论文部分内容阅读
本文讨论了低速冲撞对先进的热固性树脂基复合材料结构所产生的损伤容限,并提供了相应的背景、冲击试验结果、设计要求、某些设计方案、分析工作、结论和建议。最重要的观测結果是:低速冲撞比已研究的任何其它类型的损伤要更严重;面内压缩是冲击损伤试样的临界负荷;100英尺-磅冲击损伤减少高温湿应变15％;在周期负荷下冲击损伤的增长并不一致;S-N曲线比较平缓,静态条件可能支配设计;如果峰值负荷不超过损伤的静态抗压强度的60％,试样寿命可能超过(R=10)10~6循环;在室温干燥条件下压合是有利的。设计要求规定假设的起始损伤是一个4英寸长和0.02英寸深的表面划伤;相当于直径2英寸的剥离,以及由或是100英尺-磅能量或是0.1英寸深最小凹痕所产生的冲击损伤。就相同的冲击能量来说,较大的和较为复杂的试样与平的简单的试样相比呈现较大的损伤容限。建议使冲击试验标准化,建立能量释放速率和后冲击强度之间的关系,并且研究和验证适用于复合材料结构的损伤容限广谱的预测能力。
This paper discusses the damage tolerance of low-velocity impact on the structure of advanced thermosetting resin-based composites, and provides the corresponding background, impact test results, design requirements, some design schemes, analysis work, conclusions and recommendations. The most important observations are: low velocity impact is more severe than any other type of damage studied; in-plane compression is the critical load for impact-damaged specimens; 100-foot-lb impact damage is reduced by 15% for high-temperature wet-strain; The SN curve is relatively flat and the static conditions may dominate the design; if the peak load does not exceed 60% of the static compressive strength of the damage, the sample life may exceed (R = 10) by 10 to 6 cycles; at Pressing at room temperature under dry conditions is advantageous. The design requirement states that the assumed initial damage is a surface scratch of 4 inches in length and 0.02 inches in depth; a peel of 2 inches in diameter and a minimum dent of 100 feet-pounds of energy or 0.1 inch deep Impact damage. For the same impact energy, larger and more complex specimens show greater damage tolerance than flat, simple specimens. It is recommended that the impact test be standardized to establish the relationship between the rate of energy release and the post-impact strength and to study and validate the predictive ability of the damage tolerance broad spectrum for composite structures.