动态断裂韧性测试中的惯性效应分析

用弹簧质量模型分析了三点弯曲试样在冲击载荷作用下的惯性效应，得到了脆性断裂条件下有效载荷的修正公式。分别采用受惯性效应影响的示皮冲击试验及无惯性效应的焦散线技术对HQ785C钢进行了动态测试，验证了修正公式的有效性。     

层合梁横向冲击的动力学效应

研究了十字叠层复合材料梁横向冲击响应的动力学效应，根据冲击实验曲线及动态有限元方法计算了惯性效应和应力波效应对位移和应力响应的影响。     

Timoshenko阶梯梁在惯性效应移动载荷下的振动

变截面梁可以简化为由多段阶梯梁所组成,简化的段数越多,结果越精确。因此,基于Timoshenko梁理论,运用连续体传递矩阵法建立阶梯梁振动微分方程,并求解阶梯梁在考虑惯性效应移动载荷作用下的受迫振动响应;改变移动载荷的质量、速度和加速度,研究移动载荷参数对惯性效应的影响。与Euler梁模型和有限元模型的对比表明,该方法精度良好。选取悬臂梁自由端端点进行分析,结果表明,移动载荷的质量、速度和加速度增大,惯性系数也增大;质量是影响惯性效应的主要因素。当移动载荷的质量很小时,可以忽略由加速度和速度引起的惯性效应。     

饱和土中大直径嵌岩桩纵向振动特性研究

根据B iot饱和土理论和R ay le igh-Love杆理论,计及土层及桩的径向运动影响,导出了考虑横向惯性效应的端承桩与饱和土的纵向耦合振动频域的解析解和时域半解析解,对比了考虑与不考虑横向惯性效应时,大直径嵌岩桩纵向振动引起的土层复阻抗的异同以及桩顶导纳和时域反射的特征。研究表明:长径比越小,横向惯性效应越明显,而泊松比和激振频率对饱和土层阻抗及桩顶响应也有重要影响。通过工程实例对比表明,当桩的长径比较小时,用考虑横向惯性效应的计算方法可以得到更好的拟合效果。     

考虑横向惯性效应时黏弹性支承桩纵向振动特性研究EI北大核心CSCD

考虑土体三维波动效应及桩身横向惯性效应,建立了均质滞回阻尼土中黏弹性支承桩受稳态或瞬态纵向激振时的定解问题,并获得了严格桩土耦合条件下的解析解。首先,将桩底土层对桩及桩侧土层的作用简化为均布Vogit体,桩视为Rayleigh-Love杆,利用土体三维轴对称振动方程,土层边界条件,以及桩与桩侧土接触面上的纵向和径向位移连续条件,求解得到桩侧土作用在桩身的剪切复刚度。然后,结合桩底黏弹性支承条件,推导得到桩顶复阻抗函数的解析解。最后,采用参数分析方法,研究了横向惯性效应对单桩桩顶动力响应的影响规律及其与桩及土层参数的关系。结果表明:相对于不考虑横向惯性效应,计及横向惯性效应时单桩纵向振动特性的差异受桩及土共同的影响。     

考虑横向惯性效应时黏弹性支承桩纵向振动特性研究

考虑土体三维波动效应及桩身横向惯性效应,建立了均质滞回阻尼土中黏弹性支承桩受稳态或瞬态纵向激振时的定解问题,并获得了严格桩土耦合条件下的解析解。首先,将桩底土层对桩及桩侧土层的作用简化为均布Vogit体,桩视为Rayleigh-Love杆,利用土体三维轴对称振动方程,土层边界条件,以及桩与桩侧土接触面上的纵向和径向位移连续条件,求解得到桩侧土作用在桩身的剪切复刚度。然后,结合桩底黏弹性支承条件,推导得到桩顶复阻抗函数的解析解。最后,采用参数分析方法,研究了横向惯性效应对单桩桩顶动力响应的影响规律及其与桩及土层参数的关系。结果表明:相对于不考虑横向惯性效应,计及横向惯性效应时单桩纵向振动特性的差异受桩及土共同的影响。     

