为了研究混杂纤维的混杂效应和本构关系,进行了1CnB混杂纤维布(1层CFRP布和n层BFRP布的混杂布)单轴拉伸试验研究,采用不同的混杂比和两种铺层方式。结果表明,BFRP层数较少时,破坏形式仍然表现为完全的线弹性;随着BFRP比例的提高,混杂纤维断裂应变不断提高,本构关系曲线上开始出现"屈服平台"和多级断裂的现象,破坏过程较为平缓,并有明显的预兆,表现出一定的延性,改变了单种纤维脆性破坏的缺点。纤维铺层方式也对混杂效应有影响,夹芯铺层的极限应变高于外层铺层。最后,通过对试验数据的回归分析给出混杂纤维的混杂效应系数计算公式,推导临界体积比,并进一步提出混杂纤维的本构关系。
To study the hybrid effect of hybrid fiber sheets and its constitutive relation,uniaxial tensile tests of 1CnB(1 layer of CFRP sheet hybrid with n layers of BFRP sheets) hybrid fibers sheets with different hybrid ratio and two mixed modes are studied in this paper.The results show that when the volume ratio of BFRP is low,its damage mode still manifests in the form of linear elastic.But with the improving of the BFRP /CFRP ratio,the rupture strain become higher and higher,constitutive curve begins to show"yield point elongation"and the phenomenon of multi-level rupture;failure process is more gentle and with a clear sign,showing a certain degree of ductility and the shortcoming of brittle fracture of single fiber is overcome.The hybrid mode also has impact on the fiber hybrid effect,and the sandwich mixed mode is better than the outer layer mixed mode.Based on the test results,a formula of hybrid effect factor is put forward by regression analysis.Formula of critical volume ratio is derived,and further the constitutive relation of hybrid fiber is proposed.