改性涂料安全帽降温性能及热舒适的优越性分析

为探究高温户外作业下改性涂料安全帽在我国不同地区的隔热降温效果差异，本文采用Fluent数值仿真技术结合我国4个不同地区(北京、广州、南京、西藏)的太阳辐射特性，对比研究了改性安全帽和普通安全帽的降温性能及热舒适性差异。结果表明：改性安全帽相比普通安全帽可使帽体表面温度降低10℃左右，同时帽内外部温差降低3～4℃，说明改性安全帽能够有效降低太阳辐射得热；对于4个不同地区，改性安全帽相比普通安全帽的帽内温度可降低5～7℃，并且当太阳辐射量大于1 200 W/m²时，改性安全帽的降温性能愈发显著。进一步研究发现，相比佩戴普通安全帽，佩戴改性安全帽可使人体TEQ指数降低7.6%～9.6%，说明佩戴改性安全帽能够扩大作业者可从事体力劳动的工作范围，可提高户外安全帽佩戴者的热舒适性。     

矿用降温安全帽降温性能实验研究

本文介绍了矿用降温安全帽的结构、工作原理及性能参数,并在矿井热环境模拟实验室对其进行了降温性能实验研究。结果表明,在模拟矿井热环境下,该矿用降温安全帽具有低于环境温度的冷源,在一定时间内可以对人体头部持续降温,能够为矿工的防暑降温工作提供较好的实施方案。     

安全帽标准的执行与产品管理

安全帽是对人头部受坠落物及其他特定因素引起的伤害起防护作用的防护装备,由帽壳、帽衬、下颏带和附件组成。当作业人员头部受到坠落物的冲击时,利用安全帽帽壳、帽衬在瞬间先将冲击力分解到头盖骨的整个面积上,利用安全帽各部位缓冲结     

有限元在安全帽设计中的应用

安全帽可以防止高空坠落物对人员头部造成伤害。在材料和工艺一定的前提下,安全帽的结构对发挥安全帽的作用尤为重要。本文首先对安全帽作用机理及使用情况进行分析,指出改善安全帽帽壳缓冲性能有利于更好地发挥安全帽的作用。然后简要介绍ANSYS的建模方案以及网格划分和自由度约束情况,通过对安全帽的ANSYS有限元分析,得出安全帽的变形和应变图,并通过分析安全帽从最低端到顶端的变形和应变情况,指出安全帽在撞击过程中的能力吸收规律,根据分析数据提出建立双层安全帽帽壳的改进方案,并再次通过有限元分析得出变形和应变图,验证了双层安全帽帽壳在缓冲方面更有效果,这种分析结果可以为安全帽帽壳的设计提供参考。     

基于涂料反射隔热作用的改性安全帽降温性能研究

采用实验室试验和ANSYS数值仿真法开展安全帽降温改性材料最佳配比的实验,并以石家庄季节气候条件模拟分析了季节特征温度和风速对安全帽降温效果的影响。结果表明：(1)当PET涂料和新型纳米隔热涂料质量比为1∶3时,降温幅度最大,为11.6℃;(2)普通安全帽与改性安全帽的温度云图均随着远离帽顶区域呈现出“层状分布”的降低趋势,且外界环境温度越高,改性安全帽降温效果越好;(3)当风速低于5 m/s时,改性安全帽降温效果显著,降温1.4～3.2℃;随着风速的增大,太阳辐射吸收率急剧减小,安全帽热传递方式基本只存在与环境的对流换热,2种安全帽的降温效果趋于相同。     

辐射制冷技术在安全帽上的应用研究*

为缓解夏季配戴安全帽导致的头部高温不适，采用具有光谱选择特性的辐射降温涂料对安全帽表面光学性能进行改性，经光学测试，安全帽的太阳辐射反射率由45%提升至89%，大气窗口发射率由92%提升至95%。对安全帽进行降温效果测试，并基于测试结果建立热力学模型。结果表明:在阳光直射下，改性安全帽内部温度低于普通白色安全帽，温差最大12.2 ℃；在热力学模型中，即使在夏季最热时间段（12∶00～14∶00），改性安全帽内部温度仍可比普通安全帽低8 ℃，预测平均评价值由普通安全帽的3.5降低至1.0，预测不满意百分比从100%降低至20%。     

基于FLUENT软件的安全帽内温度场分析

针对高温环境时多因素影响的安全帽内部温度场进行了研究,确定了其内部气体流动的守恒方程,使用FLUENT数值模拟软件进行了单因素的影响分析。以安全帽内的高温区域为指标,分析了不同工作环境时的温度场分布,研究结果可为安全帽的通风散热设计以及其高温区域分布提供理论依据。     