温控中热惯性抑制方法探讨

在温度的测量，控制过程中，升，降温终点常产生热惯性效应，使温度偏离设定值，出现较大的超调量，对于分阶段升，降温时场合，这种影响尤为严重，本文介绍解决这一问题的途径和方法。     

闭孔泡沫铝在动态加载下的压缩力学行为研究

为研究闭孔泡沫铝的动态压缩力学响应过程,基于典型泡沫铝试样的孔型和分布情况构建了Voronoi模型,根据实验结果验证了模型的准确性。基于LS-DYNA分析了目前泡沫铝常用的Kelvin模型和Voronoi模型之间的差异性,研究了加载速度、基体应变率效应和压缩惯性效应对闭孔泡沫铝变形模式和应力水平的影响规律。研究结果表明:Voronoi模型应力-应变水平和变形模式与实验结果拟合较好,内部结构比单胞阵列的Kelvin模型更趋真实合理;在低速压缩下,泡沫铝惯性效应基本上可以被忽略,而高速压缩下,受压缩惯性效应影响,泡沫铝平台应力随着加载速度的增大而增大;当考虑泡沫铝基体应变率效应时,泡沫铝平台应力水平会得到有效的改善,且泡沫铝整体呈现应变率效应。     

板料成形过程动力分析中的惯性效应的研究

本文指出板料成形中采用曲面压料面时压边圈夹紧过程动力显式有限元分析存在惯性效应问题,采用能量法分析了影响惯性效应的一些主要因素,提出"虚拟补实压边圈"方法以克服惯性作用,高效实现曲面压边圈夹紧过程的动力显式有限元模拟,对于连续快速地模拟曲面压边和拉延等多阶段板料成形过程有重要意义.     

织构化纹理对于45钢摩擦学性能的数值模拟及试验分析

为探究不同形式的微织构对于柴油发动机活塞裙部表面摩擦特性的影响,在考虑惯性效应的条件下,基于CFD方法,利用Navier-Stokes方程建立了织构化试样流场的二维仿真分析模型.利用磨床在试样表面加工出规律单向条状纹理,采用激光打标机在45钢表面制备三角微织构凹坑,并在MMW-1A立式万能摩擦磨损试验机上对织构化45钢进行摩擦试验.织构化流场的数值模拟试验结果表明:在织构化流场存在流体惯性效应,使得流场获得额外的承载力;条状纹理与三角微织构凹坑之间的流场存在惯性效应的“叠加”效应,能够获得更高的承载力.摩擦试验结果表明:带有条状纹理的上试样能够有效降低摩擦过程初始阶段的摩擦系数,缩短摩擦副达到稳定磨损状态的时间.摩擦试验结果较好地证明了数值模拟试验的准确性.     

Two-dimensional oscillatory motion of inertially focused particles in microfluidic flows

Inertially focused particles flowing in microchannels form an evenly spaced streamline on each channel face due to hydrodynamic interaction. Previous studies of this interaction have only reported the oscillatory pairwise dynamics of focused particles, which was limited to the one-dimensional (1D) streamwise direction. Thus, despite its practical and intellectual importance, there remains a lack of comprehensive research on the pairwise oscillation, due to the difficulty of high-resolution observation. Here, I explore the hydrodynamic interaction between inertially focused particles in microfluidic flows to determine the ordering mechanism. Direct numerical simulation (DNS) is applied to a pressure-driven flow of a pair of particles due to the lack of established formulas for the inertial focusing of finite-sized particles; in particular, only DNS allows the author to simulate the microscale flow structures. I describe the unique periodic oscillations of the pairwise particles as they flow downstream. Upon the formation of a train structure in the steady state, the following particle shows periodic oscillations on a two-dimensional (2D) limit cycle around its equilibrium position, whereas the leading particle exhibits 1D oscillation at a specific distance downstream. The 2D oscillatory motion of the following particle is produced by a combination of the lift forces and the disturbance flow induced by the leading particle, coupled with forward/backward transport by the main flow. Thus, the spacing of the particle train is a function of the particle size and flow conditions, leading to even spacing between inertially focused particles. The finding of the asymmetric oscillatory dynamics of the pairwise system provides direct evidence for the self-assembly mechanism of inertially focused particles. I highlight a mostly overlooked aspect of the lift forces: that they stabilize focused streamlines that might otherwise break apart due to finite-particle-induced disturbance flows.     

