散斑图像相关数字技术原理及应用

研究图像处理技术在散斑测量中的应用，提出了一种散斑图像相关数字技术，该方法引进了亚像素技术，采用重心算法计算特征斑的重心，避免了数字散斑相关法计算相关系数的繁复过程；应用位移和应变的有关公式，可以获得物体变形实验曲线，实验结果表明，该方法在工程实际现场、振动过程以及变形测量的自动化等方面有着广泛的应用潜力，从而为光测力学拓展应用领域、实现自动化测量展现了新的前景。     

虚位移场方法在石墨材料力学参数测量中的应用

光测实验技术在现代力学研究中得到了广泛的应用。对于材料力学参数如杨氏模量和泊松比的测量,可利用典型加载试验如拉伸试验、弯曲试验并结合光测方法(如云纹和数字图像相关技术)得到位移值,利用载荷信息和应变场信息通过计算获得相关的力学参数。本文利用虚位移场方法测量石墨材料的力学参数。结合石墨材料的三点弯曲实验,由数字图像相关法测量得到试件表面的非均匀变形场。通过选择两组不同的虚位移场,可以反算出材料的力学参数:杨氏模量和泊松比。结果表明这种方法可以有效测量石墨材料的弹性参数。该方法可望在材料力学行为检测中得到推广应用。     

中国航空学会第五届光测力学学术会议暨中国力学学会图象处理研讨会

中国航空学会第五届光测力学学术会议暨中国力学学会光测图象处理研讨会于1986年11月2日至8日在长沙举行。出席会议代表90名,来自全国45个单位.这次会议的主题是“光测力学在航空工程及其他方面的应用”和“光测力学数据采集与处理自动化”。会议采取大小会相结合,报告与自由讨论相结合的形式。交流论文所反映的学术水平和研究深度与     

光测力学的研究现状和展望

光测力学是实验力学的一个重要分支,在工程中得到了广泛的应用。本文简要地回顾了上海光测力学三十来年的进展情况,内容涉及普通的光弹性以及现代的光测力学在基本原理、测试技术与方法的研究和在工程、生物力学、断裂力学中应用的情况,并讨论了目前研究的重点与前景。     

综述:阵列式高速摄像技术及其在动态光测力学中的应用

高速摄像技术与先进光测力学方法相结合是研究材料和结构断裂、冲击、爆破、渗透等动态力学行为的重要手段。阵列式高速摄像系统是一种具有成像通道成阵列均匀分布显著特点的高速摄像系统,已在科学研究和工程技术领域得到广泛应用。本文对阵列式高速摄像系统的设计及其动态光测力学方面的应用进行综述。首先,对阵列式高速摄像系统的发展历史和技术改进过程进行概述。其次,阐述阵列式高速摄像系统的研究现状,重点介绍双场镜、旋转镜面和物理分幅等三类典型阵列式高速摄像系统的设计原理,并对不同系统的主要技术指标进行总结。再次,对阵列式高速摄像系统光学视差的定性和定量分析方法进行总结,并对视差修正方法进行归纳。最后,结合光弹法、焦散线法、数字图像相关法、云纹法、相干梯度敏感法和数字梯度敏感法等主要光测实验技术,阐述阵列式高速摄像系统在动态光测力学领域中的应用。本文对阵列式高速摄像系统的设计和应用进行了总结和展望,对于研制动态光测力学设备、推动材料与结构动态力学行为以及阵列高通量测试的基础科学问题的创新性实验研究具有一定参考意义。     

2011年现代光测力学及其应用高级讲习班简介

随着光电技术和计算机图像处理技术的发展,现代光测力学技术也日趋成熟.除了在机械、土木、航空航天等科研与应用领域被广泛使用外,更是越来越多地被新兴学科领域,如生物科学、生命科学、新能源、新材料以及微纳科技等领域的研究人员所采用.这主要是因为诸如数字全息、云纹干涉、栅线投影、电子散斑干涉和数字图像相关测量等光测力学技术具有非接触、高分辨和全场测量的优点,而受到广大科研工作者和工程技术人员的关注和重视.中国力学学会实验力学专业委员会和教育工作委员会在连续3年举办光测力学实验教学讲习班和研讨班的基础上,2011年在国家自然科学基金委员会数理科学部主任基金的资助下,于2011年7月31日至8月5日在南京东南大学主办“现代光测力学及其应用高级讲习班”.      

