Three- and Four-Point Bend Testing for Electronic Packages

2003 ◽  
Vol 125 (4) ◽  
pp. 556-561 ◽  
Author(s):  
Santosh Shetty ◽  
Tommi Reinikainen
Keyword(s):  
Bending Test ◽  
Electronic Packages ◽  
Reliability Model ◽  
Test Results ◽  
Printed Wiring Board ◽  
Reliability Models ◽  
Four Point Bending ◽  
Three Point Bend Test ◽  
Point Bend ◽  
Wiring Board

This study demonstrates the application of three-point and four-point bending tests for evaluating the reliability of chip scale packages under curvature loads. A three-point bend test is conducted on 0.5-mm-pitch chip-scale packages (CSPs) mounted on FR4 (Flame Retardant) substrates. This test is simulated by using the finite element method and the results are calibrated experimentally to formulate a reliability model. A three-point bend scheme is an ideal choice for generating reliability models because multiple packages can be tested under multiple loads in a single test. This reliability model can be used to predict the durability of the packages in the real product under any printed wiring board (PWB) curvature loading conditions. A four-point bending simulation is also demonstrated on the test substrate. Four-point bending test is an ideal method for testing a larger sample size of packages under a particular predefined stress level. This paper describes the bending simulation and testing on packages in a generic sense. Due to the confidentiality of the test results, the package constructional details, material properties, and the actual test data have not been presented here.

Creep Rupture Bending Test of 20 Percent Cold-Prestrained Ni-Fe-Cr Alloy Straight Tubes at 1100 F(593 C)

1981 ◽  
Vol 103 (4) ◽  
pp. 337-344 ◽  
Author(s):  
H. H. Woo ◽  
R. H. Ryder ◽  
K. H. Holko ◽  
R. F. Stetson
Keyword(s):  
Crack Initiation ◽  
Creep Rupture ◽  
Bending Test ◽  
Strain History ◽  
Test Results ◽  
Local Material ◽  
Initiation And Propagation ◽  
Nonuniform Stress Field ◽  
Point Bend ◽  
Four Point Bend Test

A four-point bend test was performed on 20 percent cold-prestrained Ni-Fe-Cr alloy tubes at 1100 F (593 C) to verify that creep rupture damage can be used to predict failure in a nonuniform stress field. Deflection control and acoustic emission techniques were used to detect crack initiation, strain gages were employed to record the strain history in the specimen, and a scanning electron microscrope was utilized to check crack initiation and propagation. Stress analyses were made using simplified and finite element methods. Comparison of test results and analyses concluded that creep rupture damage can be used to predict local material failure for structural components under multiaxial nonuniform loading conditions.

Warpage Measurement Using Projection Moire´ System and Two Automatic Image Segmentation Algorithms

2007 ◽  
Author(s):  
Wei Tan ◽  
I. Charles Ume
Keyword(s):  
Image Segmentation ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Segmentation Algorithms ◽  
Out Of Plane ◽  
Cte Mismatch ◽  
Image Models ◽  
Wiring Board ◽  
Plane Displacement ◽  
Projection Moire

Out-of-plane displacement (warpage) has been a major reliability concern for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may lead to serious reliability problems. In this paper, a projection moire´ warpage measurement system and two types of automatic image segmentation algorithms were presented. In order to use the projection moire´ technique to separately determine the warpage of a PWB and assembled electronic packages in a PWBA, two image segmentation algorithms based on mask image models and active contour models (snakes) were developed. They were used to detect package locations in a PWBA displacement image generated by the projection moire´ system. The performances of the mask image and snake approaches based on their resolutions, processing rates, and measurement efficiencies were evaluated in this research. Real-time composite Hermite surface models were constructed to estimate the PWB warpage values underneath the electronic packages. The above automatic image segmentation algorithms were integrated with the projection moire´ system to accurately evaluate the warpage of PWBs and assembled chip packages individually.