Effect of friction on the performance of inertial slider

Inertial sliders are friction based drives used to position with a resolution of a few hundred of nanometers to over a range of few millimeters. The compactness and simple construction enabled it to be used as a coarse positioner in various Scanning Probe Microscopes (SPM). Even heavy masses has been thought off earlier to use the inertial slider to position precisely, lack of understanding in the dynamical friction behaviour has been the main reason why the inertial sliders potential has not been explored fully in any practical device. In this paper, we have studied the effect of different operating parameters on the step size of the slider. The inertial mass is kept on three sapphire balls, which are attached to shear piezoelectric material. The behaviour of inertial mass was studied for different input waveforms and different surface conditions that come in contact with the sapphire balls. It was observed that under lubricated conditions the step size was reduced.     

包装机横封机构平衡问题的研究

就某包装机的横封机构进行了平衡问题的探讨 ,求出惯性力及惯性力偶 ,指出了使其平衡的方法     

用于驱动次临界堆的惯性约束聚变中子源与加速器中子源的分析比较

分析了用惯性约束聚变（ＩＣＦ）中子源和加速器（ＡＤ）中子源驱动一个热功率为百万千瓦级（ＭＷｔ）的次临界包层的可能性。给出了驱动不同次临界度包层所需的中子源强度及其相应的物理参数。比较了两种中子源系统的特点及可能实现的前景。     

光纤陀螺技术及其在军事领域的应用展望

光纤陀螺作为新型的角度传感器,近年来发展非常迅速,在测量和制导领域得到广泛的应用。本文介绍了光纤陀螺的基本原理和分类、各类光纤陀螺的特点及国内外的发展状况,结合光纤陀螺的特点,展望了其在精确制导弹药、测试等军事领域中的应用。     

流面上Navier－Stokes方程和惯性形式

本文推导场流面上Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，并且证明存在惯性形式．     

Approximate Inertial Manifold Method andMultilevel Finite Element Approximationfor the Navier-Stokes Equations

This paper presents the Approximate Incrtial Manifold ∑ and its successive approximate incrtial manifold ∑i and ∑ij . We give the estimates of thickness of neighborhood of ∑, ∑j, Ejt respectively in which the every solution of Navier-Stokcs equation enters.Another part of this paper presents construction method for A.I.M. by multilevel finite clement method and give error estimates of the approximate solution of incrtial form.     

Experimental study of a thermoacoustically-driven traveling wave thermoacoustic refrigerator

New configurations of traveling wave thermoacoustic refrigerators driven by a traveling wave thermoacoustic engine were introduced and tested in this paper. First, the performance of the refrigerator with different-diameter inertance tubes was investigated experimentally. Then, investigation of substituting a flexible membrane attached to inertial mass for inertance tube was tested. The experimental results show that the substitution could improve the efficiency of the system and lead to a larger cooling power. So far, using helium gas as the working gas, the system could provide 340 W cooling power at the temperature of −20 °C with working frequency of 57 Hz and average pressure of 3.0 MPa. The total COP, i.e., cooling power divided by heating power, is 0.16.     

Present states and future prospect of fast ignition realization experiment (FIREX) with Gekko and LFEX Lasers at ILE

The fast ignition realization experiment (FIREX) project is progressing. The new short pulse laser system, LFEX laser, has been completely assembled and one of the four beamlets is now in operation. A fast-ignition experiment was performed using this single short pulse combined with the Gekko XII implosion laser. The energy of the GXII implosion laser was about 2 kJ and the pulse width was 1.5 ns. The energy of the LFEX laser was increased upto 800 J and two pulse durations 5 and 1.6 ps were compared. Targets were deuterated plastic shells with gold cones. It was found that the neutron yield was increased by a factor of 30 as a result of the fast electron-induced heating in LFEX 1.6 ps shot. The estimated coupling efficiency between the LFEX laser pulse and the compressed fuel was low (less than 5%). This may be due to pre-plasma formed by light arriving at the target before the main laser pulse. Further investigations and attempts to overcome these problems are now in progress.