Finite Element Analysis of Prosthetic Running Blades Using Different Composite Materials to Optimize Performance

2014 ◽  
Author(s):  
Mosfequr Rahman ◽  
Tyler Bennett ◽  
David Glisson ◽  
Darrell Beckley ◽  
Jobaidur Khan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Carbon Fiber ◽  
High Performance ◽  
Body Part ◽  
Sporting Events ◽  
Element Analysis ◽  
Performance Improvements ◽  
Prosthetic Limbs

A prosthetic limb is an artificial device that replaces missing body part, or parts. Prosthetic limbs are used for many different applications however the application of prosthetic limbs focused in this paper categorized as prosthetic enhancements. Prosthetic enhancements are special prosthetic that allow the patients to participate in more rigorous recreational activities, such as running. These prosthetic limbs now have started to arise in major sporting events like the Olympics. Some researchers say that the legs use only 25% of the energy that an able bodied leg would use. High performance prosthetic running legs made of carbon fiber, show great advantages over their metal counterparts. Including being lighter and being able to retain more strain energy, current carbon fiber running blades offered by Ossur provide the best performance in the market. In this study, prosthetic racing legs known as blades were analyzed using finite element analysis technique. Performance improvements of these blades were sought by creating mechanical models of the current Ossur products using the finite element analysis software ANSYS and incorporating better performing composite materials into the mechanical simulations. Two different composite materials have taken in consideration by which the legs are created from, these are thermoplastic values for polyethylene epoxy and Vinylester. The use of a new composite material reduces the strain in each of the existing blade geometries, and it permits fewer layers of carbon fiber to be required in the construction of these running blades, which reduces the weight of each leg. Three different blade designs such as Cheetah blade, Flex-Run blade and Flex-Sprint blade have been considered in this study. Also two different loading conditions on the blade such as standing and running conditions have been considered.

Energy Absorption Characteristics of a Carbon Fiber Composite Automobile Lower Rail: A Comparative Study

2015 ◽  
Author(s):  
Muhammad Ali ◽  
Khairul Alam ◽  
Eboreime Ohioma
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Energy Absorption ◽  
Reactive Force ◽  
Element Analysis ◽  
Cross Sectional Dimension ◽  
Force Displacement ◽  
Absorption Characteristics

Composite materials have emerged as promising materials in applications where low weight and high strengths are desired. Aerospace industry has been using composite materials for past several decades exploiting their characteristics of high strength to weight ratio over conventional homogenous materials. To provide a wider selection of materials for design optimization, and to develop lighter and stronger vehicles, automobile industries have been exploring the use of composites for a variety of components, assemblies, and structures. Composite materials offer an attractive alternate to traditional metals as designers have greater flexibility to optimize material and structural shapes according to functional requirements. However, any automotive structure or part constructed from composite materials must meet or exceed crashworthiness standards such as Federal Motor Vehicle Safety Standard (FMVSS) 208. Therefore, for a composite structure designed to support the integrity of the automotive structure and provide impact protection, it is imperative to understand the energy absorption characteristics of the candidate composite structures. In the present study, a detailed finite element analysis is presented to evaluate the energy absorbing characteristics of a carbon fiber reinforced polymer composite lower rail, a critical impact mitigation component in automotive chassis. For purposes of comparison, the analysis is repeated with equivalent aluminum and steel lower rails. The study was conducted using ABAQUS CZone module, finite element analysis software. The rail had a cross-sectional dimension of 62 mm (for each side), length of 457.2 mm, and a wall thickness of 3.016 mm. These values were extracted from automobile chassis manufacturer’s catalog. The rail was impacted by a rigid plate of mass 1 tonne (to mimic a vehicle of 1000 Kg gross weight) with an impact velocity of 35 mph (15646.4 mm/s), which is 5 mph over the FMVSS 208 standard, along its axis. The simulation results show that the composite rail crushes in a continuous manner under impact load (in contrast to a folding collapse deformation mode in aluminum and steel rails) which generates force-displacement curve with invariable crushing reactive force for the most part of the crushing stroke. The energy curves obtained from reactive force-displacement graphs show that the composite rail absorbs 240% and 231% more energy per unit mass as compared to aluminum and steel rails. This shows a significant performance enhancement over equivalent traditional metal (aluminum and steel) structures and suggests that composite materials in conjunction with cellular materials/configurations have a tremendous potential to improve crashworthiness of automobiles while offering opportunities of substantial weight reductions.

scholarly journals Finite Element Analysis for Nonlinear Unbonded Circular Fiber-Reinforced Elastomeric Bearings

2021 ◽  
Vol 5 (7) ◽  
pp. 170
Author(s):  
Pablo Castillo Ruano ◽  
Alfred Strauss
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Fiber ◽  
Seismic Isolation ◽  
Nonlinear Viscoelasticity ◽  
Fiber Reinforcement ◽  
Special Focus ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Elastomeric Bearings

In recent years, interest in low-cost seismic isolation systems has increased. The replacement of the steel reinforcement in conventional elastomeric bearings for a carbon fiber reinforcement is a possible solution and has garnered increasing attention. To investigate the response of fiber-reinforced elastomeric bearings (FREBs) under seismic loads, it is fundamental to understand its mechanical behavior under combined vertical and horizontal loads. An experimental investigation of the components presents complexities due to the high loads and displacements tested. The use of a finite element analysis can save time and resources by avoiding partially expensive experimental campaigns and by extending the number of geometries and topologies to be analyzed. In this work, a numerical model for carbon fiber-reinforced bearings is implemented, calibrated, and validated and a set of virtual experiments is designed to investigate the behavior of the bearings under combined compressive and lateral loading. Special focus is paid to detailed modeling of the constituent materials. The elastomeric matrix is modeled using a phenomenological rheological model based on the hyperelastic formulation developed by Yeoh and nonlinear viscoelasticity. The model aims to account for the hysteretic nonlinear hyper-viscoelastic behavior using a rheological formulation that takes into consideration hyperelasticity and nonlinear viscoelasticity and is calibrated using a series of experiments, including uniaxial tension tests, planar tests, and relaxation tests. Special interest is paid to capturing the energy dissipated in the unbonded fiber-reinforced elastomeric bearing in an accurate manner. The agreement between the numerical results and the experimental data is assessed, and the influence of parameters such as shape factor, aspect ratio, vertical pressure, and fiber reinforcement orientation on stress distribution in the bearings as well as in the mechanical properties is discussed.

Evaluation of Compressive Strengths of HPS Plate Systems Stiffened with Trapezoidal Stiffeners

2013 ◽  
Vol 671-674 ◽  
pp. 1025-1028
Author(s):  
Dong Ku Shin ◽  
Kyungsik Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Performance ◽  
Nonlinear Finite Element ◽  
Linear Strain ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Eurocode 3 ◽  
Initial Geometric Imperfections ◽  
Plate System

The ultimate compressive strengths of high performance steel (HPS) plate system stiffened longitudinally by closed stiffeners have been investigated by the nonlinear finite element analysis. Both conventional and high performance steels were considered in models following multi-linear strain hardening constitutive relationships. Initial geometric imperfections and residual stresses were also incorporated in the analysis. Numerical results have been compared to compressive strengths from Eurocode 3 EN 1993-1-5 and FHWA-TS-80-205. It has been found that although use of Eurocode 3 EN 1993-1-5 and FHWA-TS-80-205 may lead to highly conservative design strengths when very large column slenderness parameters are encountered

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