Fatigue Test for Thick Wire Bonds

2014 ◽  
Author(s):  
Turker Dagdelen ◽  
Karim El-Rayes ◽  
Sangtak Park ◽  
Mahmoud Khater ◽  
Resul Saritas ◽  
...  
Keyword(s):  
Fatigue Test ◽  
Mechanical Load ◽  
Life Time ◽  
Wheatstone Bridge ◽  
Wire Bonds ◽  
Power Modules ◽  
Wide Range ◽  
Bonding Wires ◽  
Number Of Cycles ◽  
Thick Wire

Thick bonding wires used in power modules experience a wide range of temperature and mechanical load cycling conditions. This leads to cracks at the wire heel due to fatigue. In this study, a new type of thick wire bonds, Aluminum coated copper, was subjected to fatigue test to investigate its durability. Unlike traditional thermal cycling, this test involves applying a pattern of repetitive prescribed displacements to a wire foot while fatigue failure is detected via a Wheatstone bridge. The aim is to compare different wire materials to the number-of-cycles-to-failure, thereby quantifying the reliability and life time of thick wire bond.

scholarly journals The behaviour of a single crystal of aluminium under alternating torsional stresses while immersed in a slow stream of tap water

1932 ◽  
Vol 135 (827) ◽  
pp. 392-411 ◽  
Keyword(s):  
Single Crystal ◽  
Fatigue Test ◽  
Corrosion Fatigue ◽  
Tap Water ◽  
Present Report ◽  
Cycle Number ◽  
Corrosion Fatigue Crack ◽  
Mechanical Methods ◽  
Wide Range ◽  
Number Of Cycles

The characteristics of the deformation and fracture of metals under repeated cycles of stress, generally described as “fatigue phenomena,” have received very considerable attention, both experimental and theoretical. Usually, consideration has been devoted exclusively to conditions in which the metal subjected to fatigue has its free surface exposed to the ordinary atmosphere. In many cases in actual practice, however, metals are subjected to fatigue action while surrounded by a fluid—either gaseous or liquid—which is of a corrosive nature and the endurance or “life” of the metal is controlled by the simultaneous conjoint action of the applied stresses and the corrosive agent. To such conditions the term “corrosion-fatigue” has been applied. Attention was first directed to this aspect of fatigue phenomena in 1917 by Haigh, who demonstrated experimentally that, in general, fatigue stresses and corrosive influences may be mutually accelerative, producing more destructive effects than either influence when acting separately, or when the stressing is applied subsequent to the corrosion stage. The subject then appeared to escape further attention for a period of about nine years, after which the results of the first of a series of important researches were published; in this connection reference should be made to the work of Lehmann, McAdam, Speller, McCorkle and Mumma, Binnie, Fuller, Haigh and Jones, etc. From the researches of these investigators, and particularly from those of McAdam, a very large amount of data is now available regarding the corrosion-fatigue resistance of a wide range of metals and alloys, and the separate effects of such variables as frequency of stress cycle, number of cycles, corrosion time, applied range of stress, etc., also of corrosion inhibitors and accelerators. No attention has apparently been given hitherto to the changes in microstructure occurring during a corrosion-fatigue test and, as a result, no information existed on such fundamental points as (i) the general course of a corrosion-fatigue crack; whether intercrystalline or transcrystalline; (ii) the actual point of initiation of the crack; whether it is situated at a crystal boundary, or on the site of previous slip bands, or at local corrosion pits bearing no distinct relation to these special positions. In planning a research with these general objects in view it was decided to make experiments, under corrosion-fatigue conditions, on ( a ) a single crystal, ( b ) a specimen consisting of two large crystals with the separating boundary, and ( c ) a specimen consisting of the usual finely-divided aggregate of crystals. By using single crystals and large crystal specimens and employing X-ray, microscopical and mechanical methods, it was hoped to correlate corrosion-fatigue phenomena with the fine structure. The present report describes the observations made on what is believed to be the first corrosion-fatigue test on a single crystal.

The generalized regularities of damageability and integrity in estimations of the endurance in conditions of variability of loading regimes

2019 ◽  
Vol 85 (9) ◽  
pp. 61-65
Author(s):  
N. A. Makhutov
Keyword(s):  
Life Time ◽  
Cyclic Strength ◽  
Laboratory Diagnostics ◽  
Methodological Issues ◽  
Break Points ◽  
Number Of Cycles ◽  
Cyclic Damage ◽  
Damage Summation ◽  
Temperature Factors

We consider and analyze general methodological issues regarding the strength and endurance (life-time) of the materials and structure elements under a combined effect of various force, deformation and temperature factors. The Journal "Zavodskaya laboratoriya. Diagnostika materialov" (Industrial laboratory. Diagnostics of materials) has launched systematic publications on this problematic since 2018. For many decades, domestic and foreign laboratory studies have gleaned to a traditional methodology for obtaining initial curves of the long-term and cyclic strength that related the breaking stresses with time or number of cycles. These curves, with the characteristic sections and break points, separating the areas of elastic and inelastic (plastic strain or creep strain) strain, are used in analysis of long-term and cyclic damage. Using the elementary linear law of damage summation, it is possible to calculate at a first approximation the strength and endurance under varying conditions of loading. Stepping up the requirements to the accuracy of calculations necessitates a transition from force fracture criteria (at stresses a) to deformation criteria (in elastic and inelastic deformations e). Thus, it becomes possible to construct and use a unified expression for the curve of the long-term cyclic fracture (taking into account the temporal x and cyclic N factors) and a long-term cyclic damage. With such approach it is possible to remain the linear law of damage summation though those damages are obviously nonlinear. The goal of the study is to continue and support the discussion of the most complex problems of a comprehensive assessment of the strength, resource, survivability and safety of high-risk engineering equipment within the journal pages.

