scholarly journals STRESS ANALYSIS OF INDIGENOUSLY DESIGNED ENERGY STORING POLYPROPYLENE CO-POLYMER (PPCP) PROSTHETIC FOOT

2020 ◽  
pp. 1-3
Author(s):  
Sachin S Bhagat ◽  
A.G Indalkar ◽  
Avinash Phirke
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Element Model ◽  
Heel Strike ◽  
Loading Conditions ◽  
Design Modification ◽  
Prosthetic Foot ◽  
Von Mises

Polypropylene Co-polymer (PPCP) Prosthetic Foot Model, Indigenously designed at All India Institute of Physical Medicine and Rehabilitation (AIIPMR), Mumbai. More commonly, this design is known as Modified Flex foot. Various researcher’s contributed towards its design modification, material optimization, patient trial & clinical implications and further improvements. As such, this study was conducted to observe & understand the stress analysis of this modified flexfoot under loading conditions at various orientation of gait. Finite element analysis (FEA) method was used with Ansys 12.0 software. Study objectives was to construct and analyze the finite element model, to find out & understand failure prone areas in the present design of PPCP prosthetic foot. This study was conducted into five phases. At initial phase, actual foot design was constructed and input parameters like geometrical parameters were calculated considering the standard length transtibial amputee. Similarly Material properties, loading conditions & boundary conditions were determined. AutCAD model was constructed using input parametrs & imported into Ansys 12.0 software. Finite element model were constructed and analyzed. Results were noted, which were displyed in the form of several contour plots & through colours that correspond to different stress values. FEA results obtained for various stress values like, Elemental stress, shearing stress & Von Mises stresses (Combination stresses). Peak Von Mises stress value of 28112 Mpa, observed at lower ankle fillet region during heel strike orientation of the gait. Study concluded that lower ankle fillet region & Midfoot spring region will be subjected to maximum stress during heel strike, Mid stance & push off. It was concluded that lower ankle fillet region & Midfoot spring region will be subjected to maximum stress during heel strike, Mid stance & push off.

Stress Analysis of the Pressurized-Water Reactor Control Rod Under Operating Conditions

2020 ◽  
Author(s):  
Leo A. Carrilho
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Element Model ◽  
Operating Conditions ◽  
Pressurized Water ◽  
Control Rod ◽  
The Finite Element Model

Abstract This work aims to develop a finite element model of a PWR control rod at operating conditions for stress analysis of the rod cladding. The finite element model simulates a control rod exposed to high operating temperatures and pressure while portions of the rod are irradiated, resulting in accumulated fluence of neutrons by the rod materials. These high temperature and accumulated fluence induce thermal expansion and swelling of the rod materials, especially of the absorber, which may eventually interact with the rod cladding, generating stresses and strains in the wall of the cladding tube. Moreover, if the maximum stress or strain in the tube wall exceeds the design allowable limit, the absorber rod is considered failed. The author creates the control rod finite element model and apply the operating loads on two-dimensional axisymmetric elements to obtain displacements, temperatures, stresses, and strains. The model also includes contact surface elements to evaluate eventual mechanical interactions between absorber and cladding due to thermal expansion and swelling effects. This is a coupled nonlinear static analysis solution that includes thermal expansion effects to calculate temperature distribution and subsequent thermal strains in the absorber rod due to the heat generation rates and coolant temperature; swelling analysis to calculate absorber growth induced by irradiation; and creep analysis to calculate absorber stress relaxation under coolant pressure and temperature. The finite element model is capable of determining whether or not absorber-to-cladding gap closure will occur and if so, calculate maximum stress and strain in the rod cladding associated with mechanical interaction between the two components induced by the operating temperature and thermal fluence loads.

