基于数字图像相关光测法的CFRP测试与分析

Determination and analysis of CFRP based on digital image correlation photometry

为了开展碳纤维增强复合材料(carbon fiber reinforced plastics, CFRP)片材的拉伸弹性模量和弯曲模量测试,对CFRP试件进行拉伸试验和三点弯曲试验,同时开展了电测法和数字图像相关(digital image correlation, DIC)光测法的测量与分析.研究结果表明:通过电测法与DIC光测法测得的拉伸弹性模量分别为19.1 GPa和19.3 GPa,结果较为接近;通过电测法和DIC光测法测得的弯曲模量分别为18.5 GPa和19.2 GPa,结果相差较大;基于轴拉试件的电测法数据,建立了三点弯曲有限元模型,电测法分析得到的试件位移场、应变场与DIC光测法分析结果吻合,验证了DIC光测法计算结果的可靠性;与电测法相比,DIC光测法具有非接触、场域测试特性等优点,可用于实时监测试件面域位移场,从而得到其面域应变场.

To test the tensile elastic modulus and bending modulus of carbon fiber reinforced plastics(CFRP), the tensile test and three point bending test of CFRP specimens were carried out. The measurement and analysis of electrical measurement and digital image correlation(DIC) optical measurement were also conducted. The results show that the tensile modulus values measured by electrical method and DIC optical method are 19.1 GPa and 19.3 GPa, respectively, and the results are similar. The flexural modulus values measured by electrical method and DIC optical method are 18.5 GPa and 19.2 GPa, respectively, and the results are quite different. A three-point bending finite element model is established based on the electrical data of axial tensile specimens. The displacement field and strain field of specimens by the electrical measurement method are consistent with the analysis results by the DIC optical measurement method, which verifies the reliability of the calculation results of the DIC optical measurement method. Compared with the electrical measurement method, the DIC optical measurement method has the advantages of non-contact, field test features and so on. It can be used to monitor the displacement field in the surface area of specimen in real time and obtain the strain field in the surface area.