scholarly journals Finite Element Approach Towards Selection of Appropriate Materials to Redistribute Peak Plantar Pressure in Diabetic Foot with Neuropathy

2021 ◽  
Vol 1 (2) ◽  
pp. 43-54
Author(s):  
Muhammad Nouman ◽  
Desmond Y.R. Chong ◽  
Surapong Chatpun

Objective: The aim of this study was to assess the effect of customized insole (CMI) variations on plantar pressure in diabetic foot with neuropathy, using finite element analysis (FEA). Material and Methods: A three-dimensional foot model was constructed using FEA to study the peak contact pressure between the foot and the CMI. Nora® Lunalastike, Ethylene Vinyl Acetate (EVA), Amfit® and TPU were chosen for insole materials; and from these eight CMI models were created. The top surface of the tibia and fibula were fixed, and a displacement of 3 mm was exerted from the ground along with upwards Achilles tendon force.Results: The peak contact pressure contour showed that a softer material, CMI-A (E = 1.04 MPa), resulted in a better reduction of peak contact pressure compared to a stiffer material; CMI-D (E = 11 MPa). In addition, it was shown that the use of a single material to fabricate the CMI resulted in higher peak contact pressure; with the exception of CMI-A, in comparison to a dual-layer material of CMI-E and CMI-F. Using FEA, can effectively enhance the insole material selection process, without need of a trial and error practice in a clinical setting.Conclusion: The use of dual materials to fabricate CMIs, with the softer material as a top layer, is beneficial compared to a stiffer top layer material in the reduction of peak plantar pressure for diabetic foot with neuropathy.

2021 ◽  
Vol 11 (8) ◽  
pp. 3412
Author(s):  
Muhammad Nouman ◽  
Tulaya Dissaneewate ◽  
Desmond Y. R. Chong ◽  
Surapong Chatpun

Offloading plantar pressure in a diabetic foot with neuropathy is challenging in conventional clinical practice. Custom-made insole (CMI) materials play an important role in plantar pressure reduction, but the assessment is costly and time-consuming. Finite element analysis (FEA) can provide an efficient evaluation of different insoles on the plantar pressure distribution. This study investigated the effect of CMI materials and their combinations on plantar pressure reduction for the diabetic foot with neuropathy using FEA. The study was conducted by constructing a three-dimensional foot model along with CMI to study the peak contact pressure between the foot and CMI. The softer material (E = 5 MPa) resulted in a better reduction of peak contact pressure compared with the stiffer material (E = 11 MPa). The plantar pressure was well redistributed with softer material compared with the stiffer material and its combination. In addition, the single softer material resulted in reduced frictional stress under the first metatarsal head compared with the stiffer material and the combination of materials. The softer material and its combination have a beneficial effect on plantar pressure reduction and redistribution for a diabetic foot with neuropathy. This study provided an effective approach for CMI material selection using FEA.


2018 ◽  
Vol 7 (4.13) ◽  
pp. 214-220
Author(s):  
Mohd Nasri Ishak ◽  
Abd Rahim Abu Talib ◽  
Mohammad Yazdi Harmin

Current design of safety syringes requires two handed operation and additional processes which is not similar to the normal syringes. Due to this concern, a new design of safety syringe is introduced in order to produce a safety syringe which allows a single-handed operation and similar to the operation of a normal syringes. This paper presents the material selection process and design analysis of a newly devel-oped multi-purpose disposable safety syringe. Based on the design analysis, the force which needed to dismantle the nozzle is found to be 20 N and this value is practical for the end users. The finite element analysis had also shown that the design concept is safe and has safety feature for the user to use. In addition, copolymer is proven as the best material selection for safety syringe production.


Author(s):  
Yuhua Li ◽  
KF Leong ◽  
Yaodong Gu

Running in barefoot running footwear has gained popularity among both amateur and professional runners in recent times. To date, few studies have been performed using coupled finite element model of foot and barefoot running footwear. The objective of this study was to investigate the differences in peak plantar pressure during landing in the weight-bearing period between the finite element model of a barefoot and coupled finite element model of foot and barefoot running footwear. The stress distributions and concentrations in the forefoot region for simulations of different loadings to the foot and shoe were also investigated in the coupled model through different applied loadings. The finite element analysis showed that the coupled model had better pressure distribution and less peak plantar pressure than the barefoot model. The materials and thickness of the midsole were important factors in optimizing the outcome to reduce the plantar pressure and improve pressure distribution. The results presented in this study have the potential to be used as beneficial guidelines to improve the design of barefoot running footwear, while reducing the need for laborious experimental biomechanical investigations.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Abdullah T. Şensoy ◽  
Murat Çolak ◽  
Irfan Kaymaz ◽  
Fehim Findik

