Numerical Simulation of the Post-Tensioned Beams Behaviour Under Impulse Forces Loading

The paper presents the results of numerical simulation of the dynamic behaviour of the post-tensioned beams subjected to a constant force impulse load over time and a short-term force impulse load varying over time. Abaqus programme was used for numerical analysis, introducing necessary and detailed modifications to the modelling and calibration parameters. The numerical dynamics models were calibrated using results previously obtained from our own experimental and numerical static analysis. To estimate the dynamic strength of structural materials, the dynamic strength coefficient was applied in the concrete damage plasticity model, and the Johnson-Cook model was used to describe the evolution of the dynamic yield strength of steel elements. An explicit procedure was used to solve the dynamic equilibrium equations. The selection of the Rayleigh damping parameter and the methodology for determining the external load in a dynamic problem are discussed. The study presents new results on the influence of the type of force impulse loading and variable prestressing eccentricity in numerical simulations of post-tensioned beams. The results of the simulation show that the post-tensioned beams achieved a lower dynamic load capacity under a constant force impulse load of approximately 5% compared to the static load capacity achieved in the experimental static tests, regardless of the assumed prestressing eccentricity. A dynamic load capacity significantly exceeded the static load capacity under short-term time-varying force impulse loading. The beam with the larger prestressing eccentricity achieved a dynamic load capacity of 211% of the static load capacity, while the beam with the smaller prestressing eccentricity achieved a dynamic load capacity of 198% of the static load capacity.