1) 2512 chip resistors mounted to a printed circuit board using solder joints were subjected to over 50,000 short duration (<10 min) power cycles. 2) Failure analysis found cracking in the solder joints due to low cycle fatigue. 3) Temperature data showed the resistors experienced temperature swings of up to 22°C with each power cycle, driving the low cycle fatigue of the solder joints.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Magnetic nde characterization of tempered 2.25 cr 1mo steelAPOORVKRISHNA1
A descriptive presentation on heat treatment analysis of Tempered 2.25Cr-1Mo steel ,commonly known as P22 steel. The presentation includes history of the material, objective and work-plan with procedures adopted to carry out the project.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Model Analysis of Cymbal Generator Under Different Working ConditionsIJRES Journal
In order to study the influence for natural frequency under different constraint conditions of Cymbal transducer. Through the use of ANSYS and SIMULATION with finite element method, the Cymbal transducer can be applied on different constraints and load conditions, calculation and analysis to obtain the modal under the specific natural frequencies and mode shapes. Which in the free and non free conditions yield stress limits are in the security domain, the modal analysis results of vibration mode and natural frequency shows that suitable for large load under low frequency vibration of train vibration load, the load in order to study, under low frequency vibration Cymbal transducer can provide simulation support for energy recovery applications.
Effect of Process Parameters on the Total Heat Damaged Zone (HDZ) during Micr...IJAMSE Journal
In micro electrical discharge machining, three subsurface layersare formed on the workpiece, they are; recast zone, heat affected zone and converted zone, primarily due to heating-quenching cycles. The HDZ in micro-EDM is characterized by cracks and weakness in the grain boundary and thermal residual stresses. This paper presents the effect of process parameters on the HDZ in micro-EDM of plastic mold steel 1.2738. As the energy of the sparks increases, the thickness of the HDZ increases and the average coefficient of correlation between energy and HDZ considering three different sections of the zone is 0.8099. Therefore, the effect of process parameters governing the discharge energy are analyzed; they are: average current (Ia), peak current (Ip) and pulse ‘on-time’ (Ton). An overall increase in heat-damaged zone thickness by 105% is observed with an increase in pulse on time.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Magnetic nde characterization of tempered 2.25 cr 1mo steelAPOORVKRISHNA1
A descriptive presentation on heat treatment analysis of Tempered 2.25Cr-1Mo steel ,commonly known as P22 steel. The presentation includes history of the material, objective and work-plan with procedures adopted to carry out the project.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Model Analysis of Cymbal Generator Under Different Working ConditionsIJRES Journal
In order to study the influence for natural frequency under different constraint conditions of Cymbal transducer. Through the use of ANSYS and SIMULATION with finite element method, the Cymbal transducer can be applied on different constraints and load conditions, calculation and analysis to obtain the modal under the specific natural frequencies and mode shapes. Which in the free and non free conditions yield stress limits are in the security domain, the modal analysis results of vibration mode and natural frequency shows that suitable for large load under low frequency vibration of train vibration load, the load in order to study, under low frequency vibration Cymbal transducer can provide simulation support for energy recovery applications.
Effect of Process Parameters on the Total Heat Damaged Zone (HDZ) during Micr...IJAMSE Journal
In micro electrical discharge machining, three subsurface layersare formed on the workpiece, they are; recast zone, heat affected zone and converted zone, primarily due to heating-quenching cycles. The HDZ in micro-EDM is characterized by cracks and weakness in the grain boundary and thermal residual stresses. This paper presents the effect of process parameters on the HDZ in micro-EDM of plastic mold steel 1.2738. As the energy of the sparks increases, the thickness of the HDZ increases and the average coefficient of correlation between energy and HDZ considering three different sections of the zone is 0.8099. Therefore, the effect of process parameters governing the discharge energy are analyzed; they are: average current (Ia), peak current (Ip) and pulse ‘on-time’ (Ton). An overall increase in heat-damaged zone thickness by 105% is observed with an increase in pulse on time.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier...AM Publications
Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier Discharge (DBD) Plasma has been simulated using the Simulink-Matlab R2010a software. Plasma reactor being used as the basis to determine the parameters in the circuit is in the coaxial form made of pyrex glass with an iron rod as the active electrode and spiral copper wire as passive electrode. The reactor was filled with argon gas with the flow rate of 2 L/s. Simulation circuit model which was prepared based on a DBD equivalent circuit, operated in a voltage range of 1.0 kV to 6.0 kV for frequency of 10 kHz to 66 kHz. Electrical characterization was performed to describe the plasma discharge that occurs in the reactor. The datas of supply voltage and current, as well as voltage and current discharge, was used to determine the average power during one period. From the simulation was obtained an increase in supply and discharge currents with increasing of frequency at the same operating voltage. Discharge power has increased in a specific voltage and increased frequency. It is obtained the average discharge power for 5.5 kV of 11.28 W and 10.90 W at a frequency of 21 kHz and 24 kHz, respectively. The highest efficiency obtained from the simulation that achieved at voltage of 1 kV and frequency of 45.7 kHz is equal to 56.59%.
