Modeling and Analysis of Crack Growth in SnPb and SnAgCu Solder Joints in PBGA Packages: Part II — Crack Propagation

2003 ◽  
Author(s):  
Donghyun Kim ◽  
Andrew Mawer ◽  
Glenn Y. Masada ◽  
Tess J. Moon
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Solder Joints ◽  
Propagation Model ◽  
Modeling And Analysis ◽  
Snagcu Solder ◽  
Secondary Cracks ◽  
Aging Conditions ◽  
Length Data ◽  
Crack Growth Rates

Part II of this paper describes an experimental and analytical study of crack propagation in SnPb and SnAgCu solder joints in 357-PBGA packages exposed to 30-minute thermal cycles of 0 to 100°C. Experimental results show that cracks propagate faster at the package interface than at the board interface; secondary cracks from at the package interface, but grow much slower than the primary cracks; and crack growth rates in SnPb joints are about 50% larger than in SnAgCu joints. A crack propagation model, developed using the fracture mechanics approach, calculates the energy release rate at the crack tip. Using this rate and experimental crack length data, crack propagation rates were computed. Simulation results show the effects of solder type and aging conditions on crack propagation rates and the effects of the number of cracks in a joint on crack propagation life.

Fatigue crack propagation prediction of a pressure vessel mild steel based on a strain energy density model

2017 ◽  
Author(s):  
P. J. Huffman ◽  
J. Ferreira ◽  
J.A.F.O. Correia ◽  
A.M.P. De Jesus ◽  
G. Lesiuk ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Energy Density ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Propagation Model ◽  
Crack Growth Rates

Fatigue crack growth (FCG) rates have traditionally been formulated from fracture mechanics, whereas fatigue crack initiation has been empirically described using stress-life or strain-life methods. More recently, there has been efforts towards the use of the local stress-strain and similitude concepts to formulate fatigue crack growth rates. A new model has been developed which derives stress-life, strain-life and fatigue crack growth rates from strain energy density concepts. This new model has the advantage to predict an intrinsic stress ratio effect of the form ?ar=(?amp)?·(?max )(1-?), which is dependent on the cyclic stress-strain behaviour of the material. This new fatigue crack propagation model was proposed by Huffman based on Walkerlike strain-life relation. This model is applied to FCG data available for the P355NL1 pressure vessel steel. A comparison of the experimental results and the Huffman crack propagation model is made.

Modeling and Analysis of Crack Growth in SnPb and SnAgCu Solder Joints in PBGA Packages: Part I — Crack Initiation

2003 ◽  
Author(s):  
Donghyun Kim ◽  
Andrew Mawer ◽  
Glenn Y. Masada ◽  
Tess J. Moon
Keyword(s):  
Crack Initiation ◽  
Solder Joints ◽  
Void Formation ◽  
Grain Coarsening ◽  
Modeling And Analysis ◽  
Snagcu Solder ◽  
Secondary Cracks ◽  
Plastic Ball ◽  
Accelerated Thermal Cycling ◽  
Ball Grid Array Packages

Solder joints in electronic packages deform by creep and undergo a microstructural evolution process that includes grain coarsening, voiding, microcracking, and macrocracking. This paper describes an FEM model of the crack initiation process of SnPb and SnAgCu solder joints in 357 plastic ball grid array packages for different aging conditions and simulated under 0–100°C accelerated thermal cycling tests. The simulations show that 1) cracks initiate at the package interface first, and then at the opposite side of the board interface; 2) secondary cracks initiate at the opposite end of the primary crack at the joint interfaces; 3) no secondary cracks occur at the package interface of ages SnPb joints, since compressive stresses oppose void formation; and 4) it takes longer to initiate cracks in SnAgCu joints than SnPb joints. The damage process in the solder joints was simulated from grain coarsening, voiding, to microcracking, with SnAgCu joints not undergoing grain coarsening due to their stable microstructure. The model results were consistent with experimental results in the number and location of cracks in the joints.

