Stochastic dynamics of a non-linear cable-beam system

JORGE BALLABEN; RUBENS SAMPAIO; MARTA B. ROSALES

JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING

ABCM BRAZILIAN SOC MECHANICAL SCIENCES & ENGINEERING

Lugar: SPRINGER; Año: 2016 vol. 38 p. 307 - 316

1678-5878

Cable-stayed bridges and guyed towers are examples of structures extensively used in Civil Engineering. The uniform tension in the cable may change during service life due to various causes. Thus, uncertainty studies appear desirable to provide information about the effect of the parameter variations on the structure dynamics. The non-linear dynamic behavior of a cable-beam system, as a simplified model of a guyed structure, is studied. The beam behavior is assumed linear while the cable is modeled with non-linear equations accounting for the extensibility and an initial deformed state. The deterministic equations are linearized about the reference configuration and then frequencies and modes are calculated. The modes are later used to construct a reduced order model. The non-linear equations are discretized by finite elements with a Galerkin procedure. Afterwards, a stochastic model is stated with the cable tension and beam stiffness assumed as random variables and appropriate probability density functions (PDFs) are derived through the Principle of Maximum Entropy. A numerical analysis is carried out using Monte Carlo techniques for simulations. Some unexpected features, such as multimodality of the PDFs, are observed. The structural model seems to be more sensitive to the cable tension uncertainty than to the beam stiffness.