全息干涉法测量复合材料的矢量位移及微商

本文以张量分析作为数学手段,将研究物体形变的运动学与全息像的形成相结合,利用光程差及光程差的一阶、二阶微商导出漫射物表面及内部应变与转动测量关系式。采用单张全息图的ZFC(零级条纹和条纹计数相结合)条纹观察法,测量了玻璃钢压力容器的位移、表面应变及内部应变,其结果与应变仪的结果一致。     

斜轧时金属剪切变形的产生与确定

压力加工成型过程中存在着基本变形和剪切变形。剪切变形不改变轧件的形状但对金属成型过程会产生不利的影响,因而是加工过程中不需要的。剪切变形也称为多余变形,可以用多余度系数来描述剪切变形对加工过程的影响程度。剪切变形的实质是金属的不均匀流动。在斜轧中存在着纵向、周向及扭转三种剪切变形。本文分析了这三种剪切变形的形成原因,提出了测算这些剪切变形和计算多余度系数的方法。     

复合型裂纹起裂准则的研究

本文以裂纹前缘弹塑性分界面上的体积应变能密度、等能量密度面上的三轴张力和塑性区尺寸为参数,提出了小范围屈服条件下的三个复合型表面裂纹起裂准则;推出了表面裂纹前缘任意点的起裂角(α_i,θ_i)和起裂载荷Q_i表达式;计算了LC4CS板材上表面裂纹倾斜角β分别为15°、30°、45°、60°、75°和90°时裂纹前缘定位角(?)分别为0°、15°、30°、45°、60°、75°和90°各点的起裂角(α_i、θ_i)和起裂载荷Q_i;绘制了θ_4-β、θ-(?)、a~(1/2)Q_4/WBK_(Ie)-β和a~(1/2)Q_4/WBK_(Ie)-(?)曲线。将三个准则所得的计算结果进行了讨论并与文献[1]中[G]max、[S]min和[σa]max三个准则计算值和实验值进行了比较,本文所提出的三个准则较[G]max、[S]min和[σ_θ]max准则更符合实际。     

应变滞后能损伤与Uddeholm法热疲劳寿命的相关性

采用应变能研究Uddeholm热疲劳结果表明,当材料的强度、塑性的配合使每一循环所受到的应变能损伤最小时,材料的热疲劳抗力最佳,且可根据材料的常规机械性能及物理性能,予测材料的热疲劳抗力。     

锁相控制的激振时效装置

本文介绍的数字锁相系统,用于调节激振装置中直流电动机的速度。根据激振装置的要求研制了各控制环节,在频率给定及速度反馈方面具有一定特点,并建立了系统的数学模型。该装置用于工业生产多年,实践表明该系统可获得较高的转速精度。     

钢管混凝土柱压弯剪试验与有限环层分析

文中概要记述21件钢管混凝土柱的试验资料,通过它与钢筋混凝土柱受力性能的比较,证实钢管混凝土柱的强度高、延性好。试验得知短柱的应变分布与剪跨比有关,钢管混凝土柱的受力为空间应力状态。在试验研究同时,应用电子计算机计算了钢管混凝土柱的应变与应力分布,采用的是有限环层法,实例计算结果与试验所得规律基本符合。     

Flow Characteristics of Metal with Phase Transformation and Prediction of Its Microstructure

We propose a flow-stress characteristic of SUS430F steel that takes in account the effects of temperature, strain rate and their deformation history. In the framework of this characteristic, the history effects of strain rate and temperature are estimated through the plastic strain energy stored. The formulated characteristic () may be shown as a function of temperature (), strain rate ((), and the stored energy W or the reference stress (_st). The energy is stored through plastic deformation and released during annealing process. The energy is also referred by the yield flow stress (_st), which is measured under the reference condition. The discussion on the characteristic is extended to the material at high temperature (1073–1473 K) with the + gamma phase of a given phase ratio. The equilibrium ratio of ()- or ()-phase at a given temperature can be estimated on the basis of an equilibrium phase diagram. In order to introduce the flow-stress characteristic with phase transformation using the proposed formulation, we also analyze the phase transformation rate from () to + with temperature elevation, and from () to > + in the cooling process on the basis of the time–temperature–transformation diagram that includes the quenching process as well. The flow stress characteristic and phase ratio are estimated simultaneously for a hot forging process.     

Generalized Multiple Baseline Stereo and Direct Virtual View Synthesis Using Range-Space Search, Match, and Render

A new range-space approach is described for synergistic resolution of both stereovision and reflectance (visual) modeling problems simultaneously. This synergistic approach can be applied to arbitrary camera arrangements with different intrinsic and extrinsic parameters, image types, image resolutions, and image number. These images are analyzed in a step-wise manner to extract 3-D range measurements and also to render a customized perspective view. The entire process is fully automatic. An extensive and detailed experimental validation phase supports the basic feasibility and generality of the Range-Space Approach.     

True 3‐D scanned voxel displays using single or multiple light sources

Abstract— Conventional stereoscopic displays require viewers to unnaturally keep eye accommodation fixed at one focal distance while they dynamically change vergence to view objects at different distances. This forced decoupling of reflexively linked processes fatigues eyes, causes discomfort, compromises image quality, and may lead to pathologies in developing visual systems. Volumetric displays can overcome this conflict, but only for small objects placed within a limited range of viewing distances and accommodation levels, and cannot render occlusion cues correctly. Our multi‐planar True 3‐D displays generate accommodation cues that match vergence and stereoscopic retinal disparity demands and can display images and objects at viewing distances throughout the full range of human accommodation (from 6.25 cm to infinity), better mimicking natural vision and minimizing eye fatigue.     

光纤Bragg光栅传感网络实时监测与应变分析

作为一种绝对式传感器,波长调制式光纤Bragg光栅传感器对应变的响应为0.9pm/??。开发了基于可调谐F-P滤波器的检测仪器与计算机系统之间的实时监测系统。在对白泥井3号隧道的监测过程中,该光纤Bragg光栅传感网络实时监测系统实现了对来自隧道结构的应变状态的实时采集和描绘,并可以存储波长和应变数据以便后期查寻分析;借助分析光纤Bragg光栅传感器的应变图、三维应变图,为判断隧道二次衬砌的受力趋向提供参考。