Dynamical analysis and nonlinear vibration control of integrated composite beam structure in thermal environment

Traditional dynamic analysis of mechanical structures, often limited to individual beams or plates, fails to fully capture their dynamic behaviors. In systems where space and mass are constrained, such as the battery support structures in electric aircraft, conventional absorbers and isolators are insufficient for effective vibration control. This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams, and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat. The nonlinear vibration control is performed using the Nitinol steel wire ropes (NiTi-ST), with nonlinear damping properties. The natural frequencies of system are determined using the Rayleigh-Ritz technique. Theoretical results are validated through both Finite Element Method (FEM) and hammer tests. Moreover, the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method (GTM). The Harmonic Balance Method (HBM) is used to evaluate the vibration responses of the integrated model, with further verification through the Runge-Kutta Method (RKM). The experiments are conducted to corroborate the theoretical analysis. The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection. Especially in the case of varying environments, as the temperature increases, the frequency of system will first increase to a certain maximum value and then gradually decrease. Furthermore, the NiTi-ST effectively reduces vibration in the integrated composite beam, particularly under varying temperatures and external excitations.