Research of the Connecting Form about the Spherical Shell and the Nozzle

2011 ◽  
Vol 413 ◽  
pp. 520-523
Author(s):  
Cai Xia Luo
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Spherical Shell ◽  
Maximum Stress ◽  
Peak Stress ◽  
Element Model ◽  
Small Opening ◽  
Large Opening ◽  
Reducing Stress

The Stress Distribution in the Connection of the Spherical Shell and the Opening Nozzle Is Very Complex. Sharp-Angled Transition and Round Transition Are Used Respectively in the Connection in the Light of the Spherical Shell with the Small Opening and the Large One. the Influence of the Two Connecting Forms on Stress Distribution Is Analyzed by Establishing Finite Element Model and Solving it. the Result Shows there Is Obvious Stress Concentration in the Connection. Round Transition Can Reduce the Maximum Stress in Comparison with Sharp-Angled Transition in both Cases of the Small Opening and the Large Opening, Mainly Reducing the Bending Stress and the Peak Stress, but Not the Membrane Stress. the Effect of Round Transition on Reducing Stress Was Not Significant. so Sharp-Angled Transition Should Be Adopted in the Connection when a Finite Element Model Is Built for Simplification in the Future.

scholarly journals Comparative Analysis of Static Loading Performance of Rigid and Flexible Road Wheel based on Finite Element Method

2020 ◽  
Vol 70 (1) ◽  
pp. 41-46
Author(s):  
Yaoji Deng ◽  
Youqun Zhao ◽  
Mingmin Zhu ◽  
Zhen Xiao ◽  
Qiuwei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Static Loading ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Vertical Load ◽  
New Type ◽  
Stress And Deformation ◽  
Nonlinear Finite Element Model

To overcome the shortcomings of traditional rigid road wheel, such as poor damping effect and low load-bearing efficiency, a new type of flexible road wheel, having a unique suspension-bearing mode, was introduced. The three-dimensional nonlinear finite element model of rigid and flexible road wheel, considering the triple nonlinear characteristics of geometry, material and contact, is established for numerical investigation of static loading performance. The accuracy of the finite element model of the rigid and flexible road wheel is verified by static loading experiment. The static loading performance of the rigid and flexible road wheels is numerically analyzed. The influence of vertical load on maximum stress and deformation of the rigid and flexible wheels is also studied. The results show that the contact pressure uniformity of the flexible road wheel is better than that of the rigid road wheel under the static vertical load, but the maximum stress and deformation of the flexible road wheel are greater than that of the rigid road wheel. However, this problem can be solved by increasing the number of hinge sets and optimising the joints. The research results provide theoretical basis for replacing rigid road wheel with flexible road wheel, and also provide reference for structural optimisation of flexible road wheel.

Comparison of femur strain under different loading scenarios: Experimental testing

2020 ◽  
Vol 235 (1) ◽  
pp. 17-27
Author(s):  
Ievgen Levadnyi ◽  
Jan Awrejcewicz ◽  
Yan Zhang ◽  
Yaodong Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Distribution ◽  
Element Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Loading Conditions ◽  
Bone Implant ◽  
Bone Stiffness

Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.

The Finite Element Method: A Tool to Evaluate Shear Bond Strength of Dental Bracket

2014 ◽  
Vol 984-985 ◽  
pp. 431-437
Author(s):  
Vijaykumar Hiremath ◽  
Girija Bidarimath ◽  
Basavaraj Endigeri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Conditions ◽  
Acceptable Error ◽  
Three Dimensional Finite Element ◽  
Element Method

In this paper finite element model of steel dental bracket is generated along with bonding agent, enamel & stress analysis is carried out on the bracket for different loading conditions. Three dimensional finite element model developed are constrained with boundary condition that resembles to the reality. The Vonmisses stress is recorded for each loading conditions and compared with experimental results. The experimental work for 60 samples were carried out on Universal testing machine at material testing laboratory, Basaveshwar Engineering College, Bagalkot. It is found from FEM results that the shear bonding strength for different loadings from 60 N to 80 N varies from 7.276 N/mm2 to 9.7N/mm2, which are closer to experimental values with acceptable error. The study reveals that Finite Element Method can be used as a strong tool to analyze the dental bracket and study different parameters to improve its performance and to avoid time and cost required for experimentation.

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