QUENCHING CRACK ANALYSIS OF BIG SIZE FORGING BY FE ANALYSISIAEME Publication
Heat treatment crack is one of the main defects of big size forging manufacturing
process. In this research finite element method has been applied to predict crack
initiation by mass effect during water agitation cooling. Cooling curve of specimens
was measured water quenching test and convective coefficients were calculated by
inverse method based on finite element method. Water quenching processes were
analyzed by Deform software and Jmatpro. Crack initiation has been predicted by
comparison of stress distribution and strength on the temperature basis
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
MAGNETIC FLUX CONTROL IN INDUCTION INSTALLATIONSFluxtrol Inc.
http://fluxtrol.com
It is well known that performance of some induction systems may be
significantly improved by application of magnetic flux controllers. They are used to
concentrate, shield and/or redistribute the magnetic field which generates power in the part. Theoretical and practical evidences are presented in the paper, which show that there is still significant potential for improvement in innovative and traditional induction technologies due to magnetic flux control. Utilizing magnetic flux controllers in heat treating processes results in excellent heat pattern control and improvement of parameters of inductors and entire power delivery systems. In melting systems, especially in the case of vacuum furnaces, cold crucible and other specialty furnaces, the magnetic control can provide energy savings, magnetic field shielding, shorter melting cycles and optimized field distribution for metallurgical processes. Comparison of different groups of materials for magnetic flux control (laminations, ferrites and Soft Magnetic Composites, aka Magnetodielectrics) is also presented in the paper. Several examples of magnetic flux control illustrate the presented material based on more than 20 years of R&D and practical experience of scientists and practitioners at Fluxtrol Inc.
Crystallization kinetics and phase transformation in amorphous Fe74Co10B16 an...IJERA Editor
Crystallization kinetics and phase transformation studies have been carried out on amorphous Fe74Co10B16 (S1) and Fe67Co18B14Si1 (S2) alloys using Mossbauer Spectroscopy (MS), Electrical Resistivity (ER), Differential Scanning Calorimetry(DSC), X-ray Diffraction(XRD) and Transmission Electron Microscopy(TEM) to determine the thermal stability. Results show that the transformation to an equilibrium crystalline state occurs through a two step process. Crystallization process is associated with precipitation of two or more phases which are magnetic in nature. From DSC curves, the activation energy of sample S2 has been calculated using Kissinger, Matusita-Sakka and Augis-Bennet methods and the average value is found to be 211 kJ/mol. The detected phases upon crystallization in the samples are α–(Fe-Co) and (Fe-Co)2B. Exact compositions of these phases in the completely crystallized sample are found to be α–(Fe0.7Co0.3) and (Fe0.3Co0.7)2B.
EFFECT OF TEMPERATURE IN ANALYSIS OF CREEP IN AN ISOTROPIC UNIFORM COMPOSITE ...ijiert bestjournal
The following paper discusses the effect of tempera ture in analysis of creep in an isotropic uniform composite cylinder. The paper is a part of the series of papers published under the analysis of creep in an isotropic uniform composite cylinder.
On the effects of advanced end-winding cooling on the design and performance ...Vincenzo Madonna
For citing this work:
V. Madonna, P. Giangrande, A. Walker and M. Galea, "On the Effects of Advanced End-Winding Cooling on the Design and Performance of Electrical Machines," 2018 XIII International Conference on Electrical Machines (ICEM), Alexandroupoli, 2018, pp. 311-317.
Abstract:
High performance and reliable electrical machines
are often required in modern applications and an appropriate
thermal management allows to fulfil such demand. Thermal
management is crucial for improving performance, reducing size
and preserving the insulation lifetime of electrical machines.
From this prospective, a novel cooling method for machine
end-windings is proposed in the present work. Its cooling action
focuses on the end-windings, since they are commonly identified
as the machine hot-spot. The effectiveness of the proposed
cooling method is experimentally proved and the improvement,
in terms of current density, for a given wire insulation thermal
class, is quantified.
A previously designed permanent magnet synchronous
machine, implementing a traditional housing water jacket, is
used as a case study. The influence of the improved current
density on machine torque density is investigated, through finite
element simulations, when the proposed cooling method is
integrated to the existing housing water jacket.
Copper Clad Steel and Copper Clad Aluminium Conductor is best Solution to Replace GI Flat Strip or Copper Flat Strip for Earthing Purpose Offering by JMV LPS LTD India Internationa Standard Follow IEC/IEEE and ASTM B228-4
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier...AM Publications
Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier Discharge (DBD) Plasma has been simulated using the Simulink-Matlab R2010a software. Plasma reactor being used as the basis to determine the parameters in the circuit is in the coaxial form made of pyrex glass with an iron rod as the active electrode and spiral copper wire as passive electrode. The reactor was filled with argon gas with the flow rate of 2 L/s. Simulation circuit model which was prepared based on a DBD equivalent circuit, operated in a voltage range of 1.0 kV to 6.0 kV for frequency of 10 kHz to 66 kHz. Electrical characterization was performed to describe the plasma discharge that occurs in the reactor. The datas of supply voltage and current, as well as voltage and current discharge, was used to determine the average power during one period. From the simulation was obtained an increase in supply and discharge currents with increasing of frequency at the same operating voltage. Discharge power has increased in a specific voltage and increased frequency. It is obtained the average discharge power for 5.5 kV of 11.28 W and 10.90 W at a frequency of 21 kHz and 24 kHz, respectively. The highest efficiency obtained from the simulation that achieved at voltage of 1 kV and frequency of 45.7 kHz is equal to 56.59%.
