Immortal InterConnects—Prevent Cracking and Limit Void Size

1999 ◽  
Vol 563 ◽  
Author(s):  
Z. Suo ◽  
Q. Ma ◽  
W. K. Meyer
Keyword(s):  
High Pressure ◽  
Stress State ◽  
Tensile Stress ◽  
Electric Current ◽  
Contact Area ◽  
Electrical Resistance ◽  
Processing Temperature ◽  
Thermal Contraction ◽  
Temperature Differential ◽  
Void Size

AbstractThis paper considers an aluminum line in a multilevel interconnect structure. Upon cooling from the processing temperature, differential thermal contraction causes a triaxial tensile stress state in the aluminum line; voids may initiate and grow to relax the stress. When a direct voltage is applied, the electric current causes aluminum atoms to diffuse. The interconnect will evolve to a state with a high pressure at the anode, and a large void at the cathode. The pressure may crack the surrounding insulator or debond an interface, extruding aluminum. The void may uncover the via contact area, substantially increasing electrical resistance. Provided neither failure mode occurs, aluminum electromigration will stop and the interconnect will function forever. This paper examines the conditions under which the interconnect is immortal.

scholarly journals Discrete Element Analysis of High-Pressure Zones of Sea Ice on Vertical Structures

2021 ◽  
Vol 9 (3) ◽  
pp. 348
Author(s):  
Xue Long ◽  
Lu Liu ◽  
Shewen Liu ◽  
Shunying Ji
Keyword(s):  
High Pressure ◽  
Sea Ice ◽  
Failure Mode ◽  
Contact Area ◽  
Loading Rate ◽  
Discrete Element ◽  
Offshore Platforms ◽  
Marine Structures ◽  
Element Analysis ◽  
Ice Pressure

In cold regions, ice pressure poses a serious threat to the safe operation of ship hulls and fixed offshore platforms. In this study, a discrete element method (DEM) with bonded particles was adapted to simulate the generation and distribution of local ice pressures during the interaction between level ice and vertical structures. The strength and failure mode of simulated sea ice under uniaxial compression were consistent with the experimental results, which verifies the accuracy of the discrete element parameters. The crushing process of sea ice acting on the vertical structure simulated by the DEM was compared with the field test. The distribution of ice pressure on the contact surface was calculated, and it was found that the local ice pressure was much greater than the global ice pressure. The high-pressure zones in sea ice are mainly caused by its simultaneous destruction, and these zones are primarily distributed near the midline of the contact area of sea ice and the structure. The contact area and loading rate are the two main factors affecting the high-pressure zones. The maximum local and global ice pressures decrease with an increase in the contact area. The influence of the loading rate on the local ice pressure is caused by the change in the sea ice failure mode. When the loading rate is low, ductile failure of sea ice occurs, and the ice pressure increases with the increase in the loading rate. When the loading rate is high, brittle failure of sea ice occurs, and the ice pressure decreases with an increase in the loading rate. This DEM study of sea ice can reasonably predict the distribution of high-pressure zones on marine structures and provide a reference for the anti-ice performance design of marine structures.

Electrical resistance of iodine-doped C60 under high pressure

1992 ◽  
Vol 82 (8) ◽  
pp. 605-607 ◽  
Author(s):  
Y. Akahama ◽  
M. Kobayashi ◽  
H. Kawamura ◽  
H. Shinohara ◽  
H. Sato ◽  
...  
Keyword(s):  
High Pressure ◽  
Electrical Resistance

Optical microscopic, X-ray diffraction, and electrical resistance studies of CuCl at high pressure

1979 ◽  
Vol 32 (4) ◽  
pp. 275-279 ◽  
Author(s):  
G.J. Piermarini ◽  
F.A. Mauer ◽  
S. Block ◽  
A. Jayaraman ◽  
T.H. Geballe ◽  
...  
Keyword(s):  
High Pressure ◽  
Electrical Resistance ◽  
X Ray Diffraction ◽  
X Ray

Thermal stress state of cryogenic high-pressure vessels during chilling and pressurization. Report no. 1. Method of calculation

