CFRP筋粘结型锚固系统数值模拟及失效分析

Numerical simulation and failure analysis of adhesive anchorage system for CFRP tendon

针对碳纤维增强复合材料(CFRP)筋粘结型锚固系统,采用数值分析研究了不同锚具内壁与锚固胶体间的摩擦系数、不同锥形倾角、锚具前端有无直筒过渡段及有无端堵约束对筋材应力状态的影响,找出了筋材在靠近锚具端部发生破坏的原因,提出了相关强度分析方法及锚固改进方法,并用试验结果验证了方法的有效性。分析结果表明:筋材在摩擦系数为0.7时受到的径向挤压应力峰值只有摩擦系数为0.3时受到的径向挤压应力峰值的45.01%;随着锥形倾角增大,CFRP筋在锚具锥段所受的径向挤压应力峰值逐渐减小,所受剪应力峰值逐渐增大;在锥段末端增设直筒过渡段可以缓解筋材所受到的径向挤压应力与剪应力峰值,缓解系数分别为76.78%与52.90%;端堵约束的存在使锚具端部应力集中现象明显,导致筋材在锚具端部发生破坏。

The numerical analysis of adhesive anchorage system for carbon fiber reinforced plastics （CFRP） tendon was conducted, of which including influence of different friction coefficients between anchor wall and anchorage agglomerant, influence of different cone angles and with or without straight transition section in front of anchorage and end blocking constraint to the stress state of tendons. The reason of tendons that fail near the front end of the anchorage was found out, relevant strength analysis method and anchorage improvement methods were proposed, the effectiveness of the method were verified by test results. The analysis results show that radial extrusion stress peak values of tendons at 0.7 friction coefficient are 45.01 ~//00 of the radial extrusion stress peak values at 0.3 friction coefficient. Radial extrusion stress peak values of CFRP tendons at anchorage cone section decrease with the increase of cone angles, while shear stress peak values gradually increase. The addition of straight transition section at cone section ends can relieve radial extrusion stress and shear stress peak values of tendons. Mitigation coefficients are 76.78% and 52. 900%, respectively. The existence of end blocking constraint leads an obviously stress concentration phenomenon at the front end of anchorage, which results in the failure of tendon near the front end of anchorage.