环境温度对长玻纤增强聚丙烯单向拉伸力学性能的影响

Effect of Environment Temperature on Uniaxial Tensile Properties of Long Glass Fiber Reinforced Polypropylene

长玻纤增强聚丙烯(Long glass fiber reinforced polypropylene,LGFPP)作为一种轻质、易回收的新型车用复合材料,同时具有较好的力学性能、耐热性、耐候性。通过不同温度环境下的拉伸试验研究了环境温度对LGFPP力学性能的影响并分析了其失效机理。结果表明:当环境温度为零下20℃时,基体对纤维的包裹性较好,有利于载荷传递,破坏表现为基体破坏,断裂面较为平整,其拉伸强度相对室温下提高18.93%;随着温度升高,树脂基体逐渐变软,树脂与纤维之间的界面强度降低,部分表现为纤维与基体的界面破坏,从而减少了纤维承载发生的破坏,从而导致了LGFPP强度降低;当环境温度达到100℃时,其拉伸强度相对室温下降低45.84%。建立了LGFPP的均质化RVE模型,预测了不同温度下LGFPP的力学响应和弹性常数,数值模拟结果和理论值与实验结果吻合较好。这为LGFPP在应用环境的耐适性提供了指导。

Long glass fiber reinforced polypropylene(LGFPP)is a lightweight,high-strength,and easy-to-recycle new vehicle composite material,and has good mechanical properties,heat resistance and weather resistance.In this work,the effect of ambient temperature on the mechanical properties of LGFPP was studied through tensile tests under different temperature environments and its failure mechanism was analyzed.The results show that the matrix has better encapsulation of the fibers when the ambient temperature is minus 20℃,which is conducive to load transmission.The damage is manifested as matrix failure and the fracture surface is relatively flat,and the tensile strength is increased by 18.93%compared with room temperature.As temperature arises,the resin matrix gradually becomes soft,and the interface strength between the resin and the fiber decreases,which is partly manifested as the interface failure between the fiber and the matrix.It reduces the damage of the fiber load,which leads to the decrease of the strength of LGFPP.When the ambient temperature reaches 100℃,the tensile strength is 45.84%lower than that at room temperature.The homogenized RVE model of LGFPP was established,and the mechanical response and elastic constants at different temperatures were predicted.The numerical simulation results and theoretical values were in good agreement with the experimental results.It provides guidance for the adaptability of LGFPP in the application environment.