Numerical Modeling Theory Of Shear Wall Structure Controlled By Flexural Damage Based On Force Analogy Method

Force analogy method (FAM) is a nonlinear analysis method based on the nonlinear constitutive relationship which is described by the change in displacement. It characterizes the structure’s global reaction information by the local plastic mechanism to form the key equations in which only the initial stiffness matrix is used and only once computed. Then the state space method is applied to solve the dynamic calculation. Although researches in fields such as steel moment-resistant frame, reinforced concrete frame, concentrically braced frame and so on have been carried out, the application in shear wall is not discovered.FAM is used in this paper to model the nonlinear behavior of shear wall. The failure modes are presented and summarized to gain the local displacement mechanism and a preliminary conceptual analysis system for shear wall on the basis of FAM is finally founded. Then a model that simulates shear wall controlled by flexural damage is proposed, in which the rotation in plastic location is chosen to be the local plastic displacement parameter. Especially, a practical method to calculate moment-curvature relationship’s feature parameters of shear walls controlled by flexural damage is explored to support the nonlinear time history analysis theory. Besides, a damage index is introduced and calculated based on the above theory and the superiority of the FAM-based shear wall simulation is indicated here. The main study work focuses on the following aspects:The failure modes of shear wall specimens and shear wall structures are summed up systematically, according to which the local displacement mechanism is established. In addition, the current state of load-displacement relationship research of the chosen location is fully discussed and summarized.According to the existing methods of calculating the moment-curvature relationship of shear wall, a restoring force curve defined by four reference points of crack moment, yield moment, peak moment and ultimate moment is established based on the traditional flexural theory and plane section assumptions. In the derivation, different axial compression ratios are taken into consideration especially in the discussion of two critical states. In aspect of ultimate state, reasonable discussions about the ultimate moment are made.The nonlinear time history analysis model of single shear wall is built on the foundation of the established theory in acquiring the local displacement mechanism. Furthermore, the equation is extended to the coupled shear wall simulation and a numerical example is given to prove the correctness by comparison with the SAP2000result (based on nonlinear layered shell element).A damage index is introduced combining the energy equation in FAM theory and the damage model comparing the energy dissipation before and after the damage taking place. The damage index can describe the decreased ability to store elastic strain energy and the capacity loss in hysteretic energy dissipation.