Toe Cap Research Articles

From Generation to Reuse: A Circular Economy Strategy Applied to Wind Turbine Production

The environmental impact of wind turbine rotor blades, both during manufacturing and at the end of their life cycle, can be significant. The aim of this study was to define and test a methodology for recycling the waste resulting from their production. Particles of waste from the mechanical machining of rotor blades, which were made up of a glass fibre/epoxy matrix mixture, were used to produce toe caps for use by the footwear industry. The addition of 1 wt.% of particles improved the mechanical properties of the epoxy matrix, with a 5.50% improvement in tension and an 8% improvement in stiffness. Characterisation of the laminates, manufactured by hand lay-up technique, revealed that in the three-point bending tests, the additive laminates showed improvements of 18.60% in tension, 7.50% in stiffness, and 10% in deformation compared to the control laminate. The compression test showed that the additive glass fibre toe cap had greater resistance to compression than the control glass fibre toe cap, with a reduction in deformation of 23.10%. The toe caps are suitable for use in protective footwear according to European standard EN ISO 20346:2022. They guaranteed protection against low-velocity impacts at an energy level of at least 100 J and against compression when tested at a compression load of at least 10 kN.

Optimum design of the geometry of boots and socks with the aim of minimum weight and preventing frostbite.

In order to design shoes suitable for cold environments, knowledge of the thermal conditions inside the shoes and the variables affecting those conditions is necessary. A two-dimensional model of a boot and sock was developed to investigate the effect of the materials and dimensions of various parts of shoes and to design geometry for them to prevent foot frostbite. The optimization algorithm was used to optimize the dimensions of the boots to maximize the minimum foot temperature with the lowest boot weight. Two types of shoe soles and two kinds of shoe uppers were used to design suitable shoes. The results show the following: (1) In the design boots, the thermal insulation of the toe area plays an essential role in preventing frostbite. Two variables of the thickness of the toe cap and the length of the shoe sole had the greatest impact on the design of shoes with the least weight and the most protection against frostbite. So that to increase minimum foot temperature from 7°C to 15°C, 16°C, or 17°C, only the amounts of these variables should increase. (2) In designing the suitable boot, choosing the proper shoe sole had a significant effect on increasing the thermal insulation in the shoe and reducing its weight. So, for the boot with a minimum foot temperature of 20°C, by changing the shoe sole from EVA08 to EVA12, the weight is reduced by 42%. (3) To maximize the minimum foot temperature, it is necessary to use thick socks.

Three-Dimensional Reconstruction of Shoe Soles via Binocular Vision Based on Improved Matching Cost

Aiming at the problem that the toe cap and upper part of the sole of a shoe easily appear missing when using binocular vision to reconstruct the shoe sole in the industrial production process, an improved matching cost calculation method is proposed to reconstruct shoe soles in three dimensions. Firstly, a binocular vision platform is built, and Zhang’s calibration method is used to obtain the calibration parameters. Secondly, the method of fusing Census and BT costs is used to calculate the matching cost of the image, so that the matching cost calculation result is more accurate. On this basis, 4-path aggregation is performed on the obtained cost, and the optimal matching cost is selected in combination with the WTA algorithm. Finally, left–right consistency detection and median filtering are used to optimize the disparity map and combine the camera calibration parameters to reconstruct the shoe sole in three dimensions. The experimental results show that the average mismatch rate of the four images on the Middlebury website in this method is about 6.57%, the reconstructed sole point cloud contour information is complete, and there is no material missing at the toe and heel.

