Acoustic Emission Analysis For Tensile Property Of UHMWPE/PP Laminates

The acoustic emission technology (AE) was used to investigate the damage mechanism of the UHMWPE/PP composite material by tensile testing. The tensile property of every component (PP matrix,UHMWPE fiber yarns) , [0°],[90°] single laminate and laminates were tested. AE characteristics for UHMWPE/PP composite material damage evolution were analyzed by using multi—parameters analytical method. Features of PE/PP composite material damage evolution were also found. By cluster analysis and discriminant analysis, six different types of AE parameter and discriminant were established. Meanwhile tensile rupture property of different phases was discussed quantitatively.The experiment indicates that:The qualitative analysis is applied on the parameter. AE events of matrix is small, activity is also weak. Boundary strength of [90°] is weak, because most of damage happens on the interfacial bond. In the process of manufacturing, [0°] is different from [90°]. Tension and parallelism is non—uniform obviously; the distribution of interface initial stress and matrix is asymmetry; the adhesion of the interface isn't well due to the hot pressing and cooling. The amount of damage and signals of [0°] is much. The Activity is also strong. Laminates gather the entire damage feature of components.Six different types of AE parameters quantitatively are described.Many microscopic damages, like matrix crackle, interface cross crack and fiber initial crackle/feebleness have small amplitude (<50dB), counts (<15 times) and short duration (<500us) .While matrix and fiber rupture have high amplitude (>50dB) , counts (>40 times) and long duration (>900us) . The damage of [0°/90°] laminates is mainly form interface break, accompanying with the matrix and fiber rupture by above mentioned analysis. Finally, composite has a crack abruptly and entirely.According to the six different types of AE parameters, the discriminant analysis is applied on the [0°/90°] laminates. Tensile rupture mechanism is: at the beginning, there is little break; accompany with the load's increase, interfacial failure become more serious. The composites are at the major damage stage, some fibers' rupture accelerate the break of matrix around. The cross direction fibers that have an affect on restraining rupture have already separated from matrix, the delaminating become serious. At the end of rupture, length direction fibers play the leading role. With the increase of rupture fibers, finally the residual fibers rupture all together. [0°] single laminate is the major controlling factor of tensile strength of the composites. The cross direction fibers have an affect on restraining rupture.