碳纤维复材加固钢板表面裂纹疲劳扩展研究  

FATIGUE CRACK PROPAGATION ANALYSIS ON SURFACE OF STEEL PLATES STRENGTHENED WITH CFRP

作　　者：孟兮 郑云[1] 陈煊[1] MENG Xi;ZHENG Yun;CHEN Xuan(National Engineering Research Center for Steel Construction, Central Research Institute of Building and Construction Co. Ltd, MCC, Beijing 100088, China;School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China)

机构地区：[1]中冶建筑研究总院有限公司,北京100088 [2]北京交通大学土木建筑工程学院,北京100044

出　　处：《钢结构》2018年第3期34-38,27,共6页Steel Construction

基　　金：国家自然科学基金项目(51578559);"十三五"国家重点研发计划资助项目(2016YFC0701303)

摘　　要：提出半椭圆表面裂纹疲劳扩展的一种有限元计算方法,该方法利用有限元软件计算裂纹前缘应力强度因子,采用Paris公式预测裂纹扩展量,通过有限元网格的自动重构来模拟分析表面裂纹的疲劳扩展过程。以中心表面裂纹钢板为研究对象,验证了所提方法的有效性和可行性,在此基础上,对常幅疲劳荷载作用下碳纤维复材(CFRP)加固钢板的表面裂纹扩展特性及疲劳寿命预测进行了研究。研究结果表明:CFRP加固能有效降低表面裂纹的扩展速率,长度方向由于直接受到CFRP的约束作用扩展速率降幅更大;裂纹形状比对CFRP加固效果影响较大,形状扁平的表面裂纹的疲劳寿命提升效果更好;加固后裂纹形状比相对加固前有所增大,增幅与其初始裂纹尺寸有关。A simulation scheme based on finite element method was presented for fatigue crack propagation of semielliptical cracks on surface. In the framework of the simulation method,the stress intensity factors of crack-front were calculated by finite element analysis,the crack growth extension were predicted by Paris formula,and the propagation process of fatigue cracks on surface was simulated by automatic reconstruction of finite element mesh. Taking a steel plate with cracks on the center of the surface as the research subject,the effectiveness and feasibility of the proposed method were verified. On this basis,the surface crack propagation characteristics and fatigue life prediction of steel plate strengthened with CFRP under constant amplitude fatigue load were studied. The results showed that,CFRP reinforcement could effectively reduce the crack growth velocity and the surface direction reduction was greater because of the direct constraint of CFRP; surface cracks with flat shape had a better fatigue life improvement effect; the crack shape ratio was getting larger after reinforcement,and the increase was related to the initial crack size.

关 键 词：疲劳扩展 半椭圆表面裂纹 碳纤维复材 有限元 

分 类 号：O346.1[理学—固体力学]