Life cycle impact assessment of safety shoes toe caps realized with reclaimed composite materials

Toe cap for safety shoes is an extremely important protective equipment to prevent injuries caused by falling objects. It can be considered that more than 600 millions toe caps are disposed every year, without the possibility of disassembly them from the shoes. This represents a serious concern and sustainable solutions must be found to decrease the weight on the environment generated by the safety shoe market. In this context, a valid answer can be found in the use of carbon fiber prepreg scraps that can be employed in a circular economy approach, avoiding their disposal in landfill or through incineration, to produce certified and light toe caps. Unfortunately, carbon fiber scraps are associated to high production cost and environmental impacts (mainly due to the high energy requirement for the manufacturing of carbon fiber). Thus, the development of a zero-waste system is mandatory to achieve a conscious use of the resources. In this paper, a reclaim method for prepreg scraps and the relative manufacturing process for toe caps are assessed from the environmental point of view. The impacts are compared with those of a traditional process based on a thermoplastic material (Polycarbonate). Results demonstrate that the reclaim process is extremely sustainable due to the low energy requirements. However, some improvements of the manufacturing process are necessary to make toe caps realized with prepreg scraps more sustainable than the traditional ones.

Experimental and Numerical Assessment of the Impact Test Performance Between Two UHSS Toe Cap Models

This paper presents an integrated approach for an ultimate high-performance safety toe cap with significant milestones in slim design and weight saving. The study of crashworthiness properties was performed through impact-crash test conditions exploring the potential of applicant solutions by the combination of an advanced high-strength steel and enhanced geometric stiffening models. The structural response for a significant thickness reduction was assessed and it provides an evolved discussion for improvements in energy absorption capacity. The present case study focuses on two geometric models from the S3 slim toe cap development by prototypes made of a martensitic 1200 steel alloy. The comparison of results is complemented using numerical simulation models with mathematical description of the dynamic plasticity behaviour by applying a constitutive Cowper-Symonds equation with fundamental parameters for material strain-rate dependence.

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

Toe caps are one of the most important components in safety footwear, but have a significant contribution to the weight of the shoe. Efforts have been made to replace steel toe caps by polymeric ones, since they are lighter, insulated and insensitive to magnetic fields. Nevertheless, polymeric solutions require larger volumes, which has a negative impact on the shoe’s aesthetics. Therefore, safety footwear manufacturers are pursuing the development of an easy, low-cost and reliable solution to optimize this component. In this work, a solid mechanics toolbox built in the open-source computational library, OpenFOAM®, was used to simulate two laboratory standard tests (15 kN compression and 200 J impact tests). To model the polymeric material behavior, a neo-Hookean hyper-elasto-plastic material law with J2 plastic criteria was employed. A commercially available plastic toe cap was characterized, and the collected data was used for assessment purposes. Close agreements, between experimental and simulated values, were achieved for both tests, with an approximate error of 5.4% and 6.8% for the displacement value in compression and impact test simulations, respectively. The results clearly demonstrate that the employed open-source finite volume computational models offer reliable results and can support the design of toe caps for the R&D footwear industry.

Thermal Analysis of Safety Shoe Toe Cap

Shoe toe bonnets/caps are the shielding equipment worn in the production company to care for workers' feet from heat. Steel is generally used for safety heavy toe shoe caps that have high thermal conductivity but now the usage of polymer material is growing because of the low pressure & less thermal conductivity. This study centers on the design & thermal enquiry of a safety shoe toe bonnet/cap by employing nylon 66 & carbon fiber (CF) in various weight ratios. Safety toe cap design is finished in Siemens NX Uni-graphics subsequently Finite Element Analysis (FEA) employing ANSYS software. ISO 20345: 2011 benchmark is followed for thermal analysis and then compared with steel shoe toe caps. Safety toe cap design is done in Siemens NX Uni-graphics followed by Finite Element Analysis (FEA) using ANSYS software. Comparison with steel shoe toe caps

Acute Effect of Toe Cap Choice on Toe Deviation Angle and Perceived Pain in Female Professional Ballet Dancers.

Several classical dance complex movements, such as pointe, require body weight to be supported properly to avoid risk of foot injury. Regarding the choice of toe cap for pointe shoes, it is unclear which type can better alleviate pain symptoms and toe deviation angle in dancers. The aim of the current crossover study was to investigate the acute effect of using different types of toe caps among well-trained professional dancers on pain perception and toe deviation angle. Ten young female professional dancers volunteered to participate in the study. Each participant was tested during two separate sessions with an interval of 72 h in between. Participants were tested in the two sessions with a standard commercial or a customized prototype toe cap, always with pointe shoes, and in randomized order. An anteroposterior X-ray examination was performed separately for each participant and a visual analogue scale for pain perception was administered following each situation (with a standard commercial or a customized prototype toe cap). Significant amelioration was obtained when a customized toe cap prototype was used both for toe deviation angle and for visual analogue scale. Use of a customized toe cap prototype compared to a standard one may acutely reduce both toe deviation angle and pain in elite female professional dancers.

