Mechanical Behavior and Damage of Tridimensional Multilayered Ceramics-Tungsten Power Electronic Substrates

2012 ◽  
Author(s):  
Charlotte Robert ◽  
Sylvie Pommier ◽  
Stephane Lefebvre ◽  
Marion Ortali ◽  
Michel Massiot
Keyword(s):  
Stress Concentration ◽  
Mechanical Behavior ◽  
Brittle Material ◽  
Fracture Behavior ◽  
Weibull Model ◽  
Power Electronic ◽  
Stress Singularities ◽  
Statistic Model ◽  
New Applications ◽  
Electronic Substrates

Since few years a 3D electric lines is developed. But new applications will be to expose this circuit to high variation of temperature and use them for electronic power. Circuits lines are made of tungsten and insulation in alumina. These materials have different behavior. That difference implies mechanics stress and stress singularities. Some stress concentration can fracture materials or interface between them. Alumina is a brittle material. We need to know his fracture behavior. A statistic model is already used: Weibull model. The idea is to break about hundred samples and to related the probabilities to break of alumina used in the circuit versus stress.

FINITE ELEMENT ANALYSIS OF FULL-LAYER REPAIR BASED ON IMPROVED ARTICULAR CARTILAGE MODEL

2019 ◽  
Vol 19 (08) ◽  
pp. 1940066
Author(s):  
MONAN WANG ◽  
YUANXIN JI ◽  
JIAN WANG ◽  
JUNTONG JING
Keyword(s):  
Elastic Modulus ◽  
Articular Cartilage ◽  
Stress Concentration ◽  
Mechanical Behavior ◽  
Theoretical Basis ◽  
Clinical Pathology ◽  
Mechanical State ◽  
Element Analysis ◽  
Simulation Results ◽  
Selection Of

In this paper, the tangential zone of cartilage is introduced into the fiber-reinforced model of articular cartilage. Considering the distribution content of the main fiber and the secondary fiber in the tangential layer of cartilage, the permeability and fiber stiffness of the layer are set in parallel and perpendicular directions, respectively, to more accurately reflect the mechanical behavior of cartilage. The parameters are set to reflect the mechanical behavior of the cartilage more realistically. We use a modified articular cartilage model to simulate the mechanical properties of implanted cartilage with different elastic modulus. The simulation results show that the selection of implants with different elastic modulus will affect the repair of cartilage. Appropriately increasing the elastic modulus of implanted cartilage, can increase the bearing capacity of the repaired area and reduce the stress concentration at the junction. The elastic modulus of the implant should be moderate, not too large or too small, and the damage of stress concentration on the repair surface should be considered. Through simulation, the mechanical state of the repaired cartilage under pressure can be obtained comprehensively, which provides a theoretical basis for clinical pathology.

Complex Analysis of Plane Problem of Two-Dimensional Quasicrystals

2012 ◽  
Vol 236-237 ◽  
pp. 52-54
Author(s):  
Lin Yang ◽  
Qin He ◽  
Shu Yong Zhou ◽  
Wu Li
Keyword(s):  
Stress Concentration ◽  
Plane Problem ◽  
Complex Potential ◽  
Fracture Behavior ◽  
Complex Analysis ◽  
Potential Method ◽  
Two Dimensional ◽  
Complex Potential Method ◽  
Important Significance

The fracture behavior of materials and structures are always caused by stress concentration near the defects in materials. This article describes the complex potential method for solving plane problems of quasicrystalline materials with defects. In order to prove effectiveness and success of the method, an example is given, and the results have very important significance in studying two-dimensional quasicrystals.

