Numerical simulation of isopachic parameter determined by phase-stepping interferometric photoelasticity

A phase-stepping interferometric photoelasticity method is proposed to determine whole-filed sum of principal stresses. The four phase steps are introduced by rotating quarter-wave plate and analyzer at definite optical arrangements. Light intensities and phase-stepping formula for the proposed method are derived using Jones calculus. Simulations of a circular disk under diametral compression demonstrate the feasibility of the proposed method.     

基于数字图像相关的透明材料厚度测量

提出了一种测定透明材料厚度的新方法。该方法是基于透明材料对光的折射特点,利用光斑点面内位移与材料厚度的变化关系,将厚度的测量转化为对面内位移的测量。将此方法与数字图像相关法相结合,实现了单摄像机对厚度的测定。对轴向拉伸状态下的有机玻璃板的厚度变化进行了测定,将实验结果与理论值进行了对比,两者符合较好,证明了该实验方法的有效性和可行性。     

数字仿真形貌影栅云纹法及实验系统的原理

基于影栅虚云纹场的概念,提出并实现了对形貌影栅云纹法利用计算机布置影栅云纹仪各种光场,自动生成高质量全场仿真影栅云纹图,建立了一种数字仿真形貌影栅云纹法自动测量和处理一体化实验系统（全文简称为实验系统）.系统特别适合于作为形貌影栅云纹法误差分析的评估系统,对光场布置不同的影栅云纹仪及其对应的相移值近似程度不一样引起的初始系统误差进行分析、预测和评估,给出减少这种系统误差应遵循的准则.     

Numerical simulation of isopachic parameter determined by phase-stepping interferometric photoelasticity:errata

The authors regret that errors occurred in the previous paper. If the polarizer and analyzer are generally represented by Pβwith arbitrary angleβto the reference axis in Fig. 1, original Eq. (8) can be rewritten as E1=PβQγRδ,θQπ/4Pβ. (8) It is noted that the polarizer and analyzer always keep same polarized direction. The last interfered Jones vector Etotal is revised as Etotal=E1 Pβ. (9) The final intensities Ii for four configurations are listed as Table 1 (original Eq. (11) is deleted).     

基于虚云纹原理的数字相移形貌影栅云纹仿真系统

在阐述形貌影栅云纹法的虚云纹原理的基础上,利用计算机模拟了各种光场中的全场仿真影栅云纹图,结合相移技术创建了以精确解答为基准的数字相移形貌影栅云纹仿真系统,并且讨论了点照射—点观测光场设置下使用相移法必然会引入系统初始误差的普遍现象。通过对点照射—点观测光场中参数差异所带来不同的系统初始误差进行分析和评估,得到了降低这种光场系统误差所应遵循的准则。这些新的工作对规范、合理设计数字形貌影栅云纹仪实验系统和对特殊的光场设置进行误差分析将有所帮助,进一步对研究工作的前期准备具有启发和指导作用。     

T应力对光弹性条纹影响的理论分析

以裂尖弹性应力场的多参数模型为基础,研究I型、II型以及I/II混合型裂纹参数对光弹性条纹的影响. T应力的存在和符号影响着等色线条纹环的半径大小和旋转方向,对于纯I型或II型裂纹而言,条纹环的旋转角度只与T应力有关;而对于I/II混合型裂纹,条纹环旋转角度与K_{\rm I}, K_{\rm II}和T应力有关. T应力的存在使得I型裂纹在裂尖±π/3方向上出现2个各向同性点(T应力为正时),使得II型裂纹在裂尖后的裂纹面上出现1个各向同性点. 对于I/II混合型裂纹而言,当T应力为正时等倾线出现距裂尖半径不等的3个各向同性点;反之, T应力为负时在裂尖后只存在1个各向同性点,这些各向同性点分别与I型和II型裂纹情况具有相同的规律.      

Multi-frequency lateral shear interferometer system for simultaneous measurement of thickness and three-dimensional shape

This Letter demonstrates a novel lateral shear interferometer system for simultaneous measurement of three-dimensional(3D) shape and thickness of transparent objects. Multi-frequency fringe patterns can be created by tilting mirrors at different inclination angles. With a single camera, the multi-frequency fringes are recorded in one image. The phase-shift of the fringes can be generated synchronously only by moving a plane-parallel plate along an in-plane parallel direction. According to the feature of transparent materials, the thickness and 3D shape can be reconstructed simultaneously based on the relationship between the in-plane displacement and their characteristics. The experiment was conducted on a thin transparent film subjected to a shearing force,which verifies the feasibility of the proposed system.     

一类函数项级数的求和

以微分方程为工具,推出一类一致收敛且具有分析性质的函数项级数的求和公式,进而推广了五种基本幂级数的和函数公式。     

影栅云纹法中的离面位移与斜率耦合条纹的光力学分析

基于传统的概念,影栅云纹法只能实时获得表征物体大离面位移(深度)的条纹。若要获得反映斜率的条纹,则只有用镜面试件通过反射云纹法或其它的光测法来获得。在研究中发现,在一定的条件下,用影栅云纹法可以获得离面位移与斜率的耦合条纹图。这个新发现打破了已有的传统概念。实验证实了简单实用的影栅云纹法不但能获得物体大变形时的离面位移,而且也可以获得与之对应的斜率条纹。给出了典型的可实时获得的耦合条纹图,并对其基本原理、计算方法和实验技术进行了论述。