Study on the impact behaviour of a new safety toe cap model made of ultra-high-strength steels

In this study the crashworthy performance of an ultimate safety toe cap model made of high-strength steel was evaluated. The structural response to impact loading conditions under normative requirements was properly related to the potential of lightweight design for a significant thickness reduction. Two grades of fully martensitic steels were selected and numerical models modelling extensive plastic deformation and strain-rate dependence were performed. The mathematical description of the impact behaviour with the correlation of crashworthy properties was analysed and compared by applying two fundamental constitutive models: The Cowper–Symonds and Johnson–Cook constitutive equations. Experimental results of tensile testing at different strain rates and different directions of the sheet material were used to determine fundamental constitutive parameters for both steel alloys. The numerical simulation developed using an explicit dynamics software (ANSYS) was extensively compared to an experimental standard testing program of final prototypes. A local stiffening toe cap model with high energy absorption efficiency was also validated.

Microfine toe caps: an innovative and cost-saving solution.

This article discusses the use of Microfine toe caps (Haddenham, UK) for the treatment of digit swelling. It will discuss the indications and contraindications of the device and offers some case studies where toe caps have been used in clinical practice. The use of the Microfine toe cap offers an alternative to toe bandaging, has many different applications and can be safe and time-saving to apply when used appropriately following a full and holistic assessment.

Numerical Simulation of Quasi-Static Compression Behavior of the Toe Cap Component for Safety Footwear

Geometrical changes can improve stiffness substantially. The project S3 - Safety Slim Shoe presents the potential to reduce the weight in safety toe cap components combining a new geometric redesign deeply associated to local stiffeners to realize the full potential of AHSS - Advanced High Strength Steels. The investigation aimed to examine the potential energy absorption capacity for a substantial thickness reduction of slim toe cap models. In this paper the normative quasi-static compression test in the context of the experimental validation of the two last and approved prototype models were focused. A non-linear FEA - Finite Element Analysis of the elasto-plastic deformation mode was performed, and several numerical parameters such as: hardening effects of extrapolated True-Stress-Strain material curves and simulation convergence conditions were carried out. Experimental results of the toe cap deformation behavior confront a weight saving range of over 40%, compared with the original steel toe cap. The safety footwear, in the context of the global evolution of footwear, has adopted creative and different orientations. Particularly, as an active element in the prevention of accidents fitted in PPE - Personal Protective Equipment, it is appropriate that its optimization solutions amplify the market targets, mainly combining ergonomic aspects, biological and mechanical features since its conception. The toe cap is the main component for its weight contribution, approx. 35% of total weight for each safety footwear model, and due normative context demands with high deformation resistance and impact loading (1). Currently the toe cap protection takes a subdivided position on design selection and materials, with a clear definition of two distinctive conception trends: metallic and non-metallic models. If on one hand the metallic models, especially high carbon steels with Heat Treatment processes, emphasize the security concept by the implicit mechanical strength performance, on the other hand, the weight of these solutions is a disadvantage compared to the metal-free solutions, and relegates the first one for outdated and heavier footwear concept. The non-metallic solutions with higher trend effects in the global market call on low density materials such as: reinforced Polyester composites with glass fiber, HDPE - High Strength Polyethylene, and several advanced developments in the optimization of energy

