Concurrent multi-scale computational method for fatigue damage analyses of civil structures

The fatigue analysis of civil structures in single-scale is difficult to capture the nonlinear process of structural response and accumulative fatigue damage on structural details up to failure since the process is trans-scale process of damage evolution, so that it is necessary to analyzing fatigue damage with concurrent multi-scale computation. This paper is aimed to develop a concurrent multi-scale computational method for carrying out fatigue damage analyses of civil structures with local details that are vulnerable to damage and failure. The multi-scale model is developed on the basis of the different features in macro- and meso- scales of structural response and damage behavior, and the concurrent trans-scale computation is implemented by information transferred between scales through the multi-points constraints method. The linear response of global structure and the nonlinear low-cycle fatigue damage behavior at local details are analyzed concurrently in order to meet the needs of evaluation of damage status as well as structural deteriorating. Numerical results on the damage evolution process of a steel truss structure show that, the proposed concurrent multi-scale computational method on structural fatigue damage could simultaneously carry out the analyses both on the linear response of global structure and on the nonlinear low-cycle fatigue damage evolution at local vulnerable details. Besides the accurate description on the structural multi-scale response, the local damage evolution as well as its influence on the structural response could also be obtained.