Simulação analítica e numérica dos efeitos de molas, deslocamentos prescritos e temperatura em linhas de influência

Abstract

The analysis of structures subjected to moving loads requires procedures capable of relating the load position to the structural response. In this context, influence lines make it possible to identify critical positions and to evaluate the variation of support reactions, internal forces, and displacements along the member. The representation using idealized restraints, however, does not always reproduce actual behavior, since structures often exhibit finite support stiffness, kinematic constraints, and temperature variations that induce thermal strains and additional actions. This work develops an analytical and numerical approach to evaluate the effects of elastic supports (springs) on influence lines and to analyze, through envelopes, the influence of prescribed displacements and thermal effects. The analytical stage is based on the principle of virtual work, employing the simplified force method, and considers as external actions a design train modeled by concentrated loads, prescribed displacements, and thermal effects. Numerical verification is performed using the FTOOL software. Finally, the impacts of prescribed displacements and thermal effects are highlighted in the envelopes of maximum and minimum bending moments.