玻璃纤维增强聚丙烯材料的立体混合法工艺及实验研究

发布时间：2018-01-05 18:12

本文关键词：玻璃纤维增强聚丙烯材料的立体混合法工艺及实验研究　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着玻璃纤维增强聚丙烯(GF/PP)复合材料的应用越为广泛,有关其制毡工艺、力学性能和力学特性的研究工作也变得尤为重要。其制毡工艺的优劣性关系到后续板材热压成型工艺的复杂性及可靠性。而GF/PP复合材料本身的力学性能与力学特性也会随着其制毡工艺、制作环境与保存条件等产生诸多的不确定性变化。本文研究了GF/PP复合材料的立体混合法制毡工艺,通过气流成网工艺,对GF/PP复合材料的基体结构进行改进,并进行相关的力学实验分析,从力学性能上验证了立体混合法工艺的优势与可靠性。另外,本文也对GF/PP复合材料的应变率敏感特性进行了实验研究分析,以满足其在碰撞与安全领域的应用。主要的工作如下:将PP纤维与GF经立体混合法制备成连续针刺毡。结果表明:所制立体混合毡中,PP纤维与GF混合均匀,纤维的损伤、断裂情况较少,毡层形成较为稳定的立体结构,有利于后续板材的热压成型。采用层合热压法将立体混合毡压制成板材,并对其进行力学性能测试。结果表明:在同等克重(每平方米重量)和GF含量的条件下,其拉伸强度、弯曲强度、抗冲击强度都较传统工艺所制板材有了较大幅度的提升。通过层合热压法将GF毡与PP薄膜复合成不同GF含量的板材,在不同的加载速率下进行拉伸实验,作出应力应变曲线。采用BURGERS粘弹性模型拟合预测对应的应力应变曲线,并与实验曲线相比较。结果表明:该材料在低应变率范围内对应变率是敏感的,随应变率的增加,其断裂拉伸应力值增大,随GF含量的增加,其所对应的应变率效应反而有所下降。BURGERS模型能够较为合理的拟合预测出该材料的本构关系,从理论上验证了GF/PP复合材料的应变率敏感特性。
[Abstract]:With the increasing application of glass fiber reinforced PP / PP composites, the process of making felt is concerned. The study of mechanical properties and mechanical properties has also become particularly important. The quality of the felting process is related to the complexity and reliability of the subsequent hot pressing process of sheet metal. The mechanical properties of GF/PP composites are also very important. And mechanical properties will also follow its felting process. There are many uncertain changes in the manufacturing environment and preservation conditions. In this paper, the three-dimensional mixing felting process of GF/PP composites is studied, and the airflow netting process is studied. The matrix structure of GF/PP composites was improved, and the related mechanical experiments were carried out to verify the advantages and reliability of the stereoscopic mixing process. The strain rate-sensitive properties of GF/PP composites are also studied experimentally. The main work is as follows: PP fiber and GF were prepared by stereoscopic mixing method to form continuous needle felt. PP fiber and GF mixed evenly, fiber damage, less fracture, tapetum formation of a more stable three-dimensional structure. It is advantageous to the hot pressing forming of the subsequent sheet metal. The solid mixed felt is pressed into the plate by the laminated hot pressing method. The results show that the tensile strength and bending strength of the material are under the condition of equal g weight (per square meter weight) and GF content. Compared with the traditional process, the impact strength of GF felt was greatly improved. The GF felt was combined with PP film to form different GF content sheet by laminating hot pressing method, and the tensile test was carried out at different loading rates. The stress-strain curve was obtained and the corresponding stress-strain curve was fitted by BURGERS viscoelastic model. The results show that the material is sensitive to the strain rate in the range of low strain rate. With the increase of the strain rate, the fracture tensile stress value increases and the GF content increases. On the contrary, the strain rate effect of the material decreases. The Burgers model can fit and predict the constitutive relation of the material reasonably. The strain rate sensitivity of GF/PP composites is verified theoretically.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ325.14;TB332

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