Investigation of thermo-mechanically induced stress in a PQFP 160 using finite element techniques

2003 ◽  
Author(s):  
G. Kelly ◽  
C. Lyden ◽  
C. O'Mathuna ◽  
J.S. Campbell
Keyword(s):  
Finite Element ◽  
Induced Stress

Study of Electromigration-Induced Stress of Solder

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Fei Su ◽  
Zheng Zhang ◽  
Yuan Wang ◽  
Weijia Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Temperature Gradient ◽  
Inelastic Deformation ◽  
Comprehensive Evaluation ◽  
Vacancy Concentration ◽  
Fem Model ◽  
Induced Stress ◽  
Simulation Results ◽  
Solder Reliability

This study designed and produced a special microsolder specimen (Sn3.8Ag0.7Cu) to equalize current density under stressing. The specimen was generated to avoid temperature gradient and thermal migration. The inelastic deformation of the solder with electromigration (EM) alone was then measured with moiré interferometry. In addition, the EM-induced solder stress was evaluated using a finite element method (FEM). The precision of the FEM model was verified by comparing the simulated results with the experimental results with respect to EM-induced deformation. Findings indicated that the maximum spherical stress in the solder can reach 50 MPa. Moreover, the vacancy concentration is much higher on the cathode end than on the anode end. The simulation results can illustrate the failure mode of a solder and can therefore provide a basis for the comprehensive evaluation of solder reliability under EM.

scholarly journals Finite Element Modelling of Shock-Induced Damages on Ceramic Hip Prostheses

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Juliana Uribe ◽  
Jérôme Hausselle ◽  
Jean Geringer ◽  
Bernard Forest
Keyword(s):  
Finite Element ◽  
Probability Of Failure ◽  
Element Analysis ◽  
Worst Case ◽  
Hip Prostheses ◽  
Induced Stress ◽  
Mechanical Shocks ◽  
Prosthetic Head ◽  
Abaqus Software ◽  
Good Agreement

The aim of this work was to simulate the behaviour of hip prostheses under mechanical shocks. When hip joint is replaced by prosthesis, during the swing phase of the leg, a microseparation between the prosthetic head and the cup could occur. Two different sizes of femoral heads were studied: 28 and 32 mm diameter, made, respectively, in alumina and zirconia. The shock-induced stress was determined numerically using finite element analysis (FEA), Abaqus software. The influence of inclination, force, material, and microseparation was studied. In addition, an algorithm was developed from a probabilistic model, Todinov's approach, to predict lifetime of head and cup. Simulations showed maximum tensile stresses were reached on the cup's surfaces near to rim. The worst case was the cup-head mounted at 30°. All simulations and tests showed bulk zirconia had a greater resistance to shocks than bulk alumina. The probability of failure could be bigger than 0.9 when a porosity greater than 0.7% vol. is present in the material. Simulating results showed good agreement with experimental results. The tests and simulations are promising for predicting the lifetime of ceramic prostheses.

scholarly journals Estimate of induced stress during filling and discharge of metallic silos for cement storage

DYNA ◽  
2015 ◽  
Vol 82 (194) ◽  
pp. 238-246
Author(s):  
Wilmer Bayona-Carvajal ◽  
Jairo Useche
Keyword(s):  
Finite Element ◽  
Structural Analysis ◽  
Detailed Analysis ◽  
Model Development ◽  
Sheet Thickness ◽  
Parametric Model ◽  
Shell Elements ◽  
Finite Element Software ◽  
Induced Stress ◽  
Is Development

The present article show the structural analysis realized to metallic silo for storage cement through of the parametric model development in the finite element software ASNYS APDL, the fill and discharge pressures applied on the silo wall is determined with the Eurocode normative EN 1991-4.The model is development with type shell elements allowing that the structure silo fits to the cylindrical and conical geometric of the silo. It explains each of the phases having the development of the model and is made a detailed analysis of the results delivered by the software; different models are evaluated changing the sheet thickness for select the most appropriate. Also the results are analyzed when be changing the tilting the hopper and is reviewed the behavior of the silo when is analyzed with its structure.

