scholarly journals Fiber Bragg Grating Sensors For Failure Detection Of Fip Chip BGA In Four-Point Bending Test

2021 ◽  
Author(s):  
Rasha Hussain
Keyword(s):  
Fiber Bragg Grating ◽  
Flip Chip ◽  
Structural Integrity ◽  
Failure Detection ◽  
New Method ◽  
Bending Test ◽  
Bragg Grating ◽  
Test Configuration ◽  
Mechanical Bending ◽  
Free Solder

Maintaining structural integrity is an important issue for advanced flip chip ball grid array (FC-BFA) packages especially due to the use of Pb-free solder replacing the Pb-contained solders and the large package size induced mechanical vulnerability. For such packages, the mechanical bending causes fracture in the interconnecting plastic PWB. To determine the critical load becomes a challenge to assembly manufacturers since the conventional testing methods based on monitoring electric continuity of the daisy chained solder joints fail to detect the PWB de-bonding near the interconnect. This thesis researches a new method that uses the Fiber Bragg Grating sensor to detect the interconnect fracture failure of 55 mm lead-free FC-BGA under four-point bend test. Experimental setups and procedures are studied, a proper test configuration is determined and a series of testing performed. The validity of the new method in monitoring the solder joint de-bonding is proved through analyzing the test results, which shows that the FBG sensors are sensitive to capture the onset of the fracture in different cases.

scholarly journals Fiber Bragg Grating Sensors For Failure Detection Of Fip Chip BGA In Four-Point Bending Test

2021 ◽  
Author(s):  
Rasha Hussain
Keyword(s):  
Fiber Bragg Grating ◽  
Flip Chip ◽  
Structural Integrity ◽  
Failure Detection ◽  
New Method ◽  
Bending Test ◽  
Bragg Grating ◽  
Test Configuration ◽  
Mechanical Bending ◽  
Free Solder

Maintaining structural integrity is an important issue for advanced flip chip ball grid array (FC-BFA) packages especially due to the use of Pb-free solder replacing the Pb-contained solders and the large package size induced mechanical vulnerability. For such packages, the mechanical bending causes fracture in the interconnecting plastic PWB. To determine the critical load becomes a challenge to assembly manufacturers since the conventional testing methods based on monitoring electric continuity of the daisy chained solder joints fail to detect the PWB de-bonding near the interconnect. This thesis researches a new method that uses the Fiber Bragg Grating sensor to detect the interconnect fracture failure of 55 mm lead-free FC-BGA under four-point bend test. Experimental setups and procedures are studied, a proper test configuration is determined and a series of testing performed. The validity of the new method in monitoring the solder joint de-bonding is proved through analyzing the test results, which shows that the FBG sensors are sensitive to capture the onset of the fracture in different cases.

A new method for fiber Bragg grating wavelength demodulation with calibration

2006 ◽  
Author(s):  
Jian-wei Fu ◽  
Li-zhi Xiao ◽  
Yuan-zhong Zhang ◽  
Xiao-liang Zhao ◽  
Hai-feng Chen
Keyword(s):  
Fiber Bragg Grating ◽  
New Method ◽  
Bragg Grating

scholarly journals New Method of Temperature and Strain Decoupling Based on Directivity of Fiber Bragg Grating Sensing

2021 ◽  
Vol 2101 (1) ◽  
pp. 012023
Author(s):  
Xiao Huang ◽  
Zhenkun Jin ◽  
Qing Shen
Keyword(s):  
Fiber Bragg Grating ◽  
Cantilever Beam ◽  
Experimental Analysis ◽  
Strain Measurement ◽  
The Other ◽  
New Method ◽  
Bragg Grating ◽  
Center Wavelength ◽  
Influence Of Temperature ◽  
Sensing Characteristics

Abstract Fiber Bragg Grating (FBG) has been widely used in temperature and strain measurement. Its center wavelength drift is affected by both temperature and strain. The influence of temperature and strain on center wavelength should be decoupled when measuring. In this paper, the sensing characteristics of FBG which pasted at different angles were simulated and analyzed, and it was found that FBG sensing for strain has strong directivity. A dual FBG composite construction based on the directivity of FBG sensing was proposed. Two FBGs were at an Angle of 62°. One FBG was sensitive to both temperature and strain, and the other was only sensitive to temperature. The structure can realize the decoupling of temperature and strain, and it doesn’t depend on feature of cantilever beam. It was verified by experimental analysis that the decoupling result was good by utilizing the combined FBG structure, and decoupling was realized easily.

