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用系统辨识研究人体落地冲击时身体组织的被动缓冲特性 被引量:2
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作者 裘艺 伍勰 +1 位作者 张胜年 魏文仪 《医用生物力学》 EI CAS CSCD 2008年第3期208-215,共8页
目的探索利用系统辨识寻求人体落地冲击模型中力学元件参数的方法,并结合仿真分析验证其有效性和实用性。方法将人体简化为带有一个颤摆质量和一个刚性质量的—自由度集中参数物理模型,用状态空间法导出相应的数学模型,采用n4sid子空间... 目的探索利用系统辨识寻求人体落地冲击模型中力学元件参数的方法,并结合仿真分析验证其有效性和实用性。方法将人体简化为带有一个颤摆质量和一个刚性质量的—自由度集中参数物理模型,用状态空间法导出相应的数学模型,采用n4sid子空间系统辨识方法得到广义状态方程,进一步借助约束优化方法求解模型力学元件参数估值。结果参与缓冲的颤摆质量随落地高度的增加而增大,弹性、阻尼元件参数估值有一适宜的范围,仿真计算输出量与实际人体系统输出量有更好的拟合度。结论采用系统辨识方法可有效估算两质量-自由度系统模型中反映人体缓冲特性的力学元件参数估值。 展开更多
关键词 冲击性动作 缓冲 系统辨识 计算机仿真
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Multi-degree-of-freedom coupling dynamic characteristic of TBM disc cutter under shock excitation 被引量:8
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作者 霍军周 孙晓龙 +2 位作者 李广庆 李涛 孙伟 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3326-3337,共12页
When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The stru... When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The structure of disc cutter contains many joint interfaces among cutter ring, cutter body, bearings and cutter shaft. On account of the coupling for dynamic contact and the transfer path among joint interface, mechanical behavior of disc cutter becomes extremely complex under the impact of heavy-duty, which puts forward higher requirements for disc cutter design. A multi-degree-of-freedom coupling dynamic model, which contains a cutter ring, a cutter body, two bearings and cutter shaft, is established, considering the external stochastic excitations, bearing nonlinear contact force, multidirectional mutual coupling vibration, etc. Based on the parameters of an actual project and the strong impact external excitations, the modal properties and dynamic responses are analyzed, as well as the cutter shaft and bearings' loads and load transmission law are obtained. Numerical results indicate the maximum radial and axial cutter ring amplitudes of dynamic responses are 0.568 mm and 0.112 mm; the maximum radial and axial vibration velocities are 41.1 mm/s and 38.9 mm/s; the maximum radial and axial vibration accelerations are 94.7 m/s2 and 58.6 m/s2; the maximum swing angle and angular velocity of cutter ring are 0.007° and 0.0074 rad/s, respectively. Finally, the maximum load of bearing roller is 40.3 k N. The proposed research lays a foundation for structure optimization design of disc cutter and cutter base, as well as model selection, modification and fatigue life of the cutter bearing. 展开更多
关键词 tunneling boring machine(TBM) disc cutter system joint interface coupled nonlinearity dynamical characteristics
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