Low-Temperature Joining Technique as Interconnection Technology for Power Electronics

2011 ◽  
Vol 324 ◽  
pp. 437-440
Author(s):  
Raed Amro
Keyword(s):  
Low Temperature ◽  
Power Electronics ◽  
Life Time ◽  
Junction Temperature ◽  
Limiting Factors ◽  
Power Devices ◽  
Packaging Technology ◽  
Power Cycling ◽  
Power Modules ◽  
Bond Wires

There is a demand for higher junction temperatures in power devices, but the existing packaging technology is limiting the power cycling capability if the junction temperature is increased. Limiting factors are solder interconnections and bond wires. With Replacing the chip-substrate soldering by low temperature joining technique, the power cycling capability of power modules can be increased widely. Replacing also the bond wires and using a double-sided low temperature joining technique, a further significant increase in the life-time of power devices is achieved.

Artificial Neural Network and the Taguchi Method Application for Robust Wheatstone Bridge Design

1994 ◽  
Author(s):  
Jung-eui Hong ◽  
Cihan H. Dagli ◽  
Kenneth M. Ragsdell
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Wheatstone Bridge ◽  
Parameter Design ◽  
System Response ◽  
Measurement Circuit ◽  
Wide Range ◽  
Reduce Measurement Error ◽  
On Line ◽  
Artificial Neural

Abstract The primary function of the Wheatstone bridge is to measure an unknown resistance. The elements of this well-known measurement circuit will take on different values depending upon the range and accuracy required for a particular application. The Taguchi approach to parameter design is used to select values for the measurement circuit elements so as to reduce measurement error. Next we introduce the use of an artificial neural network to extrapolate limited experimental results to predict system response over a wide range of applications. This approach can be employed for on-line quality control of the manufacture of such device.

Some Regularities of Life Time and Damage for the New Structural Material MoNiCa during Sliding Friction and Mechano-Sliding Fatigue

2021 ◽  
Vol 320 ◽  
pp. 90-96
Author(s):  
Aliaksandr Bahdanovich ◽  
Sergei Sherbakov ◽  
Ivan Lis ◽  
Regita Bendikiene ◽  
Ramūnas Česnavičius ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Structural Material ◽  
Mechanical System ◽  
Sliding Friction ◽  
Limit State ◽  
High Strength ◽  
Life Time ◽  
Average Wear ◽  
The Republic ◽  
Number Of Cycles

The results of an experimental study of damage for the structural material MoNiCa (it is high-strength cast iron VCHTG – patent of the Republic of Belarus № 15617) on sliding friction and mechano-sliding fatigue are analyzed in the report. Tests of the mechanical system shaft (a sample with a working part diameter of 10 mm made of 0.45 % carbon steel) - an insert (a prismatic counter sample with a cross section of 10 ´ 10 mm made of MoNiCa) were carried out. The kinetics of the change in average wear at 8 local points along the perimeter of the dangerous area of the sample is given for contact loads FN from 20 to 92 N of the mechanical system under study with MoNiCa inserts without heat treatment and with heat treatment. The test results of the system under study are also presented in the form of sliding friction and mechano-sliding fatigue curves in coordinates of the contact load FN – the number of cycles N until the limit state.

Study of the low cycle fatigue of 12Cr18Ni10Ti steel based on fractal analysis and artificial intelligence approaches

2021 ◽  
Vol 87 (9) ◽  
pp. 59-67
Author(s):  
A. A. Khlybov ◽  
Yu. G. Kabaldin ◽  
M. S. Anosov ◽  
D. A. Ryabov ◽  
D. A. Shatagin
Keyword(s):  
Neural Network ◽  
Growth Rate ◽  
Fractal Dimension ◽  
Low Temperatures ◽  
Main Crack ◽  
Fatigue Loading ◽  
Wide Range ◽  
Lower Temperature ◽  
Number Of Cycles ◽  
Dimension Index

The evolution of the structure and assessment of the age limit of steel 12Cr18Ni10Ti upon fatigue loading is considered using neural network modeling and approaches of fractal analysis of the microstructure. An algorithm for processing images of the microstructures has been developed to improve their quality. An indicator of the fractal dimension of the image is used as a quantitative indicator for assessing the evolution of the microstructure of the surface metal layer. A quantitative assessment of the structures at different stress amplitudes is carried out in a wide range of low temperatures using the fractal dimension index. Correlation of the fractal dimension index with the run of the sample material is shown. The appearance of the main crack was observed in the range of 0.7 - 0.8 from the number of cycles to failure, after which the crack growth rate increased. At a lower temperature, the main crack is formed later, but further loading results in a higher crack growth rate. Formation of the secondary phases in austenitic steel at a lower temperature occurred at earlier stages than that at a temperature of t = +20°C, which led to hardening of the material. An artificial neural network (ANN) has been developed and trained for assessing structural changes in metal proceeding from the fractal dimensionality of the microstructure images at different stages of fatigue loading. The developed neural network made it possible to estimate with a sufficiently high accuracy the number of cycles before damage of the sample and the residual life of the material. Thus, the developed ANN can be used to assess the current state of the material in a wide range of low temperatures.