如何正确配戴安全帽和安全带

1安全帽 安全帽主要由帽壳（帽舌、帽沿）、帽衬（帽箍、顶衬、后箍））以及帽带（下颊带、吸汗带）三部分组成,是用于保护作业者头部,起到阻挡、缓冲、分散外来冲击力的作用,达到防撞击、挤压伤害效果,安全帽是实施“安全第一,预防为主”的具体行为和外观标志,是对进入变电站作业现场所有人员的最低要求和强制性规定。安规第13．1．1条规定：任何人进入生产现场（办公室、控制室、值班室、班组活动室除外）,应正确佩戴安全帽。     

宝钢总厂换用新型安全帽

宝钢总厂安环处为了解决现场职工在低头作业时安全帽容易脱落的问题,在上海市劳动保护科学研究所、上海工业劳防用品厂的协作下,改进了安全帽芯。改进后的帽芯加装了塑料齿轮结构,帽芯弧度可根据使用者要求自行调节,使之固定,任凭头部活动,不会脱落。宝钢总厂换用新型安全帽@益鸣     

谈谈安全帽

安全帽在保护劳动者头部在生产作业中免受损伤或减轻伤害方面,发挥了相当有效的作用。许多企业中工人都称安全帽为救命帽;建筑部门把它作为安全生产三宝之一,并规定进入作业场所必须佩戴。 在国外,工业管理比较先进的国家都明确规定:上至厂长,下至任何工作人员,只要进入厂区,都必须佩戴安全帽,而且对不同职务的人员,在其安全帽上,都做有明显的不同标记,以便于指挥。国外安全帽的品种很多,除一般工业用和军用外,还有乘车用安全帽(保护摩托车驾驶员和乘员)、电业专用安全帽、消防安全帽、运动防护帽(爬山、骑马、赛车等)。此外,国外还生产一些…     

工业安全帽抗冲击性能研究*

为研究安全帽安全性与保护性问题,利用落锤冲击实验,对不同材质安全帽吸能率、冲击力峰值进行研究。结果表明:随冲击能量增加,安全帽受冲击力峰值呈指数倍增长,吸能率呈指数倍下降;ABS树脂与玻璃钢材质安全帽头模受冲击力峰值小于HDPE材质安全帽;当冲击能量大于60 J,HDPE材质安全帽丧失保护功能;ABS安全帽能够承受最大冲击力能量值为70 J,玻璃钢安全帽最大承载力高于ＡＢＳ树脂安全帽。研究结果可为安全帽质量设计提供理论依据。     

Motorcycle helmets and spinal cord injury: helmet usage and type

The objective of this study was to assess the role of helmets and helmet type in relation to injury to the cervical spinal cord. It was based on a consecutive series of 110 motorcyclists with neurological damage to the spinal cord admitted alive (referred to as acute survivors) to a specialist spinal cord injuries unit at an Australian hospital. Cases were those with injury to the cervical spinal cord and controls were those with injury to the cord of other segments of the spine. The study showed that there was no significant difference in the odds of cervical spinal cord injury among unhelmeted and helmeted motorcyclist acute survivors. In addition, it confirmed the findings of a recently published Australian fatality study demonstrating no difference in the odds of cervical spinal cord injury among full-face and open-face helmet wearers. These results contrasted with the findings of earlier studies. In consideration of the limitations of existing research on the role of helmets in spinal cord injury, further study is required based on a larger series or a series having a higher proportion of non-wearers and open-face helmet wearers, including both survivors and those killed, and including assessment of cord and non-cord spinal injuries separately, helmet type, head impact, and helmet retention.     

基于ABAQUS二次开发的头盔防碰撞仿真系统及应用

目前国内的航空头盔设计仍依赖于经验设计,设计出来的头盔冗余较大,且需要大量的实验进行验证,研制周期长,效率低。针对这些问题,笔者基于ABAQUS平台,并针对航空头盔的特殊性进行二次开发,得到了一款能够进行防碰撞仿真的系统。应用该系统,仿真了3种不同规格的头盔,3种不同装配误差的泡沫硬衬垫共计6种模型的碰撞结果。仿真结果对头盔的设计有一定的指导价值。     

