Stress Distribution in Porous Ceramic Bodies During Binder Burnout

2002 ◽  
Vol 69 (4) ◽  
pp. 497-501 ◽  
Author(s):  
Z. C. Feng ◽  
B. He ◽  
S. J. Lombardo
Keyword(s):  
Pore Space ◽  
Porous Ceramic ◽  
Three Dimensional ◽  
The Body ◽  
Shear Stresses ◽  
Element Analysis ◽  
Porous Bodies ◽  
Mechanics Model ◽  
Binder Burnout ◽  
Normal And Shear Stresses

A model has been developed for describing the stresses that arise during binder burnout in three-dimensional porous bodies. The pressure gradient that arises from the decomposition of binder in the pore space is treated as an equivalent body force. For input into the mechanics model, the pressure distribution is obtained from the analytical solution for three-dimensional porous bodies with anisotropic permeability. The normal and shear stresses are then calculated from finite element analysis for bodies of parallelepiped geometry. In general, the normal stresses occur at the center of the body and are an order of magnitude larger than the shear stresses. Both the normal and shear stresses depend on the body size, the body geometry, and on the permeability.

Pressure Distribution During Binder Burnout in Three-dimensional Porous Ceramic Bodies with Anisotropic Permeability

2002 ◽  
Vol 17 (6) ◽  
pp. 1434-1440 ◽  
Author(s):  
Stephen J. Lombardo ◽  
Z. C. Feng
Keyword(s):  
Elevated Temperature ◽  
Gas Phase ◽  
Source Term ◽  
Ceramic Body ◽  
Porous Ceramic ◽  
Three Dimensional ◽  
The Body ◽  
Anisotropic Permeability ◽  
Porous Bodies ◽  
Binder Burnout

The flow of gas-phase products in three-dimensional porous bodies was modeled for the case when a source term is present. Analytical solutions to the governing partial differential equations were obtained for bodies of parallelepiped and cylindrical geometry. An important feature of the model is that it treats the case where the permeability in the body may be anisotropic. The evolution of pressure within the body depends on a number of parameters, including the rate of production of gas-phase species, and on the dimensions of the body. The model is thus able to describe the pressure within a porous ceramic body arising from flow during a number of elevated-temperature processing operations such as drying, binder burnout, and sintering.

Bionic Lubrication System of Artificial Joints: System Design and Mechanics Simulation

2005 ◽  
Author(s):  
S. H. Su ◽  
J. H. Zhang ◽  
D. H. Tao
Keyword(s):  
Three Dimensional ◽  
Joint Capsule ◽  
The Body ◽  
Artificial Joint ◽  
Lubrication System ◽  
Wear Particles ◽  
Element Analysis ◽  
Artificial Joints ◽  
Fea Model ◽  
Capsule Thickness

A new structure of artificial joints with bionic joint capsule was proposed and designed to overcome the feedback of current prostheses that omitted many functions of lubricant and joint capsule. The new structure was composed of three components: therapeutic lubricant, artificial joints and artificial joint capsule. The lubricant sealed by capsule not only can reduce the wear of artificial joints but also can prohibit the wear particles leaking to the body liquid. So the unwilling reactions between the wear particles and liquid may be avoided completely. Meanwhile, a three-dimensional (3-D) finite element analysis (FEA) model was created for the bionic artificial joints with joint capsule. The effects of capsule thickness and the flexion angels on the stress values and distributions were discussed in detail.

Case Study of the Effect of Generator Retaining Ring Shrink Fit on Rotor Tooth Top Cracking

2011 ◽  
Author(s):  
Daniel T. Peters ◽  
Kevin M. Haley
Keyword(s):  
Three Dimensional ◽  
Cyclic Fatigue ◽  
Shear Stresses ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Retaining Ring ◽  
Rotor Tooth ◽  
Three Dimensional Finite Element ◽  
Shrink Fit

A significant concern in generator operation is cracking in the tops of the rotor teeth due to cyclic fatigue. The shrink fit of a retaining ring over the rotor end induces compressive stresses in the rotor to contain the entire assembly and reduce shear stresses in the rotor teeth during operation. This paper is a case study of the effect of this shrink fit on fatigue life using three dimensional finite element analysis with nonlinear contact to simulate the interaction between the rotor, wedges and retaining ring. For the analysis, consideration was made for both operational and shut down loading to determine the stress state in both conditions for application in fatigue analysis. Overspeed conditions were not considered for this analysis.

