复合材料冲击能量门槛值及回弹特性研究

发布时间：2018-03-02 01:06

本文关键词： 低能量冲击损伤面积冲击能量门槛值贯通伤检测回弹特性　出处：《北京建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：复合材料自问世以来,由于其优异的性能以及模块化生产的特点,使得复合材料被广泛的应用于航空航天、舰船制造、建筑等各个领域。但是由于复合材料对冲击很敏感,使得在遭受冲击作用后材料的性能衰退严重,从而造成严重的安全隐患,因而对于复合材料层合板遭受冲击后层合板损伤的研究具有非常重大的意义。本文在国家自然科学基金项目(编号:51573018)的资助下,对复合材料层合板的冲击能量门槛值及损伤回弹特性进行了研究。本文对玻纤/环氧单向板、玻纤/环氧多向板和碳纤/环氧多向板三种类型层合板在不同冲击能量下进行冲击试验,利用Keyence VHX2000C超景深三维显微镜对三种层合板冲击后表面损伤形貌进行3D扫描,分析了三种类型层合板损伤面积和凹坑深度的变化规律,并利用自行研制的贯通伤检测仪器对冲击后层合板的渗漏情况进行了检测,结合冲击试验与贯通伤检测的实验结果,得出了三种类型层合板的冲击能量门槛值。最后根据层合板表面损伤形貌特征,引入因子k,得到了冲击能量与损伤面积之间的关系式。考虑到回弹特性对表面损伤的影响,对三种不同类型层合板凹坑深度随时间的变化的情况进行测量,得出了三种层合板受冲击后凹坑深度的回弹特性。实验结果表明,随着冲击能量和板厚的增大,层合板的损伤面积和凹坑深度也不断增大,但玻纤/环氧复合单向板和玻纤/环氧复合多向板随着冲击能量的增大,变化曲线存在一个转折点,转折点之后变化趋缓,而碳纤/环氧复合多向板并未发现明显的转折点。对三种类型层合板的损伤情况(包括损伤面积和凹坑深度)进行比较可以发现,碳纤/环氧复合多向板玻纤/环氧复合多向板玻纤/环氧复合单向板。玻纤/环氧复合单向板的冲击能量计算公式见式(4-3),玻纤/环氧复合多向板的冲击能量计算公式见式(4-5),碳纤/环氧复合单向板的冲击能量计算公式见式(4-7)。计算其误差,得出玻纤/环氧复合单向板的计算误差较大在15%以内,玻纤/环氧复合多向板与碳纤/环氧复合多向板的计算误差较小,均在10%以内。贯通伤检测实验得出玻纤/环氧复合单向板的冲击能量门槛值为板厚的(2~3)倍;玻纤/环氧复合多向板的冲击能量门槛值为板厚的(3~4)倍;碳纤/环氧复合多向板的冲击能量门槛值为板厚的(2~3)倍。三种类型层合板回弹变化规律基本一致,分为三个阶段。第一阶段为快速回弹阶段;第二阶段为缓慢回弹阶段;第三阶段为凹坑稳定阶段。且回弹主要发生在24h以内,超过24h后,回弹可以忽略不计,认为损伤保持稳定。回弹率大小排序为,GS03GD03CS03,且回弹率的大小与冲击能量的大小无关。
[Abstract]:Since its advent, composite materials have been widely used in aerospace, ship manufacturing, construction and other fields because of their excellent properties and the characteristics of modular production, but the composite materials are very sensitive to impact. Which makes the properties of the material decline seriously after the impact, thus causing a serious safety hazard. Therefore, it is of great significance to study the damage of composite laminates after impact. This paper is supported by the National Natural Science Foundation of China (No.: 51573018). The impact energy threshold and damage resilience of composite laminates are studied. Three types of laminates, glass fiber / epoxy multidirectional plates and carbon fiber / epoxy multidirectional laminates, were subjected to impact tests at different impact energies. The surface damage morphology of the three laminated laminates after impact was scanned by Keyence VHX2000C hyperfield 3D microscope. The changes of damage area and pit depth of three types of laminated plates are analyzed. The leakage of laminated plates after impact is detected by using the self-developed penetrating injury detection instrument. The results of impact test and penetrating injury detection are combined. The impact energy threshold of three types of laminated plates is obtained. Finally, according to the surface damage characteristics of laminated plates, the relationship between impact energy and damage area is obtained by introducing the factor k. considering the effect of springback characteristics on surface damage, By measuring the variation of pit depth with time in three different types of laminated plates, the springback characteristics of the crater depth of three kinds of laminated plates after impact are obtained. The experimental results show that with the increase of impact energy and plate thickness, The damage area and pit depth of laminates are also increasing, but the change curve of glass fiber / epoxy composite unidirectional plate and glass fiber / epoxy composite multidirectional plate has a turning point with the increase of impact energy. However, no significant turning point was found in carbon fiber / epoxy composite multidirectional plates. The damage of three types of laminates (including damage area and pit depth) was compared. Carbon fiber / epoxy composite multidirectional plate glass fiber / epoxy composite multidirectional plate glass fiber / epoxy composite unidirectional plate. Formula for calculating impact energy of glass fiber / epoxy composite unidirectional plate. Formula can be used to calculate the impact energy of carbon fiber / epoxy composite unidirectional plate. The results show that the calculation error of glass fiber / epoxy composite unidirectional plate is larger than 15%, and the calculation error of glass fiber / epoxy composite multidirectional plate and carbon fiber / epoxy composite multidirectional plate is small. The impact energy threshold of glass fiber / epoxy composite unidirectional plate is 3 times that of plate thickness, the impact energy threshold of glass fiber / epoxy composite composite plate is 3 ~ 4 times that of plate thickness, and the impact energy threshold of glass fiber / epoxy composite plate is 3 ~ 4 times that of plate thickness, and the impact energy threshold of glass fiber / epoxy composite plate is 3 ~ 4 times that of plate thickness. The impact energy threshold of carbon fiber / epoxy composite multidirectional plate is 3 times of that of plate thickness. The springback of the three types of laminated plates is basically the same, which is divided into three stages: the first stage is the fast springback stage, the second stage is the slow springback stage, the second stage is the slow springback stage, the first stage is the fast springback stage, the second stage is the slow springback stage. The third stage is pit stabilization, and the springback mainly occurs within 24 hours. After more than 24 hours, the springback can be ignored and the damage remains stable. The springback rate is in the order of GS03GD03CS03, and the rebound rate is independent of the impact energy.
【学位授予单位】：北京建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU599

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