Testing of Mechanical Properties of Ballistic Gelatin / 医用生物力学

ABSTRACT

Objective To study the mechanical properties of ballistic gelatin and establish a dynamic constitutive model by a numerical method to lay the foundation for the related research on wound ballistics. Methods First, 20% ballistic gelatin samples at 10°C were prepared, and then, the quasi static and dynamic compressive mechanical properties of the ballistic gelatin were tested using a universal material testing machine and an aluminum Hopkinson bar, respectively. Results The quasi-static and dynamic compressive stress-strain curves of 20% ballistic gelatin at 10 ℃ were obtained. When the strain was 0.45, the true stress was 0.041, 0.083, 0.194, 14.515, 31.496, 55.597, and 96.678 MPa at a strain rate of 10-3, 10-2, 10-1, 5 800, 7 900, 10 400, and 13 000 s-1, respectively. When the strain rate was 13 000 s-1 and the strain increased from 0.4 to 0.5, the stress increased rapidly from 53.558 MPa to 164.417 MPa, equivalent to an increase by over 3.07 times. Conclusions The ballistic gelatin had a remarkable strain rate effect in the range of both low and high strain rates. The constitutive model with strain rate was established based on the experimental results with the form of σ=kε·mεn, and the material constants of 20% ballistic gelatin were obtained.