微惯性仪表技术的研究与发展

论述了当前国内外微惯性仪表设计和制造技术的研究与发展，强调了对相关基础理论研究的重要性，提出了计算机集成微制造单元的概念。     

静电悬浮式惯性仪表中的微位移检测技术

静电陀螺仪、空间静电加速度计等基于静电悬浮的惯性仪表在高精度的惯性导航和空间微重力测量领域得到广泛应用。近年来，对基于MEMS工艺的悬浮式微惯性传感器的研究引起了广泛的重视。介绍了静电悬浮式惯性仪表中采用的差动电容式微位移检测电路的原理，分别对静电陀螺、静电加速度计和MEMS微陀螺、微加速度计的电极配置方案和位移检测的接口电路进行了分析，并对不同的位移检测方案进行了比较.     

微小型惯性仪表发展现状、趋势以及对行业的影响

惯性仪表(包括陀螺和加速度计)是惯性技术的基础和核心,近年来,以高精度硅微机电陀螺、集成化微光纤陀螺、速率积分半球谐振陀螺、谐振式加速度计为代表的新型惯性仪表技术发展迅猛,相比传统惯性仪表,能够兼顾高精度和低SWaP+C(Size Weight and Power,plus Cost,体积、重量、功耗和成本)指标,正推...     

建立惯性仪表安装误差数学模型的理论研究

安装误差对系统精度有较大的影响,对捷联惯性系统的影响尤为突出,为此从仿射坐标系的坐标变换理论入手,分析并推导了建立惯性仪表安装误差数学模型的坐标变换矩阵公式,为惯性仪表安装误差数学模型的建立、测试及在惯性导航系统中的补偿提供了理论依据。     

液浮惯性仪表真空充液工艺流程自动化系统

本文通过悬浮对液浮惯性仪表的作用，以及液浮惯性仪表真空充液工艺流程中各节点关键量的控制对液浮惯性仪表的重要性分析，指出真空充液工艺流程自动化的重要性。进而设计出一个液浮惯性仪表真空充液工艺流程自动化系统的硬件和软件组成框图及有关指标和要求，为实际研制提供了有益的依据。     

双输入轴微机械陀螺仪的研究与进展

微机械陀螺仪是微机电系统（MEMS）研究的重要内容。双输入轴微机械陀螺仪可最大限度地发挥微结构的固有功能并实现最低成本。本综合了国内外在这方面的主要研究报道，概述各自的结构、工艺、测试和性能特点，以展示双输入轴微机械陀螺仪的发展历史与研究现状。     

基于微机械惯性传感器的卫星电视天线稳定系统

介绍了一套基于微机械惯性传感器测量的卫星电视接收天线稳定系统的组成、工作原理及技术要求，讨论了系统的几项关切技术，包括：微机械惯性姿态测量模块，步进电动机闭环伺服控制以及场强自动跟踪技术。计算仿真和样机实验的结果表明：系统达到了预期的技术指标，已能够满足舰船上的应用要求。由于微机械测量器件的采用，系统具有体积小、成本低、性能可靠的优点。     

梳齿式微机械力平衡加速度计

讨论了一种梳齿式微机械加速度计，介绍了表头微机构的特点和系统工作原理。通过对加速度计机械模型的分析，计算得出了加速度计的主要设计性能指标。另外还比较完整的提供了加速度计各项性能试验的数据，试验结果与理论分析能很好地吻合，说明加速度计的性能指标基本达到设计要求，证明这种加速度计的设计是成功的。     

国外惯性技术新进展述评

本文综合了国外最新发表的文献资料及考察报告，论述了陀螺仪与惯性系统的最新进展，介绍了惯性技术的最新应用领域。最后提出了作者对发展惯性技术的意见。     

微惯性传感器建模及冲击响应分析

研究了微惯性传感器在冲击环境下的可靠性问题，重点分析了微惯性传感器在冲击载荷作用下的冲击响应问题。根据微惯性传感器结构部件主要由质量块、支承梁、衬底组成的特点，建立了微惯性传感器结构部件的集总参数模型，得出了微加速度计和微陀螺在半周正弦加速度冲击载荷作用下的冲击响应解析解，并采用有限元分析软件ANSYS验证了该解析解的正确性。此冲击响应解析解对预测微惯性传感器在冲击环境下的可靠性具有重要作用。     

