Mansour Walid, Li Weiwen, Wang Peng, Fame Cheikh Makhfouss, Tam Lik-Ho, Lu Yao, Sobuz Md Habibur Rahman, Elwakkad Noha Yehia
Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, China.
Civil Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh 33516, Egypt.
Materials (Basel). 2024 Jan 8;17(2):321. doi: 10.3390/ma17020321.
This paper presents a numerical investigation of the flexural behavior of timber beams externally strengthened with carbon-fiber-reinforced polymer (CFRP) sheets. At first, the accuracy of linear elastic and elastic-plastic models in predicting the behavior of bare timber beams was compared. Then, two modeling approaches (i.e., the perfect bond method and progressive damage technique using the cohesive zone model (CZM)) were considered to simulate the interfacial behavior between FRP and timber. The models were validated against published experimental data, and the most accurate numerical procedure was identified and subsequently used for a parametric study. The length of FRP sheets varied from 50% to 100% of the total length of the beam, while different FRP layers were considered. Moreover, the effects of two strengthening configurations (i.e., FRP attached in the tensile zone only and in both the tensile and compressive zones) on load-deflection response, flexural strength, and flexural rigidity were considered. The results showed that elastic-plastic models are more accurate than linear elastic models in predicting the flexural strength and failure patterns of bare timber beams. In addition, with increasing FRP length, the increase in flexural strength ranged from 10.3% to 52.9%, while no further increase in flexural strength could be achieved beyond an effective length of 80% of the total length of the beam. Attaching the FRP to both the tensile and compressive zone was more effective in enhancing the flexural properties of the timber beam than attaching the FRP to the tensile zone only.
本文对采用碳纤维增强聚合物（CFRP）板体外加固的木梁的抗弯性能进行了数值研究。首先，比较了线性弹性模型和弹塑性模型在预测裸木梁性能方面的准确性。然后，考虑了两种建模方法（即完美粘结法和使用粘结区模型（CZM）的渐进损伤技术）来模拟FRP与木材之间的界面行为。这些模型根据已发表的实验数据进行了验证，并确定了最准确的数值程序，随后用于参数研究。FRP板的长度从梁总长度的50%变化到100%，同时考虑了不同的FRP层数。此外，还考虑了两种加固配置（即仅在受拉区粘贴FRP和在受拉区及受压区都粘贴FRP）对荷载-挠度响应、抗弯强度和抗弯刚度的影响。结果表明，在预测裸木梁的抗弯强度和破坏模式方面，弹塑性模型比线性弹性模型更准确。此外，随着FRP长度的增加，抗弯强度的增幅在10.3%至52.9%之间，而当FRP长度超过梁总长度的80%的有效长度后，抗弯强度无法进一步提高。与仅在受拉区粘贴FRP相比，在受拉区和受压区都粘贴FRP在增强木梁的抗弯性能方面更有效。
