Energy-absorbing structures are crucial for protecting vehicles during collisions. This study investigated the axial crushing behaviour of a spiderweb-inspired multicellular tube and examined the effects of connection method and cell number on its crashworthiness using numerical simulations and experiments. The edge connection of inner and outer hexagons, including connections at the endpoints (type I), the midpoint (type II), and the mixed connection of endpoints and midpoints methods (type III), significantly impacts the energy absorption (EA) and specific energy absorption (SEA) of multicellular tubes in bio-inspired spiderwebs. Overall, type III exhibits the best crashworthiness among the three designs, while type II outperforms type I. Under the three connection methods, the EA of bio-inspired spiderweb multicellular tubes increases with increasing cell number. Additionally, the crashworthiness index SEA under all three connection modes positively correlates with cell number. The bio-inspired spiderweb multicellular tube shows further potential for improving structural crashworthiness.

To reveal the relationship between car body deformation and collision velocity, a velocity solution method for right-angle side collisions was developed. Vehicle finite element models, set via pre-processing software, were simulated in LS-DYNA. An impact deformation extraction method was proposed, with extensive experiments collecting deformation data under various speed combinations. MATLAB was used to fit data, construct a speed-deformation model, and perform sensitivity analysis. Simulations at multiple angles and typical velocities verified consistency between extracted and calculated deformations. Integrating a traditional two-dimensional eccentric collision model, a velocity solution method was derived. In real accident analyses, this method’s results, compared with PC-Crash software, showed errors below 5%. Finite element simulations of deformation, strain, and shape matched actual conditions, offering advantages over classical mechanics by fully utilizing deformation data.

A bio-inspired multi-layer sandwich structure (BS) based on the microstructure of Odontodactylus scyllarus dactyl club was developed. Crashworthiness of BS variants (BSU, BSI, BSD) with varying thicknesses (t) and height-length ratios (η) was analyzed via LS-Dyna FE simulations, validated experimentally (with an average relative error of 1.98%). Evaluations using peak crush force (PCF), specific energy absorption (SEA), and crush force efficiency (CFE) revealed BSI and BSU outperformed BSD at t = 0.3 mm and t = 0.5 mm. Multi-objective optimization via Kriging models and MOPSO algorithm optimized t and η (η 1, η 2, η3) across four weight cases. The optimal design balancing all criteria was t = 0.33 mm, η 1 = 0.77, η 2 = 0.96, η 3 = 1.01. This study can provide a reference for the design and optimisation of multi-layer sandwich structures.

This study investigates the flutter and thermal buckling of foam-filled functionally graded corrugated sandwich plates in supersonic airflow under thermal loads. The sandwich plate consists of two functionally graded face sheets and a foam-filled corrugated core with equivalent thermoelastic properties. The corrugated core is homogenised as an equivalent orthotropic layer through an energy approach. Two combinations of hyperbolic and parabolic shear shape functions extend a refined shear deformation theory, accounting for transverse shear and thickness stretching effects. Unsteady aerodynamic pressure is assessed using supersonic Piston theory. The governing equations are derived via Hamilton’s principle, with solutions for simply supported sandwich plates obtained using Navier’s technique. The model's accuracy is validated by comparing natural frequencies and flutter speeds with literature results. The effects of various geometric and material parameters on dynamic and static instability are discussed, demonstrating the proposed theory's effectiveness with reduced computational effort.

The present work focuses on the dynamic compressive response of dynamically crushed auxetic structures. The aim is to propose a simplified methodology to assess the influence of geometrical/topological and material parameters on the impact response of these structures. The response also depends on the impact velocity. Based on an analogy with the propagation of shock waves in a rigid, perfectly plastic, locking (RPPL) material model, two approaches are developed to study the collapse of the structure crushed by a rigid impactor: (i) an analytical development and (ii) an iterative procedure, are proposed to evaluate the energy transfer and the impactor deceleration, thus allowing the physical quantities of interest to be deduced: dynamic stress, crushed length and strain, time for densification, stop time for the impactor. The methodology is presented and illustrated with the conventional 2D re-entrant auxetic, of which every range of geometrical data can be taken into account in the proposed formulas. Finite Element explicit simulations were carried out to confirm the analytical prediction. Results show good agreement between analytical and Finite Element results.