《实验力学》第2卷(1987)分类索引

综述流动显示技术及其现代发展概况,1,1焦散线实验方法综述,2,1光导纤维在近代光力学中应用的综述,3,固体力学的新发展对实验力学提出的挑战,声弹性应力测量,4,34,1电阻应变计测盆技术 动态加载装置和动态测量技术,1,27三轴测力传感器的剪切力高阶效应实验研究,2,朽应变片技术在动态力学测量中的应用,2,73压电陶瓷片在振动实验中的应用,2,90水泥混凝土常温电测温度补偿研究,4,59全息干涉术 双参考光全息散斑干涉技术的原理和实验,2,63 激光全息条纹三维读数仪法的误差分析,3,切散斑计皿 贴片散斑法及其应用,1,21提高直接散斑法全场分析条纹…     

光测力学的光载波研讨会在扬州举行

根据国家教委高校师资培训计划,南京工学院力学研究室和江苏农学院水利及农业工程系于1986年11月23日～30日在扬州市联合举办了光测力学的光载波研讨班。来自全国的四十余名同志参加了研讨。南工徐铸教授和上海城建学院王汝鹏高级工程师担任主讲教师。他们向大家介绍了国内外光测力学的光载波研究概况;系统讲解了光载波方法的基本原理以及光载波在光测力学上的具体应用。研讨班在载波光弹性、载波散斑法、载波全息干涉法及图象处理等方面安排了实验。     

残余应力测定的围箍压痕法模拟

本文从同工量测方法得到启发，提出了一种新型的残余应力测试方法－围箍压痕法。采用轴对称弹塑性有限元计算模拟了围箍压痕法测量结构残余应力的力学过程，得到了围箍压痕时不同残余应力程度下材料的变形，塑性区和接触应力分布。     

新书介绍

《水工建筑物光测应力分昕》是一本以光测技术为手段,研究结构物变形、应变及应力的专门著作。该书共分五篇,计十五章,全书约有五十万字,近五百幅插图。在第一篇中十分简要地论述了应力分析的基础知识;相似理论和模型设计;及光测力学的     

横观各向同性三维热弹性力学通解及其势理论法

通过引入两个位移函数，对用位移表达的运动平衡方程作了简化．利用算子理论，严格地导出了横观各向同性非耦合热弹性动力学问题的通解．对于静力学问题，通解的形式可进一步简化成用4个准调和函数来表示．具体考察了横观各向同性体内平面裂纹上下表面有对称分布温度作用的问题，推广了势理论方法，导出了一个积分方程和一个微分-积分方程．针对币状裂纹表面受均布温度作用情形，给出了具体的解。     

Closed-loop based detection of debonding of piezoelectric actuator patches in controlled beams

A practical closed loop control based damage detection scheme is presented aiming at detecting small damage in controlled structures. In this detection method, a deliberately designed sensitive control system is used to augment small frequency shifts caused by small structural damage. Since a small frequency change can destabilize such a sensitive control system, it can be easily observed and thus the small damage can be detected. To perform active control of structures, a modal velocity observer (MVO) is designed by combining two observers, which can be used for multi-mode control. By properly choosing the parameters in the MVO, it can be made very sensitive to the frequency shift suitable for small damage detection. To demonstrate this method in detecting small debonding of piezoelectric patches on a smart beam, a detailed model of beam with partly debonded piezoelectric patches is established based on the Timoshenko’s beam theory, in which both transverse and longitudinal vibrations are modeled, and a characteristic equation is also derived to examine the effect of the debonding on the control performance. Both the model and the control law are validated by an active vibration control experiment. Finally, an example is given to illustrate application of the method in piezoelectric actuator debonding detection. The results show that even a small edge debonding in a piezoelectric actuator patch can make the sensitive control system unstable, and therefore can be detected.     

一种确定非线性裂纹转子解的形式的新方法

将小波变换与Ｐｏｉｎｃａｒｅ映射相结合，即用Ｐｏｉｎｃａｒｅ映射确定周期解，用谐波小波变换区分拟周期响应和混沌运动，提出了一种分析非线性裂纹转子系统解的形式随参数变化的新方法．结果表明这种方法是非常有效的，它比以前所用的计算Ｌｉａｐｕｎｏｖ指数的方法节约了计算时间，并且较易实施．     

Spreading of a liquid over a plane rigid substrate in an electric field

The influence of an electric field on spreading of a thin conducting liquid layer over a plane rigid substrate is investigated theoretically. The conductivity of the liquid is assumed to be so low that the effect of the magnetic field of the currents generated in the liquid under the action of the electric field can be neglected. The spreading is assumed to be so slow that the quasi-steady approximation can be used to calculate the electric field strength which can be considered to be equal to zero inside the liquid. Equations that describe variations in the layer shape are obtained in the lubrication theory approximation. The general formulation of the problem is considered. The solution of the problem is obtained in parametric form when the effect of the gravity force and the surface tension can be neglected. Variations in the layer thickness along the substrate are so smooth that the charge distribution over its surface can be assumed to be the same as that over the substrate surface in the absence of the liquid.     