Three-Dimensional Modeling and Simulation of a Falling Electronic Device

2006 ◽  
Vol 2 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Hua Shan ◽  
Jianzhong Su ◽  
Jiansen Zhu ◽  
Leon Xu
Keyword(s):  
Rigid Body ◽  
Electronic Device ◽  
Impact Load ◽  
Three Dimensional ◽  
The Body ◽  
Contact Dynamics ◽  
Model Verification ◽  
Multiple Impacts ◽  
Element Analysis ◽  
The Impact

This article focuses on a realistic mathematical model for multiple impacts of a rigid body to a viscoelastic ground and its comparison to theoretic results. The methodology is used to study impact on an electronic device. When an electronic device drops to the floor at an uneven level, the rapid successions of impact sequence are important for their shock response to internal structure of the devices. A three-dimensional, continuous contact, computational impact model has been developed to simulate a sequence of multiple impacts of a falling rigid body with the ground. The model simulates the impact procedure explicitly and thus is capable of providing detailed information regarding impact load, impact contact surface, and the status of the body during the impact. For the purposes of model verification, we demonstrate the numerical simulation of a falling rod problem, in which the numerical results are in good agreement with the analytic solutions based on discrete contact dynamics impact models. It is indicated by the numerical experiments that simultaneous impacts occurred to multiple locations of the body and that subsequent impacts might be larger than initial ones due to different angles of impact. The differential equation-based computational model is shown to be realistic and efficient in simulating impact sequence and laid a foundation for detailed finite element analysis of the interior impact response of an electronic device.

Finite Element Analysis and Structure Design for Chassis of Aircraft Towbarless Tractor

2011 ◽  
Vol 328-330 ◽  
pp. 690-694
Author(s):  
Zhi Wei Xing ◽  
Yong Lv ◽  
Jun Hui Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Structure Design ◽  
The Body ◽  
Element Analysis ◽  
Future Design ◽  
Ground Support ◽  
Three Dimensional Modeling ◽  
Entire Vehicle

Aircraft tow-tractor is one of the absolutely necessary ground support equipments (GSE) in the airport. The chassis is the framework on which the body and working parts of the tow-tractor, what plays a significant role in a entire vehicle design. The endurance and rigidity of the chassis have a direct influence on the reliability and practicability. In this paper, a simplified model is established for the carriage of aircraft towbarless tractor on the three-dimensional modeling platform--Proe5.0, and then mechanical finite element analysis are proceeding by Ansys12.0. The results show that the chassis model is of a appropriate structure and the design coincides with actual requirements, the Stress Concentration at the joint between carriage and wheel-grip mechanism has been reduced substantially. All trial results have laid a foundation for future design of the entire tractor.

Tire Contact Stresses and Their Effects on Instability Rutting of Asphalt Mixture Pavements: Three-Dimensional Finite Element Analysis

2003 ◽  
Vol 1853 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Marc Novak ◽  
Bjorn Birgisson ◽  
Reynaldo Roque
Keyword(s):  
Asphalt Mixture ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Shear Stresses ◽  
Element Analysis ◽  
Surface Shear ◽  
Near Surface ◽  
Vertical Loading ◽  
Stress States

Instability rutting generally occurs within the top 2 in. of the asphalt layer when the structural properties of the asphalt concrete are inadequate to resist the stresses imposed on it. Several researchers have presented observations in attempts to explain instability rutting, but a clear identification of the mechanism does not exist. Stresses in the asphalt layer caused by measured tire interface stresses were analyzed in three dimensions by using finite elements to identify possible mechanisms for instability rutting. The analysis showed that radial tires produce high near-surface shear stresses at low confinements, which are not predicted with traditional uniform vertical loading conditions, in the region where instability rutting is known to occur. The resulting shear stresses tend to be shallower than for the uniformly loaded case, and they are focused in areas where instability rutting has been observed. The observed stress states imply that the characterization of instability rutting requires testing at these low confinement (and sometimes tensile) stress states, rather than at the higher stress states typically used in the strength characterization of mixtures.

scholarly journals Influence of the occlusal contacts in formation of Abfraction Lesions in the upper premolar

2017 ◽  
Vol 20 (4) ◽  
pp. 115 ◽  
Author(s):  
Victória Luswarghi Souza Costa ◽  
João Paulo Mendes Tribst ◽  
Alexandre Luiz Souto Borges
Keyword(s):  
Three Dimensional ◽  
Cervical Region ◽  
Shear Stresses ◽  
Dimensional Model ◽  
Analysis Software ◽  
Three Dimensional Model ◽  
Finite Elements Analysis ◽  
Element Analysis ◽  
Occlusal Contact ◽  
Biomechanical Behavior

