摘要
利用Hopkinson杆加载装置,对带有单边切口的CFRP、GFRP层板试件进行冲击拉伸加载实验。根据一维应力波理论求得作用于试件上的载荷P(t)和试件加载点的位移δ(t)。根据试样中应力随时间的变化历史σ(t),再结合断裂韧性测试原理,建立动态应力强度因子KI(t)响应曲线。利用柔度变化率方法确定起裂时间,分别得到在2种加载速率下CFRP、GFRP层板的动态断裂韧性。
Aim. To our knowledge, there is as yet no paper in the open literature dealing with impact fracture toughness of laminates. We now present the results of our research on such fracture toughness. In the full paper, we explain our research results in detail; in this abstract, we just add some pertinent remarks to listing the two topics of explanation： （1） test set-up and （2） the principles of experiments; in topic 1, we mention that the impact test specimens Hopkinson bars were prepared by Beijing Institute of Aeronautical Materials and that the tests were done at China University of Science and Technology; in topic 1, we also give Fig. 1 in the full paper as the schematic of the test set-up; the three subtopics of topic 2 are the calculation of loads and displacements （subtopic 2. 1）, the determination of dynamic stress intensity factor KID（subtopic 2. 2） and the determination of crack initiation time （subtopic 2. 3）; in subtopic 2.1, eqs. （1） and （2） are taken from the open literature; in subtopic 2.2, eqs. （3）, （4） and （5） and Table 1 are taken from the open literature, but eq. （6）, needed for the determination of KID, is proposed by us; in subtopic 2.3, we explain that crack initiation time is related to compliance changing rate △C/C, which is, in turn, determined by eq. （7） in the full paper. We conducted experiments at different strain rates： 500/s and 1100/s for CFRP laminates and 500 / s and 1200/s for GFRP laminates. The major test results, given in Figs. 2, 3, 8 and 9 in the full paper, show preliminarily that： （1） both failure strength and fracture strain increase with increasing strain rate, （2） dynamic fracture toughnesses of the two laminates decrease with increasing strain rate. （3） the modifying factor f（α/ω） used in determining the dynamic fracture toughness of CFRP should be improved for α/ω〉0. 7.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2007年第1期65-68,共4页
Journal of Northwestern Polytechnical University
基金
航空科学基金(00B53009)资助