QUENCHING CRACK ANALYSIS OF BIG SIZE FORGING BY FE ANALYSISIAEME Publication
Heat treatment crack is one of the main defects of big size forging manufacturing
process. In this research finite element method has been applied to predict crack
initiation by mass effect during water agitation cooling. Cooling curve of specimens
was measured water quenching test and convective coefficients were calculated by
inverse method based on finite element method. Water quenching processes were
analyzed by Deform software and Jmatpro. Crack initiation has been predicted by
comparison of stress distribution and strength on the temperature basis
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
MAGNETIC FLUX CONTROL IN INDUCTION INSTALLATIONSFluxtrol Inc.
http://fluxtrol.com
It is well known that performance of some induction systems may be
significantly improved by application of magnetic flux controllers. They are used to
concentrate, shield and/or redistribute the magnetic field which generates power in the part. Theoretical and practical evidences are presented in the paper, which show that there is still significant potential for improvement in innovative and traditional induction technologies due to magnetic flux control. Utilizing magnetic flux controllers in heat treating processes results in excellent heat pattern control and improvement of parameters of inductors and entire power delivery systems. In melting systems, especially in the case of vacuum furnaces, cold crucible and other specialty furnaces, the magnetic control can provide energy savings, magnetic field shielding, shorter melting cycles and optimized field distribution for metallurgical processes. Comparison of different groups of materials for magnetic flux control (laminations, ferrites and Soft Magnetic Composites, aka Magnetodielectrics) is also presented in the paper. Several examples of magnetic flux control illustrate the presented material based on more than 20 years of R&D and practical experience of scientists and practitioners at Fluxtrol Inc.
Crystallization kinetics and phase transformation in amorphous Fe74Co10B16 an...IJERA Editor
Crystallization kinetics and phase transformation studies have been carried out on amorphous Fe74Co10B16 (S1) and Fe67Co18B14Si1 (S2) alloys using Mossbauer Spectroscopy (MS), Electrical Resistivity (ER), Differential Scanning Calorimetry(DSC), X-ray Diffraction(XRD) and Transmission Electron Microscopy(TEM) to determine the thermal stability. Results show that the transformation to an equilibrium crystalline state occurs through a two step process. Crystallization process is associated with precipitation of two or more phases which are magnetic in nature. From DSC curves, the activation energy of sample S2 has been calculated using Kissinger, Matusita-Sakka and Augis-Bennet methods and the average value is found to be 211 kJ/mol. The detected phases upon crystallization in the samples are α–(Fe-Co) and (Fe-Co)2B. Exact compositions of these phases in the completely crystallized sample are found to be α–(Fe0.7Co0.3) and (Fe0.3Co0.7)2B.
EFFECT OF TEMPERATURE IN ANALYSIS OF CREEP IN AN ISOTROPIC UNIFORM COMPOSITE ...ijiert bestjournal
The following paper discusses the effect of tempera ture in analysis of creep in an isotropic uniform composite cylinder. The paper is a part of the series of papers published under the analysis of creep in an isotropic uniform composite cylinder.
On the effects of advanced end-winding cooling on the design and performance ...Vincenzo Madonna
For citing this work:
V. Madonna, P. Giangrande, A. Walker and M. Galea, "On the Effects of Advanced End-Winding Cooling on the Design and Performance of Electrical Machines," 2018 XIII International Conference on Electrical Machines (ICEM), Alexandroupoli, 2018, pp. 311-317.
Abstract:
High performance and reliable electrical machines
are often required in modern applications and an appropriate
thermal management allows to fulfil such demand. Thermal
management is crucial for improving performance, reducing size
and preserving the insulation lifetime of electrical machines.
From this prospective, a novel cooling method for machine
end-windings is proposed in the present work. Its cooling action
focuses on the end-windings, since they are commonly identified
as the machine hot-spot. The effectiveness of the proposed
cooling method is experimentally proved and the improvement,
in terms of current density, for a given wire insulation thermal
class, is quantified.
A previously designed permanent magnet synchronous
machine, implementing a traditional housing water jacket, is
used as a case study. The influence of the improved current
density on machine torque density is investigated, through finite
element simulations, when the proposed cooling method is
integrated to the existing housing water jacket.
Copper Clad Steel and Copper Clad Aluminium Conductor is best Solution to Replace GI Flat Strip or Copper Flat Strip for Earthing Purpose Offering by JMV LPS LTD India Internationa Standard Follow IEC/IEEE and ASTM B228-4
MT112 CHANNEL You don't have to dance around Dell EMC channel services...an ...Dell EMC World
From a hardware perspective, our channel goals are clear: provide maximum options for buying Dell EMC around the world. The same is true for services. There is a ton of services news to share. With simplicity, predictability and profitability as our channel pillars, we are delivering comprehensive sales readiness, technical training, certification and competencies, incentives, and an expanded portfolio. Plus, we want to hear from you. What else do you want from a new Dell EMC services program? Join us—let’s talk about why you’ve partnered with Dell EMC in the first place.
I gave a talk there recently for the earliest stage companies. This was specific to phone sales, known as "inside sales".
My talk was on:
- Is a) phone sales or b) eCommerce the best sales strategy for your specific company
- How to build out phone sales in a newly founded company
- How to manage long-term growth in an inside sales company
An Analytical Lumped Thermal Circuit for the Determination of Fast Warm up and Steady State Characteristics Of Heater/Cathode Packages for TWT’s.
The challenge of determining fast warm up rates in small heater/cathode packages is critical to many tube development programs, but suffused with difficulties. An over voltage is applied to the heater during the warm up time and current and hence power in the heater is determined by the resistance of
the wire at any point in time. The heater
wire usually consists of 97%
tungsten/3% rhenium alloy and this has
the property of resistivity variation with
temperature of over an order of
magnitude. This wire will also not be at
a uniform temperature at any time. In
addition, power is lost by a complex
combination of conductions and
radiation exchanges, with thermal
conductivities, expansivities,
emissivities, and specific heats for all
materials varying markedly with
temperature.
