石英纤维复合材料孔隙含量超声评价方法研究

发布时间：2018-01-11 13:31

本文关键词：石英纤维复合材料孔隙含量超声评价方法研究　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：RTM石英纤维复合材料具有成本低、成型速度快、强度和模量大、耐热、介电常数低和正切损耗小等优点,在航空航天、军工、生物医学工程等技术领域得到了广泛的应用。孔隙微缺陷在材料成型过程中是不可避免的,对复合材料的力学性能产生影响,因此孔隙微缺陷的无损评价成为研究热点,而目前主要采用超声方法评价孔隙含量。针对RTM石英纤维复合材料孔隙含量的无损评价问题,本文在研究了成型工艺参数对孔隙含量的影响基础上,开展了孔隙含量超声评价方法研究。首先,通过改变RTM石英/环氧复合材料成型过程中的树脂注射压力、树脂注射温度等工艺参数制作了孔隙含量不同的复合材料样品。其次,测量了RTM石英/环氧复合材料样品的孔隙含量和力学性能,研究了RTM成型工艺参数对复合材料孔隙含量的影响以及孔隙含量对力学性能的影响。最后,利用声速、声衰减系数和相对非线性系数对树脂基体不同的RTM石英纤维复合材料孔隙含量进行评价,且针对孔隙含量高,衰减大的石英/酚醛复合材料提出了测量声速和声衰减系数的改进方法。研究结果表明,RTM成型工艺参数影响着复合材料孔隙微缺陷的产生,且孔隙含量随着树脂注射压力的增大而减小;0.6MPa的注射压力时,复合材料孔隙含量随着温度的升高而增大;随着孔隙含量的增大,复合材料的弯曲强度和压缩强度逐渐减小。孔隙含量在1%以内变化时,声速不随孔隙含量呈规律性变化,而超声衰减系数和相对非线性系数随孔隙含量单调递增,能够用于评价石英纤维复合材料的孔隙含量;与超声衰减系数相比,相对非线性系数对孔隙微缺陷的敏感性更强。
[Abstract]:RTM quartz fiber composite material has the advantages of low cost, fast forming speed, strength and modulus, heat resistance, low dielectric constant and loss tangent of the advantages of small, military aerospace, biomedical engineering and other fields, the technology has been widely used. The pore micro defects are inevitable in the material forming process, the influence of mechanics the properties of composite materials, the pore micro defects nondestructive evaluation has become a research hotspot at present, mainly by ultrasonic evaluation method of void content. For nondestructive evaluation of composite void content RTM quartz fiber, the influence of process parameters on the basis of the void content, carried out research on the evaluation method of pore content of ultrasonic firstly. RTM, by changing the quartz / epoxy composite molding process of the resin injection pressure, process parameters of resin injection temperature produced with different content of pore Composite samples. Secondly, the void content and mechanical properties of RTM / epoxy composite quartz samples were measured to study impact of RTM molding process parameters on composite void content and pore content on mechanical properties. Finally, the sound velocity, attenuation of pore content of RTM quartz fiber composites and the relative coefficient of different nonlinear coefficient the resin matrix was evaluated, and the pore content is high, the attenuation of silica / phenolic composite method is proposed to improve measurement of velocity and attenuation coefficient. The results show that the RTM process parameters affect the composite micro pore defects, and pore content increases with resin injection pressure and injection pressure decreases; 0.6MPa, composite pore content increases with the increase of temperature; with the increase of pore content, the flexural strength of the composites and compression The strength decreases gradually. The pore content changes of less than 1% and the velocity changes with the void content, ultrasonic attenuation coefficient and relative nonlinear coefficient with void content increasing, can be used to evaluate the pore content of quartz fiber composite material; compared with the ultrasonic attenuation coefficient is more sensitive to relative nonlinear coefficient of pore micro defects.

【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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