现代军用防弹头盔盔形设计研究

随着士兵装备数字化程度的不断提高,陆战士兵使用的防弹头盔正在演进成为集综合防护与信息交互功能为一体的头面部作战装备系统。在这一发展进程中,现代军用防弹头盔的设计在确保安全性的同时,更加强调工效性,以保证＂头盔-盔载光电设备＂系统具有更优异的佩戴稳定性和舒适性。本文借鉴美国陆军近年开始装备的MICH头盔（Modular Integrated Communication Helmet）的设计经验,总结了现代军用防弹头盔盔形的设计要素,首次提出了采用头指数对头盔适戴性进行测评的方法,并基于三维头型和头盔分号国家标准,首次计算得出了各号型头盔适宜防护面积的理论范围,为我军未来防弹头盔的盔形设计提供了依据。     

消防头盔对冲击加速度的防护作用

本文通过论述消防头盔对冲击加速度的防护原理、试验方法和试验结果,分析了不同方向冲击时,消防头盔对冲击加速度的防护作用,提出改进消防头盔设计的一些设想。     

美国军警防暴战术服装系统

为提高与犯罪分子作斗争、进行暴乱控制的效能,美国最近正在研制开发一种军警防暴战术服装系统。该系统主要包括多功能头盔子系统、服装子系统、微型计算机子系统和作战靴子系统四个部分。1多功能头盔子系统该系统的头盔采用与陆军目标部队勇士头盔相类似的设计,具有防弹和冲击防护功能。头盔将照明器、全球定位系统、无线天线设备、图像增强器和红外成像装置结合为一体。头戴式显示器可以接收各种信息。军警小组的每个成员都装备并随身携带成像装置。激光探测器能够进行敌我识别,眼罩可以防激光和碎片。电子吹风器能够防止雾气影响视线。面…     

为热带气候环境设计的一种摩托车头盔

在印度所发生的交通伤亡事故中,大约有20％与两轮摩托车驾驶者有关。因此,两轮摩托车驾驶员的头部保护问题显得非常重要,本文叙述了在德里市所做的关于摩托头盔使用情况的调查报告,并详细介绍了一种更舒适的摩托头盔的设计细节,这份调查报告的结果对于研究与开发接受性更广泛、通风系统更理想、安全性能更好的新型头盔具     

浅谈先进战车乘员头盔

头盔显示系统能大幅增强佩戴者的态势感知能力,已广泛应用于战斗机、直升机的显示、瞄准和操控。目前,世界各国正借鉴飞行员头盔,针对地面装甲车辆开展先进战车乘员头盔研究。本文梳理了国外先进战车乘员头盔的初步研究成果。     

考虑驾驶员反应时间的车辆碰撞预警模型

为了保证车辆在行驶过程中的安全性,提出了一种考虑驾驶员反应时间的车辆碰撞预警模型,改进了传统模型中驾驶员反应时间定值化的缺点。首先,依据车辆的制动过程分析了驾驶员反应时间对制动距离的影响。其次,设计驾驶员反应时间的模糊推理算法,选取驾龄、疲劳强度和应变能力3个主要因素作为评价指标来计算反应时间。最后,采用分等级的预警策略建立考虑驾驶员反应时间的碰撞预警模型,并通过Carsim-Matlab/Simulink联合仿真与传统模型进行对比分析。结果表明,设计的预警模型可以对不同类型的驾驶员进行差异化碰撞预警,在30 km/h和80 km/h两种车速下实际停车距离与理论值的最大误差为8%。     

车辆碰撞特性的数值仿真及试验研究

运用显式动态有限元方法建立了某车辆的有限元模型 ,按照国家标准对整车进行了正面碰撞仿真计算和实车正面碰撞试验。通过仿真计算和实验的对比分析 ,其结果表明 :仿真计算的变形结果和试验吻合较好 ,车身上一些主要部位的加速度曲线在趋势上也基本吻合 ,说明运用有限元法进行车辆的仿真切实可行。分析结果为车辆的安全性设计提供了参考依据。     

大客车正面碰撞乘客约束系统仿真分析

为探究约束系统在全承载客车正面碰撞事故中对乘客损伤的影响,利用有限元分析软件LS_DYNA建立某大客车正面碰撞仿真模型,并开展整车50 km/h正面100％重叠碰撞固定刚性壁障试验;从车身变形、加速度曲线和乘员损伤等3方面验证仿真模型;基于已验证的仿真模型,开展不同座椅间距、车厢位置及安全带类型的乘员运动响应和损伤等综...     

