Jie Jia

Origami-inspired honeycomb structures have emerged as promising lightweight metamaterials for energy absorption. Nevertheless, their deformation modes are often relatively fixed, and their Poisson’s-ratio responses are largely dictated by geometric configuration, resulting in limited tunability and reduced adaptability to diverse transverse deformation requirements. In this study, a non-self-similar hierarchical re-entrant arrowhead origami honeycomb (HRAOH) is proposed to achieve enhanced mechanical performance together with wide and continuous Poisson’s-ratio tunability. Finite element simulations are conducted to systematically examine the deformation mechanism, compressive behavior, and energy-absorption performance of the proposed structure under quasi-static compression. Compared with benchmark configurations, the HRAOH exhibits a more favorable balance among plateau stress, crushing load efficiency, and specific energy absorption. Parametric analyses are further performed to reveal the effects of the fold-in ratio, dihedral angle, and wall thickness on the structural response and to identify their roles in performance optimization. Furthermore, a Gaussian process regression -based surrogate model is developed to characterize the relationship between geometric parameters and the effective Poisson’s-ratio response. The results show that the proposed structure can realize a wide and continuous tunable Poisson’s-ratio range, allowing controllable transitions between unidirectional and bidirectional auxetic states. The present study offers a numerical design framework for lightweight energy-absorbing structures with programmable directional deformation and tunable Poisson’s-ratio behavior.

The rapid development of waterborne transportation has increased the risk of vessel–bridge collisions, posing significant threats to bridge safety. However, existing protective installations often suffer from limited adaptability and high maintenance costs. Inspired by the superior compressive strength of the elytral joint structure of the iron-ringed beetle, a novel biomimetic thin-walled honeycomb energy-absorbing system was developed by integrating this joint structure with hexagonal and concave honeycomb cells. The mechanical performance of the proposed system was systematically investigated through quasi-static compression experiments and finite element (FE) simulations. By controlling the relative density, the influence of cross-sectional dimensional variations on the mechanical response was further analyzed. Results show that the system exhibits a distinctive secondary plateau stress during impact loading, with the second plateau stress increasing by 328% compared to the first. Furthermore, a pier protection device based on the proposed structure was designed and applied to the Jinma Bridge. Numerical simulations indicate that the peak vessel impact force can be reduced by up to 63.4%. Compared with conventional monolithic protection systems, the proposed interlocking modular system allows discrete unit assembly, providing improved adaptability, reduced material consumption, and higher replacement efficiency. This study offers a novel biomimetic design strategy for bridge protection systems subjected to impact loading.

With the increasing demand for high-performance vibration control in modern structures, inerter-based systems have attracted significant attention due to their pronounced inertia amplification and compact configuration. However, existing inerter systems, such as tuned viscous mass dampers (TVMDs) and tuned inerter dampers (TIDs), still suffer from limited effective bandwidth, high sensitivity to parameter variations, and possible dynamic coupling problems under strong excitations. To overcome these limitations and achieve higher vibration mitigation efficiency, this study proposes a novel dual-tuned inerter system (DTIS), which introduces a two-stage resonance mechanism into the energy transfer path to achieve broadband vibration control and improved dynamic stability. A simplified analytical model describing the interaction between the structure and DTIS is developed, and closed-form solutions of the frequency response function (FRF) are derived. The influences of key design parameters on vibration mitigation performance are systematically examined. Furthermore, a refined finite element (FE) model of a five-story reinforced concrete (RC) frame structure is established, and natural earthquake records are adopted to evaluate the seismic performance of different DTIS configurations. The results indicate that the proposed DTIS provides significantly enhanced vibration suppression and dynamic stability compared with conventional inerter-based systems. This study deepens the theoretical understanding of multi-resonant inerter mechanisms and offers a reliable basis for the design and practical implementation of high-efficiency vibration control devices in structural engineering.

Traditional probabilistic seismic demand analysis (PSDA) of bridge structures is typically formulated using a single engineering demand parameter (EDP) and assumes predefined probability distribution forms, which may be insufficient to capture the coupled seismic response of complex bridge systems. To overcome these limitations, this study proposes a multidimensional PSDA framework based on performance limit states and a non-parametric kernel density estimation (KDE) approach. By incorporating bivariate correlation KDE, a joint probabilistic seismic demand model for multiple EDPs is established without prescribing explicit parametric forms for their marginal or joint distributions. A high-pier, large-span continuous steel girder bridge is selected as a case study. Incremental dynamic analysis combined with nonlinear time-history analysis is performed to evaluate the pier curvature ductility factor (PCDF) and bearing relative displacement (BRD). Based on multidimensional performance limit state formulations, the proposed framework is integrated with seismic hazard analysis to estimate the average annual exceedance probability of structural demands. The results indicate that the multidimensional PSDA generally produces higher exceedance probabilities than conventional single-EDP-based methods, suggesting a more conservative and realistic assessment of seismic risk. Furthermore, the correlation coefficient between EDPs is shown to have a significant impact on the estimated exceedance probabilities. Overall, the proposed framework shows good potential for application in seismic performance assessment of complex bridge structures.

Tall-pier, long-span continuous rigid-frame bridges are prone to wind-induced vibration due to their large spans and pier heights; during cantilever erection, the maximum double-cantilever stage has reduced stiffness and buffeting becomes more evident. Accordingly, a time-domain framework driven by three-component aerodynamic coefficients and their angle-of-attack derivatives is adopted. Code-based target spectra are used to synthesize multi-point fluctuating wind time histories via harmonic superposition, followed by statistical and spectral consistency checks. Buffeting forces are then computed under the quasi-steady assumption, mapped to finite-element nodes, and integrated in time to obtain global responses (displacement and acceleration). In parallel, static six-component wind tunnel tests provide mean force and moment coefficients and their derivatives for comparison. The results indicate that the three-component time-domain approach captures the buffeting features dominated by vertical and torsional responses. When pronounced along-span sectional variation and high angle-of-attack sensitivity are present, errors associated with the strip assumption increase, whereas the force–moment coupling revealed by the six-component data helps explain discrepancies between simulation and tests. These response patterns and error characteristics delineate the applicability and limits of the three-component time-domain evaluation for variable-depth continuous rigid-frame bridges, offering a reference for wind resistance assessment and construction-stage checking of similar bridges.

Honeycomb structures are widely used in various fields due to their excellent compressive properties. However, most existing honeycomb structures have positive or negative Poisson’s ratios, which can easily cause overall instability during failure. Inspired by the asymmetric upper and lower structures of the diabolical ironclad beetle’s exoskeleton, this paper proposes a novel bio-inspired beetle honeycomb (BBH) structure with a zero Poisson’s ratio (ZPR) feature. A combination of experiments and finite element (FE) simulations was used to study the compressive mechanical behavior of BBH under different impact velocities. The results show that the ZPR of BBH significantly enhances the structural stability and greatly improves its compressive performance. The structure exhibits a pronounced dual-platform stress response, with the secondary platform stress increasing by 221.07% compared to the primary platform stress. This is 93.45% higher than that of the re-entrant auxetic honeycomb (RSH) structure. Finally, through parametric analysis, the effects of thickness, impact velocity, aspect ratio of the long and short axes, and slant angle on the compressive mechanical behavior of BBH were quantitatively revealed. This study provides a new biomimetic optimization design framework for the development of high-performance impact-resistant honeycomb structures. It has significant application value in aerospace, vehicle collision protection, construction, and other engineering fields.