超声压紧对低能电子束分层固化复合材料质量的影响

Effect of Ultrasonic Compaction on Quality of Composite Stepwise Cured by Low-Energy Electron Beam

针对低能电子束分层固化复合材料层间孔隙缺陷导致层间剪切强度较低的问题,设计了超声压紧装置。该装置通过压头将超声波作用于预浸带铺层上,配合低能电子束固化系统制作复合材料层合板,并研究了超声压紧参数对复合材料质量的影响。实验结果表明,超声振动在压紧过程中产生的机械效应和热效应可有效减少孔隙,增强纤维与树脂的界面结合性能,提高层间剪切强度,从而改善复合材料试件质量。其中,振幅对复合材料孔隙率及层间剪切强度影响最大,当超声振幅为7.5μm时,试件致密性明显改善,孔隙率降至1.80%,层间剪切强度提高11.7%;压紧力影响相对较小,当压紧力从100 N到220 N变化时,层间剪切强度只有3.64%的提高,孔隙率在2.62%以下。过大的振幅与压紧力都会引起压紧过程中预浸带温度升高,导致树脂固化度提高,渗透性变差,孔隙率增加,使复合材料质量降低。

To improve the interlaminar shear strength（ILSS）of composite cured by low-energy electronic beam,the ultrasonic compaction mechanism is designed to fabricate laminate with lowenergy electronic beam curing system,which transmits the energy of ultrasonic to the prepreg layers.The effects of ultrasonic compaction parameters on voids and ILSS are analyzed.Experiments show that the mechanical effect and heating effect are produced in ultrasonic compacting process,which eliminate interlaminar voids and enhance bonding strength of fibers and resin,then improve the quality of the composite.When the laminate layers are compacted with 7.5μm ultrasonic amplitude,the laminate＇s ILSS is 11.7% higher than that of the laminate fabricated without ultrasonic compaction,and the void content is reduced to 1.80%.When the compacting force changes from 100 Nto 220N,ILLS is only improved by 3.64% and the void content gets under 2.62%.Larger amplitude and compacting force will induce increasing resin cure degree due to the rising temperature,resulting in lower resin permeability and ILSS.