共查询到18条相似文献,搜索用时 178 毫秒
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3 GPa熔融盐固体介质三轴高温压力容器的轴压摩擦力标定 总被引:1,自引:0,他引:1
在温度标定和围压标定的基础上,采用轴压循环方法,对3 GPa固体介质三轴高温高压实验系统的轴压摩擦力进行了标定,分析了围压、温度、轴向位移速率、装样方式(盐套类型)等实验条件对轴压摩擦力的影响。结果表明:静摩擦力、挤压摩擦力和滑动摩擦力3种轴压摩擦力对轴向应力的影响不同,其中静摩擦力和挤压摩擦力对轴向应力的影响很小,影响应力精度的主要是滑动摩擦力。静摩擦力及滑动摩擦力与围压正相关;静摩擦力与轴向位移速率正相关,但受其影响较小,滑动摩擦力不受其影响;静摩擦力和滑动摩擦力与温度负相关,并且受其影响较显著;盐套类型对轴压摩擦力的影响较大,当实验条件接近盐套熔点时,轴压摩擦力显著降低,当样品周围的盐套处于熔融状态时,轴压摩擦力最小。基于此,确定了标定轴压摩擦力的具体步骤,并对角闪岩的应力-应变曲线进行了轴压摩擦力标定。对比轴压摩擦力校正前、后的应力-应变曲线发现,经过轴压摩擦力校正的应力-应变曲线能更好地反映样品的实际变形情况。 相似文献
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正确理解摩擦力既是高中阶段的重点,也是难点.在学习过程中学生往往只注重于摩擦力的大小计算,却忽视了对摩擦力的某些特性的理解,从而造成了对摩擦力概念的认识上的片面性,以致于在分析摩擦力的相关问题时很容易落入命题者设计的陷阱,下面我们从命题的角度来看看几种情况. 相似文献
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利用“摩擦力器”能直接观察物体在各种状态下图1所受摩擦力的大小和方向,并能测量出两种物体间的滑动摩擦系数,使抽象的摩擦力概念变为更直观、更容易理解,大幅度降低了摩擦力的教学难度。教具“摩擦力器”把摩擦力的传感器和显示器设计在一个箱体内,如图1所示。箱体的上下底板就是摩擦力传感器,它通过小轮(上下各4个)跟箱体相连,可使上下底板相对于箱体左右移动。当底板受到摩擦力(包括静摩擦或滑动摩擦,下同)的作用时,在箱体与底板间的滚动摩擦力远小于滑动摩擦力和静摩擦力可以忽略不计的情况下,连接箱体与底板间的左、右弹簧的形变相同(相同弹簧),合力为零。 相似文献
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在摩擦力的教学中,学生对摩擦力的方向判断,感到很棘手.如果用假设法判断摩擦力方向,一般不会出现错误.下面通过具体的例子介绍判断摩擦力方向的方法.1平衡问题中的摩擦力因为摩擦力 随外界因素的变化而变化,当摩擦力方向不能确定时,可利用假设法分方向判断,使物体有一定的动态变化,把摸糊问题变为明晰问题. 相似文献
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摩擦——一个古老而时髦的话题 总被引:1,自引:0,他引:1
介绍了在原子力显微镜基础上发展起来的摩擦力显微镜的原理,应用摩擦力显微可以测量原子级的摩擦力,从而为从微观上理解摩擦这一最为普遍的宏观物理象奠定了基础。同时,不评述了近十年严这一分为二或理论和实验两方面的研究进展。 相似文献
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用一维Frenkel-Kontorova模型,对相互接触的两个单原子分子链具有相对运动趋势时所产生的最大静摩擦力进行了研究.分别在相邻原子的距离与周期势场的周期比b/a为可公度(commensurate)、黄金分割(golden mean)、螺旋分割(spiral mean)三种情况下,描述了特殊垫底势力的振幅A与分子链静摩擦力的关系,在特殊垫底势力的作用下上层原子链弹性系数K对静摩擦力的影响.研究表明,垫底势力的形式对静摩擦力的大小有很重要的影响. 相似文献
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用一维Frenkel-Kontorova模型,对相互接触的两个单原子分子链具有相对运动趋势时所产生的最大静摩擦力进行了研究.分别在相邻原子的距离与周期势场的周期比b/a为可公度(commensurate)、黄金分割(golden mean)、螺旋分割(spiral mean)三种情况下,描述了特殊垫底势力的振幅A与分子链静摩擦力的关系,在特殊垫底势力的作用下上层原子链弹性系数K对静摩擦力的影响.研究表明,垫底势力的形式对静摩擦力的大小有很重要的影响.
关键词:
Frenkel-Kontorova模型
静摩擦力 相似文献
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By using the molecular dynamic simulation method with a
fourth-order Runge--Kutta algorithm, a two-dimensional dc- and
ac-driven Frenkel--Kontorova (FK) model with a square symmetry
substrate potential for a square lattice layer has been investigated
in this paper. For this system, the effects of many different
parameters on the average velocity and the static friction force
have been studied. It is found that not only the amplitude and
frequency of ac-driven force, but also the direction of the external
driving force and the misfit angle between two layers have some
strong influences on the static friction force. It can be concluded
that the superlubricity phenomenon appears easily with a larger ac
amplitude and lower ac frequency for some special direction of the
external force and misfit angle. 相似文献
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The pre-sliding regime is typically neglected in the dynamic modelling of mechanical systems. However, the change in contact state caused by static friction may decrease positional accuracy and control precision. To investigate the relationship between contact status and contact force in pre-sliding friction, an optical experimental method is presented in this paper.With this method, the real contact state at the interface of a transparent material can be observed based on the total reflection principle of light by using an image processing technique. A novel setup, which includes a pair of rectangular trapezoidal blocks, is proposed to solve the challenging issue of accurately applying different tangential and normal forces to the contact interface. The improved Otsu's method is used for measurement. Through an experimental study performed on polymethyl methacrylate(PMMA), the quantity of contact asperities is proven to be the dominant factor that affects the real contact area. The relationship between the real contact area and the contact force in the pre-sliding regime is studied, and the distribution of static friction at the contact interface is qualitatively discussed. New phenomena in which the real contact area expands along with increasing static friction are identified. The aforementioned relationship is approximately linear at the contact interface under a constant normal pressure, and the distribution of friction stress decreases from the leading edge to the trailing edge. 相似文献