复合材料孔隙超声反射法和穿透法检测对比分析

采用超声反射法和超声穿透法对碳纤维增强树脂基复合材料层压板进行孔隙缺陷检测与孔隙率数值评估。通过工艺偏离的方法制备不同孔隙级差的检测试样,采用超声反射法与超声穿透法对该批试样进行检测,得到不同级差孔隙缺陷对应的超声检测波形和成像检测结果,并基于声波衰减幅度对孔隙率进行量化评估。结果表明:孔隙率在0.0%~3.0%之间时,两种超声检测方法的评估结果相吻合,超声反射法对微米级孔隙缺陷或低孔隙级差具备更高的检测灵敏度;超声穿透法对高孔隙率级差或大厚度或高衰减材料的复合材料制件提供更高的超声穿透能力。

Ultrasonic pulse-echo reflection and through-transmission methods for porosity measurement in carbon fiber-reinforced polymer composites

To detect void defects and determine porosity levels, carbon fiber-reinforced polymer composites were characterized through two kinds of ultrasonic methods, namely pulse-echo reflection and through-transmission. In order to evaluate the ability and the advantages of these two series of experiments, the tests were carried out on a set of specimens, which were manufactured to vary the porosity by altering the pressures used during the cure cycle in an autoclave. The ultrasonic experimental measurements were shown to be in good agreement with metallographic tests in the porosity range of 0.0% to 3.0%. Despite the consistency of both techniques, ultrasonic pulse-echo reflection method has shown itself to be more sensitive to sub-millimeter voids and more capable of evaluating porosity of lower levels, whereas ultrasonic through-transmission method provides better penetration with regard to higher levels of porosity or thicker plates.