A new laboratory rig for evaluating helmets subject to oblique impacts

Current requirements and regulations governing motorcycle helmets around the world are based on test results of purely radial impacts, which are statistically rare in real accidents. This study presents a new impact rig for subjecting test helmets to oblique impacts, which therefore is able to test impacts of increased statistical relevance to real motorcycle accidents. A number of different head-helmet interfaces have been investigated. A test rig was constructed to produce oblique impacts to helmets simulating those occurring in real motorcycle accidents. A Hybrid III dummy head was fitted with accelerometers to measure the accelerations arising during impact testing. The equipment used for data collection was validated in both translational and rotational acceleration. In order to better resemble the human head, an artificial scalp was fitted to the hybrid dummy. The same test rig was used to investigate the performance of a number of different helmets. Impact velocities ranging from 7.3 to 9.9 m/s were tested using a number of different impact angles and impact areas. This study shows that the new test rig can be used to provide useful data at speeds of up to 50 km/h and with impact angles varying from purely tangential to purely radial. The rotational accelerations observed differ greatly depending on both helmet and scalp designs. For example, a helmet with a sliding outer shell placed on an experimental head fitted with an artificial scalp (made to resemble the human scalp) reduces rotational accelerations of the head by up to 56%, compared with those of an experimental head fitted with a fixed scalp and conventional helmet. The degree of slippage between the skull and the scalp, and between the scalp and the helmet, leads to considerable variation in the results. This innovative test rig appears to provide an accurate method for measuring accelerations in an oblique impact to a helmet. In order to obtain a good level of repeatability in oblique impact testing, it is crucial that the helmet be fixed to the head in the exact same way in each individual test. Both the position and the angle of impact must be reproduced identically in each test. The test rig used here has shown that this type of rig can be used to compare different helmet designs, and it therefore is able to contribute to achieving safer helmets.     

The effects of a mandatory motorcycle helmet law on helmet use and injury patterns among motorcyclist fatalities

BACKGROUND: The National Highway Traffic Safety Administration (NHTSA) has found that motorcycle helmets are 37% effective in preventing death and 65% effective in preventing brain injuries in a crash. Unfortunately, in 1995 Congress lifted federal sanctions against states without helmet laws and since then there have been a number of primary motorcycle helmet laws repealed or weakened. More lives could be saved and serious injuries avoided if there was increased helmet use throughout the United States. METHODS: This study analyzed helmet use and injury patterns among motorcycle riders in the United States involved in fatal crashes from 1995 through 2003 and compared the results between states with and without a primary helmet law. Age, sex, injury severity and helmet use are some of the variables obtained from the Fatality Analysis Reporting System (FARS). RESULTS: In the 20 states and the District of Columbia, which currently have a primary helmet law, 84.0% of fatally injured riders were wearing a helmet. In the 27 states with a secondary helmet law, 36.2% of fatalities used a helmet, and in the remaining three states with no law at all, helmet use dropped to 17.6%. In the two states (Arkansas and Texas) that changed from a primary helmet law to a secondary helmet law in 1997, helmet use decreased from 78.2% in 1996 to 31.7% in 2000. CONCLUSION: If all states were to enact a primary motorcycle helmet law, helmet use would dramatically increase while decreasing the number of motorcyclist head injuries and fatalities. IMPACT ON INDUSTRY: The results of this study will hopefully persuade law makers to enact primary helmet laws in all states throughout the nation. Helmet manufacturers can use this data to design more comfortable helmets while also improving upon the protective qualities of these safety devices.     

Cycle helmets and road casualties in the UK

OBJECTIVES: Bicycle helmets have been advocated as a means of reducing injury among cyclists. This assertion, derived from a number of case controlled studies carried out in hospitals, conflicts with results from population level studies. In the Western countries where these case control studies have been performed, it appears that cycling morbidity is dominated by sports and leisure users. The generalizability of studies on helmet effectiveness in relation to utilitarian transport cycling is not clear. This study therefore considers population level data for reported road traffic injuries of cyclists and pedestrians. METHODS: Generalized linear and generalized additive models were used to investigate patterns of pedestrian and cyclist injury in the UK based on the police reported "Stats 19" data. Comparisons have been made with survey data on helmet wearing rates to examine evidence for the effectiveness of cycle helmets on overall reported road casualties. While it must be acknowledged that police casualty reports are prone to under-reporting, particularly of incidents involving lower severity casualties the attractive feature of these data are that by definition they only concern road casualties. RESULTS: There is little evidence in UK from the subset of road collisions recorded by the police corresponding to the overall benefits that have been predicted by the results of a number of published case controlled studies. In particular, no association could be found between differing patterns of helmet wearing rates and casualty rates for adults and children. CONCLUSIONS: There is no evidence that cycle helmets reduce the overall cyclist injury burden at the population level in the UK when data on road casualties is examined. This finding, supported by research elsewhere could simply be due to cycle helmets having little potential to reduce the overall transport-related cycle injury burden. Equally, it could be a manifestation of the "ecological fallacy" where it could be conceived that the existence of various sub-groups of cyclists, with different risk profiles, may need to be accounted for in understanding the difference between predicted and realised casualty patterns.     