Rotordynamics of a Highly Flexible Hub for Inside-Out Ceramic Turbine Application: Finite Element Modeling and Experimental Validation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Céderick Landry ◽  
Patrick K. Dubois ◽  
Jean-Sébastien Plante ◽  
François Charron ◽  
Mathieu Picard
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
High Speed ◽  
Radial Displacement ◽  
Experimental Validation ◽  
Angular Position ◽  
Relative Displacement ◽  
Element Modeling ◽  
Induced Stress ◽  
Inside Out

The inside-out ceramic turbine (ICT) is a promising concept to increase turbine inlet temperatures in microturbines by integrating individual monolithic ceramic. This architecture uses a carbon–polymer composite rim to support the blades mainly in compression. High tangential velocities lead to elevated radial displacement of the rim, and therefore, the rotor hub needs to have sufficient compliance to follow this radial displacement. However, the rotordynamics of a flexible hub is not widely understood. This paper presents the rotordynamic analysis of a highly flexible hub for an ICT architecture. Finite element modeling (FEM) is used to design a simplified turbine prototype that maximizes the hub flexibility to explore the limits of the concept. The rotordynamics behavior of the highly flexible hub is measured by spinning a 171-mm diameter prototype up to 49 krpm. This paper highlights three principal challenges of this particular rotordynamics. First, critical speeds mode shape becomes highly coupled with bearings displacement, shaft bending, and hub deformation. At high-speed, the hub deforms out of phase with the shaft, which can cause high stresses in the hub. Second, the angular position between unbalance masses of the flexible hub and the composite rim changes the unbalance response significantly. Finally, vibration causes high stresses in the hub, due to the relative displacement between the composite rim and the shaft, which could lead to failure of the hub. Nevertheless, the rotordynamics of an ICT configuration is manageable as long as the vibration-induced stress in the hub is kept under its limit.

scholarly journals Subsection Forward Modeling Method of Blasting Stress Wave Underground

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Bo Yan ◽  
Xinwu Zeng ◽  
Yuan Li
Keyword(s):  
Finite Element ◽  
Stress Wave ◽  
Source Region ◽  
Stress Waves ◽  
Nonlinear Finite Element ◽  
Stress Wave Propagation ◽  
Local Structures ◽  
Nonlinear Responses ◽  
Induced Stress ◽  
Material Nonlinear

The generation of stress waves induced by explosions underground is governed by material nonlinear responses of materials surrounding explosions and affected by source region mediums and local structures. A nonlinear finite element (NFE) method can simulate the generation efficiently. However, the calculation using the NFE to observational distances, where motions are elastic, is computationally challenging. In order to tackle this problem, we present a subsection numerical simulating method for forward modelling the generation and propagation of stress waves with a hybrid method coupling the NFE and a linear finite element (LFE). The subsection idea is developed based on previous works; calculating steps of the subsection method as well as techniques of passing motions from a source region to an elastic region are discussed. 3D numerical simulations of stress wave propagation in rock generated by decoupled explosion underground with two methods for comparison are carried out. The accuracy of the subsection method is demonstrated with simulated results. The demand of PC memory and the calculating time are investigated. The subsection method provides another approach for modeling and understanding the generation and propagation of explosion-induced stress waves, though, currently, studies are preliminary.

scholarly journals Three-Dimensional Finite Element Study on Lithium Diffusion and Intercalation-Induced Stress in Polycrystalline LiCoO2 Using Anisotropic Material Properties

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Linmin Wu ◽  
Jing Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Phase Field ◽  
Three Dimensional ◽  
Stress Generation ◽  
Diffusion Pathway ◽  
Finite Element Study ◽  
Induced Stress ◽  
Anisotropic Mechanical Properties ◽  
Element Study

In this study, lithium (Li) intercalation-induced stress of LiCoO2 with anisotropic properties using three-dimensional (3D) microstructures has been studied systematically. Phase field method was employed to generate LiCoO2 polycrystals with varying grain sizes. Li diffusion and stresses inside the polycrystalline microstructure with different grain size, grain orientation, and grain boundary diffusivity were investigated using finite element method. The results show that the anisotropic mechanical properties and Li concentration-dependent volume expansion coefficient have a very small influence on the Li chemical diffusion coefficients. The low partial molar volume of LiCoO2 leads to this phenomenon. The anisotropic mechanical properties have a large influence on the magnitude of stress generation. Since the Young's modulus of LiCoO2 along the diffusion pathway (a–b axis) is higher than that along c–axis, the Li concentration gradient is larger along the diffusion pathway. Thus, for the same intercalation-induced strain, the stress generation will be higher (∼40%) than that with isotropic mechanical properties as discussed in our previous study (Wu, L., Zhang, Y., Jung, Y.-G., and Zhang, J., 2015, “Three-Dimensional Phase Field Based Finite Element Study on Li Intercalation-Induced Stress in Polycrystalline LiCoO2,” J. Power Sources, 299, pp. 57–65). This work demonstrates the importance to include anisotropic property in the model.

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