Narrow Results

Understanding of the tensile strength of the solid propellant bears important applications in materials science, aerospace, defense, and other engineering disciplines. To obtain the mechanical properties of composite modified double base (CMDB) propellant under impact loading, this paper proposes an indirect tensile testing method to measure the full dynamic tensile strength of the CMDB propellant under dynamic loads. The Flattened Brazilian Disc (FBD) specimen was impacted with a 14.5mm diameter split Hopkinson bar (SHPB) system. The pulse shaping technique is used to achieve dynamic force balance, and thus eliminates the loading inertial effect and enables quasi-static stress analysis. The experimental results show that the dynamic tensile strength of the CMDB propellant is loading rate dependent. The dynamic FBD method provides an easy and cost-effective way to measure dynamic tensile strength and other brittle composite materials.

Split Hopkinson Pressure Bar (SHPB) has become a frequently used technique for measuring uniaxial compressive stress-strain relationship of various engineering materials under high strain rates. The pulse shape generated in the incident bar is sensitive to the length of the striker bar. In this paper, a finite element simulation of a Split Hopkinson Pressure Bar is performed to estimate the effect of varying length of striker bar on the stress-strain relationship of a material. A series of striker bars with different lengths, from 200mm to 350mm, are employed to obtain the stress-strain response of AL6061-T6 in both simulation and experiment. A comparison is made between the experimental and the computed stress-strain curves. Finally the influence of variation of striker bar length on the sample's stress-strain response is presented.