复合材料界面结合强度的激光定量测量技术研究

The adhesive strength of interfaces (tensile strength) is the issue in the field of interface research. However, how to determine the tensile strength of interfaces directly and quantitatively is still a difficult problem for scientists in the world. Recently, the laser spallation technology has attracted many researchers because of its potential application on the measurement of the adhesive strength of the interfaces. This article investigates the spall process on the interfaces induced by lasers and the quantitative determination technique..First, after reviewing on the progress of measurement technique of the adhesive strength on the interfaces, a key issue of quantitatively determining the adhesive strength on the interfaces is proposed according to the conception and detection theory of adhesive strength on the interfaces. The issue is how to realize single and unite tensile fracture on the interfaces while maximally suppressing plastic deformation on neighboring area and avoiding the extension of crack. The ideal detection method is separating the interfaces by the micro-nucleation mechanism.The shortcoming and weakness with existing methods, especially with laser spallation methods are demonstrated..Next, the article discusses the principle of the coating spallation on the interfaces induced by pulsed lasers, and proposes the principle of the quantitative determination of adhesive strength on the interfaces. In the dynamic spall process of interfaces, the stress history on the free surface of coatings reflects the real loading history on coatings with unique, certain and detectable characteristics. Basing on the determination of the spallation on the interfaces and the spall information, the detection model of the interfaces between substrate and coating is built and optimized; the optimization technique of the loading stress inducing the spallation of the interfaces is also quantified to educe the optimization relationship between the pulse step of the stress wave and the time scale of the coating thickness; the design on optimizing pulsed stress wave and coating samples are obtained.Then, the real-time and quantitative determination technology of spallation is presented, through which the quantitative determination of the adhesive strength, strain rate and damage scale of the interfaces in only one experiment of laser spallation can be realized. Moreover, the finite element analysis is used to investigate the spall process on the interfaces induced by the laser impaction, and the methods to determine the threshold of stress on the interfaces are proposed, the efficiency of which have been validated by comparing with experiment data.Finally, the measurement equipments of impaction system with high energy and short pulse width lasers, and the noncontact stress wave reception monitories system, based on the Fabry-Periot interferometer technology are developed. These facilities fill a vacancy in the field in our country. Generally speaking, we have achieved creative advancement as follows:1.We develop and integrate the measurement equipment of impaction system with high energy and short pulse width lasers, and the detection system to receive and non-contactly detect the stress wave based on the Fabry-Periot interferometer technology. With the characteristics of non-contraction, high sensitivity and high convergence of optical energy, our systems can efficiently detect acoustic longitudinal wave, acoustic transversal wave and acoustic surface wave in the transmission model and reflection mode. Precise 5-Axis Cooperation NC worktable can realize the accurate localization of laser beams and samples and repeat experimentation.2.Based on multiply reflection and transmission inside coatings, the mathematic model of quantitative determination of intrinsic adhesive strength on interfaces is built; the mathematic equation for calculating the adhesive strength on the interfaces and corresponding strain rate on the situation of spallation are concluded. The mechanical behaviors of spall process on t

进行激光层裂过程的数值模拟，测量并研究激光冲击产生应力波、传播规律及与激光参数之间的关系。用激光超声波法确定界面脱粘所需的临界激光参数，确定复合材料界面脱粘所需的临界激光参数，确定复合材料界面的动态、准静态结合强度定量测量新方法。解决现有复合材料产品界面拉伸强度无法定量测试的难题，具有重大的理论价值和广阔的应用前景。