多向铺层拉挤FRP薄壁梁成型工艺及弯曲性能研究

STUDY ON THE MOULDING PROCESS AND BENDING PROPERTIES OF MULTI-DIRECTIONAL LAMINATED PULTRUDED THIN-WALLED FRP BEAM

采用适当的铺层设计和在模具口加装自主设计的导向装置,并改进拉挤工艺的进丝方法,然后通过拉挤工艺完全采用±45°纤维缝编毡作为型材腹板的预浸料生产纤维增强复合材料(FRP)薄壁梁,从而使FRP薄壁梁腹板为全±45°铺层结构。随后进行了4种不同铺层结构的FRP梁的对比弯曲试验。结果表明,与全0°铺层的FRP薄壁梁相比,腹板采用±45°铺层的梁的极限承载力提高明显;随着±45°铺层的增加和0°铺层的减少,梁的弯曲弹性模量则有所下降;腹板剪切强度提高之后,腹板剪切破坏不再是FRP薄壁梁的主要破坏形式,局部强度破坏将成为制约梁整体承载力的瓶颈。

By using proper ply design and fixing a self-designed guide device to the inlet of the mould,and improving the fiber inletting method of the pultrution technique,the FRP thin-walled beam was realized through pultrution by completely using ±45° fiber fabric as the prepreg of the web plate,so that there were completely ±45° ply structure in the web plate of the pultruded thin-walled beam.Comparative bending experiments on 4 different ply structures of FRP beams were executed.The results showed that comparing to the thin-walled FRP beams with complete 0° ply,the ultimate bearing capacities of the beams of which the webs adopt ±45° ply increased obviously.With increasing ±45° plies and decreasing 0° plies,the bending modulus of the beams declined by some extent.Since the web shear strength was improved,the shear failure of web was no longer the main failure mode of the thin-walled FRP beams,and local failure would become the overall bearing capacity bottleneck of this kind of beams instead.