对铰杆增力机构中滑柱力学模型的修正

对<机床夹具设计>[1,2]中抽象的滑柱力学模型,进行了分析,指出其错误在于滑柱承受的是一个非平衡力系,建立了基于平衡力系的力学模型,并推演出了相应的力学计算公式.     

对铰杆增力机械中滑柱力学模型的修正

对《机床夹具设计》＾「１,２」中抽象的滑柱力学模型,进行了分析,指出其错误在于滑柱承受的是一个非平衡力系,建立了基于平衡力系的力学模型,并推演出了相应的力学计算公式。     

轧机主传动轴平衡力与液压缸驱动力之间的关系

鉴于合理选择平衡力能有效降低平衡力对传动轴引起的应力集中,以某钢厂粗轧机(R2轧机)为研究对象,根据其主传动装置各组成构件尺寸,建立R2轧机主传动装置模型,对其构件进行力学分析并建立平衡方程,由此推导出R2轧机传动轴平衡力与液压缸驱动力之间的函数关系式,采用MATLAB编程,计算出传动轴所受平衡力的理论解。将该轧机主传动装置的三维模型导入ADAMS软件,提取传动轴所受平衡力的仿真解,并将其与传动轴所受平衡力的理论解相比。结果表明,在轧机主传动轴工作角度范围内、相同倾角下,传动轴所受平衡力的理论解和仿真解误差较小,可以忽略不计。由此验证了推导关系式的可靠性,研究结果对液压缸驱动力的选取具有指导意义。     

用转子重心偏移计算法求动平衡

本文用理想力学模型，推导出发电机转子由于质量不平衡所造成转子重心偏移距（ｅ值）的计算公式；然后根据，值，求出转于不平衡力的大小、用电气测振示波图，找出转子不平衡力的方向，再做动平衡配重，达到消除或减小水轮发电机组振动的目的。     

高层建筑地下室的设计探讨

地下室结构作为高层建筑的基础，既具有稳定性，又要研究其上作用的平衡力系的传递和扩散特性。作者阐明不平衡力系产生的原因及在工程中的处理途径。     

用附加平衡力系方法研究刚体运动学

本文根据加减平衡力系公里，提出用附加平衡力系方法来研究具有完整，定常，理想约束的刚体系统的运动学问题。文中对此方法进行了严格的理论推导和证明，并举例说明其应用。例题表明，在某些情况下，本文所述方法比传统的运动学方法简便。     

带锯床锯切过程的力学建模

针对带锯床锯切过程的力学问题,通过静力平衡方程和微段受力分析,提出了一种新的带锯床锯切过程力学模型,建立了初始预紧力与临界工作状态、初始预紧力与正常工作状态下各力学参量的关系.基于实验数据,验证了力学模型的正确性,研究了锯切过程中各力学参量的相互关系及影响因素.研究表明,带锯床锯切系统在锯切过程中,初始预紧力决定了带锯条的临界锯切力;正常工作过程中,带锯条紧边段拉力和松边段拉力的比值随锯切力的变化而变化;锯切过程的力学模型及相关结果为带锯床的结构设计提供了重要的理论基础.     

微机辅助冲裁力计算及冲裁工艺分析

本文对冲裁件工艺分析及其力学计算建立计算机辅助设计系统进行了研究,重点阐明了冲裁件力学模型优选、工艺分析及工艺路线设计、零件信息的描述等问题。编制了能适合各种板状类冲裁件的冲裁力学计算及工艺分析CAD系统软件,该软件可实现设计、计算和管理一体化。     

对向六斜辊管材矫直机压扁力研究

以弹塑性理论为基础，从弯曲矫直与压扁成形的分离力学模型入手，建立了计算压扁力的独立理论体系，并通过Ｃ程序计算，其结果与计算机实测动态曲线相吻合。     

锻压变形力的一种数值分析模型

为了确定开式模锻中力学参数与模具型腔几何参数之间的关系,采用精确作图法得到了锻靠阶段初期的临界滑移线场模型,并用数值分析方法确定该模型中变形几何参数与滑移线场参数的相互关系,根据滑移线场相关理论进行力学分析,确定这一特定时段的应力场以及变形力分布.该临界数值分析模型的建立为确定锻靠阶段变形区的形状与尺寸,进而求解应力场、变形力分布提供了量化的理论基础,并为运用此方法建立模锻过程其他特征时段的力学模型提供了依据.     

Application of remote monitoring technology in landslides in the Luoshan mining area

With the scale extending of mining, the landslide disaster in the earth's surface will become more and more serious, and these landslide disasters are being threatened to the sustainable safe mining of the underground mine and the open-pit mine. Based on the theory that sliding force is greater than the shear resistance (resisting force) at the potential slip surface is the necessary and sufficient condition to occur the landslide as the sliding criterion, the principle and method for sliding force remote monitoring is presented, and the functional relationship between the human mechanical quantity and the natural sliding force is derived, hereby, the natural sliding force can be calculated according to the human mechanical quantity. Based on above principle and method, a new system of landslide remote monitoring is designed and 53 systems are installed on the landslide body in the Luoshan mining area, which make up the landslide remote monitoring network. According to the results of field test around 8 months, monitoring curves between sliding force and time are obtained, which can describe and forecast the develop trend of landslide. According to above analysis, the results show that this system has some following advantages: (1) real-time monitoring; (2) remote intelligent transmission; (3) landslides early warning.     

粘性成层填土的主动土压力

为了考虑填土凝聚力及其与挡土墙墙背接触面上粘着力计算粘性成层填土挡墙的土压力,假设滑裂面为平面,运用数学、力学手段,推得了粘性成层填土挡墙的主动土压力计算公式,编制了相应的计算程序,进行了算例分析.结果表明:考虑与不考虑滑裂面上的凝聚力c及墙背上的粘着力cw,计算结果差异较大,该差异随着c、cw的增大而增大;公式精度可靠,应用方便.     

