石英纤维增强聚酰亚胺树脂基复合材料的疲劳特性

The tensile stress-strain behavior and tensile strength of quartz fiber reinforced polyimide matrix (QFRP) composite were measured at room and elevated temperatures. The average tensile strength and elasticity modulus decreased with increasing temperature, and remained 68% and 80% at 300 ℃, respectively. Tension-tension fatigue behavior of a QFRP composite was studied at room and elevated temperatures. At the same cyclic stress level, a longer fatigue life of QFRP composites was obtained at room temperature, compared to elevated temperature. Damage evolution was discussed on the basis of cross-section and mechanical variation. The dominant damage mechanism of warp yarn cracking was mitigated at elevated temperatures as a direct result of resin softening, which was also the case for the fatigue test specimens. This study yielded an improved understanding of damage mechanisms and local deformation behavior for QFRP composite, which was valuable for designers.