A Damage Integral Based Analysis and Simulation of the Thermal Fatigue of Diebonds

1993 ◽  
Vol 323 ◽  
Author(s):  
David A. Lilienfeld ◽  
Peter Børgesen ◽  
Che-Yu Li
Keyword(s):  
Computer Simulation ◽  
Thermal Expansion ◽  
Growth Parameters ◽  
Constitutive Relations ◽  
Epoxy Adhesive ◽  
Integral Approach ◽  
Test Results ◽  
Adhesive Layers ◽  
Damage And Failure ◽  
Service Conditions

AbstractMicroelectronic packages undergo substantial thermal excursions during processing and often in service. Differences in the thermal expansion of the various components may therefore lead to fatigue of the interconnects. A computer simulation has been developed which is based on a damage integral approach for the modeling of damage and failure in the various bonding layers found throughout such a package. This code should apply equally well to solder die bonds and polymeric or epoxy adhesive layers, assuming that the corresponding crack growth parameters and constitutive relations are known. Using literature values for these properties, predictions have been compared to experimental thermal cycling data for solder die bonds. Consequences for the extrapolation of accelerated test results to service conditions are discussed.

Failure in Tungsten-Filled Via Structures

1995 ◽  
Vol 391 ◽  
Author(s):  
J. J. Clement ◽  
J. R. Lloyd ◽  
C. V. Thompson
Keyword(s):  
Thermal Expansion ◽  
Current Density ◽  
Void Growth ◽  
Test Results ◽  
Resistance Increase ◽  
Test Conditions ◽  
Structure Geometry ◽  
Service Conditions ◽  
Differential Thermal Expansion ◽  
Improve Reliability

AbstractFailure of the tungsten-filled via interconnect structure is modelled. Two mechanisms contributing to void growth are considered: relief of stress due to differential thermal expansion, and electromigration. A self-limiting void volume is predicted, resulting in a self-limiting resistance increase which is a function of structure geometry and the void morphology. The relative contributions of the two mechanisms change significantly as the temperature and current density are reduced from accelerated test conditions, affecting the extrapolation of test results to service conditions. Modified procedures for extrapolating lifetimes are discussed, as well as suggested process changes to improve reliability.

Experimental characterization of composites to support an orthotropic plasticity material model

2017 ◽  
Vol 52 (14) ◽  
pp. 1847-1872 ◽  
Author(s):  
Bilal Khaled ◽  
Loukham Shyamsunder ◽  
Canio Hoffarth ◽  
Subramaniam D Rajan ◽  
Robert K Goldberg ◽  
...  
Keyword(s):  
Material Model ◽  
Unidirectional Composite ◽  
Deformation Model ◽  
Test Results ◽  
Dynamic Impact ◽  
Test Procedures ◽  
Stress Strain ◽  
Damage And Failure ◽  
Orthotropic Behavior

Test procedures for characterizing the orthotropic behavior of a unidirectional composite at room temperature and quasi-static loading conditions are developed and discussed. The resulting data consisting of 12 stress–strain curves and associated material parameters are used in a newly developed material model—an orthotropic elasto-plastic constitutive model that is driven by tabulated stress–strain curves and other material properties that allow for the elastic and inelastic deformation model to be combined with damage and failure models. A unidirectional composite—T800/F3900, commonly used in the aerospace industry, is used to illustrate how the experimental procedures are developed and used. The generated data are then used to model a dynamic impact test. Results show that the developed framework implemented into a special version of LS-DYNA yields reasonably accurate predictions of the structural behavior.

scholarly journals Carbon Fibre - Copper Composites Obtained by Foil Casting

1994 ◽  
Vol 3 (2) ◽  
pp. 096369359400300
Author(s):  
W.K. Wtosiński ◽  
W. Olesińska ◽  
K. Pietrzak ◽  
D. Kaliński
Keyword(s):  
Thermal Expansion ◽  
Carbon Fibre ◽  
Casting Process ◽  
Fibre Content ◽  
Resistance Welding ◽  
Test Results ◽  
Micro Hardness ◽  
Electric Contacts

A method for production of carbon fibre - copper composites by foil casting is presented. As follows from the test results included, the foil casting process may be applied to produce the carbon fibre -copper composites. Thanks to the use continuous fibres, the method allows to obtain composites with fibres ordered directionally. Measurements of thermal expansion and micro-hardness of a composite with 30% fibre content, as well as examination of its microstructure are presented. The composites may, among others, find application in manufacturing of electrodes for resistance welding, electric contacts and expansion wafers for semiconductor power components.

