Study On The Characteristics Of Acoustic Emission Source In The Process Of Tensile Rupture For PE/PE Composites

Composites was widely used in various aspects for its high specific tenacity, high specific modul, high tolerance of damage and designable performance. But the heterogeneity, aeolotropism, complex mode of damage and so on made the large difference of product quality, So it is especially important to make safety inspection and strength forecast before use or in use. The primary modes of damage and frature on composites are fiber breakage, matrix cracking, interface debonding or delamination etc, and each mode has shade impact on entire performance. Therefore it is important to research on the damage and performance prediction of composites at present.At first, the status of development and application of the Ultra-high Molecular Weight Polyethylene fiber and its composites are discussed in this article. And the fundamental principle of acoustic emission inspection as also the analysis and disposing technique in acoustic emission signal are introduced. Then UHMWPE/LDPE composite laminate is made by film stacking and wind molding. The tensile rupture process of fiber and matrix were monitored respectively by acoustic emission technique, and the relationship between acoustic emission parameters and fracture mode was found, it can provide the foundation for the research on acoustic emission behavior and fracture mechanism of composites. Analyze on the feature and fracture mode of unidirectional UHMWPE/LDPE composites and compare with the feature and fracture mechanism of some typical Ply stacking Angle UHMWPE/LDPE composites, and summarize the approximation relations of fiber Ply stacking Angle, tensile strength and acoustic emission behavior in tensile rupture process of UHMWPE/LDPE composites. Finally present the SEM photograph of a variety of damage and fracture in tensile rupture process of UHMWPE/LDPE composites.It is a hotspot to study on the fracture mode and fracture mechanism by acoustic emission technique in late years. But in the research of carbon fiber, glass fiber, aramid fiber reinforced epoxy resin composites and metal resin composites etc, the report of UHMWPE fiber reinforced composites is infrequent. This article namely put the UHMWPE fiber reinforced LDPE resin composite laminates as subject investigated, study on the acoustic emission behavior in tensile rupture process, discuss the relationship between acoustic emission behavior and fracture mode of composites, establish the relation of acoustic emission amplitude data and fracture mode of composites. Explore the relationship of fiber ply stacking angle, strength of composites and acoustic emission characteristic parameters, this is one of innovative spots in this article.The results of research indicated that the primary sources of acoustic emission in UHMWPE/LDPE composites were matrix cracking, interface debonding, crack propagation, fiber pull out and breakage etc. Different acoustic emission sources were corresponding to different amplitude value, and the fiber/matrix debonding or delamination is the typical characteristics of UHMWPE/LDPE laminated composites. For 0°composites, the break mechanism is tough cycle fracture including matrix cracking, interface debonding or delamination, fiber lengthwise crack and filament tow breakage. The 10° composites mostly occur friction between fibers and delamination in interface. The 45°composites are broken as a result of fiber pull out and interface debonding. And the break mechanism of 90°composites is interface debonding, delamination and fiber broadwise peeled off. The tensile strength and total acoustic emission energy of UHMWPE/LDPE composites are lessened with the increase of fiber ply stacking angleθ, and acoustic emission hits are increased with the increase ofθ. The primary fracture mode of materials is corresponding with the large acoustic emission energy and lower acoustic emission hits.It is a tried and true approach to study on the damage evolutive rule and fracture mode in tensile process of UHMWPE/LDPE composites by acoustic emission technique, and the feature of damage and fracture can be reflected clearly and directly.