1986 ◽  
Vol 18 (1) ◽  
pp. 87-92
Author(s):  
A. S. Tsybenko ◽  
B. A. Kuranov ◽  
A. D. Chepurnoi ◽  
V. A. Shaposhnikov ◽  
N. G. Krishchuk
Keyword(s):  
High Pressure ◽  
Thermal Stress ◽  
Stress State ◽  
Pressure Vessels ◽  
Thermal Stress State ◽  
Method Of Calculation

Determination of the Biaxial Anisotropy Coefficient Using a Single Layer Sheet Metal Compression Test

2021 ◽  
Vol 883 ◽  
pp. 303-308
Author(s):  
Peter Hetz ◽  
Matthias Lenzen ◽  
Martin Kraus ◽  
Marion Merklein
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Sheet Metal ◽  
Compression Test ◽  
Test Procedure ◽  
Rolling Direction ◽  
Single Layer ◽  
Material Behavior ◽  
Biaxial Tensile ◽  
Biaxial Tensile Stress

Numerical process design leads to cost and time savings in sheet metal forming processes. Therefore, a modeling of the material behavior is required to map the flow properties of sheet metal. For the identification of current yield criteria, the yield strength and the hardening behavior as well as the Lankford coefficients are taken into account. By considering the anisotropy as a function of rolling direction and stress state, the prediction quality of anisotropic materials is improved by a more accurate modeling of the yield locus curve. According to the current state of the art, the layer compression test is used to determine the corresponding Lankford coefficient for the biaxial tensile stress state. However, the test setup and the test procedure is quite challenging compared to other tests for the material characterization. Due to this, the test is only of limited suitability if only the Lankford coefficient has to be determined. In this contribution, a simplified test is presented. It is a reduction of the layer compression test to one single sheet layer. So the Lankford coefficient for the biaxial tensile stress state can be analyzed with a significantly lower test effort. The results prove the applicability of the proposed test for an easy and time efficient characterization of the biaxial Lankford coefficient.

Rotating Loosening Mechanism of a Nut Connecting a Rotary Disk Under Rotating-Bending Force

2005 ◽  
Vol 127 (6) ◽  
pp. 1191-1197 ◽  
Author(s):  
Yasuo Fujioka ◽  
Tomotsugu Sakai
Keyword(s):  
High Pressure ◽  
Contact Area ◽  
The Other ◽  
Bearing Surface ◽  
Bending Force ◽  
Rotary Disk ◽  
Rotating Bending ◽  
Dimensional Errors ◽  
The Revolution

Structures composed of a rotary disk and a shaft, which are fastened with bolts and nuts having tapered bearing surfaces, are loaded with a rotating-bending force. Upon investigation, two rotating mechanisms of the nut were derived. In one mechanism a high-pressure contact area is formed at the nearest loading point on threads and bearing surfaces. This leads to a difference in the curvature radii between the bearing surface of the disk and that of the nut. During the revolution of the disk, two friction torques occur in opposite directions on the bearing surface and the threads, respectively. The relative rotating direction of the nut is dominated by the greater torque. The other mechanism is due to the eccentricities caused by dimensional errors of the bolt, nut, and disk. By combining the two mechanisms, the rotations of the nuts either cause a loosening or tightening after many revolutions of the disk.

scholarly journals Failure analysis of the rubber track of a tracked transporter

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878952 ◽  
Author(s):  
Weiwei Liu ◽  
Kai Cheng ◽  
Jun Wang
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Failure Analysis ◽  
Test Site ◽  
Strength Theory ◽  
Cycle Index ◽  
Soil Stress ◽  
Machinery Building ◽  
Simple Stress ◽  
Working Hour

Rubber-tracked transporters are becoming increasingly popular in agriculture, forestry and military transportation. Rubber track systems are typically fitted instead of using tyres on the transporter to decrease soil stress and increase trafficability. Therefore, the accurate failure analysis of a rubber track is important. A model for predicting stress distribution along a rubber track is presented in this study. In the model, the stress along a rubber track consists of the vertical stress below the rubber track, tensile stress, bending stress and centrifugal tensile stress. Moreover, fourth strength theory was used to change a complicated stress state to a simple stress state. An experiment was performed at the test site of Harbin First Machinery Building Group Ltd, with a total weight of 61.789 kN. The experiment was conducted to verify and approve the theoretical model. The Miner rule was used to predict the cycle index and working hour of the rubber track, thereby providing a method for predicting the fatigue life of a rubber track.

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