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Streszczenie:
This paper investigates the dynamic behaviour of a thick Gao beam subjected to high-velocity inertial moving loads and substantial axial compressive forces. This approach addresses a significant gap by combining geometric nonlinearity, transverse shear deformation, and complete inertial effects (including Coriolis and centrifugal forces).
The mathematical model consists of two strongly coupled nonlinear hyperbolic partial differential equations, solved using the finite element method with space-time integration. Key findings include: (1) nonlinearity produces substantial geometric stiffening effects, with deflections decreasing by factors of 2-3 compared to linear models; (2) supercritical axial compression induces snap-through phenomena and bifurcation between equilibrium states; (3) under combined compression and moving loads, beam deflections are primarily governed by axial force magnitude rather than load weight, with multiple passages producing non-repeating response patterns; (4) maximum accelerations occur neither at mid-span nor at support entry, remaining relatively insensitive to transit velocity. The results indicate a strong detuning between the beam oscillations and the load transition cycles, especially at higher velocities. These findings have important implications for railway bridge design and structures experiencing simultaneous thermal stresses and dynamic vehicular loads, where simplified linear models may significantly underestimate dynamic effects.

Słowa kluczowe:
Structural dynamics, Extended Gao beam, Moving mass, Inertial load, Non-linear dynamics, Shear deformation