Amortiguamiento no-clásico en estructuras de péndulo invertido.

Abstract

This research estimates the influence of height, inertia, and loading frequency on the damping of single-degree-of-freedom inverted-pendulumtype steel structures through laboratory testing and numerical-model calibration, with the aim of determining the non-classical damping coefficients for this type of structure. The methodology was divided into three stages: experimental testing, signal processing, and numerical modeling and calibration to reproduce the observed response. Tests were performed using the Water Laboratory shake table as a controlled dynamic excitation, applying a unidirectional input along the X axis; because the table operates with a 10- level controller, it was characterized to associate each level with the effectively measured frequency. Instrumentation used an ESP32-based acquisition system with MPU-6050 accelerometers, installed on the table to record input acceleration and on the specimen’s top mass to record its response. From the records, the fundamental frequency of each rod configuration (square and circular sections) was determined and, subsequently, an equivalent damping was estimated from free-decay responses, adopting the Coulomb friction model due to friction-related losses. To support parameter fitting, Bayesian calibration was considered to update the model from experimental data. Results show that the shake table has limitations to excite certain specimens up to near-resonance conditions.