A Fracture Mechanics Approach to Thermal Fatigue Life Prediction of Solder Joints

1990 ◽  
Vol 203 ◽  
Author(s):  
Yi-Hsin Pao
Keyword(s):  
Fracture Mechanics ◽  
Crack Propagation ◽  
Crack Growth ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Failure Process ◽  
Growth Equation ◽  
Thermal Fatigue Crack ◽  
Runge Kutta Method ◽  
Growth History

ABSTRACTThe approach developed is based on the assumption that thermal fatigue crack propagation in solder joints is primarily controlled by C* and J integrals. The effect of microstructural coarsening on crack propagation is discussed. A fracture criterion, J≥Jc, is used to define the failure of the joints. A crack growth governing equation has been formulated and can be numerically integrated to obtain the crack growth history given stress history as an input. The approach was applied to model the experiment by Wong and Helling [15]. In their experiment, surface-mounted electronic devices using eutectic Pb/Sn solder were tested in thermal cycles of −20 to 100°C and −55 to 125°C. A unified constitutive equation was assumed for the eutectic Pb/Sn solder. An equation for solving the shear stress in the joint was formulated and is coupled with the crack growth equation. Both equations were solved simultaneously by the Runge-Kutta method for the stress-time and crack growth history. The results of the prediction are in a good agreement with the experimental data, which indicates that fracture mechanics may be applied to describe the failure process of solder joints under cyclic thermal loadings.

scholarly journals Tunnel boring machine cutterhead crack propagation life prediction with time integration method

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985345 ◽  
Author(s):  
Jianbin Li ◽  
Zhange Zhang ◽  
Zhichao Meng ◽  
Junzhou Huo ◽  
Zhaohui Xu ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Prediction Model ◽  
Crack Growth ◽  
Life Prediction ◽  
Impact Load ◽  
Time Integration ◽  
Tunnel Boring Machine ◽  
Propagation Model ◽  
Strong Impact ◽  
Tunnel Boring

Fatigue damage is one of the most common failure modes of large-scale engineering equipment, especially the full-face tunnel boring machine with characteristics of a thick plate structure bearing strong impact load. It is difficult to predict the location and propagation life of crack of cutterhead under strong impact load. Unseasonal maintenance of equipment caused by inaccurate prediction of life cycle of cutterhead seriously affects the construction efficiency of the equipment and the life safety of the operators. Determining the crack location of tunnel boring machine cutterhead structure under strong impact load and predicting the crack propagation life are difficult scientific problems. To solve them, first, the location of the stress concentration of the cutterhead is determined by using finite element analysis method of statics. Second, prediction model for crack propagation life of tunnel boring machine cutterhead characteristic substructure based on time integration is built. And the test of crack growth of cutterhead characteristic substructure is performed. The feasibility and accuracy of the prediction model are verified by contrasting crack prediction models and the results of the test. Finally, the life prediction of tunnel boring machine cutterhead of water diversion project in Northwest Liaoning Province is carried out by using crack propagation model based on time integration. Results show that the maximum error of theoretical prediction and experimental results of crack propagation is 16%. So the feasibility of crack propagation model based on time integration in predicting the crack growth of cutterhead is verified. It is predicted that the tunnel boring machine cutterhead panel can work normally for 5.9 km under the condition of ultimate load. Building the crack propagation model considering the influence of plate thickness and strong impact load has important research value for improving the working efficiency of engineering equipment, prolonging service time, and improving the working safety.

scholarly journals Fatigue-Crack Propagation Behavior of Incoloy 800 at Elevated Temperatures

1974 ◽  
Vol 96 (4) ◽  
pp. 249-254 ◽  
Author(s):  
L. A. James
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Growth Rates ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Incoloy 800 ◽  
Crack Growth Rates ◽  
Crack Propagation Behavior

Linear-elastic fracture mechanics techniques were used to characterize the fatigue-crack propagation behavior of Incoloy 800 in an air environment over the temperature range 75 to 1200 deg F (24 to 649 deg F). Crack growth rates were measured over the range 5×10−7 to 5×10−5 in./cycle. Material Grades 1 and 2 were found to exhibit essentially the same behavior over this range. In general, crack growth rates increased with increasing test temperature, although the increases were less then previously noted for austenitic stainless steels. This difference is probably related to the superior oxidation resistance of Incoloy 800.

