Experimental And Theoretical Study On The Interface Bonding Strength Of The Glass-Fiber/Polymer Matrix Composites

Composite interface is one of the most important factors that affect the overall mechanical behavior of the composite and the measurement of the mechanical properties of the interface plays a very important role in the interface study of composite. Currently, the main methods used to measure the fiber/matrix interface properties of composite were based on micro-mechanics, including single-fiber composites fragmentation test(SFC), micro-debonding technique, single-fiber pull-out test, and single-fiber push-out test, in which SFC was most widely used.The fibers in the matrix carry most of the external loads applied on composite, while the matrix only acts as the bridge to transfer the loads. Currently, the one-dimension load transfer model presented by Cox and the two-dimension load-transfer model proposed by Nairn are the representative theories in the field of the interface load-transfer study. The one-dimension model has the advantages of simplicity, convenience and feasibility, but it also has one serious shortcoming, i.e., the influence of material properties on the load-transfer ability of the interface was not taken into account. Although the two-dimension interface model considered the transverse effects of the matrix and the effects of the material properties on the load transfer ability of the interface, Its principle is very complicated, and isn't fit for dealing with the data of the SFC test. In this paper, a new two-dimension interface load-transfer model was developed after careful analysis of the one-dimension models mentioned above, the influence of material properties on the load-transfer ability of the interface was taken into account. Especially the property of the matrix have important influence on the ability of the load transfer ability of the interface, and it could well describe the bond phenomenon of the interface.Simultaneity, various single fiber strength tests(SFT) and the single fiberfragmentation techniques were discussed, and the influence of fiber surface treatment on the single fiber strength and the interface load-transfer were discussed in detail. The two parameters Weibull statistic theory was used to evaluate the scattering of the tensile strength test results of three types of single fibers with different surface treatments. The following conclusions can be drawn based on the analysis of the results. First, the bonding shear strengths obtained by SFC technique are in good agreement with the SFT technique. Second, the surface treatments of the glass fibers helped enhance the interface bonding, and also the tensile strength of the fibers and the bonding shear strength of the fiber/matrix interface.