯腰、下蹲等作业姿势的压力较小;腿部的弯曲可以有效增大腿部和脚步的承受能力以及减少腰椎间盘压力。结论除了对工人的动作进行优化,调整工序和优化工人的某些不良的动作习惯是非常有效减缓疲劳的措施。     

The effect of solution heat-treatment time on the fatigue properties of an Al-Si-Mg casting alloy

Abstract Experiments have been carried out to investigate whether reducing the solution heat-treatment time of Al-7Si-0.6Mg castings from the currently recommended values adversely affects their fatigue properties. Fatigue endurance tests have been carried out in zero-tension ( R =0) and measurements made of the casting defects that initiated the fatigue cracks. The work has been limited to stresses that produce a fatigue life of ~10⁵ cycles and to two solution–treatment times (8 and 4 h). Two statistical techniques have been applied to the fatigue life data and no effect of solution heat-treatment time was detected at a confidence level of better than 95%. Similarly, no effect of cyclic test frequency could be detected for tests carried out at 1 and 60 Hz. The conclusions are confirmed by an analysis of the relation between fatigue life and the size of the casting defects that initiated fatigue failure. The scatter in fatigue lives is related to the scatter in the sizes of casting defects in the specimens. It is clear that there is a potential for considerable savings in heat-treatment costs for castings of the size and shape chosen for the study.     

Comparison of fatigue properties of nodular cast iron production and Y-block castings

Monotonic, cyclic, low and high cycle axial fatigue and region I and II fatigue crack growth behaviour were obtained and compared for a nodular iron Y-block casting and a heavy, off-highway, ground vehicle production casting. Despite the greater size and incidence of micro-discontinuities in the production iron, the two castings had essentially the same monotonic, cyclic and fatigue properties. SEM fractography indicated the same fatigue mechanisms for both casting types. Crack closure did not completely account for mean stress effects found in both cast irons.     

The influence of porosity on the fatigue life for sand and permanent mould cast aluminium

The automotive industry always strives to achieve light weight components to reduce fuel consumption and to meet environmental requirements. One way to obtain weight reduction is to replace steel components with components made of aluminium or other light weight materials. Aluminium has good corrosion properties and a high strength to weight ratio which makes it favourable in many applications. The increased use of aluminium castings in the automotive industry does also imply that the need for design data for aluminium increases. Especially for castings, the influence of casting defects are always an issue. For this reason fatigue properties for as-cast sand and permanent mould specimens with different contents of porosity have been studied.

Sand cast and permanent mould cast aluminium specimens of two different geometries were fatigue tested in cyclic bending at R = −1. Prior to fatigue test specimens were examined by X-ray and sorted into three quality groups depending on the porosity level. The aim of this work was to investigate the fatigue life for sand cast and permanent mould cast AlSi10Mg with different amounts of porosity. An additional aim was to predict the largest defect contained in a specified volume of a component, by using a statistical analysis of extreme values, and relate it to the fatigue life.

The results showed that fatigue strength for a smooth specimen geometry decreases by up to 15% with increased porosity. For specimens with a notched geometry, no influence of porosity on the fatigue strength was found. This is believed to be due to a much smaller volume subject to high stress than for specimens with low stress concentration.     

钛合金疲劳试样加工残余应力的表征及其对低周疲劳寿命的影响

目的 探究钛合金TC4低周疲劳试样加工过程中残余应力的变化及残余应力对低周疲劳寿命的影响.方法 采用X射线衍射法分别对车、磨、抛后的试样进行表面残余应力的表征,分析加工工艺对其的影响,利用液压伺服万能试验机进行低周疲劳试验,分析其表面残余应力对寿命的影响.结果 经过粗车、精车、磨削、纵抛,试样加工表面的残余应力不断减小...     

