钢-CFRP接头胶-编混合搭接模式及力学性能

Hybrid adhesive-woven lap mode and mechanical properties of steel-CFRP joints

  • 摘要: CFRP (Carbon Fiber Reinforced Polymer, CFRP)以其轻质高强的特性在航天、汽车、土木和石油等领域广泛应用,但其与钢材的连接强度成为当前研究的重要问题。本文进行了五种试验,每种试验设有三个平行试件,总计15组试验,研究了单层钢-CFRP胶-编混合搭接接头在不同孔距和孔形组合下的最优设计。基于单层试验结果,进一步开展了六种试验,每种试验设有三个平行试样,总计18组试验,探讨了三种不同搭接形式和四种不同搭接长度对多层钢-CFRP胶-编混合搭接接头力学性能的影响。实验分析了不同搭接形式和长度下的接头荷载-位移曲线、失效模式、单位厚度峰值强度和极限承载力。同时,结合数字图像相关方法详细分析了接头的应变分布和演化过程。研究结果显示,相较于椭圆形开孔,单层矩形开孔接头的强度提高了23.51%,并且在孔距为20 mm时达到了最高强度。在多层搭接接头中,双层碳纤维布和双层钢带搭接形式显著提高了接头的强度,分别比前两种形式提升了160.33%和119.26%。进一步分析表明,增加搭接长度有效提升了接头的承载能力,但随着搭接长度进一步增加,接头强度逐渐趋于稳定甚至略有下降;当搭接长度增至60 mm时,接头强度达到最高点,比40 mm长度的接头提升了20.94%。

     

    Abstract: CFRP (Carbon Fiber Reinforced Polymer) is widely used in aerospace, automotive, civil engineering and petroleum industries due to its lightweight and high-strength characteristics. However, the strength of connections between steel and CFRP remained a significant challenge in current research. This paper investigated the optimal design of single-layer steel-CFRP hybrid adhesive-woven lap joints under different hole spacing and hole shapes through five types of experiments, each with 3 parallel tests, totaling 15 specimens. Based on the results from single-layer experiments, six types of experiments were further conducted, each with 3 parallel tests, totaling 18 specimens, the mechanical performance of multi-layer steel-CFRP hybrid adhesive-woven lap joints under the influence of three different joint overlap configurations and four different overlap lengths were examined. The load-displacement curves, failure modes, peak unit thickness strengths, and ultimate load under different configurations and lengths were analyzed. Concurrently, detailed strain distribution and evolution processes of joints were analyzed using digital image correlation (DIC) methods. The results indicate that compared to elliptical holes, rectangular hole joints exhibit 11.99% increase in mechanical strength, and the mechanical strength reaches its maximum at a 20 mm hole spacing. In multi-layer joints, double-layer carbon fiber cloths and double-layer steel configurations significantly enhance the strength of joints compared to the other two configurations, improved by 160.33% and 119.26% respectively. It’s found that increasing overlap length also effectively enhances joints’ ultimate load. However, when the overlap length exceeds a certain value, the mechanical strength of joints gradually stabilizes and slightly decreases. At the overlap length of 60 mm, the joint mechanical strength reaches its peak and is improved by 20.94% compared to the overlap length of 40 mm.

     

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