<p><strong>Objective:</strong> The aim of this study was to observe the influence of different occlusal contacts in a superior pre-molar structure using Finite Element Analysis. <strong>Material and Methods:</strong> A three-dimensional model of a superior pre-molar was designed to simulate three occlusion situations, namely central occlusion and two types of lateral occlusion contacts. The model presents enamel, dentin, a periodontal ligament and a fixation cylinder separately. All materials were considered isotropic, linear and homogeneous, and the contacts of each structure were perfectly bonded. On analysis software, a load was applied to an occlusal surface at 40° to the long axis on lateral contacts, and directed to the long axis on central occlusion contact. <strong>Results:</strong> The results were obtained in stress maps and the maximum values were then plotted in table for quantitative comparison, with the enamel concentrating more stress than dentin and the occlusal contact presenting the worst biomechanical behavior. <strong>Conclusion: </strong>Within the limitations of this study, it is possible conclude that: eccentric contacts have higher potential to develop abfraction lesions on the cervical region of teeth, thus increasing the magnitude of tensile and shear stresses.</p><p><strong>Keywords</strong></p><p>Finite Elements Analysis, Abfraction; Stress distribution; Occlusion, Premolar.</p>

scholarly journals Bedsores Management: Efficiency Simulation of a New Mattress Design

Healthcare ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1701
Author(s):  
Abdullatif Alwasel ◽  
Bandar Alossimi ◽  
Maha Alsadun ◽  
Khalid Alhussaini
Keyword(s):  
Surface Area ◽  
Three Dimensional ◽  
The Body ◽  
Absolute Amount ◽  
Body Parts ◽  
Health It ◽  
Original Design ◽  
Element Analysis ◽  
Limited Mobility ◽  
Three Dimensional Models

Bedsores, also known as pressure ulcers, are wounds caused by the applied external force (pressure) on body segments, thereby preventing blood supply from delivering the required elements to the skin tissue. Missing elements hinder the skin’s ability to maintain its health. It poses a significant threat to patients that have limited mobility. A new patented mattress design and alternative suggested designs aimed to reduce pressure are investigated in this paper for their performance in decreasing pressure. A simulation using Ansys finite element analysis (FEA) is carried out for comparison. Three-dimensional models are designed and tested in the simulation for a mattress and human anthropometric segments (Torso and Hip). All designs are carried out in solidworks. Results show that the original design can redistribute the pressure and decrease it up to 17% less than the normal mattress. The original design shows better ability to decrease the absolute amount of pressure on the body. However, increasing the surface area of the movable parts results in less pressure applied to the body parts. Thus, this work suggests changing the surface area of the cubes from 25 to 100 cm2.

Three-Dimensional Finite Element Analysis of Intervertebral Disc: Effects of In Vivo Loading Conditions and Endplate Calcification on Glucose Distributions

2010 ◽  
Author(s):  
Alicia R. Jackson ◽  
Chun-Yuh Huang ◽  
Wei Yong Gu
Keyword(s):  
Intervertebral Disc ◽  
Three Dimensional ◽  
The Body ◽  
Low Back ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Ivd Degeneration ◽  
In Vivo Loading

Degeneration of the intervertebral disc (IVD) of the spine is a common condition which has been implicated as a factor leading to low back pain. Poor nutritional supply is believed to be a primary contributor to IVD degeneration. Because the disc is the largest avascular structure in the body, cells must rely on transport of important nutrients, such as glucose and oxygen, from the surrounding vasculature in order to maintain cell viability in the disc tissue. Due to difficulty in obtaining data in vivo, theoretical modeling is a useful tool to supplement experimental results and predict in vivo conditions.

Influence of Mechanical Behavior of Adhesives on Shear Stress Distributions in the Single-Lap Adhesive Joints

2011 ◽  
Vol 306-307 ◽  
pp. 1126-1129
Author(s):  
Xiao Cong He
Keyword(s):  
Shear Stress ◽  
Mechanical Behavior ◽  
Three Dimensional ◽  
Viscoelastic Behavior ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Element Analysis ◽  
Three Dimensional Finite Element

This paper deals with the effects of mechanical behavior of adhesives on the shear stress distributions of single-lap adhesive joints under tension using the three-dimensional finite element analysis (FEA) technique. Numerical examples are provided to show the influence on the shear stresses of the joints using adhesives of different characteristics which encompass the entire spectrum of viscoelastic behavior. FEA solutions of the shear stress distributions in the adhesive layer have been obtained for four typical characteristics of adhesives. The results indicate that Young’s modulus and Poisson’s ratios of adhesives strongly affect the shear stress distributions of the joints.

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