CFRP环带拉索静力拉伸试验及数值模拟

铰销式CFRP环带是一条具有单向纤维的CFRP连续层带，以类似于赛道的方式分层缠绕在2个分离的销钉上，荷载通过销钉进行传递。进行了层压型CFRP环带静力拉伸试验，分析了试验过程中的荷载与应力关系、试件裂纹发展过程以及破坏模式，同时建立了有限元模型与试验结果进行了对比验证。在此基础上，通过对构造参数进行分析，研究了关键参数对CFRP环带的受力特点、应力分布、破坏模式及承载力的影响。研究结果表明:环带的荷载传递效率较直线条带下降了近20%；环带承载过程中，伴随着分层现象的出现和纵向裂纹的发展，最后在直曲相交段发生脆性破坏；随着曲线段曲率、环带厚度、摩擦系数的改变，环带各层和各部分的应力最大值均有不同程度的变化，但应力最大值出现的位置总是发生在直曲相交段或直线接头外侧；曲线段的应力分布受构造参数影响更大，虽然应力水平不高，但对环带整体的承载情况和破坏模式有较大影响。

STATIC TENSILE EXPERIMENT AND NUMERICAL ANALYSIS OF LAMINATED CFRP STRAPS

Pin-loaded laminated carbon fiber reinforced polymer (CFRP) straps are produced by winding unidirectional CFRP tapes around two separated pins, and the load is transferred by the pins. Axial tensile tests were performed to investigate the displacement and strain distributions in the individual layers, the crack propagation and the failure modes. A finite element model was developed and validated by the experimental results. Based on the experimental and numerical results, the effect of critical parameters on the load-bearing and failure mechanisms of the strap were analyzed. The analysis shows that the load transfer efficiency of CFRP straps was decreased by 20% compared to the straight strap. Brittle failure occurred at the intersection between the straight and the curved segments with the development of the delamination and longitudinal cracks. The curvature, strap thickness and friction coefficient had significant influence on the maximum stress of each layer, which always occurred at the intersection between the straight and the curved segments. The load bearing capacity and failure modes were greatly affected by the stress distribution in the curved segment even if the stress level was relatively low.