Influence of Fly Ash on the Mechanical Properties of Engineered Cementitious Composites Cured at High Temperature

2010 ◽  
Vol 113-116 ◽  
pp. 1293-1296
Author(s):  
Yu Zhu ◽  
Ying Zi Yang ◽  
Hong Wei Deng ◽  
Yan Yao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Bending Test ◽  
Cementitious Composites ◽  
Test Results ◽  
Four Point Bending ◽  
High Volume Fly Ash ◽  
Compressive Strength Test

In order to investigate the mechanical properties of cementitious composites (ECC) cured at 60°C, four-point bending test and compressive strength test are employed to analyze the effect of fly ash on the properties of ECC. The replacement ratio of cement with fly ash is 50%, 70% and 80%, respectively. The test results indicate that ECC with high volume fly ash still remain the characteristic of pseudo-strain hardening and the deflection of ECC increases remarkably by adding more fly ash. The observations of ECC indicate that the crack width is relatively smaller for higher volume fly ash ECC. Meanwhile, compressive strength of ECC specimens with 80% fly ash can reach to 70MPa. This is helpful to produce precast ECC with high volume of fly ash.

Acceleration Factor to relate Thermal Cycles to Power Cycles for Ceramic Ball Grid Area Array Packages

2006 ◽  
Vol 3 (4) ◽  
pp. 177-193 ◽  
Author(s):  
Andy Perkins ◽  
Krishna Tunga ◽  
Suresh Sitaraman
Keyword(s):  
Fatigue Life ◽  
Environmental Parameters ◽  
Acceleration Factor ◽  
Junction Temperature ◽  
Design Parameters ◽  
Substrate Thickness ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Ceramic Ball ◽  
Wiring Board

There is a need for a new Acceleration Factor (AF) that can relate Accelerated Thermal Cycle (ATC) fatigue life to Power Cycle (PC) fatigue life quickly and accurately in order to avoid over designing electronic packages for benign environments. An AF, such as the Norris-Landzberg AF, is only applicable when using it to predict fatigue life within the same environment, i.e. ATC to ATC or PC to PC. This work proposes an AF that takes into account the differences between ATC tests and PC tests for ceramic ball grid array (CBGA) packages by considering relevant design and environmental parameters. The new AF is based on relevant design parameters such as substrate size, substrate thermal conductivity, substrate thickness, coefficient of thermal (CTE) mismatch between the substrate and printed wiring board (PWB), PWB thickness, and environmental parameters such as temperature range (ΔT), frequency of cycles (f), and peak/junction temperature (Tj). Finite Element Models (FEM), experimental data, laser moiré interferometry, Design of Simulation (DOS), ANOVA, and regression analysis are used to develop the new AF. The new AF can be used to more accurately assess PC fatigue life from ATC tests so that expensive over-designing of electronic packages can be avoided for desktop/server/laptop applications.

Thermal Evaluation of High-Current Polyimide Rigid and Rigid-Flex Printed Wiring Board Trace Widths in a Vacuum

2013 ◽  
Vol 2013 (1) ◽  
pp. 000964-000969
Author(s):  
Bennion Cannon ◽  
Frank Friedl ◽  
Gary Gisler
Keyword(s):  
Thermal Imaging ◽  
Hot Spots ◽  
Test Results ◽  
High Current ◽  
Printed Wiring Boards ◽  
Printed Wiring Board ◽  
Thermal Imaging Camera ◽  
Industry Standards ◽  
Imaging Camera ◽  
Wiring Board

This paper details the thermal evaluation of high-current polyimide rigid and rigid-flex printed wiring boards in a vacuum. Although industry standards, such as IPC-2152 or MIL-STD-275, can be used to determine required trace width for PWB traces that carry current to between 20 or 30 amps for multiple copper plane thicknesses, they typically cannot be used to determine trace width for PWB traces that handle current greater than 15 amps. This paper presents results from testing and analysis of high-current rigid and rigid-flex PWBS that must carry current of up to 60 amps. Testing was performed in vacuum on a controlled-temperature platen, measuring board temperature at specific locations to determine performance of different trace widths using 2 and 4 ounce copper layers. A thermal imaging camera was used to identify PWB hot spots. Test results were compared to IPC-2152 standards, extrapolated to 60 amps current.