Protective Effect of Different Types of Bicycle Helmets

The effectiveness of bicycle helmets in preventing head injuries is well documented. There are different opinions about the effectiveness of helmets in preventing face injuries, and few studies have analyzed the effect of different types of helmets. This study was performed to examine the effect of different helmet types to head and face injuries. The use of helmets was analyzed in cyclists with head or face injuries and compared with two control groups. The main control group was cyclists that had injuries not including the head or neck, and another control group was cyclists that had been involved in an accident, regardless of whether they had sustained any injury. Cross-table and logistic regression analyses were applied to analyze the protective effect of helmets. A total of 991 injured patients served as a basis for this study. Most of the accidents, (82%) were single accidents with no other persons involved. Of patients with injuries to the head, excluding face, 11.4% had been using hard shell helmets, and 9.6% had been using foam helmets at the time of the accident. Among the emergency room controls, the proportion of hard shell helmet users and foam helmet users was 26.4% and 11.4%, respectively. Compared to non-helmet users, this gave an odds ratio of 0.36 (CI = 0.21–0.60) for getting head injuries if the cyclists had been using hard shell helmets at the time of the injury, and 0.83 (CI = 0.41–1.67) for users of foam helmets. The odds ratio for getting face injuries was 0.90 (CI = 0.58–1.41) among users of hard shell helmets, and 1.87 (CI = 1.03–3.40) for users of foam helmets. The use of hard shell helmets reduced the risk of getting injuries to the head. Children less than nine years old that used foam helmets had an increased risk of getting face injuries. All bicyclists should be recommended to use hard shell bicycle helmets while cycling.     

Protective effect of different types of bicycle helmets

The effectiveness of bicycle helmets in preventing head injuries is well documented. There are different opinions about the effectiveness of helmets in preventing face injuries, and few studies have analyzed the effect of different types of helmets. This study was performed to examine the effect of different helmet types to head and face injuries. The use of helmets was analyzed in cyclists with head or face injuries and compared with two control groups. The main control group was cyclists that had injuries not including the head or neck, and another control group was cyclists that had been involved in an accident, regardless of whether they had sustained any injury. Cross-table and logistic regression analyses were applied to analyze the protective effect of helmets. A total of 991 injured patients served as a basis for this study. Most of the accidents, (82%) were single accidents with no other persons involved. Of patients with injuries to the head, excluding face, 11.4% had been using hard shell helmets, and 9.6% had been using foam helmets at the time of the accident. Among the emergency room controls, the proportion of hard shell helmet users and foam helmet users was 26.4% and 11.4%, respectively. Compared to non-helmet users, this gave an odds ratio of 0.36 (CI = 0.21-0.60) for getting head injuries if the cyclists had been using hard shell helmets at the time of the injury, and 0.83 (CI = 0.41-1.67) for users of foam helmets. The odds ratio for getting face injuries was 0.90 (CI = 0.58-1.41) among users of hard shell helmets, and 1.87 (CI = 1.03-3.40) for users of foam helmets. The use of hard shell helmets reduced the risk of getting injuries to the head. Children less than nine years old that used foam helmets had an increased risk of getting face injuries. All bicyclists should be recommended to use hard shell bicycle helmets while cycling.     

Bicycle helmet use among persons 5 years and older in the United States, 2012

IntroductionIn 2013, injuries to bicyclists accounted for 925 fatalities and 493,884 nonfatal, emergency department-treated injuries in the United States. Bicyclist deaths increased by 19% from 2010 to 2013. The greatest risk of death and disability to bicyclists is head injuries. The objective of this study was to provide estimates of prevalence and associated factors of bicycle riding and helmet use among children and adults in the United States.MethodCDC analyzed self-reported data from the 2012 Summer ConsumerStyles survey. Adult respondents (18 + years) were asked about bicycle riding and helmet use in the last 30 days for themselves and their children (5 to 17 years). For bicycle riders, CDC estimated the prevalence of helmet use and conducted multivariable regression analyses to identify factors associated with helmet use.ResultsAmong adults, 21% rode bicycles within the past 30 days and 29% always wore helmets. Respondents reported that, of the 61% of children who rode bicycles within the past 30 days, 42% always wore helmets. Children were more likely to always wear helmets (90%) when their adult respondents always wore helmets than when their adult respondents did not always wear helmets (38%). Children who lived in states with a child bicycle helmet law were more likely to always wear helmets (47%) than those in states without a law (39%).ConclusionsDespite the fact that bicycle helmets are highly effective at reducing the risk for head injuries, including severe brain injuries and death, less than half of children and adults always wore bicycle helmets while riding.Practical applicationStates and communities should consider interventions that improve the safety of riding such as policies to promote helmet use, modeling of helmet wearing by adults, and focusing on high risk groups, including Hispanic cyclists, occasional riders, adults, and children ages 10 to 14.