期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
地日运动的C^1R^2P^2机构重演及其应用于向日计算
1
作者 张威 许晓峰 王立文 《机床与液压》 北大核心 2016年第5期166-170,188,共6页
通过将自由系统等效变换为非自由系统的思想,可以利用机构学方法实现天文运动关系的可视化表达。提出一套假想C^1R^2P^2串联机构作为地日运动的相当系统,以5个运动副(1个圆柱副,2个转动副和2个移动副)来耦合地球对日运动。通过对黄赤交... 通过将自由系统等效变换为非自由系统的思想,可以利用机构学方法实现天文运动关系的可视化表达。提出一套假想C^1R^2P^2串联机构作为地日运动的相当系统,以5个运动副(1个圆柱副,2个转动副和2个移动副)来耦合地球对日运动。通过对黄赤交角和黄道椭圆轨道等约束条件的满足,该机构可重演地球任意点的对日运动。同时,利用D-H参数法,在机构的运动空间中建立了日心和地球位点的时间-空间方程。把此方程应用到太阳定向上,推导出由时间及经纬度表出的太阳方向公式。将Michalsky算法中太阳高度角和方位角计算公式以及王炳忠太阳赤纬计算公式作为参考,给出传统太阳矢量公式。最后通过3个实例,将得出的两组太阳方向向量进行对比,并计算出对应的误差。结果表明:该机构和由机构正向运动学导出的太阳方向公式是正确的。此外,对地日运动的更高精度修正,可通过调整或增加运动副来层次化重演。该研究方法可为天文运动学研究提供一种形象手段,以更好地理解运动关系。 展开更多
关键词 地日运动 太阳定向 机构学 正向运动 D-H参数法
下载PDF
Simulation of Sliding Failure Occurred at Highway Embankment in 2011 Great East Japan Earthquake
2
作者 Ken-ichi Tokida Kouki Murakami Aino Tachibana 《Journal of Civil Engineering and Architecture》 2013年第1期27-38,共12页
In the 2011 Great East Japan Earthquake, the highway embankments were almost less damaged comparing with the past earthquakes in Japan. But the only one embankment close to the Naka Interchange at Joban Highway was da... In the 2011 Great East Japan Earthquake, the highway embankments were almost less damaged comparing with the past earthquakes in Japan. But the only one embankment close to the Naka Interchange at Joban Highway was damaged a little severely and remarkably because of two interesting phenomena. One phenomenon is the toe-sliding failure observed at the shallow soft base ground and the other one is one-side slope sliding failure. It can be seen that the increase in the degree of saturation at embankment body or the direction of the ground motion or the interaction between the strength of the base ground and the embankment body are involved in the stability of the embankment by modifying the phenomenon by analytical approach such as circular sliding method and dynamic response analysis. Through this research, some important lessons can be obtained for future seismic countermeasure of embankments. 展开更多
关键词 Highway embankment circular sliding method dynamic response analysis.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部