In this paper, dynamic compression tests are developed to investigate the dynamic compression mechanical properties of the aluminum honeycomb structures at different strain rates, especially at the high strain rates. The difficulties at the high strain rates exist due to the large deformation, the low wave resistance and the size effect of the honeycomb structures. The Split Hopkinson Pressure Bar (SPHB) test method is carried out and special measures such as the adoption of waveform shaper, the size optimization of the impact bar and the specimen, and employment of the semiconductor strain gauge, etc. are taken to overcome the difficulties. It is discovered that the dynamic compression mechanical properties possess a stress hardening effect at a high strain rate from 1.3 × 10³ s⁻¹ to 2.0 × 10³ s⁻¹, but then a stress softening effect at a high strain rate of 4.6 × 10³ s⁻¹. It is also discovered that the yield strength and the average plateau stress at the strain rate of 2.0 × 10³ s⁻¹ is higher than that at the strain rate of 1.3 × 10³ s⁻¹. However, the yield strength and the average plateau stress at the strain rate of 4.6 × 10³ s⁻¹ is lower than that at the strain rate of 2.0 × 10³ s⁻¹ and 1.3 × 10³ s⁻¹, but higher than that at a quasi-static state. This indicates that the aluminum honeycomb structure is sensitive to the strain rate. Additionally, the damage mode of the aluminum honeycomb structure is plastic buckling, collapse and folding of the cell wall, which is carried out using dynamic compression tests. The folding length of the cell wall at a higher strain rate is found to be longer than that at a lower strain rate. The test results can also be used as the stress–strain curves of the honeycomb constitutive model at the high strain rates to carry out the numerical simulation of high-speed impact.

The all-solid-state lithium battery (ASSLIB) is one of the key points of future lithium battery technology development. Because solid-state electrolytes (SSEs) have higher safety performance than liquid electrolytes, and they can promote the application of Li-metal anodes to endow batteries with higher energy density. Glass-ceramic SSEs with excellent ionic conductivity and mechanical strength are one of the main focuses of SSE research. In this review paper, we discuss recent advances in the synthesis and characterization of glass-ceramic SSEs. Additionally, some discussions on the interface problems commonly found in glass-ceramic SSEs and their solutions are provided. At the end of this review, some drawbacks of glass-ceramic SSEs are summarized, and future development directions are prospected. We hope that this review paper can help the development of glass-ceramic solid-state electrolytes.

T700/TDE-85 composites were aged in cyclic hygrothermal tests in accordance with the service environment of military aircraft, and the variations in interlaminar shear strength (ILSS) and ballistic impact resistance during the aging cycles were determined. It was found that cycling hygrothermal aging induced the damage of the resin surface, long cracking along the fibre/matrix interface, and interlayer interface due to the combined action of swelling stress and thermal stress. ILSS first increased by 12.4% after 14 cycles due to the plasticising effect and then reduced due to the damage caused to the fibre/matrix interface. The critical energy absorption after 280 cycles was 15.6% higher than that of the unaged composite, suggesting the improvement effect of cyclic hygrothermal aging on the impact performance from the aspects of energy absorption and ballistic limit. The maximum energy absorption was achieved by the specimen aged for 70 cycles. Cyclic hygrothermal aging altered the damage morphology and failure modes dramatically. The unaged composite target had the lowest delamination area among all impact velocities, which explains the improvement in impact resistance and energy absorption capability after cyclic hygrothermal aging.

The three-dimensional braided composites, with intertwined fiber bundles in the through-thickness direction, have advantages of high interlaminar shear strength, fracture toughness, and excellent impact resistance, making them a promising material for applications in the field of aeroengine fan blades. As the bird impact behavior of the fan blade directly affects the safety of the aeroengines, it is of great significance to study the dynamic response and damage mechanism of 3D braided composites under bird strike load. In this paper, the bird impact tests on the 3D four-step braided composite targets were carried out using the gas gun system. The effects of impact velocity, impact location, and braiding angle on the bird impact behavior were studied. It is concluded that the damage and failure become more severe with the increasing impact velocity. The whole impact event could be divided into 3 stages, i.e., local deformation stage, postflow impact stage, and bending deflection stage. The braided composite presents flexible characteristics and could bear extraordinary deformation during the bird impact. One distinguishing feature of bird impact damage is the destruction of the clamping root due to bending load caused by cantilever construction. The internal damage form at the impact area was mainly the separation of the fiber bundles from the matrix while the breakage of the fiber bundles and the crushing of the matrix play the primary role at the root part. The target plate impacted at the 70% height had the largest bending angle and most serious damage, followed by those impacted at the 90% and 50% heights. Both the appearance damage and internal damage extent are smallest for 45° braiding composites.