http://yetl.yabesh.ir/yetl1/handle/yetl/19025 2026-06-05T15:45:21Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309416 A Novel Constrained-Layer Damper for Vibration Mitigation of High-Mast Illumination Poles Mona Shaheen; Jian Li; Caroline R. Bennett; William N. Collins This study proposes a novel constrained-layer damper (CLD) design for reducing buffeting-induced vibration on high-mast illumination poles (HMIPs). The conventional CLD utilizes a single-piece constraining layer, making it ineffective when applied to circular sections due to the overlapping neutral axes between the constraining layer and the base structure. To address this issue, the proposed CLD incorporates several longitudinal slits in the constraining layer such that the neutral axes of the slitted constraining layer are separated from the base structure. This design enables the viscoelastic layer to develop shear strain under the bending deformation of the base structure, thereby developing viscoelastic damping to mitigate vibrations. Comprehensive numerical simulations were conducted to examine the impact of different CLD parameters on damping enhancement for tubular structures, including the thickness of the viscoelastic layer, the thickness of the constraining layer, and the percentage of longitudinal coverage. The study found that the proposed CLD can increase the damping level of the HMIP to 235% of the inherent damping of the HMIP and reduce its steady-state response at resonance by 57%. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309415 Convergence and Optimal Parameters of the Inertial Relaxed Lattice Boltzmann Method in Fluid and Solid Simulations Ziche Gong; Yuan Lei; Guangcai Gong This paper introduces an accelerated lattice Boltzmann method (LBM) tailored for both fluid and solid simulations, utilizing the inertial relaxed Bhatnagar-Gross-Krook (IR-BGK) operator, referred to as IR-LBM. The Navier-Stokes equations and the elastic lamina deformation equation are derived from the Boltzmann equation using the Chapman-Enskog expansion. It is demonstrated that the Boltzmann equation based the IR-BGK operator exhibits a second-order error related to both the time step and the inertia term. Numerical tests employing the D2Q9 and D3Q15 lattice velocity models are conducted to simulate the streamline distribution of cavity flow across various Reynolds numbers and the deformation of elastic lamina under different load patterns using IR-LBM. Results indicate that IR-LBM achieves acceptable accuracy and superior convergence rates compared to the original LBM. Optimal configurations for the inertia term in fluid and solid simulations are provided. This work potentially offers a new approach for enhancing LBM-based algorithms for fluid-structure interaction in future applications. This paper proposes an algorithm based on the lattice Boltzmann method, referred to as the inertial relaxed lattice Boltzmann method, which incorporates an inertial term into the Boltzmann equation to achieve a faster convergence rate compared to the traditional lattice Boltzmann method with the Bhatnagar-Gross-Krook operator. With a suitable choice of equilibrium distribution function, this method is applicable to both fluid and solid simulations. The results of the numerical experiments demonstrate that, by selecting a proper range for the inertia term, the method accelerates convergence rate in algorithms based on the lattice Boltzmann method involving fluid-structure interaction, enhancing computational efficiency while maintaining the relative error with respect to the benchmark solution within an acceptable range. This model is well suited for fluid-structure coupling calculations in fields such as engineering structures and biomechanics, with potential applications including the response of bridges to wind forces and interactions between cardiovascular structures and blood flow. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309414 Nonlinear Seismic Assessment of Concrete Dams Using a Novel Elastoplastic Damage Numerical Framework Li Zhang; Jia Mao; Lanhao Zhao Numerical simulations were conducted to investigate the damage modes of concrete dams under seismic loading. The employed numerical model is based on an elastoplastic damage numerical framework for concrete, which innovatively unifies the stress–strain curves and the damage variables for both tension and compression. A scalar equivalent strain, with few parameters and concise form, is used to transform the complex multiaxial stress state of concrete into a simple uniaxial stress state. A net equivalent strain and a nominal damage variable are creatively defined to overcome the tensile-stress conversion problem due to the nonnegativity of the equivalent strain during the numerical realization. The numerical implementation process is independent of the mathematical models, which can be flexibly adapted according to the practical situation to better describe the stress state of concrete structures. By comparison with multiple classical experiments, it is demonstrated that the framework, with high accuracy and generality, can reflect a range of nonlinear behaviors for concrete under cyclic loading. Finally, a three-dimensional finite-element model of the Baihetan arch dam in China is established, and the effects of transverse joint contact nonlinearity and foundation radiation damping are considered. Based on the proposed framework, the dynamic response of the dam under different peak ground accelerations is calculated. The ultimate seismic capacity of the dam is comprehensively evaluated by examining the damage distribution and acceleration. The results showed that the damage at the bottom of the dam is relatively obvious under seismic loading. Under the influence of water pressure and gravity, the peak acceleration at the dam crest in the downriver direction is the largest, and the nonlinear effect of the dam in the downriver and vertical directions is also more obvious. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309413 Mechanism of Elastic–Plastic Crack Initiation in Unsaturated Rock Cracks under Gas–Ice Pressure at Low Temperatures Tian Xiang; Wenhua Chen While analyzing the frost heaving and cracking of rock mass in cold regions, it is generally assumed that the cracks are fully saturated. However, rock mass cracks are often in an unsaturated state in actual engineering practice. Upon moisture freezing, the volume of ice increases, the volume of gas decreases, and the gas pressure increases, while the crack walls are subjected to gas pressure, freezing pressure, and the frictional force of the ice, resulting in complex stress conditions. In this paper, the mechanism of crack initiation in unsaturated rock cracks under the influence of gas–ice pressure is investigated. Assuming a small yield range, the calculation formulae for gas pressure after freezing, plastic zone, stress intensity factor, crack initiation angle, and crack initiation stress were derived from the complex variable function and elastic–plastic crack mechanics theory. Critical parameters such as freezing temperature Ti, volume ratio of filling water sw, and crack shape were analyzed and discussed. The results showed that effective gas pressure (>1  atm) is generated after freezing only when sw>0.7; the lower the Ti, the smaller the gas pressure after freezing. Further, the more the crack shape tends toward a circular shape, the easier it is to generate effective gas pressure after freezing, whereas the lower the Ti, the more the crack shape tends toward an elliptical shape. Also, the smaller the Ti, the larger the crack initiation angle, while changes in sw and crack shape have almost no effect on the crack initiation angle. 2025-01-01T00:00:00Z