At present, the multi-targets autonomous vehicles identify are mainly various road users such as vehicles and pedestrians in cities. However, in recent years, there are increasing vehicle-animal accidents in pastoral areas of China, and there is a lack of corresponding practical intelligent safety warning measurements. In order to realise the identification and collision avoidance of typical animals, this study obtains the basic characteristics of collisions and the animals’ behavioural characteristics from the pastoral accidents investigation. Firstly, an attempt to focus on the use of the algorithm of the binocular infra-red equipment is made, with the main targets of identification being domestic animals at night or under low brightness conditions. Secondly, the algorithm technology roadmap from the identification and the risk assessment to collision avoidance decision-making is designed. Further, based on the technical route, a feasible solution and overall technical program is presented, which outlines the five aspects of the proposed engineering-ready scheme’s architecture. The methodology used involves transfer learning and the PSMNet network model. The paper concludes that the system can predict the animal’s movement and make proper decisions by utilising binocular infra-red equipment, integrating its algorithms and the support of its behavioural risk assessment. The research results will contribute to the animal collision avoidance technology and the traffic safety in pastoral areas in the future.

In order to gain a more detailed understanding of novice driver involved crashes, this paper compares the injury severity of at-fault and not-at-fault novice driver involved crashes with the consideration of risky driving behaviours. The crash data of novice drivers in Shenyang, China, from 2012 to 2017 is used. The correlated random parameters logit model with heterogeneity in means is built for the whole dataset, at-fault dataset, and not-at-fault dataset to explore the significant factors determining the injury severity, and obtain insight into hidden and common factors. The hidden factors indicate factors that are only significant in one dataset, while the common factors indicate factors that are significant in two or more datasets. The results show that nine common factors significantly affect injury severity of novice driver involved crashes. Among them, speeding, legal but unsafe driving behaviours, and improper operation are related to risky driving behaviour. Moreover, road type, functional zone, time interval, and conflict and improper passing are hidden factors, among which conflict and improper passing is related to risky driving behaviour. Finally, some valuable insights for regulatory authorities in formulating targeted policies are provided to mitigate the severity of novice drivers involved crashes.

Chest injuries are commonly encountered in traffic accidents, with ribs playing a crucial role in chest impact response. This study focuses on the damping performance of ribs and its influence on chest response during collisions. Employing mechanical bionics principles, the mechanical equivalence of ribs under collision impact was determined. Consequently, a rib impact dynamic model based on equivalent damping theory was developed. This model was integrated with a rib drop hammer impact test system, yielding a numerical solution for the equivalent damping ratio of the rib, quantified as 0.085. Additionally, to validate the accuracy of the rib impact dynamics model, a verification method based on the half-power bandwidth method was proposed. Through the implementation of the rib force hammer impact test, the equivalent damping ratio was determined to be 0.093, showing an 8.6% deviation from the result of the impact dynamics model. These findings not only confirm the validity of the rib equivalent damping theory within the impact dynamics model but also provide theoretical support for the design and improvement of dummy ribs and, potentially, the overall development of crash test dummies.

Secondary impact is a significant contributor to occupant injuries in train crashes. To mitigate collision injuries, a workbench with energy-absorbing properties was developed, drawing inspiration from leaf-vein and honeycomb structures. A local collision model of a dummy compartment was established to evaluate the impact of different sandwich thicknesses on occupant injuries. By optimizing the wall thickness of the energy-absorbing sandwich, the optimal gradient parameters were determined. The assessment of occupant collision injury from the workstation table with a graded wall thickness sandwich was conducted using the LSTC Hybrid III 50th seating dummy. The results demonstrate that the workstation table influences the occupant's movement posture during a collision, preventing head impact with the tabletop. Apart from slightly elevated leg injuries in the dummy, which remained within permissible values, the head, neck, and chest injuries were reduced by 98.45%, 48.17%, and 81.18%, respectively.

A shock absorber characterised by fixed-to-hinged transforming joints and inward-folding composite tubes was demonstrated for the first time. Polymethacrylimide foam can be filled into the composite tube to enhance energy absorption. A pair of shock absorbers were installed in the subfloor structure as stanchions. The shock absorber, inclined at an angle to the impact direction, was joined to the subfloor structure with five fasteners arranged so that one is in the centre and the others around it. The five fasteners bore a static load during normal operations. During the crash, the eccentric load is exerted on the shock absorber as the crushing of the composite tube; then, the surrounding fastener is served, with the central fastener left as a pin. Hence, the fixed joint is transformed into a hinged joint, making the shock absorber only subject to an axial load, and a large crush ratio for the absorber is available. A method to calculate the crash load of a subfloor structure was demonstrated. Experiments were conducted using a drop tower, which verified the schematic and crash-load calculations. The results also show that the specific energy absorption of the composite tube filled with foam is improved. The proposed schematic of the subfloor structure has the potential for use as an aircraft cargo floor.