Dynamic behaviour of an earthen material under different impact loading conditions

The dynamic behaviour of earthen materials reinforced with natural fibres is little studied although earth buildings are often built in seismic areas. In this paper the dynamic behaviour of an earthen material reinforced with hemp fibres under different impact loadings has been experimentally investigated. The dynamic response of the material in 3-point bending was investigated through an instrumented dropweight device, while the response in tension and in compression was investigated through a modified Hopkinson bar device. Typical impact response curves for tension, compression and bending impact tests have been obtained. The favourable effect of fibres in dissipating fracture energy under impact loads has been observed in all these types of test.

Statistical Laws of Dynamic Fragmentation of ZrO2 Ceramics

Dynamic fragmentation of ceramic samples with different porosity were carried out using modified Hopkinson bar setup, which allow us to keep samples safe (in order to define fragment size distribution) and to measure fractoluminescence impulses occurred on the fracture surfaces (in order to establish the distribution of intervals between impulses). The analysis of experimental data reveals that the fragment size distribution and distribution of interval between fractoluminescence impulses obeys a power law, which exponent depends on ceramics porosity.

Study on Impact Protection Properties of Titanium Alloy Using Modified SHPB

In order to evaluate the impact protection capacity of armor material quantitatively, direct impact testing loaded by modified Hopkinson bar was used to simulate the impaction between penetrator and armor. Protection coefficient k was defined to describe the protective performance. Using the direct impact testing, Ti-6Al-4V specimens with different microstructure and thickness were tested. Results show that k decreases with increased impact velocity and increases with increased thickness of specimen. Under a given loading condition, binary microstructure exhibits the highest k, indicating the best protective performance. Moreover, its k shows the most sensitivity to thickness (mt) and the least sensitivity to impact energy (me), which means that its protective performance can be improved most efficiently by increasing its thickness and it will exhibit good protective performance in a wider impact velocity range. This new method can evaluate the impact protective properties of armor materials efficiently, which may have a broad application prospect.