With the increasing number of automobiles on the road, passive safety has become a particularly important issue. In this paper, an energy-absorbing material, origami aluminum honeycomb, was manufactured by a welding process for use as an automobile energy absorbing box. The mechanical properties and deformation of welded origami aluminum honeycomb in three directions were studied through quasi-static and dynamic compression tests. The results show that the origami aluminum honeycomb had good mechanical energy absorption performance, and the optimal directions are identified. Combined with theoretical analysis, the errors between experiments and simulations are shown. The origami honeycomb structure was designed for use as an automobile energy absorbing box. Analysis shows that it could absorb at least 10% of the kinetic energy of a vehicle during a collision, and could play a role in protecting the interior of the vehicle.

At the core of additive manufacturing (3D printing) is the ability to rapidly print with multiple materials for arbitrary distribution with high resolution, which can remove challenges and limits of traditional assembly and enable us to make increasingly complex objects, especially exciting meta-materials. Here we demonstrate a simple and effective strategy to achieve nano-resolution printing of multiple materials for arbitrary distribution via layer-by-layer deposition on a special deposition surface. The established physical model reveals that complex distribution on a section can be achieved by vertical deformation of simple lamination of multiple materials. The deformation is controlled by a special surface of the mold and a contour-by-contour (instead of point-by-point) printing mode is revealed in the actual process. A large-scale concentric ring array with a minimum feature size below 50 nm is printed within less than two hours, verifying the capacity of high-throughput, high-resolution and rapidity of printing. The proposed printing method opens the way towards the programming of internal compositions of object (such as functional microdevices with multiple materials).

With the continuous development of the new energy vehicle industry, in order to further improve the safety and range of electric vehicles, vehicle lightweighting has been a key focus of major car companies. However, research on lightweighting and the impact protection effect of battery pack protective plates is lacking. The bottom protective plate of the battery pack in this study has a sandwich-type multi-layer structure, which is mainly composed of upper and lower glass-fiber-reinforced resin protective layers, steel plate impact resistant layers, and honeycomb buffer layers. In order to study the relationship between the impact damage response and material characteristics of the multi-material battery pack protective plate, a matrix experimental design was adopted in this study to obtain the energy absorption ratio of different material properties when the protective plate is subjected to impact damage. This work innovatively used a low-cost equivalent model method. During the drop hammer impact test, a 6061-T6 aluminum plate in direct contact with the lower part of the bottom guard plate test piece was used to simulate the deformation of the water-cooled plate in practical applications. High-strength aluminum honeycomb was arranged below the aluminum plate to simulate the deformation of the battery cell. This method provides a scientific quantitative standard for evaluating the impact resistance performance of the protective plate. The most preferred specimen in this work had a surface depression deformation of only 8.44 mm after being subjected to a 400 J high-energy impact, while the simulated water-cooled plate had a depression deformation of 4.07 mm. Among them, the high-strength steel plate played the main role in absorbing energy during the impact process, absorbing energy. It can account for about 34.3%, providing reference for further characterizing the impact resistance performance of the protective plate under different working conditions. At the same time, an equivalence analysis of the damage mode between the quasi-static indentation test and the dynamic drop hammer impact test was also conducted. Under the same conditions, the protective effect of the protective plate on impact damage was better than that of static pressure marks. From the perspective of energy absorption, the ratio coefficient of the two was about 1.2~1.3.

Thin-walled structures are widely used in anti-collision devices for various vehicles due to their light weight and high energy absorption. Offset collision is a common scene in various traffic accidents. Because the commonly used thin-walled structures do not consider this complex collision method, the energy absorption effect of the structure cannot meet the requirements. In this paper, a C-shaped frame structure composed of thin-walled steel tubes is proposed. The configuration of the structure is studied through theoretical analysis and numerical simulation, and it is found that the structure can absorb energy stably in the offset collision. The offset experiment and simulation were carried out, and the crashworthiness of the structure was investigated to verify the accuracy and feasibility of the numerical analysis method. A large-scale parameter simulation analysis was carried out, and the influence characteristics of the structure configuration, different materials and different sections were investigated. Based on the above test and numerical analysis results, an optimal design method for improving the crashworthiness of structures considering offset collisions is proposed. This paper can provide theoretical and technical support for the related research on the integrated anti-climbing energy-absorbing parts of rail trains under offset collision.

Collisions between rail transit vehicles are unavoidable. In order to alleviate the disaster caused by the collision, energy-absorbing and shock-absorbing materials are generally installed at the front end of the rail vehicle. In this paper, a variable buffer-force planing energy-absorbing device for rail transit vehicles was prepared. The buffer force was changed by length (D_x), angle (A) and thickness (W). First, we manufactured one type of material, and data were obtained through experimentation. Second, we used Ls-DYNA to simulate this material, and determined the accuracy between the simulation and the test. Third, various parameters of the material were simulated by Ls-DYNA. The results show that changing D_x greatly affects the performance of the material, W has no obvious effect on the performance, and A is important for the materials properties. Based on finite element simulation, the functional model relationship between the average force and various parameters was deduced. This lays the groundwork for the application of the variable buffer-force planing energy absorbing device.