Electrical discharge machining is basically a non-conventional material removal process which is widely used to produce dies, punches and moulds, finishing parts for aerospace and automotive industry, and surgical components. This process can be successfully employed to machine electrically conductive parts irrespective of their hardness, shape and toughness.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
In recent years, the application of high-power semiconductor lasers has been expanding, and they are more and more widely used in industry and medical treatment. The thermal characteristics of lasers seriously restrict their reliability and service life. In order to improve the reliability and prolong the service life of the device,high power semiconductor laser bars with different solders, different thickness of solders and different thickness of WCu heat sink packages were simulated by COMSOL Multiphysics, and the "Smile" values of laser bars under different packaging conditions were measured. The results show that the maximum thermal stress of in solder or AuSn solder occurs at the interface between WCu secondary heat sink and Cu heat sink; the thermal stress of laser chips packaged with the same thickness of In solder and AuSn solder is 3.57 GPa and 3.83 GPa respectively,and the peak spectra are 800.5 and 798 nm, respectively.; reducing the thickness of solder is beneficial to reducing the thermal stress and temperature in the laser chips,but the solder is not. If the thickness is too thin,it may lead to weak welding of the laser core or uneven distribution of solder,and voids in the solder layer,so the selection of solder thickness should be considered as a whole. With the increase of the thickness of WCu secondary heat sink, the thermal stress of the laser chip decreases,but the temperature of the core rises,and the optimal thickness of tungsten-copper secondary heat sink is 380 um. This paper provides a basis for optimizing the packaging of high power semiconductor lasers and has guiding significance for practical production.
Cascade forward neural network based on resilient backpropagation for simulta...Mellah Hacene
Cascade-Forward Neural Network Based on Resilient Backpropagation for Simultaneous Parameters and State Space Estimations of Brushed DC Machines
Advances in Modelling and Analysis B
Temperature Cycling and Fatigue in ElectronicsCheryl Tulkoff
The majority of electronic failures occur due to thermally induced stresses and strains caused by excessive differences in coefficients of thermal expansion (CTE) across materials.
CTE mismatches occur in both 1st and 2nd level interconnects in electronics assemblies.
-1st level interconnects connect the die to a substrate.
-This substrate can be underfilled so there are both global and local CTE mismatches to consider.
-2nd level interconnects connect the substrate, or package, to the printed circuit board (PCB). This would be considered a “board level” CTE mismatch.
-Several stress and strain mitigation techniques exist including the use of conformal coating.
The purpose of this presentation is to show that accelerated testing can be successfully used to predict solder joint and plated through hole (PTH) fatigue behavior.
Role of αc–relaxation in high-temperature polymer deformation.
Proceedings of the American Society for Composites 2009-Twenty-Fourth Technical ConferenceWith the Canadian Association for Composite Structures and Materials (Joint Canadian-American International Conference), September 15-17, Newark, DE
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
1. f
Predicting Fatigue of Solder Joints Subjected to High Number of Power Cycles
Craig Hillman1, Nathan Blattau1, Matt Lacy2
1
DfR Solutions, Beltsville, MD
2
Advanced Energy Industries, Fort Collins, CO
Abstract
Solder joint reliability of SMT components connected to printed circuit boards is well documented. However, much of the
testing and data is related to high-strain energy thermal cycling experiments relevant to product qualification testing (i.e.,
-55C to 125C). Relatively little information is available on low-strain, high-cycle fatigue behavior of solder joints, even
though this is increasingly common in a number of applications due to energy savings sleep mode, high variation in
bandwidth usage and computational requirements, and normal operational profiles in a number of power supply applications.
In this paper, 2512 chip resistors were subjected to a high (>50,000) number of short duration (<10 min) power cycles.
Environmental conditions and relevant material properties were documented and the information was inputted into a number
of published solder joint fatigue models. The requirements of each model, its approach (crack growth or damage
accumulation) and its relevance to high cycle fatigue are discussed. Predicted cycles to failure are compared to test results as
well as warranty information from fielded product. Failure modes were confirmed through cross-sectioning. Results were
used to evaluate if failures during accelerated reliability testing indicate a high risk of failures to units in the field. Potential
design changes are evaluated to quantify the change in expected life of the solder joint.
Solder Joint Fatigue Prediction - Theory
Degradation of solder joints due to differential expansion and contraction of joined materials has been a known issue in the
electronics industry1
since the basic construction of modern electronic design was finalized in the late 1950’s / early 1960’s.
Initial assessment of the behavior borrowed heavily from observation of structural materials in the early 1950’s, such as
solder fatigue in automotive radiators2
and thermal fatigue of steels3,4,5
. The resulting Coffin-Manson relation states that the
number of cycles to failure has a power law dependence on the magnitude of the plastic strain, or inelastic deformation,
experienced during that specific thermal cycle.
1 c
N ( )f
2 2
where f, and c are empirically derived constants. This approach provided a predictive model for low-cycle (< 10,000 cycles)
fatigue behavior and, in combination with the Basquin equation for high-cycle (> 100,000 cycles) fatigue, resulted in a
uniform approach for fatigue prediction across a wide range of use conditions as seen in Figure 1.
