GFRP面板-冷弯薄壁型钢组合梁受弯性能试验研究

Experimental study on flexural behavior of GFRP composite laminates-cold formed steel composite sandwich beams

土木工程领域通常采用的纤维增强复合材料夹层结构主要以模量较低的轻质材料作为芯材,使其设计承载力由截面刚度控制,而非强度控制,限制了纤维增强材料强度的充分发挥。为此,提出一种轻质、高强的玻璃纤维增强复合材料（GFRP）面板-冷弯薄壁型钢组合梁（GCS组合梁）,该组合梁由GFRP面板与夹层轻质泡沫和冷弯薄壁型钢组合而成,薄壁型钢和纤维面板之间采用剪力键（抽芯铆钉）连接。通过四点弯曲试验探讨了该组合梁的破坏模式、荷载-位移曲线和应变分布的发展规律,并与传统夹层梁进行对比,分析了有无薄壁型钢增强、薄壁型钢开口方向、界面增强方式等参数对组合梁弯曲性能影响。研究结果表明：GCS组合梁具有良好的刚度和承载能力。相对于传统复合材料夹层梁,其正常使用极限状态（挠度限值L/250）和承载力极限状态下对应荷载分别提高了306.2%和157.5%;不锈钢抽芯铆钉能有效抑制GFRP面板与压型钢板界面剥离裂纹扩展,显著改善GCS组合梁的变形能力。研究为该组合构件的加工设计与实际工程应用提供参考。

Traditional composite sandwich structures used in civil engineering applications mainly use lightweight and low modulus materials as core material, which results in ultimate strength being controlled by the stiffness of the crosssection rather than by strength of material, i.e., the strength of the FRP material is not fully mobilized. A glass fiber reinforced polymer （GFRP） composite laminates-cold formed steel composite sandwich beam （GCS beam） with properties of light weight, high strength was proposed. The GCS beam composed of GFRP skins, light-weight polyurethane （PU） foam core and cold formed steel （profiled steel sheet） , where the GFRP skins and the profiled steel sheet was enhanced by stainless steel core rivets. Four point bending tests were carried out to explore the flexural behavior of the GCS beams, and analyse the effect of parameters of open direction of the profiled steel sheet and the interface enhancement on the failure modes, bending stiffness, ultimate bending strength and ductility properties of the novel sandwich beams. Test results show that GCS beams have a better serviceability limit state and ultimate limit state load bearing capacity, which are increased by 306.2% and 157.5% compared to the conventional sandwich beam, respectively. The stainless steel core rivets, used as interface enhancement, can restrain the interface crack propagation effectively and improve the deformability of GCS beams remarkably. The whole work can be taken as a reference for manufacture, design and application of this kind of structural members.