Analysis On Tensile Damage Performance Of PPTA/PP Compsite Based On Acoustic Emission Technique

Based on the tensile performance analysis,acoustic emission(AE) parameter analysis and correlation chart analysis,this paper discusses the damage forms and evolution process of PPTA/PP composite from different aspects.Tensile aspect:studied the tensile properties of PP,PPTA,[90] single layer,[45] single layer,[0] single layer,[0/90] laminated board, obtained load-displacement curve and stress-strain curve, discussed the character of the tensile curves, and analysed the tensile failure of the samples at various stages. AE aspect:Monitored the whole tensile failure process of the samples, obtained AE character of each sample, got every stage of the detailed information according to AE parameters,finally we knew the failure mechanism and reasoned PPTA/PP laminated board failure mechanism.Through experiment and data analysis, the conclusion is as follows: PP matrix:AE amplitude is mainly distributed between 42dB and 65dB, duration time is less than 1000us, and there is one above 90dB, duration is between 3000us and 4000us, the main damages:matrix crack, matrix fracture.PPTA:AE amplitude is mainly distributed between 42dB and 90dB,duration time is less than 600us,and there is one above 90dB, duration is between 1500us and 2000us, the main damages:fiber breakage. [90] single layer:AE amplitude is mainly distributed between 42dB and 65dB, duration time is less than 1000us, and there are some between 70dB and 100dB, duration time is between 3000us and 4000us, the main damages:interface horizontal damage, interface separation. [45] single layer:AE amplitude is mainly distributed between 42dB and 65dB, duration time is less than 1500us, and there are some above 70dB, duration time is more than 3000us, even more than 15000us, the main damages:interface debonding,fiber pull out. [0] single layer:AE amplitude is mainly distributed between 42dB and 80dB, duration time is less than 1000us, and distributed between 80dB and 100dB, duration time is between 1200us and 2000us, the main damages:matrix crack,interface debonding,fiber pull out and fiber breakage. [0/90] laminated board:AE amplitude is distributed between 42dB and 80dB, duration time is less than 2000us, and distributed between 80dB and 90dB, duration time is between 2000us and 6000us, even one above 90dB, duration is between 8000us and 12000us,the main damages:matrix crack,interface debonding and separation, fiber pull out and fiber breakage.In the analysis process of the tensile failure mechanism, AE parameters provide a powerful real-time monitoring information. The AE amplitude,duration time,energy of each damage form is different in every tensile stages, thus to be as signal data reference for the [0/90] laminated board. From the whole AE process of tensile failure, the early damages mainly are matrix crack and interface original damage, there are many signals, but the damage energy is low; Mid-term damage mainly are matrix crack,interface debonding and separation and few defect fiber fracture, signals are dense, AE amplitude increases,duration time is longer, and the damager energy increases; the last damage is subject to fiber breakage, along with the friction of the fiber bundle between each other, and finally the sample can not bear the huge load, and happen destructive fracture. After gradually increasing, the signals are gradually reducing, AE count,amplitude,energy and duration time all appeared the great changes at the peak when the main fibers happen breakage, which means the damage is reach to the limit, and AE activities could explain the tensile failure process.