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Micro-structure and frictional characteristics of beetle's joint

Science China(Physics,Mechanics & Astronomy) 2004年第Z1期47卷 99-106页

作者： DAI Zhendong Stanislav N.Gorb College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Biological Microtribology Group Max-Planck-Institute of Developmental BiologySpemannstr.35D-72076 TuebingenGermany Evolutionary Biomaterials Group Max-Planck-Institute for Metal ResearchHeisenbergstrasse 3D-70569 StuttgartGermany

Geometric and micro-structure design, tribology properties of beetle joints were experimentally studied, which aimed to enlighten ideas for the joint design of *** observation by using SEM and microscopy suggested that beetle's joints consist of a concave surface matched with a convex surface. The heads of the beetles, rubbing with flat glass, were tested in fresh and dried statuses and compared with sapphire ball with flat glass. Frictional coefficient of the joint material on glass was significantly lower than that of the sapphire sphere on glass. The material of the joint cuticle for convex surface is rather stiff (the elastic modulus 4.5 Gpa) and smooth. The surface is hydrophobic (the contact angle of distilled water was 88.3° ). It is suggested here that the high stiffness of the joint material and hydrophobicity of the joint surface are parts of the mechanism minimizing friction in insect joints.

关键词： beetle's joint, friction, geometry, micro-structure.

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Development of joints and shear fractures in the Kuqa depression and its implication to regional stress field switching

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Science China Earth Sciences 2004年第Z2期47卷 74-85页

作者： ZHANG Zhongpei WANG Qingchen Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The superimposed basin must have undergone the changes of regional stress field. Study on the nature and switch of regional stress field of superimposed basin is very useful to understanding its stress state and tectonic events during its formation and evolution. As sensitive markers of small stress changes, joint and shear fracture, characterized by consistency of ori-entation over wide area, can be used to reconstruct paleostress state and its evolution. Detailed observations and analysis on the orientations, geometrical patterns, sequences of joints and shear fractures and their chronological relation to faults and folds show that, the NEE-SWW systematic joints and NNW-SSE systematic joints developed in the Mesozoic and Cenozoic strata are much more prominent than NW-SE systematic joints and shear fractures with different orientations. And the NWW-SEE and NW-SE systematic joints formed later than NEE-SWW systematic joints but earlier than shear fractures with different orientations. According to the rela-tionships between joint and shear fractures and stress, the NEE-SWW systematic joints are in-ferred to result from lateral weak extension caused by the late Cretaceous regional uplift, while the NNW-SSE and NW-SE systematic joints are interpreted as syn-tectonic deformation relating to strong N-S compression in the Neogene. But some conjugate shear fractures occur probably due to sinistral strike-slip faulting in the Kuqa depression. At the beginning of the Neogene, the stress field changed and the maximal principal stress s1 switched from vertical to horizontal.

关键词： joint, shear fracture, paleostress, paleostress field, Kuqa depression.

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基于Simulink的数控机床多惯量伺服进给系统的建模与仿真（英文）

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机床与液压 2015年第24期43卷 51-55页

作者：沙丰永高军李学伟罗超骆飞山东理工大学机械工程学院山东淄博255049

针对双惯量伺服进给系统对其中间环节分析不足、参数整定算法精度较低等问题,提出了一种多惯量伺服进给系统模块化建模的方法。将数控机床伺服进给系统转化为多惯量系统,分为电机、丝杠、工作台3个单元,单元间的连接件(联轴器和丝杠螺母...

针对双惯量伺服进给系统对其中间环节分析不足、参数整定算法精度较低等问题,提出了一种多惯量伺服进给系统模块化建模的方法。将数控机床伺服进给系统转化为多惯量系统,分为电机、丝杠、工作台3个单元,单元间的连接件(联轴器和丝杠螺母)均等效为柔性连接件。基于PID的三闭环控制系统,运用Matlab对永磁同步电机矢量控制系统模型、机械传动系统模型进行仿真,整定优化各项参数。仿真结果表明:模块化建模方法能够对多惯量伺服系统存在的问题进行精准分析,对系统中间连接环节具有更为有效的分析效果;提高了仿真模型以及参数整定算法的精度,且仿真效果较好。

关键词： Dynamic modeling, Multi-inertia system, Flexible joint, Permanent Magnet Synchronous Motor, Pa-rameter setting algorithm

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