正交异性钢桥面疲劳损伤机理和断裂力学疲劳寿命评估方法研究

he research program is aiming at developing the fatigue design theory and fatigue evaluation based on fracture mechanics approach for the orthotropic steel bridge decks. The scopes of the study include key issues involving in the fatigue mechanism, fatigue design procedures and evaluations of the fatigue strength and fatigue life for the orthotropic steel bridge decks. The study will also illustrate and clarify the influences on the fatigue performances of the bridge decks contributed from the factors such as the deck detailing, fabrication tolerance, welding procedure and welding residual flaws etc. Based on the typical fatigue cracks observed in orthotropic steel decks that govern the fatigue failures of the steel decks, and configuration detailing of the orthotropic decks, finite element models which are able to reflect the geometric connection detailing between the rib to deck, and the rib to rib are developed. Sub-structural finite element analyses are conducted based on the fine mesh element approach. Instead of the conventional full-scale model fatigue tests, a tentative assessing approach of fatigue strength and fatigue life evaluation which integrates the FE analysis of steel deck models and the fatigue tests of specimens of welding connections will be also explored. The stress distribution and stress variation in the orthotropic steel decks under the cycling load are analyzed and identified in attempt of revealing the fatigue crack development and fatigue failure mechanism in the orthotropic steel bridge decks. Influences of the welding and geometric detailing of the bridge decks on the fatigue performance of the orthotropic steel decks will be studied and revealed by means of the experimental and numerical analysis tools. The results are expected to contribute to the better fatigue performances and the optimal fatigue design of the orthotropic steel bridge decks. Fatigue evaluation of the the orthotropic steel bridge decks based on fracture mechanics approach is explored.

针对正交异性钢桥面的疲劳问题，开展正交异性钢桥面疲劳机理、疲劳设计理论、断裂力学疲劳损伤和疲劳寿命评估等关键技术的研究，揭示材性、细部构造、焊接工艺、焊接缺陷和钢桥面制作等因素对正交异性钢桥面的疲劳承载力和寿命的影响，针对各种控制钢桥面疲劳破坏的常见裂纹，基于正交异性钢桥面疲劳细节，建立反映正交异性钢桥面几何构造和焊接细节的有限元力学模型，进行正交异性钢桥面的子结构精细化有限元分析，研究并提出疲劳细节子结构有限元分析和细节疲劳试验的混合法来代替正交异性钢桥面板足尺试验方法，通过试验、数值计算来研究焊接尺寸、细节构造对钢桥面疲劳性能的影响，予以优化，研究考虑焊接方式、构造细节的正交异性钢桥面疲劳强度和寿命预测的计算方法，探讨正交异性钢桥面的疲劳损伤和疲劳寿命的断裂力学评估方法。

针对正交异性钢桥面的疲劳开裂问题，开展了正交异性钢桥面的计算模型、数值模拟和疲劳强度的基础理论研究。完成了4组12个正交异性钢桥面足尺试件的静力和疲劳试验，通过这些足尺试件的各种疲劳裂缝研究正交异性钢桥面横向栓焊、焊接连接处、纵肋腹板与横梁帽孔处、UHPC铺装层等构造细节的疲劳损伤机理；采用ANSYS、ABAQUS等有限元计算程序建立了正交异性钢桥面和包含各类裂缝的正交异性钢桥面精细有限元计算模型，模拟各类构造细节的正交异性钢桥面力学特性，研究正交异性钢桥面疲劳损伤机理及裂缝对其力学性能的影响；将数值模拟结果与试验结果进行分析对比，提出了各类构造细节的疲劳寿命计算模型，计算评估正交异性钢桥面的疲劳寿命；通过对正交异性钢桥面和UHPC铺装层板厚、横向连接焊缝、螺栓、拼接板、帽孔等各类构造细节与正交异性钢桥面疲劳损伤机理影响分析，提出了用断裂力学方法评估正交异性钢桥面板疲劳寿命方法。通过对实际运营线路的列车、轴重、运行图、客运量等资料的调查研究，提出了高速铁路的标准疲劳车和典型疲劳荷载弯矩谱。. 项目发表SCI、EI收录研究论文3篇（国外学术期刊），EI收录中文期刊论文3篇，其他期刊论文2篇；参加在境外举行的国际学术会议2次，发表国际学术会议论文2篇；参加上海举行的国际学术会议1次，大会报告1个；参加在国内的学术会议1次，发表会议论文1篇。培养毕业的硕士研究生6名，培养在读的硕士、博士研究生各1名。