本文介绍了自行研制的材料拉压加载试验实时同步辐射CT分析系统,该套系统既可得到试件拉压试验P-△曲线,也可得到对应曲线上任意点的试件CT重建图。该系统的关键设备之一是自行研制的一体化拉压加载和转动装置,文中以X射线CCD的像素尺寸10.9μm×10.9μm为基础,通过分析,给出了加载和转动装置应满足的运动学定位精度要求。该装置采用了四柱式框架结构,采用上下夹头同步转动实现试件相对于框架的刚性转动;上夹头作相对于框架的轴向运动(下夹头轴向位置固定)实现对试件的加载;在加载和转动装置中采用了诸多高精技术,实现了试件高精度的轴向定位、径向定位和刚性角度定位;对装置的精度检测表明其实际的定位精度优于运动学定位精度要求;对系统的计量考评初步表明,系统不计噪声的空间分辨率优于X射线CCD的像素10.9μm。
A real-time synchrotron radiation CT system for materials analysis in the tension/ compression testing was introduced. By using this system, the macro P-△ curve of the specimen can be obtained, as well as the micro CT photograph at any loading state. One of the key components of this system was the integral loading/rotating device. Based on the pixel size (10.9μm×10.9μm) of the X-ray CCD, The kinematic positioning accuracy requirement was given through analysis. In the device, a four-post frame was adopted, two synchronously rotating grip holders were used to realize rigidity rotation of the specimen, and the axial movement of the upper grip holder implemented the tension/compression loading. Positioning accuracy in the axis, radial and circumferential directions were achieved by adopting many advanced and delicate technologies. Measurement on the device indicated that the actual positioning accuracy of the device was better than the kinematic positioning accuracy. Evaluation test on the system indicated that the spatial resolution is better than the pixel size without considering the noise.