玻璃纤维增强聚丙烯钢筋热导率及加热软化弯曲的实验与理论研究

Experimental and Theoretical Investigation into the Thermal Conductivity and Heating-Softening Bending of Glass-Fiber-Reinforced Polypropylene Rebars.

作者信息

Xu Mingxue, Wang Anni, Liu Xiaogang

机构信息

Research Institute of Urbanization and Urban Safety, School of Future Cities, University of Science and Technology Beijing, Beijing 100083, China.

出版信息

Polymers (Basel). 2025 Feb 24;17(5):595. doi: 10.3390/polym17050595.

DOI:10.3390/polym17050595

PMID:40076088

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11902518/

Abstract

Thermoplastic fiber-reinforced polymer (FRP) reinforcement has a significant advantage over traditional thermosetting FRP reinforcements in that it can be bent on site by heating-softening processing. However, current experimental and theoretical research on the thermal conductivity and heating-softening processing characteristics of thermoplastic FRP reinforcements is quite insufficient. Through heating-softening processing tests, numerical simulation, and theoretical calculation, this study investigated the heating-softening processing time of a thermoplastic glass-fiber-reinforced polypropylene (GFRPP) reinforcement. In the heat transfer process, thermal conductivity is typically treated as a constant. However, the experimental results indicated that the thermal conductivity/diffusivity coefficient of the GFRPP reinforcement was temperature-dependent. On this basis, an equivalent modified thermal diffusivity coefficient of glass fiber was proposed to account for the time-temperature-dependent heat conductivity of the GFRPP reinforcement, utilizing a series model. Utilizing the modified thermal diffusivity coefficient, the simulation model presented a heating-softening processing time that coincided well with the experimental results, with a mean ratio of 1.005 and a coefficient of variation of 0.033. Moreover, based on an equivalent homogeneous circular cross-section assumption of the GFRPP reinforcement, an analytical solution to the heat conduction equation was derived. Combining the experimental and simulation results, a semi-analytical and semi-empirical calculation model was also proposed for predicting the heating-softening processing time of a GFRPP reinforcement with a silicone tube cover. The model's calculated results align with the simulation trends, with an average deviation of 1.0% and a coefficient of variation of 0.026, demonstrating strong potential for engineering applications.

摘要

热塑性纤维增强聚合物（FRP）增强材料相较于传统热固性FRP增强材料具有显著优势，即它可以通过加热软化加工在现场进行弯曲。然而，目前关于热塑性FRP增强材料的热导率和加热软化加工特性的实验和理论研究相当不足。通过加热软化加工试验、数值模拟和理论计算，本研究调查了热塑性玻璃纤维增强聚丙烯（GFRPP）增强材料的加热软化加工时间。在传热过程中，热导率通常被视为常数。然而，实验结果表明，GFRPP增强材料的热导率/扩散系数与温度有关。在此基础上，利用串联模型提出了玻璃纤维的等效修正热扩散系数，以考虑GFRPP增强材料随时间和温度变化的热导率。利用修正后的热扩散系数，模拟模型得出的加热软化加工时间与实验结果吻合良好，平均比值为1.005，变异系数为0.033。此外，基于GFRPP增强材料等效均匀圆形横截面的假设，推导了热传导方程的解析解。结合实验和模拟结果，还提出了一个半解析半经验计算模型，用于预测带硅胶管套的GFRPP增强材料的加热软化加工时间。该模型的计算结果与模拟趋势一致，平均偏差为1.0%，变异系数为0.026，显示出强大的工程应用潜力。