湿热环境对7781/CYCOM 7701玻璃纤维/环氧复合材料典型力学性能的影响
Effect of hygro-thermal condition on typical mechanical property of 7781/CYCOM 7701 fiberglass/epoxy composite

采用7781/CYCOM 7701玻璃纤维/环氧织物预浸料和中温固化工艺制造了复合材料单向层压板试验件。将试验件分为3组，分别对应低温干态（CTD）、室温干态（RTD）和高温湿态（ETW）3种试验环境条件。在这3种试验环境条件下，分别测试了复合材料单向层压板的拉伸、压缩、剪切、孔挤压和拉脱等力学性能。并在试验中适当考虑了复合材料经向和纬向力学性能差异、是否含缺口和是否含冲击损伤等情况。根据试验结果，研究了湿热环境对7781/CYCOM 7701玻璃纤维/环氧复合材料单向层压板典型力学性能的影响。研究表明：以RTD条件为基准，各项强度性能在CTD条件下均上升，而在ETW条件下均下降。其中，在ETW条件下，拉伸强度下降18%~25%，压缩强度下降10%~40%，剪切强度下降30%~50%，孔挤压强度下降约20%，拉脱强度下降接近30%；拉伸和压缩弹性模量受温度和吸湿条件影响较小，均在10%左右或以内；而泊松比和剪切弹性模量则受温度和吸湿条件影响很大，两者在ETW条件下的性能比在RTD条件下的性能分别下降约30%和50%。 7781/CYCOM 7701 fiberglass/epoxy fabric prepreg was used to fabricate the composite lamina test specimens in medium temperature curing process. These test specimens were categorized into three groups, respectively corresponding to three types of environmental condition of testing:cold temperature dry(CTD), room temperature dry(RTD) and elevated temperature wet (ETW). Under the three types of test environmental condition, the composite lamina mechanical properties of tension, compression, shear, bearing and pull-through were tested. Meanwhile the mechanical properties difference between warp and fill direction of the composite, the existence of notch and impact damage, were properly considered in the test. Based on the test results, the effect of hygro-thermal condition on typical mechanical properties of 7781/CYCOM 7701 fiberglass/epoxy composite lamina was studied. Study indicates:Taking RTD condition as baseline, it rises in CTD condition but descends in ETW condition for each type of strength property. Of these, tensile strength descends 18% to 25%, compressive strength descends 10% to 40%, shear strength descends about 30% to 50%, bearing strength descends about 20%, and pull-through strength descends about 30% in ETW condition; Temperature and moisture absorption condition have a minor effect on tensile and compressive modulus, which is about 10% or below. But they have a major effect on Poisson's ratio and shear modulus. Taking RTD condition as baseline, it descends about 30% and 50% respectively for Poisson's ratio and shear modulus in ETW condition. 大型客机国家科技重大专项