scholarly journals Finite element study of contact pressure distribution on inner and outer liner in the bipolar hip prosthesis

Author(s):  
Eko Saputra ◽  
Iwan Budiwan Anwar ◽  
Rifky Ismail ◽  
J. Jamari ◽  
Emile van der Heide
Author(s):  
Rajeev Madazhy ◽  
Sheril Mathews ◽  
Erik Howard

A novel design using 3 bolts for a self-energized seal connector is proposed for quick assembly applications. Contact pressure distribution on the surface of the seal ring during initial bolt-up and subsequent operating pressure is analyzed for 3″ and 10″ connectors using Finite Element Analysis. FEA is performed on a 3″ and 10″ ANSI RF flange assembly and contact pressure distribution on the RF gasket is compared with the tapered seal ring assemblies. Hydrostatic tests are carried out for the tapered seal and ANSI bolted connectors to evaluate maximum pressure at which leak occurs for both size assemblies.


1983 ◽  
Vol 11 (1) ◽  
pp. 50-63 ◽  
Author(s):  
J. T. Tielking

Abstract A finite element tire model, based on nonlinear shell of revolution elements, has been developed to investigate tire-pavement interaction. The basic characteristics of this relatively comprehensive model are reviewed here, with attention focused on its ability to calculate the effect of tire design variables on tire performance data. A four-ply bias tire is used to show the ability of the model to predict the different effects that nylon and polyester cords have on tire deformation, contact pressure distribution, and traction.


1999 ◽  
Vol 122 (4) ◽  
pp. 781-789
Author(s):  
L. B. Shulkin ◽  
D. A. Mendelsohn ◽  
G. L. Kinzel ◽  
T. Altan

Many manufacturing situations involve a finite thickness plate or layer of material which is pressed against a much thicker foundation of the same or different material. One key example is a blank holder (plate) pressed against a die (foundation) in a sheet metal forming operation. In designing such a plate/foundation system the design objective often involves the contact stress distribution between the plate and foundation and the design variables are typically the thickness and modulus of the plate, the stiffness of the foundation and the applied pressure distribution on the noncontacting side of the plate. In general the problem relating the variables to the contact pressure distribution is three-dimensional and requires a complex finite element or boundary element solution. However, if the applied pressure distribution consists of sufficiently localized patches, which is often the case in applications, then an approximate 3D solution can be constructed by superposition. Specifically, the paper provides a convenient calculation procedure for the contact pressure due to a single circular patch of applied pressure on an infinite, isotropic, elastic layer which rests on a Winkler foundation. The procedure is validated by using known analytical solutions and the finite element method (FEM). Next a sensitivity study is presented for ascertaining the validity of the solution’s use in constructing solutions to practical problems involving multiple patches of loading. This is accomplished through a parametric study of the effects of loading radius, layer thickness, layer elastic properties, foundation stiffness and the form of the applied pressure distribution on the magnitude and extent of the contact pressure distribution. Finally, a procedure for determining an appropriate Winkler stiffness parameter for a foundation is presented. [S1087-1357(00)00603-1]


2012 ◽  
Vol 25 (04) ◽  
pp. 301-306 ◽  
Author(s):  
J. Jalali ◽  
F. Schmidutz ◽  
C. Schröder ◽  
M. Woiczinski ◽  
J. Maierl ◽  
...  

SummaryObjectives: The ovine hip is often used as an experimental research model to simulate the human hip. However, little is known about the contact pressures on the femoral and acetabular cartilage in the ovine hip, and if those are representative for the human hip.Methods: A model of the ovine hip, including the pelvis, femur, acetabular cartilage, femoral cartilage and ligamentum transversum, was built using computed tomography and microcomputed tomography. Using the finite element method, the peak forces were analysed during simulated walking.Results: The evaluation revealed that the contact pressure distribution on the femoral cartilage is horseshoe-shaped and reaches a maximum value of approximately 6 MPa. The maximum contact pressure is located on the dorsal acetabular side and is predominantly aligned in the cranial-to-caudal direction. The surface stresses acting on the pelvic bone reach an average value of approximately 2 MPa.Conclusions: The contact pressure distribution, magnitude, and the mean surface stress in the ovine hip are similar to those described in the current literature for the human hip. This suggests that in terms of load distribution, the ovine hip is well suited for the preclinical testing of medical devices designed for the human hip.


2018 ◽  
Vol 18 (02) ◽  
pp. 1850018
Author(s):  
FEI LI ◽  
HEJUAN CHEN ◽  
TARO MAWATARI ◽  
YUKIHIDE IWAMOTO ◽  
FEI JIANG ◽  
...  