Figure 1: Fatigue curve of 24ST aluminum, showing low cycle and high cycle fatigue6
While the Coffin-Manson equation was based on a sound understanding of material science and mechanics, it was difficult to
implement for applications relevant to electronics packaging. Solder, the key interconnect material at risk of thermo-
mechanical fatigue in electronic packaging, was applied in volumes too small to directly measure plastic strain and in
2. geometries too complicated to solve through simple mechanics models (Coffin and Manson’s original papers used flat plate
geometries as an example).
Norris and Landzberg7
attempted to address these deficiencies by proposing that plastic strain dominated thermo-mechanical
fatigue of eutectic SnPb alloy, the primary solder of choice in electronic packaging at that time. In ignoring the influence of
elastic strain, Norris-Landzberg were able to draw a direct relationship between change in temperature and plastic strain. To
account for the influence of creep-driven plasticity, a mechanism of less concern for high temperature steels, Norris-
Landzberg added additional correction factors based on cyclic frequency (which is directly related to dwell times) and
maximumtemperature.
This approach to predicting solder joint lifetime under thermal cycling was widely embraced by the electronics community,
to the extent that the Norris-Landzberg equation is the only technique referenced in the relevant JEDEC qualification
documents, JESD478
and JESD949
.
The Norris-Landzberg equation, while eminently practical, has several key limitations. The most critical is the inability to
make a fatigue prediction without test data. This effectively eliminates the use of Norris-Landzberg from any design
activities. The equation is also based on the assumption that creep behavior is driven exclusively by temperature and time,
whereas there is a critical applied stress element. Depending upon the packaging architecture, the change in applied stress at
different thermal cycles could have a more substantive effect then identified through frequency and temperature, possibly
changing rate constants depending on the solder joint configuration and overall packaging architecture10
. Finally, the equation
is dependent upon the plastic strain being driven by the same mechanism in both environments. As demonstrated by
deformation maps (Figure 2), different atomic-level mechanisms can be triggered to induce plasticity and creep behaviors
depending on the specific combination of temperature and applied stress. The limitation of this approach has been made most
obvious by the inability to develop a Norris-Landzberg equivalent for Pb-free solders (SAC305)11,12
.
Figure 2: A representative schematic of a deformation map showing the various mechanisms that can induce damage during
cyclic fatigue
Further improvement to the prediction of solder fatigue was provided by Engelmaier13
, who returned back to the principles of
Coffin Manson, but used solid mechanics models more relevant to the solder joint geometry and low-cycle fatigue data for
SnPb solder14
. To determine the plastic strain, or strain range, Engelmaier assumed that the in-plane (shear) steady-state
strains dominated low-cycle fatigue behavior. This allowed for the use of a distance-to-neutral model, where
3. with C being a geometry-dependent constant (1/2 for leadless ceramic chip carriers), LD is the diagonal distance from the
neutral point (assumes a square/rectangle shape), is the difference in thermal expansion between the die/component and
substrate/printed board, and T is the thermal cycle. Engelmaier then derived f and c through curve fitting of the Wild data,
with
f = 0.325 and
c = (-0.442) – (6x10-4
Ts) + (1.74x10-2
)[ln (1+f)]
where Ts is the average temperature during the thermal cycle and f is the frequency of the thermal cycle.
In some respects, the Engelmaier model was even more successful than the Norris-Landzberg. Like Norris-Landzberg, the
inputs required to use the Engelmaier model was available to the practicing engineer. It was also widely adopted in the
industry, primarily through IPC SM-78515
. The Engelmaier model overcame some of the limitations of the Norris-Landzberg
model, including a strong link to the original Coffin-Manson methodology, ability to predict fatigue performance without
testing, consideration of the package geometry, and a basis on experimental fatigue results.
The Engelmaier approach, while superior to previous attempts to predict low-cycle solder fatigue both in accuracy and
practicality, had some limitations. One of the flaws of the Engelmaier approach lies with the Wild data that is the basis of its
fatigue exponent. Wild performed isothermal mechanical fatigue experiments at 25C and 100C at between 4 and 300 cycles
per hour. These temperature ranges are above room temperature and therefore provide limited insight into fatigue behavior at
colder temperatures where creep-based mechanisms are reduced and plasticity-driven mechanisms play a larger role in
fatigue behavior. The cyclic frequency is higher than most thermal cycling test conditions, which are typically one (1) to two
21
per hour, and far higher than field conditions, which can require several hours to go through a thermal cycle. This has the
effect of minimizing the time-dependency of creep mechanisms and the resulting damage evolution. This tendency to
overestimate and underestimate creep effects may have contributed to the accuracy of the predictions.
An additional challenge to both Coffin-Manson and the derived Engelmaier model was their assumption that the plastic strain
was constant over the entire temperature cycle. Work by Hall16
measured a hysteresis loop, where the stress-strain
relationship could vary dramatically as the solder joint was exposed to a range of temperatures (see Figure 3). It is important
to note that the nominal shape of hysteresis loops can be more uniform, depending upon the applied stress, temperature, and
dwell time. The cycle measured by Hall induced failure in less than 500 cycles, which is typically too low to be accurately
predicted through analytical means).
Figure 3: Hysteresis loop of a leadless ceramic chip carrier solder joint during thermal cycling between -25°C and 125°C16
(obtainedthroughhttp://www.msed.nist.gov/solder/clech/Sn-Pb_Creep.htm)
Additional experiments also demonstrated a more consistent correlation between strain energy and cycles to failure with
fewer dependencies on geometry or load orientation17
. These observed behaviors necessitated a move to a strain energy based
prediction scheme. Blattau18
introduced a modification of the Engelmaier model that replaced strain range with strain energy.
