Elastic-Plastic Finite Element Analysis of Indented Layered Media

1989 ◽  
Vol 111 (3) ◽  
pp. 430-439 ◽  
Author(s):  
K. Komvopoulos
Keyword(s):  
Finite Element ◽  
Plastic Zone ◽  
Contact Pressure ◽  
Critical Parameters ◽  
The Finite Element Method ◽  
Contact Pressure Distribution ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Substrate Properties ◽  
Layered Half Space

The elastic-plastic contact problem of a layered half-space indented by a rigid surface is solved with the finite element method. The case of a layer stiffer and harder than the substrate is analyzed and solutions for the contact pressure, subsurface stresses and strains, and location, shape, and growth of the plastic zone are presented for various layer thicknesses and indentation depths. Finite element results for a halfspace having the substrate properties are also given for comparison purposes. Differences between the elastic and elastic-plastic solutions are discussed and the significance of critical parameters such as the layer thickness, mechanical properties of layer and substrate materials, indentation depth, and interfacial friction on the threshold of plasticity, contact pressure distribution, and growth of the plastic zone are examined. Additionally, the mechanisms of layer decohesion and subsurface crack initiation are interpreted in light of the results obtained in this study.

Analysis of Contact Pressure Distribution on 3-Bolt Self-Energized Connector Seals

2009 ◽  
Author(s):  
Rajeev Madazhy ◽  
Sheril Mathews ◽  
Erik Howard
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Distribution ◽  
Contact Pressure ◽  
Maximum Pressure ◽  
Operating Pressure ◽  
Seal Ring ◽  
Contact Pressure Distribution ◽  
Element Analysis ◽  
Novel Design

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.

Finite element analysis of the ovine hip: Development, results and comparison with the human hip

2012 ◽  
Vol 25 (04) ◽  
pp. 301-306 ◽  
Author(s):  
J. Jalali ◽  
F. Schmidutz ◽  
C. Schröder ◽  
M. Woiczinski ◽  
J. Maierl ◽  
...  
Keyword(s):  
Finite Element ◽  
Pressure Distribution ◽  
Contact Pressure ◽  
Pelvic Bone ◽  
Acetabular Cartilage ◽  
Contact Pressure Distribution ◽  
Element Analysis ◽  
Average Value ◽  
Femoral Cartilage ◽  
Acetabular Side

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.

Finite Element Analysis of the Material Properties’ Influence on Tire/Road Contact Pressure and Area

2013 ◽  
Vol 367 ◽  
pp. 73-77
Author(s):  
You Shan Wang ◽  
Zhi Bo Cui ◽  
Qiang Liu
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Contact Area ◽  
Material Properties ◽  
Positive Relation ◽  
Contact Pressure Distribution ◽  
Element Analysis ◽  
Negative Effect ◽  
Good Contact ◽  
Tread Rubber

When designing a tire, a good contact pressure distribution and a good contact area are necessary. The contact pressure and contact area are determined by tire material and structure, but there is few public researches on these. So, in this article, tire material properties’ influence on tire/road contact pressure and area are analyzed by using finite element method. The results show that there are ten rubber materials have negative correlation with contact pressure, the most effective material is tread rubber; there are four rebar materials have positive relation with contact pressure, the major is the first belt rebar. But they are different in contact area: the most effective rebar to contact area is bead rebar. The positive and negative effect factors and the effect coefficients are obtained for the seventeen rubber materials and seven rebar materials in tire about contact pressure and contact area. That has an important guidance on tire design and engineering applications.

Finite Element Analysis of Repeated Indentation of an Elastic-Plastic Layered Medium by a Rigid Sphere, Part I: Surface Results

1995 ◽  
Vol 62 (1) ◽  
pp. 20-28 ◽  
Author(s):  
E. R. Kral ◽  
K. Komvopoulos ◽  
D. B. Bogy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Half Space ◽  
Contact Pressure ◽  
Peak Load ◽  
Rigid Sphere ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Surface Stresses ◽  
Residual Displacements

A comprehensive elastic-plastic finite element analysis is presented for the axisym-metric problem of a frictionless rigid sphere indenting a half-space with a harder and stiffer layer. The indenter is modeled by contact elements, thereby avoiding a priori assumptions for the pressure profile. Two layer thicknesses are examined, with layer elastic modulus and yield stress both two and four times greater than those of the substrate. Perfectly plastic and isotropic strain-hardening behavior of the layer and substrate media are investigated. At least three complete load-unload cycles are applied to a peak load of 300 times the load necessary to initiate yielding in a half-space of the substrate material. The effect of hardening properties on the loaded and residual stresses is presented and the consequences for crack initiation at the surface are discussed. Results for the contact pressure and surface stresses and deformations are presented, and the influence of residual displacements and load cycles on the contact pressure and the loaded and residual surface stresses is investigated.

Elastic-Plastic Finite Element Analysis of the Effect of the Compressive Loading on the Crack Tip Plasticity

2006 ◽  
Vol 324-325 ◽  
pp. 73-76
Author(s):  
J.Z. Zhang ◽  
Xiao Dong He ◽  
X. Song ◽  
Shan Yi Du
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Zone ◽  
Significant Contribution ◽  
Crack Opening ◽  
Compressive Loading ◽  
Crack Tip ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Crack Tip Plasticity

An elastic-plastic finite element analysis of the effect of the compressive loading on crack tip plasticity is presented. Two center-cracked panel specimens with different crack lengths are analysed under tension-compression loading. The size and shape of the crack tip reverse plastic zone, the crack opening profiles of the crack tip for short (0.1 mm) and long crack (2 mm) have been studied. The analysis shows that the compressive loading has a significant contribution towards the crack tip plasticity.

A Study of a Non-API Flange

2017 ◽  
Author(s):  
Shah Alam ◽  
Ulan Dakeev
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Oil And Gas ◽  
Band Width ◽  
Element Analysis ◽  
Acceptance Criterion ◽  
Elastic Plastic ◽  
Section Viii ◽  
Leak Tightness

API rated flanges [1] are used in oil and gas industries frequently. The current practice is to select a flange and its seal/gasket from a tabulated range of load and area of application. Some applications may require a unique flange or seal for a pressure and temperature that is not listed on the table. To design such non-API flange (geometry such as thickness, number of bolts, bolts pattern, etc. are different from API flange) that meets system requirements is a challenge. Currently there is no standard available as per authors knowledge to design non-API flange. Therefore, in this study, a finite element analysis with new acceptance criterion for the 5”-15-ksi non-API flange connection for different pressure and temperature has been performed. Elastic-plastic finite element analysis method is used to check the leak tightness [2]. A fatigue calculation based on elastic-plastic analysis with twice yield method as per ASME Section VIII, Division 2 [3], sec. 5.5.4, has also been performed. A new acceptance criterion based on industry practices are used for leak tightness. The contact pressure and contact pressure band width are used to check the leak tightness. The results showed that for all load cases seals have enough contact pressure and contact pressure band width to prevent leakage and they meet the acceptance criteria. The calculated fatigue life was found more than the required life for an application.

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