Assessing the Compressive and Impact Behavior of Plastic Safety Toe Caps through Computational Modelling

Biomechanical modeling of footwear-fluid-floor interaction during slips

Slips and falls are among the major concerns for public safety. Slipping risks can be reduced by ensuring adequate traction at the shoe-floor interface. The outsole design of footwear is a critical factor to maintain sufficient shoe-floor traction in the presence of slippery contaminants such as water or oil. While the role of floorings and contaminants on footwear traction has been studied widely, limited works have investigated the role of footwear outsole geometry and tread patterns on shoe-floor traction. In this work, eight footwear outsole designs and their traction performance were tested on a common flooring with water contamination, through the development of a novel fluid-structure interaction based computational framework. Induced fluid pressure, mass flow rates, and contact areas were quantified across the outsole patterns, and their effect on footwear friction was investigated. The study results were validated using mechanical slip testing experiments. The results indicated that the outsoles which had horizontal treads or untreaded heel regions can lead to drastic reduction of footwear friction. Also, contact area alone was quantified to be a poor choice in estimating the traction performance of footwear on water contaminated floorings. Such novel study results have not been reported to date, and are anticipated to provide important guidelines to footwear manufacturers to evaluate and optimize footwear tread parameters which would help in reducing the risk of slips.

Analysis of the Impact Resistance of Toecaps by the Finite Element Method: Preliminary Studies

A key property in the manufacture of toecaps for protective footwear is resistance to impacts, deformations, and cracking, as the resulting defects may lead to serious workplace accidents involving the lower extremities. The present paper proposes a new approach to qualitative verification of toecap design based on numerical simulations of impact tests. Computational experiments were conducted for toecaps made from different materials (AISI 10450, S235, S355 and A36 steels, as well as Lexan polycarbonate) and characterized by different geometries, which were recreated by 3D scanning. The impact resistance of the toecaps was analyzed using a numerical model simulating an experimental impact test. The results were used to determine the location of critical stresses and to plot equivalent stress maps for the studied toecaps. The finite element analysis of the impact tests was carried out with an explicit elastoplastic finite element code: ANSYS (Ansys, Inc., Canonsburg, PA, USA) with the Explicit Dynamics module of the Workbench solver. The presented analysis of the impact resistance of toecaps by the finite element method for impact simulation may be used to optimize the spatial geometry of toecaps and to verify the construction of toecaps and the material deformations that may occur. In addition, it could eliminate unsuitable materials that are likely to undergo dangerous deformations, and draw attention to the deformation caused by the impact of the toecaps used in footwear in the working environment.

Tactile Sensing Using Magnetic Foam

For biomedical applications, smart materials that are used as sensors or actuators have to match some criteria, especially bio-compatibility and softness. Smart polymers are candidates that fulfill these two criteria. A sensitivity to compression is created by adding magnetic particles to a compressible foam polymer. A foam-based composite is fabricated for its small Poisson’s ratio, which enables significant compression, up to 50%. This large compression induces a change in its magnetic properties, which can be detected using coils. By setting the sensing coils as a compact array of 3 × 3, the sensor successfully detected and localized an applied deformation.