To compute strain energy, Blattau used a foundation stiffness model to calculate the force being applied to the solder joint
based on displacement equations, where
4. where LD is the diagonal length (distance to neutral point), E is the elastic modulus, A is the area, h is the thickness, G is the
shear modulus, a is the edge length of the bond pad, 1 refers to the component, 2 refers to the board, s refers to the solder
joint, c refers to the bond pad, and b refers to the board. The shear stress can then be computed by dividing the force by the
effective solder joint area.
Once the strain range and the shear stress are computed, the strain energy is calculated assuming a hysteresis loop that is
roughly equilateral in shape (Figure 4)
Figure 4: Representative schematic of a solder joint hysteresis loop19
The relationship between cycles to failure and strain energy is then determined based on work performed by Syed20
, who
demonstrated a power law correlation between strain energy and cycles to failure with an exponent of -1. The foundation of
this behavior is based on first principles of secondary creep behavior. The Blattau approach, which combines the first-order
equations derived from the original Coffin-Manson equation with the observed dependence on strain energy, has been
validated for both chip components and ball grid array packaging technology (see Figure 5).
Figure 5
Solder Joint Prediction – Validation (Power Cycling)
Almost all solder prediction models go through a validation process where predictions are compared to experimental results.
These validation processes can be a direct comparison of measured time to failure to theoretical predictions or the
experimental results can be correlated to normalized parameters relevant to the model algorithm. Most validation activities
attempt to provide a correlation over three orders of magnitude, typically between 100 to 10,000 cycles.
5. Isothermal testing tends to be the dominant vehicle for validation studies. A study by the University of Maryland determined
that over 82% of the test conditions reported in the IEEE literature were isothermal thermal cycles21
. This is true even though
one of the initial concerns regarding solder joint fatigue was the performance of devices subjected to power cycling. The
majority of publications on solder fatigue under power cycling focus on the die attach structure common within high power
insulated gate bipolar transistors (IGBT)22,23
. This specific structure does not necessarily lend itself to common surface mount
(SMT) solder joints due to the highly constrained layer architecture and the inability to directly monitor or define die attach
failure.
The limited studies on power cycling of standard surface mount devices have primarily focused on correlation to isothermal
cycling or shock. An earlier paper by Popps et. al.24
showed a 50% increase in lifetime with power cycling, even though the
power cycle had a longer dwell time (15 minutes vs. 5 minutes) and a faster ramp rate (60C/min vs. 20C/min). A similar
increase in number of cycles to failure was predicted and observed by Li et. al.25
; they assigned this difference in behavior to
the large thermal gradient across the ball grid array package, which effectively increased the CTE of the BGA under the die
shadow while limiting the degree of expansion over the diagonal length.
The limiting factor of these papers and other investigations on power cycling of SMT packages is that the time is typically
less than 10,000 cycles. While this cycle count could be considered as the outer bound of low cycle fatigue (others believe
plastic strain is dominant out to 100,000 cycles), it fails to consider that an increasing number of applications are expected to
have tens of thousands of power cycles in the actual field application. Enterprise applications are increasingly powering
down, either to sleep mode or turned off, to save energy. To conserve battery charge, consumer mobile devices (smart
phones, tablets, and laptops) can experience between 10 to 50 power cycles per day for three (3) to five (5) years, which can
result in a total of 15,000 to 90,000 power cycles over its lifetime. A similar environmental profile is starting to ramp up in
automotive applications, where start-stop technology can introduce a power down 12 times for every four (4) miles driven.
With the average urban driving of 25 miles per day, this works out to 250,000 cycles over ten (10) years.
The purpose of this paper is to provide a better understanding of the relevance of standard strain energy based models for low
cycle fatigue of solder joints in predicting the behavior of standard SMT packages subjected to a very high number of power
cycles.
ExperimentalProcedure
A RF power supply was subjected to an accelerated life test (ALT). The test conditions for these units are shown below
• Coolant Temperature:
• Inlet Air Temperature: 50°C / Inlet Water Temperature: 45°C
• Output Power Cycling:
• RF ON: 4 min / RF OFF: 1min
• Output Load:
• Two Months at 50 Ohms
• Four Months at 31.3 +j34.3 (complex load)
Three units failed during ALT. Circuit troubleshooting identified the failure sites as 2512 resistors in the gate drive circuit.
The last failure initiated after 53,215 Output ON events. Visual examination of the 2515 SMT resistors in the RF Gate Drive
circuit revealed problems with solder joint cracking (see Figure 6).
Figure 6: Optical image of failed solder joints at R4 and R5
6. To obtain a better understanding of the extent of solder joint cracking, all eight resistors in the RF Gate Drive circuit were
cross-sectioned and the cross-sectional views are shown in order from R2 thru R9 in Figure 7. Based on the crack
propagation path and the phase coarsening observed around the crack path, it was concluded that the solder joint cracking
was due to low cycle fatigue. A diagram from a typical solder fatigue26
is shown in Figure 8 with the cross-section of the
failed R5 solder joint. Based on the schematic, the R5 solder joint crack followed a “typical” path starting from the inner end
(heel) and propagating until failure occurred.
Figure 7: Cross section views of R2 (top) to R9 (bottom). “Heatsink” end is on the Left.
