高温下复合材料螺栓接头强度的试验研究

目的研究高温环境对树脂基复合材料螺栓连接接头的强度和破坏模式的影响规律。方法以T300/BMP316复合材料为研究对象,在室温~310℃范围内对不同宽孔比的螺栓连接接头开展拉伸试验研究。结果获得了不同宽孔比、不同温度环境下树脂基复合材料螺栓连接接头强度和破坏模式的变化规律。结论不同宽孔比螺栓接头试件的载荷-位移曲线既具有共性特征,又具有明显的差异。宽孔比对复合材料螺栓接头的拉伸强度和破坏模式均具有明显的影响,在相同温度下,接头的拉伸强度随着宽孔比的增大而下降,其破坏模式将由拉伸-挤压破坏逐步向剪切-挤压破坏转变,宽孔比越大,拉伸破坏模式占的比重越小,而剪切破坏占的比重越大。试验温度虽然没有改变同一宽孔比复合材料螺栓接头的破坏模式,但对其拉伸强度影响明显,相同宽孔比下复合材料螺栓接头静载强度随着温度的升高而降低,这是由于随着温度的升高,树脂基体的性能下降明显,使得接头中更易出现拉伸破坏和挤压破坏等,进而大大降低了复合材料螺栓接头的强度。

Experimental Study on Strength of Bolted Joint of Composites at Elevated Temperature

Objective To study effects rules of high temperature on strength and damage modes in bolted joints made of composites. Methods Various tensile tests for bolted joints of T300/BMP316 composites with different W/D were conducted at indoor temperature-310℃ .Results Change rules on strength and failure mode of bolted joints made of resin matrix composites with different W/D and temperature were obtained. Conclusion There are common features and apparent differences in load-displacement curves of bolted joints with different W/D which has apparent influences on the tensile strength and damage mode of bolted joints made of composites. At the same temperature, the tensile strength decreases with the increase of W/D. The damage mode changes from tensile-crushing failure mode to shear-crushing failure mode. When W/D increases, the domination mode changes from tensile failure to shear failure. The damage modes of joints are insensitive to the temperature, but the strength of joints decreases greatly when the temperature increases, which is because it is easy to cause the tensile failure and crushing failure in joints due to the mechanical properties degradation of resin at elevated temperature.