Characterization of process-induced defects in automated fiber placement manufacturing of composites using fiber Bragg grating sensors

2017 ◽  
Vol 17 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Ebrahim Oromiehie ◽  
B Gangadhara Prusty ◽  
Paul Compston ◽  
Ginu Rajan
Keyword(s):  
Fiber Bragg Grating ◽  
Structural Integrity ◽  
Bragg Grating ◽  
Inspection Method ◽  
Manufacturing Defects ◽  
Fiber Placement ◽  
Fiber Bragg Grating Sensors ◽  
Placement Method ◽  
Automated Fiber Placement ◽  
On Line

With the increasing use of automated fiber placement method for manufacturing highly precise bespoke composite components in the aerospace industry, the level of manufacturing defects within the laminate structure needs to be monitored and minimized for structural integrity. One of the main common defects in automated fiber placement process is misalignment between the tape paths in successive courses which leads to non-integrity of laminate and consequently significant reduction in mechanical strength of the laminate. Therefore, it is necessary to find an appropriate inspection method to monitor and identify these processing defects at the earlier stages of manufacturing. Since optical fiber Bragg grating sensors are being increasingly utilized for structural health monitoring in composite materials and as they were successfully implemented by Oromiehie et al. in their earlier work for on-line lay-up process monitoring, the same methodology is once again tried for identifying the misalignment defects in automated fiber placement process. The experiments are carried out on glass-fiber/nylon laminate with embedded fiber Bragg gratings for the automated tape placement method. The defects due to misalignment are identified by the fiber Bragg grating sensors through their reflected wavelength changes during the automated manufacturing process. The analysis of results indicates that the fiber Bragg grating sensors can be reliably implemented for on-line defect monitoring during the automated fiber placement process to ensure the quality of final product and maintain the expected design life.

Effect of Board-Level Reflow on Adhesion Between Lead-Free Solder and Underfill in Flip-Chip BGA Packages

2007 ◽  
Author(s):  
Zhenming Tang ◽  
Seungbae Park ◽  
H. C. John Lee ◽  
Soonwan Chung
Keyword(s):  
Fatigue Life ◽  
Flip Chip ◽  
Structural Integrity ◽  
Fea Model ◽  
Bga Packages ◽  
Life Model ◽  
Strong Adhesion ◽  
The Difference ◽  
Free Solder ◽  
Perfect Adhesion

The change in solder/underfill adhesion and its effect on fatigue life were investigated for Pb-free solder joints for which, during the reflow process, the solder has melted and resolidified inside the underfill cavities. The change in interfacial adhesion was simulated and its strength compared using button shear test. Surprisingly, the difference was found to be only about 11%. Suspecting the validity of the result, the study was extended to further investigate the adhesion effect on fatigue life under thermal cycles. The effect was assessed analytically using FEA model. Energy-based Darveaux’s fatigue life model [1] is used to calculate solder fatigue life under two extreme conditions: perfect adhesion (without delamination or void between underfill and solder) and non adhesion. The failure parameter, accumulated plastic work per cycle for non adhesion was significantly less than that for perfect adhesion case suggesting adverse effect of strong adhesion to the enhancement of structural integrity. In this simulation, the room temperature was taken as the stress free state.

scholarly journals Fiber Bragg Grating-Based Sensors and Systems

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8225
Author(s):  
Oleg G. Morozov
Keyword(s):  
Biological Activity ◽  
Fiber Bragg Grating ