Cyclic and Residual Stresses Generated in the UHMWPE Component of Total Knee Replacements During the Walking Cycle

1999 ◽  
Author(s):  
Raghu N. Natarajan
Keyword(s):  
Residual Stresses ◽  
Failure Modes ◽  
Contact Region ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Element Model ◽  
Clear Understanding ◽  
Dimensional Finite Element ◽  
Total Knee ◽  
Three Dimensional Finite Element

Abstract Fatigue due to cyclic stresses is one of the predominant failure modes seen in retrieved tibial polyethylene components. There is no clear understanding of the influence of knee kinematics on wear seen in retrieved samples. Magnitude, direction and location of the contact load at the tibial surface were taken from the measurement obtained from gait analysis of a patient with a total knee replacement and was input into a three dimensional finite element model of a tibial component. The analyses showed that stress fluctuations and stress reversals occur both on the surface and just below the surface in the posterior region of the component. Residual stresses were produced due to plastic deformation in the posterior contact region of the component.

Behaviour of concrete block masonry prisms under axial compression

1995 ◽  
Vol 22 (5) ◽  
pp. 898-915 ◽  
Author(s):  
E. H. Fahmy ◽  
T. G. M. Ghoneim
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Modulus Of Elasticity ◽  
Failure Modes ◽  
Three Dimensional ◽  
Concrete Block ◽  
Element Model ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A nonlinear three-dimensional finite element model was developed to study the complex behavior of ungrouted and grouted concrete block masonry prisms under axial compression. The model detects crack initiation and traces crack propagation in the masonry assemblage. Variable strengths for blocks, mortar, and grout were used to study the effect of the mechanical properties of prism constituents, and their combinations, on the prism strength and modulus of elasticity. The effect of the number of courses was also investigated. The results of the finite element analysis were used to develop simplified relationships to predict prism strength and modulus of elasticity. Good agreement was observed between the available experimental data and the predicted prism strengths. Key words: compressive strength, concrete blocks, failure modes, finite element, masonry, modulus of elasticity, prisms.

Effect of Temperature Variation on the Service Life of a Riveted Joint

2015 ◽  
Author(s):  
Gurinder Singh Brar ◽  
Yogeshwar Hari ◽  
Akhil Deep Ayri
Keyword(s):  
Residual Stress ◽  
Service Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Element Model ◽  
Effect Of Temperature ◽  
Riveted Joint ◽  
Minimum Residual ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Rivets are widely used as a means of fastening in airframe construction industry. Among the other types of fasteners riveted joints are preferred in such applications due to their permanence after installation and their economical advantages. In a riveted joint, it is known that residual stresses are present as a result of the installation process. Furthermore, during the flight of an aircraft, the fuselage comes across pressurization and depressurization cycle. During one flight pressurization-depressurization cycle is completed and such cycles are repeated throughout the service life of the aircraft. As a result, the panels and the rivets are subjected to fatigue type loading. The integrity of the joint must be maintained against this combination of service loads and the residual stresses. The present study is aimed to develop and analyze three-dimensional finite element model of riveted lap, and then the numerical analysis (SolidWorks Simulation) are carried out to calculate the residual stress values and fatigue values in the riveted lap joint under the effect of varying temperature. The result shows that the fatigue life varies inversely proportion to residual stresses whereas damage varies directly proportion to residual stresses. The maximum residual stress obtained is 292 MPa at temperature of 150°C and the minimum residual stress obtained is 15 MPa at temperature of −50°C. Maximum damage is 60% at 150°C and minimum is 8% at −50°C. Maximum life is 234346 cycles at −50°C and minimum life is 33111 cycles at 150°C.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

Process Modeling in Laser Deposition of Multilayer SS410 Steel

2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli
Keyword(s):  
Phase Transformation ◽  
Temperature Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Traverse Speed ◽  
Processing Parameters ◽  
Dimensional Finite Element ◽  
Net Shaping ◽  
Three Dimensional Finite Element ◽  
Continuous Cooling Transformation Diagram

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.

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