Reduced Order Finite Element Modeling of Thermally Induced Bearing Loads in Machine Tool Spindles

1999 ◽  
Author(s):  
Alex O. Gibson ◽  
Jeffrey L. Stein
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Machine Tool ◽  
Mechanical Load ◽  
Machining Process ◽  
Thermally Induced ◽  
Reduced Order ◽  
Wide Range ◽  
Bearing Load ◽  
Bearing Loads

Abstract Machine tool spindle bearings are subjected to a large range of axial and radial loads due to the machining process. Further the rotating spindle must be extremely stiff to minimize the cutting tool’s deflection. The high spindle stiffness is achieved by applying a mechanical load to the bearings, the preload. In fixed preload spindles the bearing loads tend to increase with increasing spindle speed due to thermal expansion and it is well established that these thermally induced loads can lead to premature bearing failure. A model of thermally induced bearing load in angular contact bearing spindles is developed that includes an axis-symmetric reduced order finite element model of the heat transfer and thermal expansion within the spindle’s housing and shaft and the bearing and shaft dynamics. Nodal reduction is used in the reduced order model to minimize the number of temperature states and the computational load. The reduced order model’s calculated temperature and bearing load values are shown to closely match experimentally measured values over a wide range of spindle speeds. The paper ends with a parameter variation study which predicts a dramatic decrease in the thermally induced bearing load when silicon nitride balls are substituted for steel balls.

Mechanical Characterization of Transient Liquid Phase Sintered (TLPS) Cu-Sn

2018 ◽  
Author(s):  
Erick Gutierrez ◽  
Subramani Manoharan ◽  
Maxim Serebreni ◽  
Patrick McCluskey
Keyword(s):  
Liquid Phase ◽  
Mechanical Load ◽  
Transient Liquid Phase ◽  
Electronic Systems ◽  
Power Electronic ◽  
Nano Indentation ◽  
Lap Shear ◽  
Die Attach ◽  
Power Modules

The increasing thermal demands in power electronic systems require the application of high temperature die attach materials. Transient Liquid Phase Sintered (TLPS) paste-based solder alloys have been demonstrated to effectively manage the thermal and mechanical load requirements of power modules. The microstructural features of these alloys provide interconnects with the necessary strength required to sustain high loads at high temperatures. To properly understand the influence of microstructure on mechanical behavior of these alloys, single lap shear experiments were performed on a TLPS system consisting of Copper and Tin particles (Cu-Sn). Nano-indentation measurements were performed on intermetallic phases of the TLPS, and the results obtained from lap shear testing and nano-indentation measurements are presented.

Comparison Between ASME Code-Case N-761, NUREG/CR-6909 and Stainless Steel Component Fatigue Test Results

2014 ◽  
Author(s):  
H. T. Harrison ◽  
Robert Gurdal
Keyword(s):  
Stainless Steel ◽  
Fatigue Test ◽  
Fatigue Tests ◽  
Test Series ◽  
Test Results ◽  
Actual Number ◽  
Steel Component ◽  
Class 1 ◽  
Asme Code ◽  
Number Of Cycles

For Class 1 components, the consideration of the environmental effects on fatigue has been suggested to be evaluated through two different methodologies: either NUREG/CR-6909 from March 2007 or ASME-Code Case N-761 from August 2010. The purpose of this technical paper is to compare these two methods. In addition, the equations from Revision 1 of the NUREG/CR-6909 will be evaluated. For these comparisons, two stainless steel component fatigue test series with documented results are considered. These two fatigue test series are completely different from each other (applied cyclic displacements vs. insurge/outsurge types of transients). Therefore, they are producing an appropriate foundation for these comparisons. In general, the severities of the two methods are compared, where the severity is defined as the actual number of cycles from the fatigue tests, including an evaluation of the scatter, divided by the number of design cycles from the two methods. Also, how stable the methods are is being evaluated through the calculation of the coefficient of variation for each method.

Real-Time Monitoring of Thermal Response and Life-Time Varying Parameters in Power Modules

2020 ◽  
Vol 56 (5) ◽  
pp. 5279-5291 ◽  
Author(s):  
Christoph H. van der Broeck ◽  
Timothy A. Polom ◽  
Robert D. Lorenz ◽  
Rik W. De Doncker
Keyword(s):  
Real Time ◽  
Thermal Response ◽  
Life Time ◽  
Time Varying ◽  
Real Time Monitoring ◽  
Varying Parameters ◽  
Power Modules ◽  
Time Varying Parameters
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