221 Mechanical Behavior of Braided Composite with a Hole(I) : Micro Fracture Behavior

2000 ◽  
Vol 2000.8 (0) ◽  
pp. 217-218
Author(s):  
Asami NAKAI ◽  
Takeshi OHKAWA ◽  
Atsushi YOKOYAMA ◽  
Hiroyuki HAMADA
Keyword(s):  
Mechanical Behavior ◽  
Fracture Behavior ◽  
Braided Composite

Analysis Research of Frame-Supported Transfer Beam with Opening Using Finite Element

2010 ◽  
Vol 163-167 ◽  
pp. 1620-1625
Author(s):  
Ji Yao ◽  
Ze Li ◽  
Ming Jun Peng
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Mechanical Behavior ◽  
Local Stress ◽  
Weak Spot ◽  
High Rise ◽  
Finite Element Software ◽  
Weak Part ◽  
Working Performance

This paper presents research on mechanical behavior of frame-supported transfer beams with or without opening in the high-rise buildings using commercial finite element software ANSYS. The result indicated that the hole only impacted the local stress distribution of transfer beam. From the overall view, stress distribution of frame-supported transfer beam with or without opening was almost same. But hole undermined the whole working performance of transfer beam and reduced transfer beam bearing capacity. Influence of the hole as the result of the stress concentration on transfer beam maked the spot became weak part. This weak spot needed to be strengthened in the practical struction members.

scholarly journals Predicting Performance of Aluminum - Glass Composite Facade Systems Based on Mechanical Properties of the Connection

2017 ◽  
Author(s):  
Maciej Cwyl Warszawska ◽  
Andrzej Garbacz ◽  
Rafał Michalczyk ◽  
Natalia Grzegorzewska
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stress Concentration ◽  
Mechanical Behavior ◽  
Numerical Study ◽  
Field Research ◽  
Glass Composite ◽  
Predicting Performance ◽  
Metal Framework ◽  
Aluminum Panels

In this paper, an extensive Finite-Element (FE) numerical study is carried out on a glass framing with point mechanical connectors. The models have been calibrated based on literature studies and field research. The simulations have been performed in order to assess the mechanical behavior of the examined glass-aluminum panels. In frame-support glass structures, such as curtain walls, where glass plates are mounted onto a metal framework, the composite behavior between glass and the supporting aluminum elements is usually a problem. It has been showed that an application of elastomer gaskets decreases the stress concentration at the interface between aluminum and glass while does not significantly change the working scheme of the profile. Based on the proposed models, the failure mechanism for wider set of geometrical configurations can be analyzed.

Effect of Die Chip-Outs and Reflow Temperature on the Mechanical Behavior of a 5-Die-Stacked Chip Scale Package

2007 ◽  
Author(s):  
Dennis Evan ◽  
L. Balacano ◽  
Lito P. De La Rama
Keyword(s):  
Stress Concentration ◽  
Mechanical Behavior ◽  
Failure Mechanism ◽  
Mechanical Model ◽  
Fracture Analysis ◽  
Active Area ◽  
Corner Crack ◽  
Reflow Temperature ◽  
Chip Scale Package ◽  
Corrective Actions

Abstract During package qualification, a 5-die-stacked chip scale package was being marginally triggered on high stand-by current collectively known as Power ICCS failure. Affected lots are subjected to 3x reflow at 240°C. Post reflow failures include blown_up, high standby current in Vcc pin (ISBLO), and high standby current in Vccq pin (ISBLOQ). Backside chip-outs are observed on Die 1 and Die 3 of the three failures. Electrical validation showed that only Die 3 is failing. Corner crack on Die 3 is common to the blown_up and ISBLO failing units while crack on Die 3 backside is observed to propagate toward the active area on ISBLOQ failing units. Fracture analysis results show that the crack of the three failures all originated from die backside chip-out. Thermo-mechanical model of the package shows that, by design, Die 3 generates the highest stress concentration. Results show that if chip-outs are present on the area of the die with the highest stress concentration and the unit is subjected to reflow temperature of 240°C, die crack will propagate from the chip-out. This paper presents the unique failure mechanism observed on a 5-die-stacked chip scale package and the corrective actions applied to solve the issue.

scholarly journals On Fracture Behavior of Disk Made of Brittle Material under Impact Load

1977 ◽  
Vol 43 (373) ◽  
pp. 3218-3226
Author(s):  
Juhachi ODA ◽  
Kouetu YAMAZAKI ◽  
Katuhiko KOSHINO ◽  
Osamu KUROYANAGI
Keyword(s):  
Brittle Material ◽  
Fracture Behavior ◽  
Impact Load
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