Finite elements modelling of cracking in pavements

2004 ◽  
pp. 96-105
Keyword(s):  
Finite Elements ◽  
Finite Elements Modelling

Finite Elements Modelling of Elastoplastic Structures Using Self-Consistent Constitutive Relation

1991 ◽  
pp. 659-662
Author(s):  
E. Scacciatella ◽  
J. M. Genevaux ◽  
P. Lipinski ◽  
M. Berveiller ◽  
J. M. Detraux ◽  
...  
Keyword(s):  
Finite Elements ◽  
Constitutive Relation ◽  
Self Consistent ◽  
Finite Elements Modelling

scholarly journals Analysis of some key aspects of soil/foundation interaction-Finite elements modelling

2018 ◽  
Vol 149 ◽  
pp. 02019
Author(s):  
Hamidi Ahmed ◽  
Bouafia Ali
Keyword(s):  
Finite Elements ◽  
Threshold Value ◽  
Shallow Foundation ◽  
Threshold Distance ◽  
Saturated Clay ◽  
Foundation Base ◽  
Soil Foundation ◽  
Finite Elements Modelling ◽  
Key Aspects ◽  
Strip Footings

This paper is aimed to contribute to the analysis of three important aspects of soil-foundation interaction, which are not clearly investigated, by means of a detailed parametric study based on a finite elements modelling. The first aspect focuses on the effect of the bedrock proximity on the load-settlement behaviour of a continuous or circular shallow foundation. It was found there exists a threshold distance between the foundation base and the top of the bedrock layer beyond which the foundation behaves as in an infinitely deep medium. The second one deals with the behaviour of shallow foundation on a bi-layered soil where the effect of the underlying layer on the bearing capacity as well as on the settlements depends on the distance between the foundation base and the top of the underlying layer, and beyond a threshold value this effect vanishes. The third aspect studied was the interference between two strip footings installed on saturated clay. It was shown within a threshold distance between these foundations, an important modification of the foundation behaviour may occur. Finally, the numerical results were fitted and interpreted which allowed suggesting simple practical formulae for shallow foundations design.

TN X SN Fatigue Curves for KS Hook and Chain Using Finite Elements Modelling and Model Test

2007 ◽  
Author(s):  
Jose´ Carlos Lima de Almeida ◽  
Ronaldo Rosa Rossi ◽  
Ricardo Sobral
Keyword(s):  
Finite Elements ◽  
Model Test ◽  
Fatigue Curve ◽  
Functional Condition ◽  
Mooring Line ◽  
Hardness Profile ◽  
Mooring Lines ◽  
Finite Elements Modeling ◽  
Predicting Behavior ◽  
Finite Elements Modelling

The new scenario of oil exploration in ultra deep water moves forward to 3000 m, has been putting for the companies that accept this technological challenger significant, border of the techno-scientific knowledge. Therefore, nowadays in this case of ultra deep waters, where the forces above the mooring lines are increase and the use of the new material in Petrobras Floating Production Units, it is necessary the good numerical analyses and experimental test by the mooring line. It appears the need to look for a solution for the problems according to the changes of the polyester rope in the production platform without the bottom extension change and its foundation (fixed point). According to this challenge it was necessary to develop a remote connection and disconnection device. This device is the KS hook and its optimization has been created using the fracture mechanical conception optics and computers tools (FEM and mooring software). There are two conditions to develop this device: one condition is functional and the other is structural. For the functional condition, it’s necessary to create the facilities for handling and installations. For the structural conditions, it is necessary to use the special wrought steel material, treatment for steel characteristic and right geometry. Finite Elements Modeling analyze used the Ansys software, considered the hardness profile material for Minimum Break Load (MBL). The lifetime design is about 25 years for this case and the fatigue analysis considered the residual stress and plasticity for structural device. Previous simulation is especially important in predicting behavior and in the development of new design products before testing. The model was meshed with 3D first order tetrahedral elements solid45. The mesh was sufficiently fine to ensure minimal loss of accuracy in curved geometry. There isn’t a TN fatigue curve (reference API Fatigue curves) for this KS Hook device geometry, in this case become necessary to use the model test to obtain this curve with the extrapolation of the results. The Finite Elements Modeling analyze used with the Material SN Fatigue curve will be used for this validation. Previous simulation is especially important in predicting behavior and in the development of new design products before testing.

Lifetime and Reliability Assessment of AlN Substrates Used in Harsh Aeronautic Environments Power Switch Modules

2010 ◽  
Vol 112 ◽  
pp. 113-127 ◽  
Author(s):  
Adrien Zéanh ◽  
Olivier Dalverny ◽  
Moussa Karama ◽  
Arezki Bouzourene
Keyword(s):  
Finite Elements ◽  
External Loading ◽  
Principal Stresses ◽  
Ceramic Substrates ◽  
Ceramic Fracture ◽  
Bending Tests ◽  
Weakest Link ◽  
Power Switch ◽  
Finite Elements Modelling ◽  
Switch Module

This paper presents a Finite Elements Modelling (FEM) based methodology dedicated to the evaluation of the lifetime and the reliability of assemblies involving brittle materials under cyclic loading. It focuses on the particular case of metal bonded Aluminium Nitride (AlN) substrates used in power electronic switch modules. The ceramic fracture criterion was formulated according to the weakest link concept, under Weibull's approach. The material's parameters were determined by running three points bending tests. In order to check the relevancy of the proposed methodology, a non linear thermomechanical Finite Elements Model allowed computing the number of thermal cycles before substrate brittle fracture within a test vehicle, which was then compared to experimental results. Once validated, the methodology was applied to two different configurations of a power switch module, designed for harsh environment aeronautic applications. The corresponding external loading profile was considered to compute and monitor the evolution of the maximal principal stresses within the ceramic substrates whole volumes. Their lifetimes and reliabilities was finally assessed and compared to the applications requirements.

Comparison of Several Behaviour Laws Intended to Produce a Realistic Ti6Al4V Chip by Finite Elements Modelling

2015 ◽  
Vol 651-653 ◽  
pp. 1197-1203 ◽  
Author(s):  
François Ducobu ◽  
Pedro José Arrazola ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi
Keyword(s):  
Finite Elements ◽  
Strain Softening ◽  
Chip Morphology ◽  
Cutting Parameters ◽  
Realistic Model ◽  
Extreme Conditions ◽  
Finite Elements Modelling ◽  
Behaviour Law ◽  
Experimental Reference ◽  
Key Parameter

The final aim of finite elements modelling is to help in the choice of the cutting parameters and in the comprehension of the involved phenomena. Representing correctly the behaviour of the machined material is hard due to the extreme conditions encountered, although this is a key parameter to develop a realistic model. Four laws are used in this paper to represent the Ti6Al4V. They are all based on the Johnson-Cook law. This study shows that the influence of the behaviour law is high on the chip morphology and on the forces and that the strain softening phenomenon should be taken into account. For the cutting conditions adopted, it is however necessary to add damage properties in the chip to obtain a morphology and a cutting force evolution close to the experimental reference.

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