A method for conformal mapping of a two-connected region onto an annulus

This paper presents a method for conformal of a two-connectedregion onto an annulus.The philosophy of the method is toconvert the problem into a Dirichlet problem and to prove thereal part of the analytic function transformation should be aharmonic function satisfying certain boundary conditions.Ac-cording to the theory of harmonic function we can determine theinner radius of the annulus from the condition that the harmonic function defined in two-connected region should be single-valued.It is then easy to see that the imaginary part can directly beobtained with the aid of Cauchy-Riemann conditions.The unknownconstants of integration only influence the argument of imagepoints and can easily be derived by using the one-to-one mappingof region onto an annulus.Without loss of generality,themethod can be used to conformally map other two-connected regionsonto an annulus if they can be subdivided into several rectang-ulars.The method has been programmed for a digital computer.It is demonstrated that the meth     

Analogy solutions of axisymmetrical twist problems by axisymmetrical finite element program

It used to be considered that an axisymmetrical problem and a twist problem of an axisymmetrical body cannot be simulated by each other, because the number of unknown variables in an axisymmetrical problem is greater than that in a twist problem, and the governing equations are not the same. This paper proposes a degenerated analogy method, by which the twist problems of axisymmetrical bodies can be simulated by axisymmetrical problems with finite element programs.An ordinary structural analysis method can be used to analyze an axisymmetrical problem, but a twist problem of axisymmetrical bodies is treated as a 3-dimensional problem usually. According to the method proposed in this paper, the analysis of a twist problem can be simulated by the analysis of an axisymmetrical body with a structural analysis problem. The example of analysis computation is also given. Thecomputed result is in agreement with the theoretical result.In this paper, the constitutive relation of the degenerated analogy problem is given.The authors suggest that a twist problem of a body made of any materials is simulated by an axisymmetrical problem of a body made of orthotropic material. If you have to use some program for the axisymmetrical problem to be limited to isotropic materials the penalty coefficient method can be used to solve the problem.     

Multiple scattering of elastic waves by pinned dislocation segments in a continuum

The coherent propagation of elastic waves in a solid filled with a random distribution of pinned dislocation segments is studied to all orders in perturbation theory. It is shown that, within the independent scattering approximation, the perturbation series that generates the mass operator is a geometric series that can thus be formally summed. A divergent quantity is shown to be renormalizable to zero at low frequencies. At higher frequencies said quantity can be expressed in terms of a cut-off with dimensions of length, related to the dislocation length, and physical quantities can be computed in terms of two parameters, to be determined by experiment. The approach used in this problem is compared and contrasted with the scattering of de Broglie waves by delta-function potentials as described by the Schrödinger equation.     

一种构造高维Nilpotent正规型的方法

正规型方法是一种有效的简化一类非线方程的方法。今提出了一种简便的代数方法去构造高维非线性系统的Nilpotent范式。通过引入一系列简单的变换和代数运算,而无需求解任何偏微分方程,即可得到高维非线性系统的Nilpotent范式。以四维非线性系统为例介绍这个方法。该方法完全适用于分析高于四维的非线性系统的Nilpotent范式。     

含非理想约束多柔体系统递推建模方法

基于多体系统中邻接物体运动学递推关系,可以证明树状多体系统中末端物体的作用体现为传递给其内接物体的惯性和外力. 由于闭环系统切断铰约束反力和非理想约束反力可看作为系统外力,任何复杂系统都可以转化为等效的树系统,并且系统约束方程中所涉及的广义加速度可以系统化地用描述约束反力的拉氏乘子替换. 基于以上结果,提出了针对含非理想约束多柔体系统递推建模方法. 利用该方法可以将复杂多体系统动态减缩为单个物体,从而在求解系统加速度时不需对整个系统的质量矩阵进行求逆运算,同时大幅度地降低了非理想约束反力方程的维数. 通过一个算例具体说明了所提方法的求解过程,算例结果与现有商业软件所得结果一致.