Evaluation Technology For Surface And Interface Properties Of Glasses And Laminated Glass

In the field of property evaluation of glass and the glass lamination material, there are lots of questions that are difficult to solve by using the conventional experimental techniques and the instruments, such as the estimation of the residual stress and the uniformity of the glass materials, the spontaneous breakage risk of tempered glass, damage evolution of the surface defect, and so on. Therefore, it was the urgent and vital duty of material scientists and mechanical workers to explore new testing technique and instruments, which was also the key to assure the application of brittle materials in engineering. This work focuses on the property evaluation and the equipments development of the glass and the glass composites.Based on the modularization design, a testing machine for surface and interface properties was developed and designed which mainly include the loading system, the supporting platform, the control system, the software module and the functional module, and so on. Four kind of experimental models, namely, vertical type, horizontal type, in-site sucker, local–loading could be realized using the different coordination between the modules which could meet the different experimental need. The tester could test not only the convention mechanical properties of brittle materials, but also the local strength of glass materials and the proof test of the glass component by combining acoustic emission module to improve the reliability of the glass component in service. Simultaneously, the friction and wear testing device and software which supported the surface tester was developed to obtain the friction coefficients of glass materials to different materials.Spherical-indentation method was used for non-destructive test of the local strength and residual stress of the glass and tempered glass. And the critical cracking load was determined using indenter containing acoustic emission sensor which was successful in non-destructive testing strength. "Cross-sample" experimental device was proven as a simple and accurate testing method for evaluation and analysis of the interface tensile and shear strength of laminated materials and laminated glass.Vertical working pattern of the device being as the working platform, the friction and wear properties of the soda-lime glass abrasion with 45 steel was investigated under the different load. And the residual strength of the soda-lime glass samples after the wear tests were measured with double-ring tests. It was indicated that the rate of wear fluctuates with the increasing normal pressure. The friction coefficient increased largely with the increase of load when the load was lower than 10N. The wear-out failure of the soda-lime glass resulted mainly from the spot corrosion under the low load whereas it was from the surface plastic deformation under the high load. Through the analysis in Mean-stress criterion of the crack growth of brittle material and the stress distribution of particle, it was proven that crack growth of glass was influenced by the space and the time of applied stress, i.e., the peak value of cracking stress increases with the increasing of stress gradient, and with the decreasing of stressing time. According to this analysis, it was predicted that the critical size of impurity which caused the spontaneous breakage in tempered glass was approximately 0.2 mm. The research indicated that the residual stress in the tempered glass make the bending strength higher, but also make the probability of the spontaneous breakage higher.The residual stress and failure mechanism of the glass-alumina laminated materials for teeth were studied through the finite element method and three-spot bending tests, and ball-on -ring tests. The axial symmetry test was carried out with the small bi-layer disc sample using the self-made mini-tester. The result indicated that thermal coefficient of expansion between layers resulted in the residual stress. Meanwhile the stress distribution was related to the thickness ratio and the temperature difference.Based on the national 863 projects and the international cooperation projects, many test instruments were successfully devised. The main innovations of these instruments laid in modulation, multi-function, intellectualization, and they also integrated the fundamental function of the acoustic emission, depth-sensing indentation,visual monitoring and general universal material testing machine. The study provides a simple and convenient way and equipment to test the surface properties and interfacial behavior of the glass and laminated galss.