Micro contact and stick-slip number between AFM probe tip and sample surface

Atomic force microscope (AFM) has become a main instrument in characterization of micro topography and micro tribology of surfaces. Under its contact mode, AFM probe tip slides on the surface in the direction perpendicular to its longitudinal axis to get topography and lateral force images simultaneously. During the scanning, the AFM tip is loaded by both a normal force and a lateral force, which make the probe bend and twist. In their pioneering work, Mate et al.[1] used AFM to measure m…     

往复荷载下预紧力对露出型柱脚力学性能的影响

预紧力作用下锚栓与结构协同工作时柱脚各组件的应力和柱脚刚度发生怎样的变化,有待于进一步研究.以露出型柱脚为研究对象,利用ANSYS软件,建立考虑接触的三维有限元模型,进行循环荷载下的非线性分析,研究锚栓预紧力对柱脚整体及各部分组件的力学性能影响.结果表明：预紧力可使锚栓与底板的连接更加紧密,增强柱脚的整体性和初始抗弯刚度,延缓底板的翘曲,但是由于锚栓预紧力的影响,锚栓的塑性变形发展趋势增加.考虑抗震设防要求进行柱脚设计时宜合理选择锚栓预紧力.     

低周反复试验轴力加载装置的系统摩擦力

在柱、剪力墙等的低周反复加载试验中,与施加轴压力的竖向作动器相连的钢铰轴处或滑动导轨处存在的摩擦力会导致加载水平力的测量结果不同程度地较真实值偏高。通过试验和有限元计算,分析了该摩擦力的规律和量化取值。为了消除材料非线性并准确考虑几何非线性的影响,设计两个型钢柱进行了材料弹性状态下的低周反复试验,并在OpenSees平台上建立了能够准确计算二阶效应的有限元模型。根据试验测量结果、有限元分析结果对该试验的轴力加载装置引起的摩擦力进行计算,研究了摩擦系数的取值方法,并考察了摩擦力对柱试验结果的影响。研究结果表明：由轴力加载装置引起的摩擦力主要受轴压力值影响,柱顶位移的影响较小;随着轴压力增大,摩擦力增大、摩擦系数变小;最大摩擦力、最小摩擦系数均趋于较稳定的取值;对于轴压力为350~900 kN的钢筋混凝土柱,由该装置摩擦力引起的低周反复试验的柱顶水平力测量结果误差约为5~13 kN。     

基础滑移隔震房屋计算恢复力曲线的确定

以多层砖混隔震结构足尺试验为依据,通过隔震房屋对有无线弹性限位装置的恢复力特性的研究,找出了线位消能元件Ｕ型环个数与其刚度关系,提出了多层砖房隔震结构恢复力计算模型,为隔震房屋的设计计算提供了依据．     

Study of Slope Reinforcement Force Based on FLAC

A slope will slide if the unbalanced force does not tend to zero when the stability of the slope is analyzed with the help of FLAC. Thus the ultimate reason of slope sliding is the unbalanced force determined by FLAC. The slope will remain stable if the unbalanced force is counterbalanced by a reinforcement force which is produced by a suitable reinforcement method. In this paper, the stability of the slope was analyzed by using FLAC, and the unbalanced force of the slope was obtained through the FISH function in FLAC. According to the equilibrium conditions, the relationship between the reinforcement force and unbalanced force was derived and accordingly the reinforcement force was determined. The reinforcement design was adopted by using pre-stressed anchor bars on the basis of the reinforcement force. An example is used to show that the effect of slope reinforcement based on the reinforcement force is safe and economical. The method doesn＇t need to suppose a sliding surface to obtain the reinforcement force, and it is also clear in physical meaning. So this method realized the organic unification of the stability analysis and the slope reinforcement.     

Numerical Simulation Study on Wear of Spur Gears under Dynamic Conditions

A numerical simulation model is proposed to predict the wear depth of gears, where Archard''s wear equation and a nonlinear dynamic model are combined to establish a wear calculation model under dynamic conditions. The dynamic meshing force, determined by the non-linear dynamic model, and the sliding coefficient are used by Archard''s wear equation to calculate the surface wear. Then the dynamic meshing force and sliding coefficient would be recalculated according to the surface wear state. After repeated iterations, the simulation results show that the peak and fluctuation of the meshing force increase first, then decrease, and eventually maintain stability during the process of wear. As for the distribution of wear depth, its fluctuation also increases first and then declines. Finally, the distribution of wear depth becomes V-shaped. Comparing the trends of the two factors, it is clear that the meshing force and wear depth are closely related. Moreover, the wear rate maintains a higher constant value first and then declines to a lower constant value.     

基于滑模控制的半主动悬架系统仿真分析

建立1/4车2自由度半主动悬架系统动力学模型,并根据滑模变结构方法设计了车辆半主动悬架滑模控制器。控制器将天棚阻尼系统作为参考模型,把半主动悬架和参考模型间的广义误差动力学引入渐进稳定的滑模动态中,使用等速趋近率改善运动段的动态品质。仿真结果表明,滑模控制器的性能稳定,能有效地提高车辆行驶的平顺性和行驶的安全性。     

基于Matlab的三叉杆滑块式万向联轴器的动力学分析

利用方向余弦矩阵工具,在三叉杆滑块式等角速万向联轴器运动学分析的基础上,计入摩擦力和惯性力,对该联轴器建立起动力学模型,进行了全面的受力分析。数值分析结果表明:各构件的受力按正弦规律或近似于正弦规律相对于输入轴转角呈周期性变化;摩擦系数对回转副和球面副中各力影响较大,对移动副中各力影响较小。