Fiber Bridging Degradation Based Fatigue Analysis of ECC under Flexure

This paper proposes a fatigue analysis method of Engineered Cementitious Composite (ECC) under fatigue flexure by applying the concept of fiber bridging degradation. The mechanical degradation of materials under fatigue load is considered amajor factor for fatigue crack propagation and subsequent fracture. FEM with theconcept of both smeared crack and discrete crack is introduced for representing the consequences of multiple cracks and a localized crack, respectively. The bridging stress degradation law under fatigue load as well as the constitutive relation under static load is introduced as essential input material properties in the fatigue analysis. In order to verify the fatigue analysis, a flexural fatiguetest program of two kinds of ECC, PVA-ECC and PE-ECC, was conducted. The fatiguecharacteristics of flexural beams predicted by the proposed model such as S-N relation and the evolution of midspan deflection agree well with those from the test results. It is also shown that the fatigue analysis is applicable to determine the bridging stress degradation relation of ECC by flexural fatiguetests.