7. R2
R3
R4
R5
R6
R7
R8
R9
Inlet Air
Exhaus
t Air
Temperature(C)
Figure 8: Typical failure diagram from Lui et. al. and a cross-section of failed R5 solder joint
To better understand the drivers for solder fatigue under the 2512 resistors, T-type thermocouples were placed on the gate
drive resistors (see Figure 9). The temperatures were recorded using a 343970 data logger and a graph of the resistor
temperature data for multiple power cycles is shown in Figure 10 and a table of peak temperatures is displayed in Table 1.
Figure 9: Thermocouple placement on Gate Drive Resistors
ALT Resistor R2-R9 Temperatures during 4min ON, min OFF Power cycles
80
75
70
65
60
55
50
45
0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 0:36:00 0:43:12 0:50:24 0:57:36
Time (minutes)
Figure 10: Thermocouple data for Gate Drive Resistors
Table 1: Table of Temperatures for Gate Drive Resistors (*temperatures seem low; possible measurement issue)
Resist
or
6kW Output Power 0.5kW Output Power
Max Temp
(°
C
Min Temp
(°C)
ΔT
(°C
)
Max Temp
(°
C
Min Temp
(°C)
ΔT
(°C
)R2* 6
8.
5
5.
12.
6
5
6.
4
7.
8.8
R
3
7
3.
5
5.
18.
3
6
3.
4
8.
15.
5R
4
7
5.
5
6.
19.
9
6
4.
4
8.
16.
2R
5
7
8.
5
6.
22.
1
6
9.
4
8.
20.
3R
6
7
7.
5
6.
20.
6
6
8.
4
9.
19.
3R7* 7
3.
5
6.
16.
6
6
3.
4
9.
14.
6R
8
7
9.
5
6.
22.
7
7
1.
4
9.
22.
1
8. R
9
7
8.
5
6.
21.
6
7
0.
4
9.
20.
7
Correlation of Failure Behavior to Strain Energy Models
The results from thermal measurements and design and material parameters were inputted into the Blattau model and
compared to ALT results. The inputs used for the calculation are shown in Figure 11. The solder joint height (h) of 0.036mm
was determined using a cross-section of a resistor on an unfailed board.
Figure 11: Inputs for the Blattau model
It can be seen that the cycles to failure prediction provided by the Blattau model (50,614 cycles) is within 5% of the observed
time to failure (53,215 cycles). These results would seem to suggest that plastic strain energy is still a critical driver for solder
fatigue under these conditions, even given the short dwell times (4 minutes) and high number of cycles (>50,000).
Additional modeling was performed using a crack propagation proposed by Han and Song27
specifically for chip resistors,
where
with N = crack propagation life, a = length of crack, K3 = 0.0044 (model constant for SnPb), K4 = 1.3227 (model constant for
SnPb), and ΔWave = averaged strain energy density change per thermal cycle. This equation ignores crack initiation (region 1)
and assumes that the life is dominated by crack propagation (region 2). Thermal data and FEA simulation was used to
determine the range of ΔWave based on the Han and Song model (see Figure 12). ΔWave was determined to be 0.020MPa for a
similar operating profile (5.67 min ON, 1.33 min OFF) to the ALT application. The ALT failures occurred at 50C ambient
and an output profile of 4min ON and 1 min OFF, which works out to the equivalent of 0.030MPa. Using this value of strain
energy density and a critical crack length of 1mm, based on the pad length, gives the following:
9. Figure 12: FEA model and estimate of ΔWave
Assessment of Potential Design Changes
Changes to the circuit design, PCBA layout, materials or operating conditions could be used to improve the robustness of the
2512 resistor solder joints under ALT. The Blattau model, due to its higher accuracy, was used to evaluate how particular
design changes would influence the expected lifetime. Table 2 below lists the proposed change and the estimated impact to
the expected life compared to the baseline.
Table 2: Proposed change and estimated impact to expected life compared to baseline.
10. Description Comment
CTF
Estima
te
Solde
r
Pack
age
Pad L
x W
(mm
Ambi
en
t
RF ON/OFF
Time
Out
put
PoBaseline ALT conditions 50,6
14
63Sn37
Pb
251
2
1.28 x
3.2
5
0
4min ON, 1min
OFF
6k
WChange to Pb-
free solder
Pb-free solder
performs better
with low strain
279,5
20
SAC30
5
251
2
1.28 x
3.2
5
0
4min ON, 1min
OFF
6k
W
Change Resistor
Package to 2010
from 2512
smaller solder joint 71,4
30
63Sn37
Pb
201
0
1.28 x
2.5
5
0
4min ON, 1min
OFF
6k
W
Lower Ambient
Temperature
from 50°C to
more like customer
operating
temperature
68,7
27
63Sn37
Pb
251
2
1.28 x
3.2
2
5
4min ON, 1min
OFF
6k
W
Increase Pad
Width from 3.2
slightly more cycles
for crack to
53,6
22
63Sn37
Pb
251
2
1.28 x
3.5
5
0
4min ON, 1min
OFF
6k
W
RF Output Power
reduced from
6kW to 0.5kW
shows ΔT
dependence
66,2
60
63Sn37
Pb
251
2
1.28 x
3.2
5
0
4min ON, 1min
OFF
0.5k
W
Conclusions
A strain energy based first order model is capable of relatively accurate prediction out to 50,000 power cycles with dwell
times less than 5 minutes. This would suggest that plastic strain and creep continue to play a critical role in solder joint
fatigue even under conditions that would tend to be extended beyond typical low-cycle fatigue.
