Formulation for the matrix analysis of frame structures including fracture mechanics concepts: Applications in tunnel linings and airplane fuselage panels

This paper proposes a procedure for analyzing crack propagation in complex structures based on lumped damage mechanics. This theory combines the concept of a plastic hinge with the procedures of damage and fracture mechanics. Models of damage for monotonic loading and high-cycle fatigue are proposed. The paper also describes the numerical implementation of the models in conventional finite-element programs. The models are validated by comparison with experimental results and classic fracture mechanics analyses. It is shown that the model can be used in multi-scale schemes for the structural assessment of structures in civil, offshore, and aeronautical engineering. Therefore, the proposed model might be useful as a macro-modeling step in multi-scale analysis, as well as a tool for preliminary analysis of structures under fatigue loads.