考虑摩擦和间隙影响的机床进给伺服系统建模与分析

进给伺服系统的性能对数控机床的跟踪及定位精度、加工质量等有着重要的作用。摩擦和间隙的非线性会导致系统的爬行、振荡等不稳定行为。针对闭环控制的直联式进给伺服系统,建立了考虑摩擦和间隙的综合力学模型和数学模型。研究了低速进给条件下摩擦和间隙非线性对工作台输出的影响,得出了工作台产生爬行现象的几种可能条件,并给出消除进给系统爬行现象的几种常见措施。所得结论为进给伺服系统的优化设计和性能预测提供了理论支持。

程各庄断裂断层泥显微结构特征及其断裂活动性探讨

程各庄断裂是马坊—夏垫断裂带北段的一条东分支断裂,根据其断层泥的显微结构、石英碎屑SEM特征、热释光年龄综合分析,结果表明,该断裂不同区段的最新活动都是以粘滑为主,但各个区段不同地质时期其活动方式和强度不同.

三轴转台执行机构起动摩擦特性的测试与研究

本文以液压马达作为研究对象，对其起动摩擦特性进行了测试与分析。实时获得了驱动扭矩、被测马达转角的变化过程。通过建模分析，准确估计出了起动时动、静摩擦特性的变化规律。得出了液压马达在起动的瞬间不存在摩擦力瞬态突变的结论，并据此对摩擦振动的产生机理加以分析，推导了产生爬行的各种临界条件。

地下化爆与粘滑实验变形样品的微观对比研究

借助于两种变形产物的定向微观对比观测，鉴别高速变形微观特征标志。对比结果表明：石英冲击微页理、继形玻璃、切砾微断裂、撞击楔入、放射状破裂、碎砾随机排列和锯齿状破裂等变形形迹是典型高速变形微观标志。从而为天然古地震震源体的识别提供了客观依据。与此同时。

沂沭活断层分段特征及地震趋势的预测

沂沭活断层以莒南—汤头一线为界可分成南北两大段。其中,北段以蠕滑为主,南段则表现为强烈的粘滑错动。另外,在南段内还存在着一个次一级的段落。文中详细分析了各段的断层滑动方式及地震活动的特点,并对沂沭断裂带今后的地震趋势作了预测。

大位移井钻具组合设计及摩阻扭矩分析

大位移井技术是衡量钻井技术水平高低的关键因素,大位移井钻具组合设计是大位移井钻探中的核心内容之一。国外大位移井的钻具组合设计主要考虑摩阻和扭矩及不均匀转动和震动这两大类问题。摩阻和扭矩分析主要校核钻柱的三轴应力、侧向力、屈曲变形。文中简要介绍了钻具组合设计中的三轴应力、侧向力、屈曲、不均匀转动和震动等五个基本概念。重点介绍了国外大位移井钻具组合设计的基本原则,结合实例作了简略分析。提出了国内水平井钻柱设计需要关注的技术要点,阐述了随钻测量仪对不均匀转动和震动测量等参数的现场需求及重要性。文章认为,不断地消化吸收国外先进的技术和理念,国内未来的水平井技术、大位移井技术将会不断进步和稳步发展。

ANALOG SIMULATION OF DYNAMIC RESPONSE IN DRY FRICTION PAIR BY THERMODYNAMICS

Research shows that dynamic response is the origin of the phenomena. While a friction pair is in motion,the dynamic response force corresponding to the rate of elastoplastic deformation of contact makes the surfaces of the pair dynamically harden and separate a certain level from the equilibrium position. Consequently, the real area of contact decreases with an increase in sliding speed. While the friction pair comes to rest, the remaining process of dynamic response would not disappear instantaneously but will gradually return to normal position, and as a result the contact area is increased during the rest period. These processes appear as F─v descent and F─t ascent characters. Because of the dynamic response, the real contact area is seriously decreased,consequently there occurs serious stress concentration and intensive wear. Thus, the dynamic response may be used to evaluate matching character of a friction pair. It is prospective that to study dynamic response of solid is of great significance on wear research. Conceptual and experimental explanation on dynamic response was introduced in 1981 ￣[4] . But the concept is too abstract to understand.In order to imaginarily recognize the phenomenon,by using the universality of natural law,the dynamic response in dry friction pair is simulated by thermodynamics. Thus, the concept of dynamic response is vividly depicted.