Sharp Tips Produced by the Breakage of Popsicle Sticks and Their Puncture Injury Potential

Sharp tips generated by the fracture of popsicle sticks may cause human injury. This study systematically investigated the fracture behavior of popsicle sticks under different loading patterns and the associated potential risk of puncture injuries to the human body through mechanical experiments. Popsicle sticks made of Betula platyphylla Suk. wood were used in the experiments. Two moisture conditions (dry and wet) and three fracture loading patterns (cantilever bending fracture, three-point bending fracture, and axial compressive buckling fracture) were applied, with a total sample size of 600. Based on the geometric morphology of the fracture fragments, the hazard level was classified into Levels I, II, and III, with specific classification criteria provided. Surrogate human tissue blocks were created by simulating human skin with silicone films and subcutaneous tissue with gelatin blocks. A free-fall apparatus was employed to evaluate the penetration depth and unit energy penetration area of popsicle stick fragments into human tissues. The experimental results showed that after fracture, the number of dry specimens posing a high risk of human injury was significantly greater than that of wet specimens. The plasticizing effect of moisture on wood fibers inhibited the formation of sharp tips. The penetration risk were significantly greater for dry specimens than for wet specimens, and the inhibitory effect of moisture on puncture capability was more pronounced for smaller sharp tips. It is recommended that techniques aimed at improving the water permeability of wood be adopted to reduce the risk of puncture injuries caused by accidental fracture of popsicle sticks.