一种用于空投产品着地速度测量的无线电测速装置

设计了一种用于空投产品着地速度测量的无线电测速装置,该装置将无线电引信模块加装到被测物体内,结合运动时产生的多普勒频率实现对空投产品着地速度的测量。与常规测量装置相比,该装置具有较高的可靠性、测速精度、耐冲击过载能力。经外场验证,在产品落角大于45°着地情况下,该装置的测速精度满足测速要求,可以用于空投产品着地速度的测量。

对我国优秀800m运动员着地缓冲技术的研究

以我国优秀男子中跑运动员为研究对象,采用平面摄像与解析法,对2005年5月参加全国田径大奖赛暨亚洲田径公开赛和2005年6月全国田径锦标赛两站比赛,男子800 m中38人的途中跑着地缓冲技术进行了分析,得出以下结论:运动员的脚着地速度为1.42 m/s,与世界优秀运动员相比仍有一定的差距,而运动员的着地距离平均为33.3 cm,与世界优秀运动员相比,着地距离偏大。并提出改进建议。

跳远踏跳技术的生物力学分析

本文采用测力平台和高速摄影机对运动员进行测试,将数据进行了同步分析。认为跳远踏跳落地垂直速度是影响腾起垂直速度的重要指标。缓冲垂直平均力和缓冲冲量是评定成绩的重要指标。同时,对起蹬角和起跳幅角等参数进行了探讨,并应用力学模型对踏跳各相关参数进行了理论分析。

Impact shock frequency components and attenuation in rearfoot and forefoot running

Background:The forefoot running footfall pattern has been suggested to reduce the risk of developing running related overuse injuries due to a reduction of impact related variables compared with the rearfoot running footfall pattern.However,only time-domain impact variables have been compared between footfall patterns.The frequency content of the impact shock and the degree to which it is attenuated may be of greater importance for injury risk and prevention than time-domain variables.Therefore,the purpose of this study was to determine the differences in head and tibial acceleration signal power and shock attenuation between rearfoot and forefoot running.Methods:Nineteen habitual rearfoot runners and 19 habitual forefoot runners ran on a treadmill at 3.5 m/s using their preferred footfall patterns while tibial and head acceleration data were collected.The magnitude of the first and second head acceleration peaks,and peak positive tibial acceleration were calculated.The power spectral density of each signal was calculated to transform the head and tibial accelerations in the frequency domain.Shock attenuation was calculated by a transfer function of the head signal relative to the tibia.Results:Peak positive tibial acceleration and signal power in the lower and higher ranges were significantly greater during rearfoot than forefoot running(/】 【 0.05).The first and second head acceleration peaks and head signal power were not statistically different between patterns(p 】 0.05).Rearfoot running resulted in significantly greater shock attenuation for the lower and higher frequency ranges as a result of greater tibial acceleration(p 【 0.05).Conclusion:The difference in impact shock frequency content between footfall patterns suggests that the primary mechanisms for attenuation may differ.The relationship between shock attenuation mechanisms and injury is not clear but given the differences in impact frequency content,neither footfall pattern may be more beneficial for injury,rather the type of injury sustained may vary with footfall pattern preference.

空降车-气囊系统着地缓冲过程仿真分析

为了给空降车及其气囊的优化设计提供技术支持,采用有限元方法对空降车气囊缓冲过程进行仿真分析。计算了正常着地工况下的气囊缓冲过程,得到速度、加速度以及气囊内压等时间特性曲线。结果表明:空降车在该工况下着地速度小于3m/s,该气囊符合空降车着地的缓冲性能要求。车体加速度和冲击应力在误差许可范围内,验证了采用此种方法进行空降车气囊缓冲过程的虚拟测试是可行的。