No abstract

Over the past decade, unmanned aerial vehicles (UAVs) have received a significant attention due to their diverse capabilities for non-combatant and military applications. The primary aim of this study is to unveil a clear categorization overview for more than a decade worth of substantial progress in UAVs. The paper will begin with a general overview of the advancements, followed by an up-to-date explanation of the different mechanical structures and technical elements that have been included. The paper will then explore and examine various vertical take-off and landing (VTOL) configurations, followed by expressing the dynamics, applicable simulation tools and control strategies for a Quadrotor. In conclusion to this review, the dynamic system presented will always face limitations such as internal and/or external disturbances. Hence, this can be minimised by the choice of introducing appropriate control techniques or mechanical enhancements.

Large earthquakes are rare natural hazards, having catastrophic impact on society due to loss of lives, damage to constructed facilities, and business interruption. Because of damage accumulation due to the main strong shaking, aftershocks potentially endanger the safety of residents and subsequently increase financial loss due to downtime and repair costs. Therefore, accurate prediction of the seismic performance of structures in the post-earthquake stage is critical for disaster risk mitigation. This paper employs an advanced structural modeling technique, which can simulate various features of cyclic degradation in material and structural components using nonlinear fiber beamcolumn elements. The model accounts for inelastic buckling and low-cycle fatigue degradation of longitudinal reinforcement and can simulate multiple failure modes of reinforced concrete structures under dynamic loading. Furthermore, a comprehensive ground motion selection accounting for multiple types of ground motions, such as shallow crustal, deep inslab, and subduction earthquakes, is implemented. Finally, a new set of fragility curves has been developed for each ground motion type, which accounts for the aftershock effects and influence of ground motion types on cyclic degradation and failure modes of low-rise reinforced concrete structures. It was found that slight and moderate damage is not significantly affected by major aftershocks for different ground motions types. However, considering aftershocks increases the probability of exceedance of damage for extensive and complete damage up to 5% and 10% for inslab and crustal event, respectively. The proposed methodology significantly improves the accuracy of seismic risk and vulnerability assessment by reducing the uncertainties associated with structural modeling and variability of earthquake ground motions.

An advanced fibre-based modelling technique is developed to characterise the nonlinear flexural behaviour of rectangular reinforced concrete (RC) columns by accounting for the influence of inelastic buckling and low-cycle fatigue degradation of vertical reinforcement. The proposed uniaxial material model of reinforcing steel is calibrated using 22 rectangular RC column tests. The influence of inelastic buckling of vertical reinforcement on the nonlinear cyclic response of rectangular RC columns is investigated. The calibrated model is capable of accurately predicting the nonlinear response of rectangular RC columns up to complete collapse by taking into account the additional failure modes of the RC columns.

No abstract