Nonlinear Vibration of Conical–Cylindrical Shells with Bolt Boundary under Non-Uniform Thermal Field

Conical–cylindrical shells (CCSs) with bolt connections are critical components in aerospace systems, where they always operate under extreme thermal environments. Existing studies predominantly focus on idealized boundary conditions or uniform thermal fields, neglecting the synergistic effects of non-uniform thermal gradients and bolt-induced nonlinearities in practical scenarios. This limitation hinders the accurate prediction of the dynamic responses of the bolted CCSs under non-uniform thermal fields. To address this problem, a novel thermo-mechanical framework is developed, integrating bidirectional thermal gradients, temperature-dependent material degradation and a nonlinear bolt interface model with stick–slip friction. Experimental validation, including modal and response tests, is conducted via a custom platform by incorporating built-in heat sources to simulate non-uniform thermal fields. The nonlinear vibration mechanism of structural dynamic softening is revealed by stiffness attenuation and friction dissipation based on the connection interface. This study establishes an effective model for predicting nonlinear vibration behaviors in bolted CCSs under thermal heterogeneity, offering critical insights for optimizing vibration-resistant designs in high-temperature aerospace applications.