References
12
WB Green, "A fatigue-free silicon device structure," American Institute of Electrical Engineers, Part I:
Communication and Electronics, Transactions of the , vol.80, no.2, pp.186-192, May 1961
13
HE Pattee and RM Evans, “The Performance of Some Soft Solders at Elevated Temperatures and Pressures,”
Special Technical Publication 189, ASTM, Philadelphia, PA, 1956, p. 103
14
LF Coffin, “The Problem of Thermal Stress Fatigue in Austenitic Steels,” Special Technical Publication 165, ASTM,
1954,
p. 31
15
LF Coffin, “A study of the Effects of Cyclic Thermal Stresses on a Ductile Metal,” Trans. ASME, 76, 931–950
(August 1954).
16
SS Manson, “Behavior of materials under conditions of thermal stress,” Proceedings of the Heat Transfer
Symposium, University of Michigan Engineering Research Institute, Ann Arbor, Mich, pp. 9-75, 1953.
17
SS Manson, “Discussion”, J. of Basic Engineering / Trans. ASME, p. 537-541, December 1962
18
Norris, K C, and A H Landzberg. “Reliability of Controlled Collapse Interconnections.” IBM Journal of
Research and Development 13, no. 3 (1969): 266-271
19
JESD47I, Stress-Test-Driven Qualification of Integrated Circuits, JEDEC, July 2012
20
JESD94A, Application Specific Qualification Using Knowledge Based Test Methodology, JEDEC, July 2008 (reaffirmed
September 2011)
21
Syed, A., "Limitations of Norris-Landzberg equation and application of damage accumulation based methodology for
estimating acceleration factors for Pb free solders," Thermal, Mechanical & Multi-Physics Simulation, and Experiments in
Microelectronics and Microsystems (EuroSimE), 2010 11th International Conference on , vol., no., pp.1,11, 26-28 April 2010
11
Hillman, C., “Assessment of Pb-Free Norris Landzberg Model to JG-PP Test Data” DfR Solutions Presentation, February
21, 2006
1
Miremadi, J., Henshall, G., Allen, A., Benedetto, E., Roesch, M., “Lead-Free Solder-Joint-Reliability Model
Enhancement”, IMAPS 2009
2
W. Engelmaier, Fatigue Life of Leadless Chip Carrier Solder Joints During Power Cycling, IEEE Trans. Comp. Hybrids
Manuf. Tech., vol CHMT-6, no. 3, September 1983, p. 232-237
3
R. N. Wild, “Properties of some low melt fusible solder alloys,” IBM Tech. Rep. No. 712000408, Oct. 1971
4
IPC SM-785 standard, Guidelines for Accelerated Reliability Testing of Surface Mount Solder Attachments.
5
Hall, P. M., "Strain measurements during thermal chamber cycling on leadless ceramic chip carriers soldered to printed
boards", Proceedings, 34th Electronic Components Conference, New Orleans, LA, May 14-16, 1984, pp. 107-116
6
TS Park and SB Lee, Isothermal Low Cycle Fatigue Tests of Sn/3.5Ag/0.75Cu and 63Sn-37Pb Solder Joints under Mixed
Mode Loading Cases, 52nd
Electronic Components and Materials Conference Proceedings, 2002, p. 23p4-s23p9
11. 7
Blattau, N. and Hillman, C. “An Engelmaier Model for Leadless Ceramic Chip Devices with Pb-free Solder,” IPC/JEDEC
Lead Free Conference, Santa Clara, CA, March 2006
19
Lead Free Solder: Mechanics and Reliability, by John Hock Lye Pang, Theory on Mechanics of Solder Materials chapter 2
20
Syed, A., “Accumulated Creep Strain and Energy Density Based Thermal Fatigue Life Prediction Models for SnAgCu
Solder Joints,” ECTC 2004, pp. 737-746 - corrected
(2) M. Osterman, Effect of Temperature Cycling Parameters (Dwell and Mean Temperature) on Durability of Pb-free
Solders, IMAPS Winter Technical Symposium, Chesapeake Chapter, January 2010
(3) O'Keefe, M.; Vlahinos, A., "Impacts of cooling technology on solder fatigue for power modules in electric traction
drive vehicles," Vehicle Power and Propulsion Conference, 2009. VPPC '09. IEEE , vol., no., pp.1182,1188, 7-10 Sept.
2009
(4) Herrmann, T.; Feller, M.; Lutz, J.; Bayerer, R.; Licht, T., "Power cycling induced failure mechanisms in solder
layers," Power Electronics and Applications, 2007 European Conference on , vol., no., pp.1,7, 2-5 Sept. 2007
(5) D. E. Hodges Popp et al., “Flip chip PBGA solder joint reliability: Power cycling versus thermal cycling”, Flip Chip
Technology Workshop and Exhibition, IMAPS, January 2003
(6) Jue Li; Karppinen, J.; Laurila, T.; Kivilahti, J.K., "Reliability of Lead-Free Solder Interconnections in Thermal and
Power Cycling Tests," Components and Packaging Technologies, IEEE Transactions on , vol.32, no.2, pp.302,308, June
2009
(7) D.R. Liu and Yi-Hsin Pao, Fatigue-creep crack propagation path in solder joints under thermal cycling, Journal of
Electronic Materials, V 26, N 9, 1997
(8) Changwoon Han and Byeongsuk Song, “Development of Life Prediction Model for Lead-free Solder at Chip
Resistor,” 2006 Electronics Packaging Technology Conference.