SIMULATING THE HYSTERETIC BEHAVIOR OF A SLB ENERGY DISSIPATION DEVICE VIA UNIFIED MECHANICS THEORY

Hernández Morales H.; Bozzo Rotondo L.; Scaletti Farina H. · World Conference on Earthquake Engineering proceedings (2024)

Resumen

The use of seismic protection systems has been steadily increasing in the last decades, in particular of passive control devices due to their proven effectiveness in the mitigation of damaging effects of strong ground motions without need of complex control systems neither external energy supply. Indeed, metallic yielding dampers as Shear Link Bozzo (SLB) devices are well recognized because they provide structures with additional stiffness and major energy dissipation capacity, two key features that make them ideal for using in new construction and seismic retrofitting projects of, for example, hospital and educational facilities. Hence, modeling the mechanical behavior of SLB dampers accounting for degradation during severe earthquakes is fundamental to design those critical structures as securely as possible. Until now, the hysteretic behavior of SLB devices has been usually represented by Bouc–Wen model adjusting the values of variables “α" and exponent of “z” based on laboratory tests results. This model is then implemented in structural analysis programs often without considering damage mechanics effects due to high lateral displacements, which can be important. Precisely, in this article, the Unified Mechanics Theory – which integrates laws of Thermodynamics and Newtonian mechanics – is applied to model the force-displacement response of a SLB dissipator more realistically. The main advantage is the no need for phenomenological approaches to describe the damage behavior because degradation is calculated at every point using entropy generation along the Thermodynamics State Index (TSI) axis. A finite element model of a SLB supplemental damping device is constructed including a modification in the viscoplastic constitutive model of steel to define the Unified Mechanics equations. Finally, FEA results are compared with experimental data.

Instituciones: Universidad Nacional de Ingeniería