针对板料变形中应变检测的常规方法和传统方法存在的不足,通过数字散斑相关方法、计算机双目视觉理论和材料力学理论分析了试件表面变形前后的散斑图像,来动态跟踪试件表面上几何点的运动并得到三维位移场,在此基础上计算得到试件的三维应变场。基于此原理开发了XJTUDIC三维数字散斑动态应变测量分析系统。应用带孔铝质制件进行了单向拉伸实验。测量结果表明,该系统能较好的反映板料变形过程中的三维应变状态,较好的测量试件表面的三维轮廓,直观再现工件表面的变形场、应变场和成形极限图(FLD),对于需要测量的关键点可以实现重点跟踪,动态测量出该点在任意时刻任意位移的应变。该系统可以应用到不同的力学测量现场。
To avoid the shortcomings of traditional strain detection in sheet deformation,digital speckle correlation method,computer binocular vision theory and mechanics theory of materials were introduced to trace the motion of specimen surface geometric points dynamically by analyzing the speckle images of the sample surfaces before and after deformation.According to the motion of geometric points on the foundations of getting the 3D displacement field,the 3D strain field could be calculated.Based on this principle,the 3D digital speckle analysis system for dynamic strain measurement(XJTUDIC) was developed.Perforated aluminum workpiece was used for uniaxial tension test.It is found that the system can reflect the 3D strain state well in sheet deformation,reconstruct the 3D profile of the specimen surfaces vividly and reproduce the deformation field,the strain field and the forming limit diagram of the workpiece surfaces intuitively.For critical points,the system can also track their trajectory and calculate their strain at any time and arbitrary displacement.Furthermore the system can be utilized to various mechanical sites.