Micromechanical modelling of remanent properties of morphotropic PZT

The present paper investigates the capability of micromechanical material models to predict the ferroelectric behaviour of morphotropic PZT ceramics in a rate-independent approximation based on realistic microscopic material parameters. Starting point is a three-dimensional tetragonal model, which builds on the model of Pathak and McMeeking [2008. Three-dimensional finite element simulations of ferroelectric polycrystals under electrical and mechanical loading. Journal of the Mechanics and Physics of Solids 56, 663-683]. Volume fractions of the crystallographic variants represent the domain structure inside the grains. Interactions between the grains are taken into account by means of a representative volume element of the grain compound. A simplified set of realistic microscopic material parameters of the lattice in terms of Young's modulus, Poisson's ratio, dielectric constant, and spontaneous strain and polarisation is derived from experimental data and theoretical results given in the literature. The simulation of the macroscopic remanent polarisation and strain response due to two load cases shows explicitly that the tetragonal model is not capable to reproduce the behaviour of morphotropic PZT. Therefore, the model is extended by the rhombohedral phase, allowing a mixture of both phases with varying quantities inside the grains. A comparison of our results with experimental data shows a remarkably good agreement, revealing the capability of the extended model.     

Micromechanical modeling of packing and size effects in particulate composites

This paper is devoted to the introduction of packing and size effects in micromechanical predictions of the overall elastic moduli of particulate composite materials. Whereas micromechanical models derived from the classical ‘point approach’ are known to be unable to model such effects, it is shown that the so-called ‘morphologically representative pattern-based approach’ (MRP-based approach) offers new means of taking some geometrical parameters into account such as the mean distance between nearest-neighbor particles or their size, so as to predict the dependence of the overall moduli on these parameters, at least in a relative way. Moreover, when internal lengths, such as the thickness of interphase shells of coated particles, are introduced, absolute size effects can be predicted as well. Illustrative applications are reported in view of comparisons between such new treatments and the predictions of some classical models which are shown to coincide with the ones derived from MRP-based models in definite limiting cases only.     

Micromechanical model of the high temperature cyclic behavior of 9–12%Cr martensitic steels

9–12%Cr quenched and tempered martensitic steels are known to soften under cyclic loadings at high temperature. The present article proposes a model based on physical mechanisms described at the scale of slip systems. This model describes explicitly the microstructural recovery (corresponding to a decrease of the dislocation density and subgrain coarsening) observed experimentally. The scale transition is carried out in the framework of self-consistent homogenization schemes. The model assumptions and its physical basis are explicitly discussed. The parameters are identified on a very limited amount of experimental data. The model turns out to give very good predictions and extrapolations for the cyclic softening effect observed in uniaxial tension–compression loadings for strain ranges larger than 0.3%. Stress–relaxation and creep behavior can also be simulated for high stresses. In addition the cyclic softening effect is reproduced for multiaxial tension–torsion loadings.     

Micromechanical consideration of tensile crack behavior based on virtual internal bond in contrast to cohesive stress

A modified version of the virtual internal bond model (VIB) is presented. This involves the introduction of a R-bond restricting the relative rotation freedom of pairwise mass particle. Such a modification allows the VIB model to consider arbitrary values of the Poisson ratio. A linear elastic cohesive law considering both the R-bond and L-bond are assumed. The constitutive relationship is derived using the Cauchy–Born rules. The derived constitutive associates the bond stiffness with the Young’s modulus and Poisson ratio of materials. This gives the bond stiffness in terms of the Young’s modulus and Poisson ratio of materials.The modified VIB model is then used to analyze the tensile crack behavior. In contrast to the cohesive stress method, the deformation-governed concept will be used. The local materials failure is assumed to coincide with the reduction of the bond density due to the local deformation rather than by the local cohesive stress. A phenomenological relationship between the bond density and the deformation is established. The criterion which is applied to determined crack initiation and propagation is built into the constitutive model. As an example, the method is used to study the crack initiation and propagation behavior under tensile loading.     

