散斑打印技术及其在纸弹性模量测试中的应用

Speckle Printing Technology and Its Application in Elastic Modulus Measurement of Paper

目的基于数字图像相关方法和可控散斑打印技术实现纸弹性模量的非接触测试。方法由于纸是可打印材料,可利用打印机将设计制作的高质量散斑图打印在纸试样的标距两端,在单轴拉伸过程中,利用数字图像相关方法测试标距线应变,将应变值与拉伸机得到的应力值进行线性拟合,即可计算得到纸的弹性模量。结果利用文中方法测试定量为80 g/m^2牛皮纸的纵向弹性模量3个试件平均值为1900MPa。结论通过对模拟图像参数的合理设计,使纸张具有高质量的散斑图,并且印刷油墨对纸张力学性能的影响最小。将提出的方法用于测量牛皮纸的弹性模量,3个试样的测量结果偏差很小,在一定程度上证明了该方法具有良好的可靠性。

The work aims to realize the non-contact testing of paper elastic modulus based on digital image correlation method and controlled speckle printing technology. Because the paper was a printable material, the high quality speckle pattern designed and fabricated could be printed on both ends of the gauge distance of the sample paper by the printer. In the uniaxial tension process, the linear strain of the gauge was measured by digital image correlation method, and the elastic modulus of the paper could be calculated by linearly fitting the strain value with the stress value obtained by the stretcher. In the proposed method, three samples with longitudinal modulus of elasticity of 80 g/m^2 kraft paper was tested, and the average test value was 1900 MPa. Based on the reasonable design of the simulated image parameters, the paper possesses high quality speckle pattern and the effect of the print ink on the mechanical property of the paper is the least. The proposed method is applied to measure elastic modulus of the kraft paper. The deviation of the measured results of three samples is small, which proves the good reliability of the proposed method to some extent.