Mechanical and fatigue properties of pearlitic ductile iron castings characterized by long solidification times

In this paper, the fatigue behaviour of heavy section pearlitic ductile iron castings has been investigated. The inoculation treatment has been changed for each casting in order to investigate its influence on the mechanical and fatigue properties of the materials.Tensile tests and axial fatigue tests under nominal ratio R = 0.01 have been performed on specimens taken from the core of casting components characterized by long solidification times. Scanning Electron Microscopy has been used to investigate the fracture surface of the broken samples in order to identify crack initiation points and fracture mechanisms. Metallographic analyses have been carried out to measure nodule count and nodules dimensions and to identify matrices structures.It has been found that fatigue behaviour is strongly influenced by defects, such as microshrinkages or degenerated graphite particles near to specimens' surface. It has been also found that inoculation process influences the microstructure and the fatigue resistance of heavy section pearlitic ductile iron castings.     

Oxide bifilms in aluminium alloy castings – a review

Abstract

Aluminium alloy castings are most widely used in automobile industry because of their light weight, better castability and improved properties. The liquid aluminium surface easily oxidises during melting, transferring and pouring operation which may entrain oxide films into the casting. Research work has shown that the entrainment of this surface film and formation of bifilms in castings appear to be the source of most of the casting defects leading to a significant reduction in the mechanical properties of aluminium alloy castings. In this paper, the phenomenon of formation of oxide bifilms in aluminium alloy castings, effect of these bifilms on casting properties and their assessment techniques are discussed. For enhancing the quality of casting, research should focus towards development of process techniques for healing of bifilms in liquid metal during solidification.     

Fatigue performance of the aluminium-magnesium/magnesium aluminate in-situ composites synthesized through manganese dioxide and copper oxide reinforcement

Aluminium-2magnesium alloy castings find its application in engineering sectors where fatigue property is a key requirement. Few researches have been carried out in the past to improve its fatigue property by micro, nano reinforcements. However, the requirement of intended application has not yet attained and hence this current research study has been taken up to provide a solution. This research work focuses through a novel approach for synthesizing in-situ magnesium aluminate particles in aluminium-2magnesium alloy by the addition of manganese dioxide and copper oxide precursor addition (1 wt.%, 1.5 wt.% and 2 wt.%) during the casting process. Microstructure of fabricated composites were examined through field emission scanning electron microscopy to characterize the morphology and distribution of magnesium aluminate particles. The fabricated aluminium-2magnesium/magnesium aluminate in-situ composite specimens were subjected to low cycle fatigue testing at two different strain amplitudes of 0.3 % and 0.4 % and a frequency of 0.3 Hz. Among all composite specimens, specimens reinforced with 2 wt.% manganese dioxide and 2 wt.% copper oxide outperformed when tested in strain amplitudes of 0.3 % and 0.4 % respectively. Fractography studies were performed on failed composite specimens to study the modes of failure that resulted after fatigue testing.     

Hot tensile and fatigue behaviour of zinc–aluminum alloys produced by gravity and squeeze casting

The tensile and fatigue properties of zinc–aluminum alloys (ZA-8, ZA-12 and ZA-27) in squeeze and gravity cast forms have been investigated. Tensile tests were conducted at ambient and elevated temperatures up to 150 °C. At low temperatures, the ultimate tensile strength and yielding strength of the squeeze cast alloys have been found to be superior those of the gravity-cast alloys, as the temperature increased they decreased. In the same way, Brinell hardness of the squeeze cast alloys were obtained at higher values than gravity castings. The fatigue tests were performed at a constant speed of 400 rev/min and under a number of stress levels ranging from 100 to 150 MPa. The fatigue behaviour results of the ZA alloys were similar to obtained from the tensile testing. The squeeze cast alloys exhibited good fatigue resistance in proportion to the gravity castings. Metallography examinations showed that the microstructure of the castings differed according to the method of casting used. It was considered that the mechanical properties of the alloys were affected from these micro-structural changes.     

机械行业工人肌肉骨骼损伤的调查

选择机械行业８７９名工人作为观察组,另选年龄、性别、工龄相近的９４６名行政管理人员作为对照组,通过询问调查及体验,观察组人员肌肉骨骼损伤的检出率显著高于对照组（Ｐ０．０１）,且随着工龄延长而升高。体验的各种指标阳性率显著高于对照组（Ｐ０．０１）。患有肌肉骨骼损伤的观察组工人中有９０．３％的人认为长期固定的作业姿势是造成肌肉骨骼损伤的原因。提示：长时间固定的作业姿势是肌肉骨骼损伤的一个危险因素。