Influence of 3D-printed cellular shoe soles on plantar pressure during running − Experimental and numerical studies

The paper explores the potential of additive manufacturing (AM), experiments and simulations to develop a personalized shoe sole, with cellular topology used as the insert that minimizes the plantar pressure during running. Five different topologies were manufactured by Fused Filament Fabrication 3D printing technique using thermoplastic polyurethane TPU 95 filaments and tested experimentally and using FEA under compression conditions. The error between the maximum peak force and specific energy absorbed (SEA) from the model and experiment were less than 4.0 % and 6.0 %, respectively. A deformable FE foot model was developed, which was validated against data from the literature on balanced standing and the landing impact test carried out in the study. For the first case, the predicted maximum pressure (P_peak = 0.20 MPa) was positioned between the data presented in previous papers (0.16 MPa ÷ 0.30 MPa). In the second case, the experimentally measured and numerically predicted force peak values were nearly identical: 1760 N and 1720 N, respectively, falling with the range of 2.2 ÷ 2.5 BW similarly to other studies. Finally, a shoe sole design was proposed based on these topologies, which was simulated in the rearfoot impact to investigate the deformation of the sole and its influence on the foot plantar pressure peak and its distribution. The findings indicated that the sole with cellular structure could drastically reduce plantar pressure and improve overall footwear performance. This research provides valuable guidance and insights for designing, modelling, and simulating customized shoe sole manufactured using the 3D printing technique.