Extending the Fatigue Life of Solder Grid Array (SGA) Electronic Packages

2003 ◽  
Vol 125 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Michael C. Larson ◽  
Melody A. Verges
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Opening ◽  
Shear Loading ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Solder Interconnects ◽  
Force Mode ◽  
Wiring Board ◽  
Crack Growth Model

A fracture mechanics approach is used to investigate how the fatigue life of a solder grid array (SGA) may be increased or decreased by the application of an axial force to individual solder interconnects, such as may be induced by use of an underfill, by warping of a printed wiring board, or by some other mechanical constraint. The predominant loading on the SGA is assumed to be the shear resulting from a difference in thermal expansion between the package and the printed wiring board in the presence of cyclic temperature variations. A fatigue crack growth model, akin to the Paris law, is proposed for the cycles to failure of an individual cracked interconnect which undergoes a cyclic mode-II shear loading in conjunction with either a constant crack opening force (mode-I) or a constant crack closing force. For typical SGA packages in use today, the model predicts that forces on the order of only one newton can significantly impede or accelerate the propagation of a fatigue crack.

A Study on Experimental Evaluation for Fracture Behavior of Carbon Steel Pipes for High Pressure Service with Local Wall Thinning

2007 ◽  
Vol 345-346 ◽  
pp. 1349-1352 ◽  
Author(s):  
Seok Hwan Ahn ◽  
Kum Cheol Seok ◽  
Ki Woo Nam
Keyword(s):  
Carbon Steel ◽  
Nuclear Power ◽  
Failure Modes ◽  
Bending Test ◽  
Metal Loss ◽  
Test Results ◽  
Steel Pipes ◽  
Four Point Bending ◽  
Wall Thinning ◽  
Local Wall Thinning

The locally wall thinned phenomenon of pipes is simulated as metal loss due to erosion/corrosion. Therefore, fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. In this study, monotonic bending tests without internal pressure are conducted on 1.91-inch diameter Schedule 80 STS370 full-scale carbon steel pipe specimens. We investigated fracture strengths and failure modes of locally wall thinned pipes that welded and unwelded by four point bending test. From test results, we could be divided three types of failure modes.

Cement Composite Reinforced with Synthetic Fibers: Comparison of Three-Point and Four-Point Bending Test Results

2016 ◽  
Vol 827 ◽  
pp. 332-335 ◽  
Author(s):  
Jaroslav Topič ◽  
Jan Bartoš ◽  
Lubomír Kopecký ◽  
Karel Šeps ◽  
Zdeněk Prošek ◽  
...  
Keyword(s):  
Bending Strength ◽  
Cement Composite ◽  
Bending Test ◽  
Test Results ◽  
Recycled Pet ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Four Point Bending ◽  
Pet Fibers ◽  
Four Point Bending Test

Presented article deals with the influence of PET fiber production on the bending strength of cement-based composite when incorporated into the fresh mortar, and comparison of results of 3-point and 4-point bending test. Cement paste samples were reinforced with 2 wt. % of primary or recycled PET fibers. The bending test was performed on prismatic samples with dimension of 40 × 40 × 160 mm. It was found that samples with recycled PET fibers, compared to primary ones, exhibit a decrease in bending strength. In the case of 4-point bending tests, the samples with recycled PET fibers exhibited higher bending strength than reference samples without any fibers. However, in the case of 3-point bending tests, the samples with recycled PET fibers had lower bending strength than the reference ones. The results suggest that recycled PET fibers could be used as an alternative to reinforce cement-based composites.

Comparison of Warpage Measurement Capabilities and Results Obtained by Using Laser and Digital Fringe Projection Methods

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Sungbum Kang ◽  
I. Charles Ume
Keyword(s):  
Projection Methods ◽  
Fringe Projection ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Full Field ◽  
Digital Fringe Projection ◽  
Accuracy And Precision ◽  
Wiring Board ◽  
Thermomechanical Reliability ◽  
Measurement Capabilities

Electronic packaged devices are becoming increasingly smaller in size and higher in density while requiring higher performance and superior reliability. Warpage is one of the crucial factors for the thermomechanical reliability of electronic packages and warpage control becomes a more crucial process during the printed wiring board (PWB) fabrication and package assembly processes. This requirement necessitates more accurate methods of measuring warpage. The fringe projection methods are recent trends for measuring the warpage of chip packages, PWBs, and PWB assemblies (PWBAs) because of their noncontact, full-field, and high-resolution measurement capabilities. This paper presents a comparison of two fringe projection methods: laser fringe projection (LFP) (projection moiré) and digital fringe projection (DFP). Experimental results show that digital fringe projection has higher practical resolution, and better accuracy and precision than laser fringe projection.

Sign in / Sign up

Export Citation Format

Share Document