A Study of Process-Induced Residual Stress in PBGA Packages

1999 ◽  
Vol 122 (3) ◽  
pp. 262-266 ◽  
Author(s):  
Zhu Wu ◽  
Jian Lu ◽  
Yifan Guo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Electronic Packaging ◽  
Accurate Determination ◽  
Hole Drilling ◽  
3D Fem ◽  
Molding Compound ◽  
Plastic Ball ◽  
Calibration Coefficients

Process-induced residual stresses can play a significant role in the reliability of electronic components and packages. In this paper, a practical method is developed to determine residual stresses for electronic packaging. In this method, blind holes are drilled into the specimens and relationships are established, between the released surface displacements and the corresponding residual stress, by introducing a set of calibration coefficients. A multilayer 3D-FEM model is established to determine the relevant calibration coefficients. This methodology, which combines moire´ interferometry and the incremental hole drilling method, can provide an accurate determination of residual stresses in materials and structures by precisely controlled incremental blind-hole drilling and an accurate determination of the surface in-plane displacement fields in the hole drilling region. The methodology is implemented by investigating the residual stress in the Plastic Ball Grid Array (PBGA) packages. The tensile residual stresses are determined in both the plastic molding compound and the glass/epoxy laminate chip carrier. The method is accurate, simple, convenient, and practical. More applications, in residual stress determinations and in process evaluations in electronic packaging, are anticipated. [S1043-7398(00)00103-1]

Measurement of Residual Stresses Near the Surface Using the Crack Compliance Method

1991 ◽  
Vol 113 (2) ◽  
pp. 199-204 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
O¨. Vardar
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Computational Model ◽  
Strain Measurement ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Drilling Method

The use of thin cuts for residual stress measurement is referred to as the crack compliance method. A computational model is presented for the determination of normal and shear residual stresses near the surface by introducing shallow cuts. The optimum regions for strain measurement are obtained. This method is shown to be considerably more sensitive than the conventional hole drilling method and is capable of measuring residual stresses which vary with depth below the surface.

Determination of Residual Stresses in Austenite and Martensite in Case-Hardened Steels by the sin2ψ Method

1981 ◽  
Vol 25 ◽  
pp. 343-353 ◽  
Author(s):  
Chongmin Kim
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Fracture Resistance ◽  
Compressive Residual Stress ◽  
Accurate Determination ◽  
Essential Elements ◽  
Hardened Steels

Compressive residual stress is one of the essential elements which contributes to the exceptional fracture resistance of case-hardened components. The sign and magnitude of residual stress are determined by transformation characteristics, thermal and mechanical histories of the steel. Accurate determination of residual stresses is essential in research on case-hardened steels.

Dependence Between Aging Treatments and Residual Stresses on Composite Laminate

2006 ◽  
Vol 524-525 ◽  
pp. 813-817 ◽  
Author(s):  
Olivier Sicot ◽  
X.L. Gong ◽  
Xiao Jing Gong ◽  
Abel Cherouat ◽  
Jian Lu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Composite Structures ◽  
Hole Drilling ◽  
The Finite Element Method ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method ◽  
Initial Cycle ◽  
Calibration Coefficients

The objective of this paper is to study the influence of residual stresses due to fabrication conditions on the thermomechanical behavior of carbon/epoxy laminate structures (cross ply). These studied laminates have undergone various cycles of thermal aging. The addition of a post-cure cycle after the end of the initial cycle makes it possible to reduce the residual stresses level. The incremental hole-drilling method is used to measure the residual strain in the laminates. These measured strains and the numerical calibration coefficients obtained by the finite element method allow to calculating the residual stress distribution in composite depth. The obtained results show that heat treatments of composite structures do not lead to an important reduction the initial residual stress due the fabrication conditions.

