铺放参数对复合材料厚度方向力学行为影响

Effect of laying parameters on mechanical behavior of composite in thickness direction

为了探究铺放工艺参数的变化对复合材料厚度方向力学行为的影响,通过面外拉伸实验分析了铺放压力与铺放温度对复合材料厚度方向面外拉伸强度与拉伸模量的影响,并对不同铺放工艺的试件失效模式进行了分析。试验结果表明,增大铺放压力会减小层间富树脂区厚度,使复合材料面外拉伸强度不断增大,当铺放压力为0.225 MPa时取得实验组最大值,与铺放压力0.075MPa相较强度提升约13.1%,失效模式由纤维断裂与纤维层剥离的组合转变为纤维断裂;铺放压力的进一步增大会挤压层间树脂,改变树脂富集形态,使面外拉伸强度下降,剥离失效模式再度出现。实验用复合材料的适宜铺放温度为30℃,过高的铺放温度会导致孔隙率的上升,使复合材料的面外拉伸强度严重下降,裂纹扩展失去规律性;与铺放温度25℃相比,铺放温度为45℃时复合材料面外拉伸强度下降达19.2%,失效模式由纤维断裂与纤维层剥离的组合失效转化为单一的纤维层剥离失效。

To explore the effect of the change in laying process parameters on the mechanical behavior of composite materials in thickness direction,the influence of laying pressure and laying temperature on the tensile strength and modulus was measured through an out-of-plane tensile experiment,and the failure mode of the specimen was analyzed.The test results showed that the increased laying pressure would decrease the thickness of the interlayer resin rich area while increasing the out-of-plane tensile strength of the composite materials.The maximum strength of test groups was obtained at laying pressure of 0.225 MPa,and the strength increased by 13.1%compared with that at 0.075 MPa.The failure mode changed from the combination of fiber fracture and layer peeling to fiber fracture.Further increase of laying pressure would squeeze the interlayer resin,and change the form of the resin rich area,thereby causing the tensile strength decrease and reemergence of peeling failure.The suitable laying temperature of the composite material used in the experiment was 30℃.Excessive laying temperature will lead to porosity increase,causing serious decrease in the out-of-plane tensile strength and resulting in irregular crack propagation.Compared with the laying temperature of 25℃,when it was 45℃,the out-of-plane tensile strength of the composite material decreased by 19.2%,and the failure mode was transformed from the combined failure of fiber fracture and layer peeling to dominant layer peeling.