Analytical and numerical solutions of the Local Inertial Equations

Neglecting the convective terms in the Saint-Venant Equations (SVE) in flood hydrodynamic modelling can be done without a loss in accuracy of the simulation results. In this case the Local Inertial Equations (LInE) are obtained. Herein we present two analytical solutions for the Local Inertial Equations. The first is the classical instantaneous Dam-Break Problem and the second a steady state solution over a bump. These solutions are compared with two numerical schemes, namely the first order Roe scheme and the second order MacCormack scheme. Comparison between analytical and numerical results shows that the numerical schemes and the analytical solution converge to a unique solution. Furthermore, by neglecting the convective terms the original numerical schemes remain stable without the need for adding entropy correction, artificial viscosity or special initial conditions, as in the case of the full SVE.     

Turbulent Flow and Dispersion of Inertial Particles in a Confined Jet Issued by a Long Cylindrical Pipe

In this work we examine first the flow field of a confined jet produced by a turbulent flow in a long cylindrical pipe issuing in an abrupt angle diffuser. Second, we examine the dispersion of inertial micro-particles entrained by the turbulent flow. Specifically, we examine how the particle dispersion field evolves in the multiscale flow generated by the interactions between the large-scale structures, which are geometry dependent, with the smaller turbulent scales issued by the pipe which are advected downstream. We use Large-Eddy-Simulation (LES) for the flow field and Lagrangian tracking for particle dispersion. The complex shape of the domain is modelled using the immersed-boundaries method. Fully developed turbulence inlet conditions are derived from an independent LES of a spatially periodic cylindrical pipe flow. The flow field is analyzed in terms of local velocity signals to determine spatial coherence and decay rate of the coherent K–H vortices and to make quantitative comparisons with experimental data on free jets. Particle dispersion is analyzed in terms of statistical quantities and also with reference to the dynamics of the coherent structures. Results show that the particle dynamics is initially dominated by the Kelvin–Helmholtz (K–H) rolls which form at the expansion and only eventually by the advected smaller turbulence scales.     

Micromechanical analysis on tensile properties prediction of discontinuous randomized zalacca fibre/high-density polyethylene composites under critical fibre length

In this research, the tensile properties' performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method and micromechanical models. These investigations were used to verify the tensile properties models toward the effect of fibre length and volume fraction on the composites. The experimental results showed that the tensile properties of composites had significantly increased due to the enhancement of fibre length. On the contrary, a decline in the tensile properties was observed with the increase of volume fraction. A comparison was made between the available experimental results and the performances of Tsai-Pagano, Christensen and Cox-Krechel models in their prediction of composites elastic modulus. The results showed that the consideration of fibre's elastic anisotropy in the Cox-Krenchel model had yielded a good prediction of the composites modulus, nevertheless the models could not accurately predict the composites modulus for fibre length study.     

Two-Phase Inertial Flow in Homogeneous Porous Media: A Theoretical Derivation of a Macroscopic Model

The purpose of this article is to derive a macroscopic model for a certain class of inertial two-phase, incompressible, Newtonian fluid flow through homogenous porous media. Starting from the continuity and Navier–Stokes equations in each phase β and γ, the method of volume averaging is employed subjected to constraints that are explicitly provided to obtain the macroscopic mass and momentum balance equations. These constraints are on the length- and time-scales, as well as, on some quantities involving capillary, Weber and Reynolds numbers that define the class of two-phase flow under consideration. The resulting macroscopic momentum equation relates the phase-averaged pressure gradient to the filtration or Darcy velocity in a coupled nonlinear form explicitly given by

特征向量导数计算各种模态法的比较和发展

在结构动力学修改以及结构动态设计中，灵敏度分析是十分重要的一环，往往也是主要工作量所在。如何在保证精度前提下减少灵敏度分析工作量和计算时间，具有重要意义。本文对特征向量灵敏度分析中计算特征向量导数的模态法作了综合评述，除了经典模态法和修正模态法之外，还对新近发展的迭代模态法和移位模态法进行了介绍。最后通过典型结构实例的计算仿真，对各种模态法作了比较。