Abstract Materials used for dental crowns show a wide range of variety, and a dentist’s choice can depend on several factors such as patient desires, esthetics, tooth factors, etc. One of the most important issues for implant surgery is the primary stability and it should be provided to minimize the risks of screw loosening, failed osseointegration, or nonunion. The current study aims to present the Finite Element Analysis (FEA)-based material selection strategy for a dental crown in terms of reducing the aforementioned risks of dental implants. A virtual surgery mandible model obtained using MIMICS software was transferred to the ANSYS and material candidates determined using CES software were compared using FEA. The results indicated that Zr02+Y2O3 (zirconia) has shown a 12.79% worse performance compared to Au83-88/Pt4-12/Pd4.5-6 alloy in terms of abutment loosening. On the other hand, zirconia is the most promising material for dental crowns in terms of the stability of the bone-implant complex. Therefore, it may show the best overall performance for clinical use. Moreover, as suggested in this study, a better outcome and more accurate predictions can be achieved using a patient-specific FEA approach for the material selection process.


1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.


2021 ◽  
Author(s):  
R. M. Farizuan ◽  
A. R. Irfan ◽  
H. Radhwan ◽  
Shafeeq Ahmad Shamim Ahmad ◽  
Khoo Kin Fai ◽  
...  

Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.


2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Kenji Kitamura ◽  
Masanori Fujii ◽  
Miho Iwamoto ◽  
Satoshi Ikemura ◽  
Satoshi Hamai ◽  
...  

Abstract Background The ideal acetabular position for optimizing hip joint biomechanics in periacetabular osteotomy (PAO) remains unclear. We aimed to determine the relationship between acetabular correction in the coronal plane and joint contact pressure (CP) and identify morphological factors associated with residual abnormal CP after correction. Methods Using CT images from 44 patients with hip dysplasia, we performed three patterns of virtual PAOs on patient-specific 3D hip models; the acetabulum was rotated laterally to the lateral center-edge angles (LCEA) of 30°, 35°, and 40°. Finite-element analysis was used to calculate the CP of the acetabular cartilage during a single-leg stance. Results Coronal correction to the LCEA of 30° decreased the median maximum CP 0.5-fold compared to preoperatively (p <  0.001). Additional correction to the LCEA of 40° further decreased CP in 15 hips (34%) but conversely increased CP in 29 hips (66%). The increase in CP was associated with greater preoperative extrusion index (p = 0.030) and roundness index (p = 0.038). Overall, virtual PAO failed to normalize CP in 11 hips (25%), and a small anterior wall index (p = 0.049) and a large roundness index (p = 0.003) were associated with residual abnormal CP. Conclusions The degree of acetabular correction in the coronal plane where CP is minimized varied among patients. Coronal plane correction alone failed to normalize CP in 25% of patients in this study. In patients with an anterior acetabular deficiency (anterior wall index < 0.21) and an aspherical femoral head (roundness index > 53.2%), coronal plane correction alone may not normalize CP. Further studies are needed to clarify the effectiveness of multiplanar correction, including in the sagittal and axial planes, in optimizing the hip joint’s contact mechanics.


2019 ◽  
Vol 11 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Benedict Jain A.R. Tony ◽  
Masilamany S. Alphin

SummaryStudy aim: Interactions between the fingers and a handle can be analyzed using a finite element finger model. Hence, the biomechanical response of a hybrid human finger model during contact with varying diameter cylindrical handles was investigated numerically in the present study using ABAQUS/CAE.Materials and methods: The finite element index finger model consists of three segments: the proximal, middle, and distal phalanges. The finger model comprises skin, bone, subcutaneous tissue and nail. The skin and subcutaneous tissues were assumed to be non-linearly elastic and linearly visco-elastic. The FE model was applied to predict the contact interaction between the fingers and a handle with 10 N, 20 N, 40 N and 50 N grip forces for four different diameter handles (30 mm, 40 mm, 44mm and 50 mm). The model predictions projected the biomechanical response of the finger during the static gripping analysis with 200 incremental steps.Results: The simulation results showed that the increase in contact area reduced the maximal compressive stress/strain and also the contact pressure on finger skin. It was hypothesized in this study that the diameter of the handle influences the stress/strain and contact pressure within the soft tissue during the contact interactions.Conclusions: The present study may be useful to study the behavior of the finger model under the static gripping of hand-held power tools.


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