As an environmentally friendly energy-absorbing material, shear-thickening fluid (STF) can be applied to protective structures to improve impact resistance. STF was obtained by mixing fumed silica particles with polyethylene glycol solution. It was then filled into a honeycomb core layer to make STF-filled honeycomb sandwich panels. Finally, the effect of STF on the impact resistance of the structure was explored. The impact force-displacement curves were obtained by using the drop weight impact experiment, and the effects of impact velocity (1.0, 1.5, 2.0 m/s), honeycomb aperture diameter (2.0, 2.5, 3.0 mm), and wall thickness (0.04, 0.06, 0.08 mm) on the mechanical properties of the sandwich panel were studied. At the same time, digital image correlation technology was utilized, which is an optical method for measuring the deformation of the surface of an object. By comparing the pixel displacements in multiple images, the strain history and deflection field distribution of the back panel of the structure were obtained, and the low-velocity impact response process of the structure was discussed. The experimental results show that under low-velocity impact, there is bump deformation in the center area of the back panel of the STF-unfilled honeycomb sandwich panel, and there is obvious bulging deformation in the surrounding area. The central area of the back panel of the STF-filled honeycomb sandwich panels has a wider range of bump deformations and no bulging around it. The shear-thickening effect of STF can increase the honeycomb elements involved in energy absorption, expand the local deformation area of the structure, and reduce the deflection of the back panel of the structure. Increasing the impact velocity, increasing the honeycomb aperture diameter, or decreasing the wall thickness are all more conducive to the shear-thickening effect of STF. The results provide a reference for the application of STF in protective structures.

As lightweight and high-strength functional-structural integrated materials, cellular structural materials are widely applied in aerospace, automotive manufacturing, and biomedical fields. However, traditional single-configuration cellular materials (e.g., honeycomb structures and point-lattice lattices) gradually exhibit performance limitations under complex conditions such as impact shock waves, multi-directional impacts, or nonlinear deformations. Against this backdrop, heterogeneous cellular structure material (HCSM) have emerged as a research hot pot in impact protection. This paper systematically reviews recent design strategies and impact resistance performance of HCSM. HCSMs are primarily categorized into two types: topological configuration heterogeneity (including complementary and enhanced fusion) and material heterogeneity (e.g., filling with foam materials and shear-thickening materials). Through innovative “functional fusion” approaches, they overcome the performance bottlenecks of single-configuration cellular materials. The study further elucidates the synergistic reinforcement effects and deformation mechanisms of HCSM under impact loads, while analyzing their intrinsic mechanisms for improving energy absorption efficiency, stiffness, and stability. Despite significant progress in HCSM research, challenges remain in connectivity optimization, additive manufacturing process compatibility, complex condition validation, and multifunctional integration. Going forward, the integration of artificial intelligence and machine learning technologies holds promise for achieving end-to-end optimization of HCSMs from design to manufacturing, thereby providing new directions for developing next-generation high-performance impact-resistant structural materials.

A novel prefabricated wall panel structure for substations was developed by integrating fiber cement board, aluminum honeycomb plate, and aluminum alloy plate. The dynamic response characteristics of the structure under explosive loads were investigated through experimental studies. The effects of overpressure loads at different explosive mass and loading distances were examined, and the impact of varying honeycomb cell sizes on structural deformation failure mode, back face deflection and strain, core compression, and fiber cement board crack distribution was analyzed. The results indicate that within a confined space, the time characteristics of explosion overpressure are similar to those in an unconfined space. The peak overpressure measured independently at the center is between 2.4 and 10.0 times that measured directly at the edge. The positive pressure duration measured independently at the center is between 0.44 and 0.71 times that measured directly at the edge. The predominant deformation mode of the structure involves front panel depression and rear panel bulging. Horizontal cracks in the front face of the fiber cement board are predominantly located near its long side boundary, while cracks in the back face are mainly distributed near its center and diagonal areas. Compared with structures featuring smaller honeycomb cell sizes, those with larger honeycomb cell sizes exhibit greater residual deflection on their back faces and longer total crack lengths in their fiber cement boards.

A sandwich panel with superior blast resistance was designed and fabricated by filling aluminum honeycomb cores with two shear thickening gels (STGs) of different compositions, SG and TG. A series of blast experiments were conducted to investigate its dynamic response. The digital image correlation (DIC) technique was used to record and analyze the experimental process, exploring the coupling mechanism between the STG filling and the honeycomb core and its effect on the dynamic behavior of the structure. In addition, by analyzing the deformation modes, strain histories, and failure patterns of the front and back face sheets as well as the core layer, the effects of honeycomb cell size and STG type on the blast resistance of the sandwich panel were determined. Experimental results showed that the unfilled honeycomb sandwich panel suffered severe damage to both face sheets, indicating poor protective performance. The STG filling significantly enhanced the blast resistance, and the TG-filled panel achieved better protection than the SG-filled panel due to its stronger shear thickening effect. When the honeycomb cell size was 4 mm, the front face sheet of the SG-filled panel fractured, whereas the TG-filled panel exhibited more uniform plastic indentation, and the back face sheet deflection was reduced by 61.0%. When the honeycomb cell size was 8 mm, the TG-filled panel achieved reductions of 5.6% (front panel) and 17.7% (back panel) in deflection compared to the SG-filled panel. The experimental results indicate that optimizing the type of STG and honeycomb structural parameters can effectively modulate the blast resistance of the sandwich panel.