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为了研究SMA(沥青玛蹄脂)摊铺高温作用后CFRP板-混凝土界面剥离破坏,采用SMA摊铺的高温作用后的界面有限单元进行剥离破坏准则定义和回归分析。借助大型通用有限元软件MSC.MARC调用界面有限单元并对CFRP板箱梁桥顶板进行有限元模拟。通过有限元分析可以看出:当荷载值比较小时,CFRP板-混凝土界面未产生裂缝,CFRP板与混凝土间黏结性能较好,沿着梁跨中至梁端方向,CFRP板应变值呈递减趋势。随着荷载值增大,在试验梁跨中位置附近,CFRP板-混凝土界面层出现初始剥离,在界面层剥离区域,CFRP板应变值曲线斜率明显下降,CFRP板应变曲线形状近似S形。随着荷载值增加,在剥离区长度范围内,CFRP板S形应变值沿自由端方向扩展逐渐增大,初始剥离一旦开始,荷载值随之骤然下降;在剥离区域,CFRP板应变值维持恒值不变。研究表明:通过定义SMA摊铺高温作用后CFRP板-混凝土界面单元,引入双重剥离破坏准则,CFRP板-混凝土的界面受剪可通过恒定的裂面剪力传递系数来描述,根据箍筋量配置的不同来描述开裂后混凝土受剪行为,混凝土的开裂形态借助开裂应力描述,受拉软化形态借助软化模量描述,较好地模拟了特殊环境下的CFRP板-混凝土界面的剥离破坏过程。
In order to study the debonding failure of CFRP board-concrete interface after the high temperature of paving SMA (asphalt mastic), the definition of the debonding failure criterion and the regression analysis were conducted by the finite element unit of SMA interface after being exposed to high temperature. With the finite element software MSC.MARC, a large general finite element software is used to call the finite element interface and to simulate the CFRP plate girder bridge roof. Through the finite element analysis, it can be seen that when the load value is relatively small, there is no crack in the CFRP board-concrete interface, and the bonding performance between the CFRP board and the concrete is better. Along the middle to the beam end direction, the CFRP board strain value decreases . With the increase of load, the initial delamination of the CFRP board-concrete interface layer occurs near the midspan of the test beam. The slope of the strain curve of the CFRP board obviously decreases in the delamination area of the interface layer, and the strain curve of the CFRP board is approximately S-shaped. With the increase of load, the S-shaped strain of CFRP plate gradually increases along the free end within the length of the peel zone, and the load value suddenly drops once the initial peel begins. In the peeled area, the strain of CFRP plate maintains constant The same value. The research shows that the interface between CFRP plate and concrete can be described by the constant shear transfer coefficient by defining the interface between CFRP plate and concrete after SMA pavement is exposed to the double-delamination failure criterion. According to the stirrups configuration, The cracking behavior of concrete after cracking is described. The cracking behavior of concrete is described by means of cracking stress. The tension-softening morphology is described by means of softening modulus, which better simulates the peeling failure process of CFRP board-concrete interface in special environment.