3D Numerical Foot Model for Running Shoe Design

3D numerical foot model

Simulation Saves Time, Costs and Materials

ASICS use 3D computational models to better understand the role of stability in running shoes. Optimizing with simulation reduces the risk of lower extremity injuries for runners, as well as enhancing performance. Sole structure and heel eversion angle are particularly important for understanding stability. Alongside experimental methods, models created in Simpleware software for export to Abaqus simulation tools help ASICS reduce prototyping time and costs, as well as manufacturing waste.

Characteristics:

  • Highly accurate, multi-part 3D foot model generated in Simpleware ScanIP from CT data
  • Simulation in Abaqus used to accurately predict sole stability
  • ASICS successfully updated sole design to improve customers performance
  • Technique helped ASICS reduce prototyping time and costs, as well as manufacturing waste

Thanks to:

Tsuyoshi Nishiwaki and Mai Nonogawa

ASICS Corporation, Institute of Sport Science

References:

Generating a Foot Model

To predict shoe stability, a scan of the foot of a healthy female volunteer was obtained using X-ray computed tomography. The image data was imported to Simpleware ScanIP software to build a 3D model prior to the generation of a Finite Element model representing different parts of the foot (soft tissue, bones, cartilage, ligaments and plantar fascia). The detail of the model enabled ASICS to be confident in the accuracy of their anatomical simulation.

3D numerical foot model

Heterogeneous numerical model considering soft tissue, bones, cartilage, ligaments and plantar fascia

Simulating Shoe Performance

Abaqus v.6.14-2 was used with the model to calculate deformation modes on polymer foam sheets with three types of hardness. Results showed good agreement with experimental testing, validating simulation as a way of enhancing existing ASICS methods. The numerical model was confirmed to accurately predict sole stability, leading ASICS to successfully update the design of their soles to improve performance for customers.

Heel eversion model

Heel eversion calculated by the proposed model corresponding to foot flat phase

Motion capture system

Motion capture system with force plate to measure heel eversion angle, shoe stability parameter

Conclusions

ASICS have successfully created accurate, highly optimized models tailored to specific running conditions. The model is therefore valuable for shoe stability designing, reducing prototyping costs and time, and skipping practical prototyping to improve sustainability. Products have been introduced as practical designing examples, with research contributing to an improved understanding of running shoe stability and reducing excessive foot joint motion, or pronation, during the contact phase in running.

ASICS GEL-Kayano 25 running shoe

The new ASICS GEL-Kayano 25 (released June 1, 2018) developed with Simpleware Software