汽车行人碰撞接触中行人运动学规律仿真研究

基于交通事故模拟分析PC-Crash软件及其内嵌多体系统动力学分析MADYMO模块,建立并验证了车辆多体模型和行人多体模型;对汽车与行人碰撞接触阶段的行人运动学具有较大影响的因素展开广泛分析,并构建汽车行人碰撞仿真试验方案;通过选取对汽车与行人碰撞接触阶段具有较大影响的因素作为仿真试验的自变量,对不同碰撞环境下汽车与行人碰撞接触过程中的行人运动学规律(包括运动姿态和对应的碰撞车速阈值)进行深入研究;汽车行人碰撞仿真与真实事故以及碰撞试验对比具有较好的规律吻合性和一致性。研究表明,笔者采用的计算机建模仿真方法在汽车行人碰撞运动学研究中具有实用价值。     

"军用头盔系列"通过设计定型评审

总后勤部军需部最近组织召开了“军用头盔系列”产品设计定型评审会。该项目研究的目的是建立健全我军军用头盔体系,实现我军单兵头面部防护装备的更新换代。“军用头盔系列”由步兵头盔、空降兵头盔、装甲兵头盔及陆航直升机驾驶员头盔构成。其中,步兵头盔为通用型作战防护头盔,已于2002年先期实现设计定型和生产定型,并已装备全军。空降兵头盔是在步兵头盔基础上针对伞降作战特点研制的,主要装备空降兵及其他执行伞降作战任务的人员。装甲兵头盔采用半盔式盔形设计,具有防破片、抗冲击、抗穿刺功能,其防护功能比现役的坦克工作帽有了显著…     

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。     

一种分离式可降温安全帽设计

为了解决高温作业环境下安全帽内部微环境积热严重问题,运用ANSYS软件模拟分析了安全帽内部微环境积热的空间和时间分布情况。基于模拟结果,设计了一款分离式可降温安全帽,其由帽体、喷嘴、风管、风机和开关组成。在高温高湿环境下,模拟人员分别佩戴在帽衬带上装有温度传感器的普通安全帽和分离式可降温安全帽进行剧烈运动模拟高温作业人员高强度劳动,记录其温度变化。结果表明:分离式可降温安全帽有良好的降温效果,同时具有不破坏安全帽的结构和强度,几乎不增加安全帽重量,无噪声、无电磁辐射,拆装简便等优点。     

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.     

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.     

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。     

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.     

The determinants of motorcyclists helmet use: Urban arterial road in Khon Kaen City,Thailand

IntroductionCurrently, Thailand incurs the highest death toll of motorcyclists in the world. The aim of this study was to explore the factors influencing helmet use of motorcyclists in Khon Kaen City, Thailand by using the Logistic regression analysis.MethodThe samples, consisting of 27,977 riders and 6,947 riding passengers, were collected by CCTV installed at several signalized intersections along urban arterial roads.ResultsThe observation results reveal that only 67% of motorcyclists wore the helmets. The analysis results reveal that the helmet use of motorcyclists was significantly associated with the riding status, number of passengers, apparent age, motorcycle class, time of day, the presence of police booths at intersections and, especially, red light running behavior. The riders tended to wear helmets at 2.7 times higher rates than passengers. Adult motorcyclists tended to wear the helmets at 2.8 times higher rates than children. The motorcyclists riding the motorcycles over 125 cc tended to wear the helmets 1.9 times higher than those riding motorcycles under 125 cc. The motorcyclists riding in the morning and the afternoon tended to wear the helmets 5.0 and 3.8 times higher than in the evening. The motorcyclists riding through intersections with police booths tended to wear the helmets 2.2 times higher than those riding through intersection without police booths. However, the red light running riders intend to wear the helmets 0.6 times less than the legal riders.ConclusionsThe outcome of this study could determine the factors influencing motorcyclist's helmet use.Practical ImplicationsIt will be useful for a development of 100% helmet use program designed to lessen the fatality of motorcyclists along the urban arterial roads.     

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.