Profile

Mrs. Anthony Christopher

Contact Details

Bio

Fatigue Characteristics and Numerical Modelling Prosthetic for Chopart Amputation

Introduction

Partial foot amputation is a foot amputation between the ankle joint and the lower distal limb. Prostheses for partial foot amputations vary in design and function. Partial foot amputation is a type of amputation, which has many challenges for write my essay, the prosthesis technicians, and the patient himself in comparison to other types of amputations due to the complexity of this type of amputation. The structure of the partial foot prosthesis should be strong to protect the amputation edges from the impact at heel strike and toe off, which should also be able to control the foot deformation in dorsiflexion, plantar flexion, eversion, and inversion. Also, the prosthesis should simulate a suitable gait pattern which can allow the patient to perform normal activities. Then, the prosthesis appearance should be cosmetically acceptable. There are a wide range of partial foot amputation prostheses which can be simple as bunched up socks or foam toe fillers. They also can be a sculptured Plastazote, elastomers2, or orthoprosthesis which can have some extension that reaches to the patella tendon-bearing area.

Abbas investigates the effects of composite material layers on the prosthetic mechanical properties for partial foot amputation. Abbas et al. investigate the mechanical properties of a prosthesis designed for partial foot amputation. Takhakh et al. studied the different types of composite material lamination layers for prosthetic applications. S. M. Abbas and M. H. Abbas used carbon fiber with four layers to make a composite material for an above-the-knee amputation socket. Salman et al. studied a composite material with a wide range of fiber reinforcements . Also, Mostafa et al., Sharba et al., and Salman et al. investigate the hybrid composite material and found its mechanical properties with biaxial tensile, compression, and fatigue tests.

The aim of this work is to design and manufacture a prosthesis for Chopart amputation. This prosthesis is using one of the three composite material groups. The selected composite material is processed by simulating the prosthetic model for these three groups using the mechanical properties collected from the tests that were utilized in this write my essay for me. The aim of the study was achieved by the following phases.

In the beginning, three types of lamination samples were tested in tensile and fatigue tests, and they are 3 Perlon-2 carbon fiber-3 Perlon, 3 Perlon-2 glass fiber-3 Perlon, and 6 Perlon with a matrix of lamination (80 : 20) resin. Then, a study of the mechanical properties for these materials was done to select the best option among them to make a socket with the required performance. This study was utilized by finite element analysis using ANSYS (14.5) to determine the fatigue safety factor numerally.

The experimental and numerical data used to support the findings of this study are included within the article.

2. Experimental Procedures

The tools and devices used for this research are listed as follows:(1)A  mould from Jepson(2)Pressure vacuum to prevent gaps between the fiber and the resin(3)Tensile test machine(4)Fatigue test for a flat specimen suitable for the composite material

Three samples were tested for each type of composite material in the tensile test device. 

Ten samples for each group combination were utilized for the fatigue test. The samples are made according to the standard of the fatigue device while thickness of the samples varies with each group.

The following steps are measuring the partial foot amputation socket dimensions for the patient to manufacture a socket. After manufacturing, the alignment of the partial foot prosthesis was done using the alignment tools to be ready to use by the patient.

The procedure to manufacture a socket can be listed in the following steps:(1)Measuring the following parameters from the patient:(a)The circumferences of the stump(b)Mediolateral diameter at the calcaneus and malleolus(c)The amputee’s length(d)The normal foot’s length(e)The patient shoe’s heel height(2)Handing casting(3)Preparing for rectification and cast rectification(4)Soft socket manufacturing(5)Adding lamination for the socket(6)Trimming and then finishing

Measure the interface pressure using an F-socket at different regions of the patient who wears a prosthetic type PF (age (55 years), height (190 cm), and weight (88 kg)). The patient suffered from left foot amputation (Chopart amputation) due to an explosion. The interface pressure was taken by using a paper writing service online.

Numerical Analysis

In this research, a finite element method was used to evaluate the fatigue characteristics of the prosthetic part. The prosthesis geometry was measured and modelled in ANSYS software. This model used the collected mechanical properties from the tests of the three groups of the composite material, which were used to make the socket. The mechanical properties of the three different groups were used to evaluate the stresses that were generated in the prosthetics due to the weight and walking loading.

Conclusions

(1)The material selection procedure for the prosthesis used in this research can be used in a wide range of prosthetics and orthotics, as most of these applications are custom-made for each patient due to the special amputation specifications, body dimensions, patient’s weight, and other factors. So, by modelling the proposed prosthesis, it can find what material is the best for the patient’s requirements from the total deflection to the factor of safety from the model results(2)There is good improvement in the mechanical properties of the laminations in groups A and B compared to group C due to adding two layers of glass fiber and carbon fiber, respectively. This improvement can be noticed in both the custom essay writer and the fatigue life of the prosthesis from the finite element model(3)The maximum contact or interface pressure values measured on the prosthesis are as follows: at the lateral area, it was 164 kPa, and at the posterior area, it was 190 kPa. These maximum pressure values are due to the extra activity of the patient’s muscles in this area during walking compared to the anterior regions and medial region which lead to reduced pressure on the tibia area. This contact pressure distribution should be noticed in a wide range of prostheses. Otherwise, high interface contact pressure on the tibia will make the patient uncomfortable and hurt the patient with time(4)In this research, the selected composite material for the prosthetic model shows that the fatigue factor of safety for group A is 1.037 which can be considered safe for this type of application