摘要
碳纤维复合材料具有优异的力学性能,在航空航天及地面交通运输领域得到了广泛的应用。应用在车辆上的碳纤维复合材料在车辆长时间的行驶过程中,会受到交变载荷的作用,导致其性能下降从而影响复合材料的使用寿命。本文选用692-3K型环氧树脂为基体,24K-T300碳纤维为增强体,采用VARTM的方法制备碳纤维树脂基复合材料板,对三种不同铺层层数的复合材料板进行静态弯曲试验,得到在6层铺层下的极限弯曲应力为572.9 MPa。采用20Hz频率和50%载荷水平对复合材料进行三点弯曲疲劳试验,探究了复合材料在循环周次逐渐增加的过程中的剩余模量变化。随着循环周次的增加,弹性模量呈现先降低再升高的趋势,然而循环周次进一步的增加并没有导致弹性模量升高,反而导致下降。这表明循环周次对弹性模量存在影响。进一步研究发现,复合材料内部存在部分尚未完全固化的树脂,推测这部分未固化树脂在疲劳循环过程中吸收热量开始固化从而修复了疲劳循环过程中产生的微裂纹,这是导致弹性模量出现先下降后上升趋势的原因。
Carbon fiber composite materials have excellent mechanical properties and are widely used in the fields of aerospace and ground transportation.The carbon fiber composite material applied to vehicles will be subjected to alternating loads during long-term driving,resulting in a decrease in its performance and affecting the service life of the composite material.This article selects 692-3K epoxy resin as the matrix,24K-T300 carbon fiber as the reinforcement,and uses VARTM method to prepare carbon fiber resin based composite material plates,Static bending experiments were conducted on three composite material plates with different number of layers,and the ultimate bending stress under six layers was obtained to be 572.9 MPa.Three point bending fatigue experiment was conducted on composite materials under 20Hz frequency and 50%load level,Explored the residual modulus changes of composite materials during the gradual increase of cyclic cycles.As the number of cycles increases,the elastic modulus shows a trend of first decreasing and then increasing.However,further increasing the number of cycles does not lead to an increase in the elastic modulus,but rather a decrease.This indicates that there may be a critical point at which the stress level affects the elastic modulus due to the number of cycles.Further research has found that there are some uncured resins inside the composite material,It is speculated that this portion of uncured resin absorbs heat during the fatigue cycle and begins to cure,thereby repairing the flaw generated during the fatigue cycle,This is the reason why the elastic modulus first decreases and then increases.
作者
谢俊
于洪浩
冷利
张罡
XIE Jun;YU Honghao;LENG Li;ZHANG Gang(Shenyang Ligong University,Shenyang 110159)
出处
《纤维复合材料》
CAS
2024年第1期30-35,共6页
Fiber Composites
基金
沈阳市科技局双百项目(Y18-1-018)。
关键词
复合材料
弯曲性能
疲劳性能
剩余模量
composite materials
bending performance
fatigue performance
residual modulus
