玄武岩纤维增强复合材料拉挤圆管抗弯性能研究

Study on Bending Behavior of Basalt Fiber Reinforced Polymer Pultruded Circular Tube

为使玄武岩纤维增强复合材料(Basalt Fiber Reinforced Polymer,BFRP)拉挤圆管在桥梁工程中得到更广泛地应用,对其抗弯性能进行试验及有限元分析。对2根长度为750 mm的BFRP拉挤圆管进行三点抗弯试验;采用LS-DYNA有限元软件对试验过程进行模拟,验证有限元模拟的正确性;在保持BFRP拉挤圆管总厚度不变的条件下,研究内、外层双向纤维布的铺设厚度和角度对抗弯性能的影响。结果表明:试件从加载至破坏分为线弹性阶段、下降阶段和残余阶段,试件破坏后残余强度较大且卸载后迅速回弹恢复几何形状;有限元模拟试件的荷载~滑移曲线、失效现象和试验结果吻合较好,有限元模拟正确;布置适量厚度的内、外层双向纤维布可以提高试件的抗弯承载力;将内、外层双向纤维布铺设方向由90°变为45°后,抗弯承载力进一步提高,随着外层45°纤维布厚度增加,破坏时的挠度下降。建议制作BFRP拉挤圆管时,布置适量厚度的双向纤维布,角度以45°为宜。

To optimize the design of basalt fiber reinforced polymer(BFRP)pultruded circular tube and promote its application in bridge engineering,a three-point bending test of two BFRP pultruded circular tubes with a length of 750 mm was carried out.Then,test process was numerically simulated in LS-DYNA software to verify the correctness of the finite element simulation.When the skin thickness of BFRP pultruded circular tubes was kept constant,the influences of thickness and laying angles of the inner and outer bidirectional fiber cloth on the bending capacity of the tubes were examined.It is shown that the specimens underwent three stages from the beginning of load application to failure,including the elastic,falling and residual stages.The failed tubes still had great residual strength,and rapidly returned to its original geometry after de-loading.The simulated load-slip curves and failure modes agreed well with the test results,proving the correctness of the finite element modeling.Adding inner and outer bidirectional fiber cloth with proper thickness can improve the bending capacity of the tubes,and when the laying angle of the inner and outer fiber cloth was changed from 90°to 45°,the bending capacity gained a further increase.As the thickness of the outer fiber cloth laid at an angle of 45°increased,the deflection of the failed tubes decreased.It is recommended to add proper amount of bidirectional fiber cloth while manufacturing the BFRP pultruded circular tubes,at a laying angle of 45°.