A Novel Active Suspension System for Automotive Application

1994 ◽  
Vol 208 (4) ◽  
pp. 243-250 ◽  
Author(s):  
N J Leighton ◽  
J Pullen
Keyword(s):  
Computer Simulation ◽  
Active Suspension ◽  
Input Power ◽  
Suspension System ◽  
Automotive Application ◽  
Test Results ◽  
Active System ◽  
Spring Element

This paper describes a novel type of active suspension based on a buckling spring element installed in an actively controlled variable leverage system. The development of the suspension system through stages of computer simulation, implementation and test is outlined, together with the test results. The suspension system does not fall into any of the established categories of active system but may be seen as fitting into a recently identified category of variably leverage systems. The system is shown to be capable of controlling a vehicle body's motion while providing excellent road input isolation and requiring input power levels of below 150 watts per wheel.

scholarly journals Pullout Behavior of GFRP Anti-Floating Anchor Based on the FBG Sensor Technology

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ming-yi Zhang ◽  
Zheng Kuang ◽  
Xiao-yu Bai ◽  
Xiao-yu Chen
Keyword(s):  
Axial Force ◽  
Shear Failure ◽  
Distribution Functions ◽  
Sensor Technology ◽  
Force Distribution ◽  
Test Results ◽  
Glass Fiber Reinforcement ◽  
Promising Solution ◽  
Service Conditions ◽  
Fbg Sensors

Building anti-floating anchors have been increasingly used in recent years, but conventional steel anchors under service conditions are easily subjected to chemical erosion. Glass fiber reinforcement polymer (GFRP) is a promising solution to this problem. In this study, field pullout tests were conducted on three full instrumented GFRP anti-floating anchors in weathered granite. Specifically, the GFRP anchors during pultrusion were innovatively embedded with bare fiber Bragg grating (FBG) sensors to monitor the axial force distribution along depth. It was found that the embedded FBG could reliably monitor the axial force distribution of GFRP anchors. The ultimate pullout force of a GFRP anchor with diameter of 28 mm and anchorage length of 5 m was up to 400 kN. The GFRP anchor yielded at 0.8 m underground. Force distribution and field photos at failure indicated shear failure occurred at the anchor/bolt interface at the end of the tests. The feasibility of the GFRP anti-floating anchor was also verified in civil engineering. Finally, an elastic mechanical model and Mindlin’s displacement solution are used to get distribution functions of axial force and shear stress along the depth, and the results accord with the test results.

Statistical Evaluation Tensile Properties of High-Density Polyethylenes

2012 ◽  
Vol 445 ◽  
pp. 213-218 ◽  
Author(s):  
Ahmet Koyun ◽  
Baris Koksal ◽  
Esma Ahlatcioglu ◽  
A. Binnaz Hazar Yoruc
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Statistical Evaluation ◽  
Test Results ◽  
Plastic Materials ◽  
Service Conditions ◽  
End Use ◽  
Chain Lengths

The mechanical properties, among all the properties of plastic materials, are often the most important properties because virtually all service conditions and the majority of end-use applications involve some degree of mechanical loading [1]. In the present work three different commercial polyethylene materials are tensile tested at four or five different tensile rates and two or three temperatures. Tensile test results against tensile rate include stress at 0.5 % elongation, tensile strength, yield strength, modulus of elasticity, elongation at yield and % elongation are determined. It is concluded that the structure, chain lengths and branching rates of polymer matrix significantly effected tensile test curve characteristic.

Influence of Baking on Thermal–Expansion Ability of Quartz Sands

2011 ◽  
Vol 211-212 ◽  
pp. 1226-1229
Author(s):  
Hai Ou Jing ◽  
Shu Hua Wang
Keyword(s):  
Thermal Expansion ◽  
Expansion Ratio ◽  
Test Results ◽  
Quartz Sands ◽  
Expansion Ability ◽  
Changing Tendency

In order to understand the changing tendency of thermal–expansion abilities of used sands in foundry, the four groups of quartz sands were measured in this paper. The influencing laws of baked-times and temperatures on the property of quartz sands were analyzed. And the test results showed that volume thermal-expansion ratio of quartz sands decreases with increasing of the baked-times.

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