Experimental Investigations of Fatigue Crack Propagation for Pipe Under Torsional Loading

2010 ◽  
Author(s):  
Motoki Nakane ◽  
Satoshi Kanno ◽  
Shota Hashimoto ◽  
Takayuki Watanabe ◽  
Yukio Takahashi
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Growth Rates ◽  
Torsional Loading ◽  
Crack Growth Rates

This study discusses methods for evaluating fatigue crack propagation under torsional loading for pipes. To achieve this objective, fatigue crack propagation tests were carried out on both stainless steel and carbon steel used in piping systems of nuclear power plants. Two different kinds of pipes were tested in this study. These pipes had the same shape but the diameter and thickness of the larger pipe were twice those of the smaller pipe. The nominal shear stress amplitudes applied to the specimen were set between 50 and 100 MPa depending on the dimension of the specimen and desired crack growth rates. All fatigue tests were conducted under pure torsional loading with stress ratio R = −1 and at room temperature. The geometrical correction factors for the specimen were derived from elastic J-integral calculated by the FEM. The fatigue crack propagation tests results show that the crack growth rates estimated by the elastic stress intensity factor with the geometrical correction factor were much faster than curves prescribed in The Japan Society of Mechanical Engineers (JSME) codes. These results suggest that elastic plastic fracture parameters should be considered into the stress intensity factor because yield stresses for torsional loading would be smaller than those of uniaxial loading. The plastic zone correction method and modified reference stress method were examined as alternative methods. The crack growth rates estimated by the proposed methods almost totally correspond to the JSME curves. The two proposed methods were found to be quite effective at correctly evaluating the crack growth rates under torsional loading.

Crack Growth Sensitivity to the Magnitude and Frequency of Load Fluctuation in Stage 1b of High pH Stress Corrosion Cracking

CORROSION ◽  
10.5006/3711 ◽  
2021 ◽  
Author(s):  
Hamid Niazi ◽  
Greg Nelson ◽  
Lyndon Lamborn ◽  
Reg Eadie ◽  
Weixing Chen ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Initiation ◽  
Plastic Zone ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Tip ◽  
Cyclic Plastic Zone ◽  
Secondary Cracks

Pipelines undergo sequential stages before failure caused by High pH Stress Corrosion Cracking (HpHSCC). These sequential stages are incubation stage, intergranular crack initiation (Stage 1a), crack evolution to provide the condition for mechanically driven crack growth (Stage 1b), sustainable mechanically driven crack propagation (Stage 2), and rapid crack propagation to failure (Stage 3). The crack propagation mechanisms in Stage 1b are composed of the nucleation and growth of secondary cracks on the free surface and crack coalescence of secondary cracks with one another and the primary crack. These mechanisms continue until the stress intensity factor (<i>K</i>) at the crack tip reaches a critical value, known as <i>K</i><sub>ISCC</sub>. This investigation took a novel approach to study Stage 1b in using pre-cracked Compact Tension (CT) specimens. Using pre-cracked specimens and maintaining <i>K</i> at less than <i>K</i><sub>ISCC</sub> provided an opportunity to study crack initiation on the surface of the specimen under plane stress conditions in the presence of a pre-existing crack. In the present work, the effects of cyclic loading characteristics on crack growth behavior during Stage 1b were studied. It was observed that the pre-existing cracks during Stage 1b led to the initiation of secondary cracks. The initiation of the secondary cracks at the crack tip depended on loading characteristics, <i>i.e</i>., the amplitude and frequency of load fluctuations. The secondary cracks at the crack tip can be classified into four categories based on their positions with respect to the primary crack. A high density of intergranular cracks formed in the cyclic plastic zone generated by low R-ratio cycles. The higher the frequency of the low <i>R</i>-ratio cycles, the higher the density of the intergranular cracks forming in the cyclic plastic zone. The crack growth rate increased with an increase in either the amplitude or the frequency of the load fluctuations. The minimum and maximum crack growth rates were 8×10<sup>-9</sup> mm/s and 4.2×10<sup>-7</sup> mm/s, respectively, with <i>R</i>-ratio varying between 0.2 and 0.9, frequency varying between 10<sup>-4</sup> Hz and 5×10<sup>-2</sup> Hz, and at a fixed stress intensity factor of 15 MPa.m<sup>0.5</sup>. It was found that avoiding rapid and large load fluctuations slowed down crack geometry evolution and delayed onset of Stage 2. The implication of these results for pipeline operators is that reducing internal pressure fluctuations by reducing the frequency and/or amplitude of the fluctuations can expand Stage 1 and increase the reliable lifetime of operating pipelines.

