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.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Effects of convection in laser-guided transportation

2004 ◽  
Vol 218 (7) ◽  
pp. 775-782
Author(s):  
L Chen ◽  
Y Yan ◽  
R Zhang
Keyword(s):  
Laser Beam ◽  
Three Dimensional ◽  
Biological Research ◽  
Convection Flow ◽  
Direct Write ◽  
Laser Guidance ◽  
Element Analysis ◽  
Research Areas ◽  
Fea Model ◽  
Set Up

Weak focusing laser beams can guide micrometre-sized beads to direct-write two-dimensional patterns or three-dimensional structures. Applications based on laser guidance have been found in many fields including biological research areas. This paper discusses the effects of convection, which is the main disturbance during laser-guided transportation. The heat generated by optical absorption causes the convection flow, as observed in experiments. To investigate this convection flow, a finite element analysis (FEA) model was set up and computation under different heat load conditions was carried out. The results show that the convection flow velocity at the laser beam centre has a direct proportional relation to the incident power and varies with the position of the laser beam.

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.

Numerical Investigation on Suction Pile’s Holding Capacity Installed in Carbonate-Type Soils

2020 ◽  
Author(s):  
Jianchun Cao ◽  
Zhibin Zhong ◽  
Ashish Budhiraja
Keyword(s):  
Skin Friction ◽  
Three Dimensional ◽  
Sensitivity Study ◽  
Element Analysis ◽  
Low Level ◽  
Total Displacement ◽  
Fea Model ◽  
Displacement Vectors ◽  
Three Dimensional Finite Element ◽  
Different Levels

Abstract Suction piles have not been widely used in carbonate-type soils (i.e., muds/silts) because the pile skin frictions in this type of soils are only about 5% of that in normal clayey soils. The holding capacity of a suction pile installed in these types of soils may be affected by its lower friction. Moreover, pile designers have concerns not only on the development of the Reverse End Bearing (REB) but also on how long the REB can sustain. This paper presents the development of a three-Dimensional Finite Element Analysis (3D FEA) model and the analysis results to investigate the behavior of suction pile for different levels of skin frictions. Firstly, the FEA model is used to investigate the development of the Reverse End Bearing (REB) of a suction pile by assigning two different levels of pile external skin frictions, i.e., 5% and 100% (full skin friction). A vertical load is applied at the center of the pile top. Secondly, the FEA model is used to investigate the behavior of a suction pile for a very low level of pile skin friction (i.e., 5% skin friction). An inclined load with various load angles from horizontal is applied at the padeye (i.e., 16m below seabed). Thirdly, the load carrying (failure) mechanism has been checked by examining the total displacement vectors of soil masses around the pile. Fourthly, a sensitivity study is carried out to investigate the capacity of a suction pile for different usage factors of REB. Finally, suction pile design requirements for carbonate-type soils (i.e., low level of pile skin frictions) are recommended.

Structural Integrity Assessment Criteria and Service Life Prediction of Cold Wrinklebends

2012 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Brian N. Leis
Keyword(s):  
Finite Element ◽  
Service Life ◽  
Structural Integrity ◽  
Pipeline Steel ◽  
Three Dimensional ◽  
Computation Time ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Fea Model ◽  
Hardening Models

Three-dimensional elastic-plastic finite element analysis (FEA) is performed in this paper to simulate the complicated stresses and deformation of wrinklebends in a pipeline from its bending formation to operation under cyclic loading. Three plastic hardening models (isotropic, kinematic and combined isotropic/kinematic) are discussed and used in FEA of wrinklebend response that considers strain hardening and Bauschinger effects. The FEA simulation is carried out first for an elbow held at constant pressure while subject to cyclic bending, which serves as a benchmark case. The results show that the three hardening models lead to very different outcomes. Comparable FEA simulations are then developed for wrinklebends under cyclic pressure. Detailed parametric analysis is considered, including finite-element type, element sensitivity, computation time, and material input data. Based on those results viable nonlinear FEA model is developed as the basis to quantify wrinklebend response under service-like conditions. Based on the FEA results, fatigue damage is quantified using the Smith, Watson and Topper (SWT) parameter, and thereafter a damage criterion is proposed to predict the fatigue life of a wrinklebend under the pressure cycles of 72%–10% of SMYS for typical X42 pipeline steel. The results show that the wrinkle aspect ratio H/L is a key parameter to control the service life of a wrinklebend.

Finite Element Modeling and Quantification of Mechanical Damage Severity in Pipelines

2016 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Brian N. Leis
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Pipeline Steel ◽  
Three Dimensional ◽  
Mechanical Damage ◽  
Failure Behavior ◽  
Element Analysis ◽  
Fea Model ◽  
Transmission Pipeline ◽  
Element Type

Mechanical damage is one of the major threats to oil and gas transmission pipeline integrity, which has been the case now for decades. Although much work has been done in that context, due to the complexity of its effects mechanical damage severity remains difficult to quantify. Thus, work continues to better understand the failure mechanism and develop the means to screen damage severity. The present paper adopts a validated elastic-plastic finite element analysis (FEA) model to simulate mechanical dents in pipelines and to quantify the effects of damage through a broad parametric study. This considers the need for three-dimensional FEA models and the effects of FEA element type, soil constraint condition, indenter type, pipeline grade and initial pipe pressure on dent response. The FEA model is also used to assess the minimum wall thickness for which a dent has the minimal effect on pipeline integrity. Finally, application of the proposed FEA model is illustrated by successfully predicting the failure behavior of a dent in a full-scale fatigue test involving a modern pipeline steel.

Evaluation of UHMWPE Component under Various Positions for UKA

2008 ◽  
Vol 594 ◽  
pp. 72-77 ◽  
Author(s):  
Chien Wei Liu ◽  
Wen Lung Li ◽  
Chen Tung Yu ◽  
Chia Chi Lo
Keyword(s):  
Finite Element Analysis ◽  
Tibial Component ◽  
Tibial Plateau ◽  
Positional Error ◽  
Artificial Joint ◽  
Positioning Error ◽  
Knee Prostheses ◽  
Element Analysis ◽  
Artificial Joints ◽  
Unicompartmental Knee

The development of artificial joints is now considered quite mature, and the main treatment for osteoarthritis. However, in recent unicompartmental knee arthroplasty (UKA) clinical follow-ups, complications due to wear of polyethylene (PE) tibial components still exist. Therefore, this study focused on the possibility of avoiding and minimizing damage to the PE tibial component. Currently, the most common problem in the application of UKA is the malresection of the tibial plateau, often resulting in malpositioning of the tibial implant. This positioning problem may be the main reason for advanced wear and dislocation of a PE tibial component. In this study, finite element analysis (FEA) was used to study the stress change of malpositioned PE tibial components in order to better understand the damaging mechanism on PE tibial components. It was found that anatomically designed unicompartmental knee prostheses (UKP) allowed more positioning error in varus tilt than symmetrically designed ones. And both should avoid any positional error greater than 10° valgus tilt. Otherwise, increased wear of PE tibial components would result in shortened lifetime of the artificial joint.

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.

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.

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