Finite element (FE) analysis has been used in the simulation of periacetabular osteotomy (PAO) to predict the improvement of contact pressure concentration in dysplastic hip joint. Since the cartilage layer is difficult to be segmented from CT or MRI images, most hip joint models were assumed to be a simple perfect ball and socket joint. However, the influence of different cartilage modeling methods on the reliability of the simulation has not been assessed. The objective of this study is to elucidate the influence of different cartilage modeling methods on predictions of cartilage layers’ contact pressure by FE contact analysis. In this study, the cartilage layer was generated by applying three typical kinds of modeling methods (spherical, uniform thickness, and midline-based). After comparisons with these cartilage modeling methods, the computational results demonstrate that the cartilage modeling methods have a dramatic influence on predictions of contact pressure in the PAO. The relatively continuous contact pressure distribution and lower peak contact pressure are observed in spherical cartilage modeling method. The discontinuous contact pressure distribution and higher peak contact pressure are obtained in uniform thickness and midline-based cartilage modeling methods. And the degree of discontinuous pressure distribution is even worse in the midline-based cartilage modeling method.


Author(s):  
Sripati Sah ◽  
Robert X. Gao ◽  
Timothy Kurp

On-line measurement of contact pressure distribution (CPD) at the tool-workpiece interface during sheet metal stamping processes plays a critical role in tool wear and product quality monitoring and control. Realizing such measurement poses a significant challenge, due to the severe operating conditions at the contact interface. Since the number of sensors that can be integrated into a tooling structure is limited by concerns of structural integrity, a mathematical framework is needed for estimating the contact pressure distribution measured by sparse sensors. This paper investigates a new technique termed the Spatial Blending Functions (SBF), which provides an improved estimate of the contact pressure distribution by merging measurements from tooling-embedded sensors with simulation results from Finite Element modeling. The effectiveness of the SBF-based merging technique is demonstrated for the case of a panel stamping operation through Finite Element simulations and experiments performed on a stamping press with a tooling-integrated sensing system. Analysis of the results demonstrates that the SBF-based CPD estimation is more accurate than classic numeric surface interpolation methods, thus enhances contact pressure distribution estimation for stamping process monitoring.


2012 ◽  
Author(s):  
Abd Rahim Abu Bakar ◽  
Mohd Kameil Abdul Hamid ◽  
Huajiang Ouyang

Taburan tekanan sentuhan dinamik masih lagi tidak dapat diukur secara uji kaji. Ini menjadikan kaedah berangka melalui analisis unsur terhingga merupakan pilihan alternatif yang terbaik bagi tujuan tersebut. Namun begitu, model unsur terhingga yang dibina perlu terlebih dahulu diujisahkan agar hasil ramalan yang diperolehi memuaskan dan realistik. Kertas kerja ini mencadangkan dan menjalankan pengujisahan ke atas model secara tiga peringkat iaitu mengujisahkan aspek kelakuan dinamik pada setiap komponen brek cakera dan juga pemasangan selain daripada pengujisahan tekanan sentuhan statik dengan keputusan daripada pengujian. Model 3-dimensi telah dibina berdasarkan komponen sebenar. Permukaan topografi bahan geseran diambilkira dan dimodelkan dalam model unsur terhingga. Hasil analisis mencatatkan keputusan yang memberangsangkan di mana model menunjukkan persamaan dengan keputusan uji kaji bagi kelakukan dinamik dan juga tekanan sentuhan statik. Setelah model diujisahkan, analisis tekanan sentuhan dinamik dilakukan. Kata kunci: brek cakera, tekanan sentuhan dinamik, topografi permukaan, ujian sentuhan, analisis modal, unsur terhingga The dynamic contact pressure distribution in a disc brake system remains impossible to measure through experimental methods. This makes numerical analysis using the finite element method an indispensable alternative tool to its prediction. However, the finite element model must first be validated through appropriate analyses so that realistic predicted results can be obtained. This paper proposes and carries out a three-stage validation methodology: validating the dynamic aspect of each brake component and the brake assembly using modal testing data and the contact aspect using the experimental results of static contact pressure. A detailed 3-dimensional finite element model of an actual disc brake was developed. Brake pad surface topography is also taken into consideration. Good agreement is achieved between predicted and experimental results both in modal analysis and static contact pressure distributions. Once a validated model was obtained, contact analysis for dynamic condition of the disc brake is performed. Key words: disc brake, dynamic contact pressure, surface topography, contact tests, modal analysis, finite element


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