Study on Hypervelocity Impact Characteristics of Polypropylene Spheres on Whipple Shields

The hypervelocity impact characteristics of 7 mm diameter polypropylene spheres on Whipple shields with different bumper thicknesses at a velocity ranging from 2.257 to 4.012 km/s are studied in this work. The study has found that the hypervelocity impact characteristics of the polypropylene sphere contrast markedly with those of the aluminum sphere. The polypropylene sphere transfers greater energy to the bumper upon impact, leading to a larger perforation. Meanwhile, the microstructure at the perforation site is complex. The polypropylene sphere undergoes a phase change after impacting the bumper, forming a debris cloud primarily composed of 'liquid filaments'. This debris cloud creates a 'groove'-shaped damage morphology on the rear wall. The polypropylene sphere exhibits weaker perforation capabilities but generates a more extensive damage area on the rear wall.