This study presents a hydrodynamic analysis of an optimised heaving buoy for a single-body point absorber wave energy converter (WEC). A conventional deep-draft cylindrical buoy is modified into a composite single-body configuration consisting of three rigidly coupled sections to improve frequency-dependent hydrodynamic performance while reducing structural volume. The proposed buoy is compared with a reference cylindrical buoy adapted from Ruezga (2019). The governing equations are formulated considering added mass, radiation damping, and hydrostatic restoring forces. Numerical simulations are performed in Ansys AQWA under both frequency-domain and time-domain conditions using regular and irregular wave analyses. The results show that the proposed buoy increases peak absorbed power to 58.4 kW, achieving a 6.8% improvement over the reference buoy, together with a 15% broader operational frequency bandwidth. These improvements are achieved with approximately 10% reduction in structural volume while maintaining a simple oscillating system configuration. The findings demonstrate the effectiveness of geometry-based optimisation for improving the hydrodynamic performance of point absorber WECs.
Unreinforced masonry walls (UMWs) exhibit insufficient seismic capacity owing to their low tensile strength, rapid stiffness degradation, and brittle failure under cyclic in-plane loading. This study proposed a detailed micro-modelling approach to simulate the in-plane behaviour of UMWs. The finite element model was initially validated against experimental data for load–displacement response, stiffness degradation, energy dissipation, ductility, and failure mode, indicating good agreement with observed behaviour. Following validation, a one-at-a-time parametric study was conducted to examine the relative effects of aspect ratio, masonry compressive strength, and wall thickness on the structural performance of UMWs. The results suggest that aspect ratio plays a significant role in determining deformation mode, energy dissipation, and ductility, with intermediate aspect ratios providing an effective compromise between strength and deformation capacity. Increasing masonry strength significantly improves shear resistance and initial stiffness; however, its effectiveness in improving ductility and post-peak behaviour remains limited. The wall thickness has a significant effect on the shear resistance and stiffness retention due to the increased cross-sectional area; however, excessive thickness may lead to reduced deformability. Overall, the findings highlight the fundamental limitations of UMWs under cyclic in-plane loading and underscore the importance of geometric characteristics in influencing seismic performance.
To obtain numerical simulation methods and optimised construction measures applicable to the bolted timber joint with slotted-in steel plates considering the action of shaped sections, the carbon fibre reinforced polymer (CFRP)-bolted timber joint with slotted-in corrugated steel plates was proposed. Corresponding research was carried out, mainly considering wavelength, wave height, wave angle, timber thickness, number of layers of CFRP, and the number of bolts. Among them, it was found through experiment research that timber exhibited obvious shear fracture, compression damage, and tangential-longitudinal fracture caused by the shaped cross section, but the radial-longitudinal fracture characteristics have a certain delayed effect; a suitable method of the range coefficient of the wooden foundation was proposed-(min(bolt spacing/d), min(bolt spacing/d)-1) or in (min (bolt spacing/d) + min (bolt spacing/d)-1)/2, and the joint model achieved a better analysis of joint mechanical behaviour. In addition, the effectiveness of annular and double-layer slotted-in Z-type steel plates configurations for optimising mechanical properties were clarified through parametric analysis, the key parameters were identified and appropriate design measures were proposed, which provide the basis for fracture characterisation, ductility prediction, and design methodology for this type of joint.
In this study, an elasto-plastic damage model (EPDRAC) for recycled aggregate concrete (RAC) is proposed, capable of predicting the behaviour of RAC subjected to a multiaxial state of stress. The proposed model used four parameters: α, β, γ, and critical strain energy release rate (Rc). Parameters α and β are used to predict the behaviour of concrete in tension and compression, respectively, while γ is used for predicting volumetric dilatation, and Rc controls the damage growth rate. These parameters are functions of concrete compressive strength (fc′), its initial elastic modulus (Eo), and normalised invariants of strain I1ε3 and J2′e32. Initially, artificial neural networks (ANN) were used to estimate the compressive strength and modulus of elasticity of RAC. Furthermore, parameters α and β were then estimated using ANN. The proposed model was calibrated and validated using the experimental data generated during the course of the study as well as available in existing literature. The proposed model was able to capture the pre- and post-peak behaviour of RAC accurately. The integration of ANN for parameter estimation significantly enhanced the proposed model’s performance compared with prior models, both by the authors and in the existing literature.