Effect of a Steel Toe Cap on Forefoot Injury Pattern in a Cadaveric Model

Crush injuries to the foot are a common workplace injury and a significant source of morbidity, disability and lost wages. Many regulatory bodies including the Occupational Safety and Health Administration (OSHA) recommend the use of safety shoes in certain occupations to help protect against these occupational hazards. However there remains controversy and paucity of published data regarding the protection afforded by a steel toe cap in regards to clinical injury pattern. This study looks to investigates the protective influence of a steel toe cap on crush injuries of the forefoot. Five non-osteoporotic paired cadaver lower extremities were appropriately fitted to a standard work boot. One foot of each pair was fitted into a steel toe capped boot (designated ``ST'' group) while the other foot was fitted into an identical version of the work boot but without the protective steel toe cap (designated ``NST'' group). Each foot was crushed using a custom designed rig with a load of 150 lb dropped from a calibrated height of 3 feet to the forefoot. X-rays were obtained to assess fracture location & comminution and stress fluoroscopy was used to assess for any ligamentous Lisfranc injury. The NST group averaged 8.2 fractured bones per foot while the ST group averaged 3.6 fractured bones per foot (p = 0.001). The NST group demonstrated significantly more metatarsal fractures (3.2 fractures/foot) versus the ST group (one fracture/foot) (p = 0.020). The NST group demonstrated significantly more proximal phalanx fractures (4.2 fractures/foot) compared to the ST group (2.6 fractures/foot) (p = 0.035). Middle and distal phalanx fractures were not significantly different between the two groups. A higher percentage of the bones fractured were deemed comminuted in the NST group (53.6%) versus the ST group (38.8%) although this did not reach statistical significance. This study demonstrated that the steel toe affords protective advantages in crush injuries to the foot in limiting the number and severity of metatarsal and proximal phalanx fractures. However the steel toe does not fully protect the forefoot from injury. Crush injuries to the foot are a common workplace injury. Strict adherence to workplace safety standards may limit the severity of crush injuries to the foot and additional safety measures such as metatarsal guards should be considered when appropriate.

Design and Testing of a New Metallic Solution for Toecap Component on Safety Footwear

This paper explores an innovative solution based on the geometric redesign of integrant safety shoe`s component, the toe cap component. The investigation program covered some steps as the computational modeling of the toecap component, a set of numerical simulations in the FEM context with the toecap model discretization used for multiple Non-Linear Analysis on plastic domain, and experimental tests for ISO EN 20345 certification to support and comparing results. The aim of the study is to explore the work hardening phenomenon of the high strength steel DP600 on toecap component formed, to predict an expected mechanical strength increase and a consequent significant reduction of the weight. The study points to a thickness decreasing value of approximately 50% and equivalent reduce of weight.

Microfine glove and toe caps and their use in lymphoedema management

Lymphoedema garments have progressed in the last 10 years, so gone are the days when only one colour is available (that lovely beige!). How many patients would have to be persuaded to wear their compression hosiery in that desirable colour? Not just have the colours become more acceptable, so have the fabrics. There are a wide range of compression gloves available to the lymphoedema specialist to fit on the patient but that cannot be said of toe caps. The Microfine toe cap is the only one available as an off-the-shelf garment, and when the lymphoedema is deemed to be manageable in these garments, it offers an alternative to flat knit. The Microfine glove and Microfine toe cap are adaptable and can offer colour options and a fabric that is less bulky and fine. It also allows therapists to trim the length of each digit for a better fit without reducing compression. The author will present three case studies of patients that are using.

BIOMECHANICAL ANALYSIS OF THE 10KM-RUN IN A TRIATHLON WORLD CUP EVENT: DIFFERENCES PRESENTED BY WOMEN GOLD MEDAL

In most of the triathlon races, the 10km-run is critical to win and, just a few seconds, may separate the gold and the silver medal. To our best knowledge, no study has analyzed the biomechanical differences among the first qualified triathletes during a top-level competition. The aims of the present study were: (1) to examine the different responses to the previous cycling between the gold medal and the other participants, and (2) to compare the biomechanical profiles during the 10km-run presented by the top-ranked triathletes. 16 women, participants at Madrid 2008 Triathlon World Cup, were analyzed. The first qualified triathlete (gold medal) showed significant differences (p<0.05) with the other participants in many of the analyzed variables. A higher stride length, a smaller stride frequency, a higher and more consistent horizontal distance hip- toe cap and a more extended knee angle of the support-leg at toe-off could explain the differences in 10km-run time between gold medal and the other participants.