Residual Stress Measurements in an Autofrettage Tube Using Hole Drilling Method

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hamid Jahed ◽  
Mohammad Reza Faritus ◽  
Zeinab Jahed
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Hoop Stress ◽  
Test Method ◽  
Test Material ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Ring Sample ◽  
Drilling Method ◽  
American Society

Relieved strains due to drilling hole in a ring sample cut from an autofrettage cylinder are measured. Measured strains are then transformed to residual stresses using calibration constants and mathematical relations of elasticity based on ASTM standard recommendations (American Society for Testing and Materials, ASTM E 837-08, 2008, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method,” American Society for Testing and Materials). The hydraulic autofrettage is pressurizing a closed-end long cylinder beyond its elastic limits and subsequently removing the pressure. In contrast to three-dimensional stress state in the autofrettage tube, the stress measurement in hole drilling method is performed on a traction free surface formed from cutting the ring sample. The process of cutting the ring sample from a long autofrettaged tube is simulated using finite element method (FEM) and the redistribution of the residual stress due to the cut is discussed. Hence, transformation of the hole drilling measurements on the ring slice to the autofrettage residual stresses is revealed. The residual stresses are also predicted by variable material properties (VMP) method (Jahed, H., and Dubey, R. N., 1997, “An Axisymmetric Method of Elastic-Plastic Analysis Capable of Predicting Residual Stress Field,” Trans. ASME J. Pressure Vessel Technol., 119, pp. 264–273) using real loading and unloading behavior of the test material. Prediction results for residual hoop stress agree very well with the measurements. However, radial stress predictions are less than measured values particularly in the middle of the ring. To remove the discrepancy in radial residual stresses, the measured residual hoop stress that shows a self-balanced distribution was taken as the basis for calculating residual radial stresses using field equations of elasticity. The obtained residual stresses were improved a lot and were in good agreement with the VMP solution.

NRC/EPRI Residual Stress Validation Program Phase I: Experimental Specimen Modeling and Measurement

2011 ◽  
Author(s):  
J. Broussard ◽  
P. Crooker
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Phase 1 ◽  
Measurement Techniques ◽  
Corrosion Cracking ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Pressurized Water

The US Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are working cooperatively under a memorandum of understanding to validate welding residual stress predictions in pressurized water reactor primary cooling loop components containing dissimilar metal welds. These stresses are of interest as DM welds in pressurized water reactors are susceptible to primary water stress corrosion cracking (PWSCC) and tensile weld residual stresses are one of the primary drivers of this stress corrosion cracking mechanism. The NRC/EPRI weld residual stress (WRS) program currently consists of four phases, with each phase increasing in complexity from lab size specimens to component mock-ups and ex-plant material. This paper describes the Phase 1 program, which comprised an initial period of learning and research for both FEA methods and measurement techniques using simple welded specimens. The Phase 1 specimens include a number of plate and cylinder geometries, each designed to provide a controlled configuration for maximum repeatability of measurements and modeling. A spectrum of surface and through-wall residual stress measurement techniques have been explored using the Phase 1 specimens, including incremental hole drilling, ring-core, and x-ray diffraction for surface stresses and neutron diffraction, deep-hole drilling, and contour method for through-wall stresses. The measured residual stresses are compared to the predicted stress results from a number of researchers employing a variety of modeling techniques. Comparisons between the various measurement techniques and among the modeling results have allowed for greater insight into the impact of various parameters on predicted versus measured residual stress. This paper will also discuss the technical challenges and lessons learned as part of the DM weld materials residual stress measurements.

Numerical Simulation of Residual Stresses due to Multipass Welding in High Strength Steel Plates and Validation against Experimental Measurements

2018 ◽  
Vol 941 ◽  
pp. 269-273
Author(s):  
Constant Ramard ◽  
Denis Carron ◽  
Philippe Pilvin ◽  
Florent Bridier
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Plates ◽  
Contour Method ◽  
Hole Drilling ◽  
Experimental Measurements ◽  
Element Analysis ◽  
Multipass Welding

Multipass arc welding is commonly used for thick plates assemblies in shipbuilding. Sever thermal cycles induced by the process generate inhomogeneous plastic deformation and residual stresses. Metallurgical transformations contribute at each pass to the residual stress evolution. Since residual stresses can be detrimental to the performance of the welded product, their estimation is essential and numerical modelling is useful to predict them. Finite element analysis of multipass welding of a high strength steel is achieved with a special emphasis on mechanical and metallurgical effects on residual stress. A welding mock-up was specially designed for experimental measurements of in-depth residual stresses using contour method and deep hole drilling and to provide a simplified case for simulation. The computed results are discussed through a comparison with experimental measurements.

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