Fatigue Crack Propagation in 8- and 22-Layer 7075-T6 Aluminum Alloy Laminates

1978 ◽  
Vol 100 (1) ◽  
pp. 32-38 ◽  
Author(s):  
N. J. Pfeiffer ◽  
J. A. Alic
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Propagation Rate ◽  
Crack Arrest ◽  
Propagation Rate ◽  
Adhesively Bonded ◽  
Crack Divider ◽  
Crack Growth Rates

Rates of fatigue crack propagation have been determined for adhesively bonded 7075-T6 laminates having a crack divider geometry. Two lamina thicknesses were used, the resulting laminates having either 8 or 22 layers. Crack growth rates were generally within the same range as for monolithic 7076-T6 alloy, and were somewhat slower in the 22-layer laminates than in those with 8 layers. Instances of decreasing crack propagation rate with increasing stress intensity amplitude, as well as of crack arrest, were observed. These are interpreted in terms of interactions between the layers during the progressive transition from a flat mode of crack growth to a slant mode.

Three Dimensional Criterion for Creep Crack Propagation in C(T) Specimen

2016 ◽  
Vol 853 ◽  
pp. 142-147
Author(s):  
Wen Ming Ye ◽  
Xu Teng Hu ◽  
Wan Lin Guo ◽  
Ying Dong Song
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Growth Rates ◽  
Three Dimensional ◽  
Creep Crack Growth ◽  
Growth Control ◽  
Compact Tension ◽  
Thickness Effect ◽  
Creep Crack ◽  
Crack Growth Rates

Experimental of two kinds of compact tension (CT) specimens’ creep crack propagation are carried out in this paper. Traditional fracture mechanics and three-dimensional fracture theory are compared and the results show that: The K-Tz two-parameter model can eliminate the thickness-effect on the crack growth rates in the relatively low K range, however when K exceed certain values the effect of thickness for crack growth rates still exists; The Ct and Ct-Tz model can describe the thickness-effect of creep crack growth rates in regions of high Ct; When the crack tip stress intensity factor K of the two kinds of thickness (B=5 mm, B=10 mm) specimens equal to 35 and 31 respectively, this material’s creep crack growth control parameter change from K to Ct.

Transient Fatigue Crack-Growth Behavior and Damage Zones in Zr-Based Bulk Metallic Glass

2003 ◽  
Vol 806 ◽  
Author(s):  
Peter A. Hess ◽  
Reinhold H. Dauskardt
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
Growth Rates ◽  
Fatigue Loading ◽  
Structural Applications ◽  
Crack Growth Rates

ABSTRACTFatigue crack propagation mechanisms of bulk metallic glasses (BMGs) are not well understood, limiting their use in safety-critical structural applications particularly where complex fatigue loading may occur. Accordingly, the present study examines the effects of variable amplitude fatigue loading associated with block loading and tensile overloads on fatigue crack-growth rates in a Zr-based BMG. Crack growth studies were conducted on compact tension specimens using computer control of the applied stress intensity range, ΔK. Fatigue crack closure loads, which represent the initial contact of mating crack surfaces during the unloading cycle, were continuously monitored during testing. Abrupt drops in ΔK were found to significantly decrease fatigue crack-growth rates far below equilibrium values, arresting growth completely at a ΔK twice the nominal fatigue threshold ΔKTH. Conversely, an abrupt increase in ΔK was found to accelerate fatigue crack-growth rates. The effects of roughness-induced crack closure were assessed and found to be consistent with the suppression or acceleration of growth rates. However, in order to fully explain the observed transient growth rate response, other mechanisms that may be related to the fatigue mechanism itself were also considered. Specifically, the nature of the fatigue crack tip damage zone was also investigated. As BMGs lack distributed plasticity at low temperatures, the plastic zone differs greatly from that seen in ductile crystalline materials, and its role in fatigue crack propagation mechanisms is examined.

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