光学空间频率合成器及其在无分散三维形状计测中的应用

传统的白光干涉法、光学频谱扫描干涉法、低相干度断层扫描法以及其他三维形状计测法均采用宽带光学频谱光源实现绝对高度的测量,因此当测量对象存在不均匀的折射率分布或者光学吸收特性时,以上方法将不能给出准确的测量结果.针对传统绝对干涉法的这些制约,本研究通过干涉现象中时空参数的类比,提出了宽带空间频谱单色光源的概念,并通过改变光源的空间频谱构造验证了无分散三维绝对形状测定方法的可行性.     

光学空间频率合成器及其在无分散三维形状计测中的应用(英文)

传统的白光干涉法、光学频谱扫描干涉法、低相干度断层扫描法以及其他三维形状计测法均采用宽带光学频谱光源实现绝对高度的测量,因此当测量对象存在不均匀的折射率分布或者光学吸收特性时,以上方法将不能给出准确的测量结果。针对传统绝对干涉法的这些制约,本研究通过干涉现象中时空参数的类比,提出了宽带空间频谱单色光源的概念,并通过改变光源的空间频谱构造验证了无分散三维绝对形状测定方法的可行性。     

非共轴高频光学信息处理系统及其在散斑计量学中的应用

本文通过移动光源或变换透镜,将标准的共轴光学信息处理系统变成不共轴系统,提高了系统的截止频率,甚至可以不因不共轴性而增大系统象差,同时保证了严格的傅里叶变换。本文还将不共轴系统用于散斑计量学的滤波处理,得到了良好的结果。     

局部正交无网格伽辽金法的研究及其在含多裂纹多孔结构中的应用

通过对无网格法中正交基函数的研究,提出局部正交无网格伽辽金法,局部正交基函数保持原正交基函数的性质,但其导数具有了通式,简洁明了,易于编程实现,计算效率高,并将其应用到求解含多裂纹多孔均匀拉伸板的应力强度因子中,计算结果与用正交无网格伽辽金法和有限元法得到的结果进行比较,证明了局部正交无网格伽辽金法的可行性和正确性。     

激光全息干涉法测三维位移的误差分析

激光全息干涉法测三维位移,通常采用多张全息图法和单张全息图法。本文推导了这两种方法的测量误差计算公式。并应用这些公式对全息条纹三维读数仪作了较为详尽的误差分析。     

振动频谱再分析的模糊模式识别法

本文首先讨论工程振动信号频谱再分析技术,针对所存在问题,提出模糊式识别再分析方法,以滚动轴承振动成因研究中的谱分析为例,具体介绍了频谱的峰值频率分布模式,模糊子集及隶属函数的确定,以及综合评判的识别过程,最后给出一具体计算结果。     

Polarized speckle-photoelasticity for 3-D stress analysis

Combining speckle interferometry with photoelasticity, the absolute retardation fringes in 3-D model are obtained by interference of the polarized rays reflected from the two surfaces of a sandwiched plate inside the model. This method can avoid the troubles introduced by Poisson's ratio μ=0.5 and stress-optical constants' ratioA/B=-2 of the photoelastic material, in a stress-frozen state and yield the results which provide necessary supplementary information for the completely-experimental solution of 3-D stress state. A comparison of experimental results with theoretical ones shows the feasibility of the method proposed in the present paper. The project is supported by the National Natural Science Foundation of China.     

三维位移场(U,V,W)实时观测的云纹干涉法

本文将一特殊布置的云纹干涉系统和一垂直入射试件栅的麦克尔逊干涉系统组和起来,利用云纹干涉系统测量两个面内位移分量U、V,垂直入射的麦克尔逊干涉系统测量离面位移分量 W。调节云纹干涉系统中入射光的入射角,使正、负一级衍涉波的传播方向偏离开试件栅法向一微小角度,从而使一级衍涉波的频谱点与麦克尔逊干涉系统中的零级衍涉波的频谱点在频谱面上分开。利用小反射镜的反射来改变一级衍射波的传播方向,从而使我们在三个彼此分开的成像面上同步实时观测到三维位移场的条纹图。文中给出了严格的理论推导和实验验证。     

An optical interferometric system for 3-D displacement measurement

Experimental Techniques -     

Cut cell strategy for 3-D blast waves numerical simulations

   Abstract. This paper presents the results obtained by a generalized cut cells strategy on 3-D blast waves problems. The mesh is cartesian except when it is intersected by the surface of the solids inserted in the computational domain. The improvement, relatively to a classical cut-cells method, is the treatment of the cut which preserves the real geometry of the surface instead of approximating it by a plane. This approach avoids a loss of precision of the numerical scheme at the boundaries and allows future extension to higher order schemes (). Moreover it is useful for any kind of geometry with a high efficiency in computation time. The drawback is the complexity of the geometrical problems which can rise because of the diversity of situations in the treatment of the cuts. The performance of the approach is tested on a few examples allowing comparisons with experiments or other techniques and physical discussions. Received 15 November 1999 / Accepted 11 July 2000     

Polarized shearing-moire interferometry for separated 3-D strain fringe patterns

Utilizing laser's properties of both polarization and temporal coherence, a real time method of moire interferometry is proposed to obtain the separated 3-D displacement derivative fringe patterns. For dual beams that contain identical polarization components, the optical-path difference is larger than that of the coherent length to eliminate the interaction between the wavefronts due to the shearing. For dual beams that contain no identical components of polarization, the vibration planes are perpendicular to each other to have the frame-separation of the in-plane derivative patterns. The out-of-plane displacement derivative patterns are achieved by the shearing of the zero-order diffractions of the grating.     

水闸闸室结构三维样条边界元分析

用三维样边界元法分析水闸闸室结构。底板，闸墩和载水墙等为其子结构，交通桥，工作桥和胸墙等处理为内部支撑。地基和边载可以是任意的，只要能给定地表位移面力关系。在各种工况下，不论是设置平板门还是弧形门，是平底板是反拱底板，即使在稀疏剖分下也能给出高精度的位移场，应力场和地基反力场。     

用于截瘫FES行走的三维上肢力动态测量系统

功能性电刺激(FES)技术已被广泛用于截瘫病人行走能力的恢复,但作为评估截瘫FES行走效率的重要指标,三维上肢力状况的研究至今仍十分有限,亟待深入开展。本文研制出了一套可用于截瘫FES行走的三维上肢力动态测量系统,该系统在一个标准步行器框架上装备有 12个应力应变片电桥,通过专用的隔离放大及A/D转换装置与计算机相连,经过标定后,截瘫FES行走时的上肢支撑力数据就可以被系统实时获得并显示。测力系统在应变片位置的确定以及“冗余-优化”方法的采用等多个方面保证了测量的可靠性和准确性,后续的校准实验显示系统的非线性、交互干扰和力学精度误差分别小于 2. 901%, 3. 188%和 1. 01%。研究中,一例截瘫患者作为志愿者按照正常的FES行走训练程序进行了相关测试,以验证新系统在行走能力评估方面的临床前景,结果表明其可用于: 1)截瘫FES行走效率的评估; 2)病人自我训练的控制指导; 3)作为反馈信号选择一种有效的FES模式和阵列。