A Deformation Method for Shoe Last Customization

AbstractThe production of custom tailored product is widely required in the manufacturing industry nowadays. This paper proposes a new method for designing custom shoe last. In this method, a consumer preferred last form is selected as the base form. By calculating the difference between the base form and scanned foot data from the consumer, a distance map is obtained to indicate how well the selected shoe last fits the specific foot shape and to guide the deformation. An amendment map is set up offline based on the experience information from experienced last maker to cater for last design regulations; it can also incorporate the function of preserving original last style by keeping the original last shape on specific regions such as ‘toe cap’. The base last form is then deformed by minimizing the SSD of a designed equation, to fit the particular foot shape according to the distance map and amendment map, with the minimal change of the original last style. Preliminary experimental results are given to de...

Thermal effects of steel toe caps in footgear

This study investigated cold weather safety footwear and the possible thermal effects of steel toe caps in footwear. Two models of boots were used. Both models were manufactured in two variants – with and without steel toe cap. The boot insulation was measured with an artificial, heated foot (AHF). One model was used in experiment with subjects ( n=6). Cold exposure consisted of sitting for 60 min at −10°C. There were no differences between insulation levels of boots with and without steel cap for one boot model, but the differences were statistically significant for the second model showing slightly higher insulation values for the boot without steel cap. No significant differences due to insulation dissimilarities could be found from the measurements on subjects. Statistically significant differences were found for both models regarding the rate of change of heat loss from AHF when its location was changed from warm to cold and back to warm. The rise and decrease of heat loss from AHF depended on the rate of temperature change of the boots. The results showed that a faster change in heat loss from AHF occurred for boots without steel toe caps. Data from subjects seemed to confirm this by a somewhat faster, though not significant, rise in toe skin temperatures after cold exposure in boots without steel toe caps. The effect may be attributed to the higher mass and heat contents of the boots with steel toe cap. Relevance to industry Many jobs need additional protection of the toes or shins. The steel toe cap and its alleged cooling effect have been a frequent subject of complaints. This study discusses reasons that could explain the complaints, and presents a standard method for evaluating thermal properties of footwear.

Effect of Footwear Insulation on Thermal Responses in the Cold

The influence of footwear insulation on foot skin temperature in the cold at low activity was investigated. Simultaneously, the thermal and pain sensations, and the influence of steel toe cap were studied. Eight participants were exposed for 85 min to 3 environmental temperatures ( + 3, –12, and –25°C) wearing 5 different boots. Insulation of footwear was determined with thermal foot model. The study showed the importance of insulation for keeping feet warm. Other factors, such as wetness and vasomotor response, however, modified the thermal response. The most affected parts were toes and heels. Cold and pain sensations were connected with considerably lower temperatures in these local points. No significant differences were observed between boots with and without steel toe cap.

Effect of Sweating on Insulation of Footwear

The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19–25% (30–37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.

A method for dynamic measurement of the resistance to dry heat exchange by footwear

Five different types of cold protective footwear have been tested with regard to their resistance to dry heat loss (i.e. the insulation) with a new electrically heated foot model. The model is able to simulate ‘walking’ movements in order to provide a more realistic simulation of wear conditions. Thermal insulation of shoes with and without a steel toe cap was the same. The insulating properties during simulated walking movements were 10–25% lower compared with static conditions. For two of the shoe models a significantly lower insulation value for the sole area was obtained when adding a weight of 30 kg. A significant difference could also be found between the insulation values of two different sizes of one of the models. Measurements with the standard method (EN 344) correlated well with the local insulation value of the sole part of the thermal foot. Correlation with the insulation value for the whole shoe was much less, variation was bigger and ranking in terms of cold protection differed between methods. The electrically heated foot model appears to provide a reproducible, accurate and more realistic method for measuring the insulation properties of shoes than EN 344.