Loading-unloading test analysis of anisotropic columnar jointed basalts

To evaluate the columnar jointed basalts in the dam site of Baihetan hydropower station in southwest China, we developed a basic conceptual model of single jointed rock mass. Considering that the rock mass deformation consists of rock block deformation and joints deformation, the linear mechanical characteristics of the cell （including the elastic joints and the nonlinear mechanical behaviors of the cell） with a combined frictional-elastic interface were analyzed. We developed formulas to calculate the rock block deformation, which can be adapted for multiple jointed rock mass and columnar jointed basalts. The formulas are effective in calculating the equivalent modulus of multiple jointed rock mass, and precisely reveal the anisotropic properties of columnar jointed basalts. Furthermore, the in situ rigid bearing plate tests were analyzed and calculated, and the types of loading-unloading curves and the equivalent modulus along different directions of columnar jointed basalts were obtained. The analytical results are in close compliance with the test results.     

治疗运动员膝关节粘连纤维性僵直41例报告

报告了膝关节粘连纤维性僵直41例治疗结果,涉及柔道、摔跤、足球等9项运动。治疗采用我院传统的中医骨伤科疗法,治疗前后膝关节活动范围平均改善76度,最佳者改善130度,效果良好。结合其诊治经验就膝关节粘连纤维性僵直的临床特征与病理改变、治疗方法的选择和治疗特点进行了分析讨论。     

专项武术训练对男性青少年骨骼质量的影响

为了了解专项武术训练对青少年骨骼质量的影响，采用定量超声骨质成像与测量系统对长期进行专项武术训练的男性青少年进行研究。结论：武术专项的运动员虽然身高、体重较低，但骨密度和骨硬度均显著高于对照组，提示长期有规律地进行武术锻炼有利于提高人体的骨骼质量。     

车削螺纹时发生“啃刀”现象的分析

车削螺纹时发生的＂啃刀＂现象,其主要原因是：刀架部件刚度变化;加工硬化和小滑板产生了爬行。防止产生此现象的方法是：调整中、小滑板的塞铁间隙;保持车刀刃口的锋利以减小加工硬化程度,同时可在车刀前刀面上磨出圆弧和预防＂爬行＂产生。     

调心球轴承动态特性参数分析

基于Jones-Harris方法建立了调心球轴承的动力学模型,应用Newton-Raphson方法对轴承动力学方程组进行了求解,开发了相应的计算程序.完成了该轴承的离心力、陀螺力矩、接触载荷、接触角、径向变形与径向刚度等动态特性参数分析.分析结果表明：转速与载荷是影响接触角大小与接触载荷分布最主要的2个因素;滚子的离心力与陀螺力矩随着转速的上升而增大,在此影响下外圈接触载荷增大而内圈接触载荷减小;受离心力的影响,外圈的接触角减小而内圈的接触角增大,且随着转速的增加,内外圈接触角的差值越来越大;轴承的径向刚度随着转速的上升而下降,而滚道沟曲率系数也对轴承径向刚度有一定程度的影响.     

基于刚度的框架结构抗震能力评估简化方法(英文)

针对结构物在地震作用下的灾害评估问题,提出了一种基于刚度退化概念的框架结构整体与层间损伤指标.该指标通过结构静力弹塑性分析方法进行计算,利用塑性铰考虑结构的地震损伤.同时,根据能力谱方法建立了该损伤指标与抗震设防等级的关系.然后,将建议指标应用于2个3层钢筋混凝土框架结构,并与其他损伤指标进行了对比.结果表明:建议的损伤指标偏于安全,且对静力弹塑性分析的水平荷载模式不敏感;层间损伤指标能够清晰地反映各楼层的损伤情况,从而判断薄弱层的位置.最后,通过统计分析给出了结构不同性能水准与损伤指标的对应关系,为基于性能的框架结构抗震评估提供参考.     

道岔竖向刚度不均匀分析及在线检测研究

轨道竖向刚度不均匀是道岔的主要缺陷之一。文章通过应用有限元方法对道岔区轨道竖向刚度不均匀进行分析,探讨道岔区轨道竖向刚度不均匀对列车运行舒适性和安全运营的影响,研究控制平顺的必要性,进一步探讨提出相应的在线检测方法。     

Relationship between skeletal muscle contractile properties and power production capacity in female Olympic rugby players

This study aimed to determine which contractile properties measured by tensiomyography (TMG) could better differentiate athletes with high- and low-power values, as well as to analyse the relationship between contractile properties and power production capacity. The contractile properties of the vastus medialis (VM), rectus femoris (RF) and vastus lateralis (VL) of an Olympic women’s Rugby Sevens team (n?=?14) were analysed before a Wingate test in which their peak power output (PPO) was determined. Athletes were then divided into a high-power (HP) and a low-power (LP) group. HP presented an almost certainly higher PPO (9.8?±?0.3 vs. 8.9?±?0.4 W kg^?1, ES?=?3.00) than LP, as well as a very likely lower radial displacement (3.39?±?1.16 vs. 5.65?±?1.50?mm, ES?=?1.68) and velocity of deformation (0.08?±?0.02 vs. 0.13?±?0.03 mm ms^?1, ES?=?1.87) of the VL. A likely lower time of delay was observed in HP for all analysed muscles (ES?>?0.60). PPO was very largely related to the radial displacement (r?=??0.75, 90% CI?=??0.90 to ?0.44) and velocity of deformation (r?=??0.70, 90% CI?=??0.87 to ?0.34) of the VL. A large correlation was found between PPO and the time of delay of the VL (r?=??0.61, 90% CI?=??0.84 to ?0.22). No correlations were found for the contractile properties of RF or VM. These results highlight the importance of VL contractile properties (but not so much those of RF and VM) for maximal power production and suggest TMG as a practical technique for its evaluation.     

基于COSMOS/Works的构件静强度与刚度分析

运用与SolidWorks无缝集成的有限元分析软件COSMOS/Works,可以方便、快速、准确地对工程构件进行强度和刚度分析,使工程设计人员从繁琐而又容易出现错误的强度与刚度计算中解脱出来。文章介绍了COSMOS/Works软件的有限元分析功能在结构静强度和刚度计算上的具体运用。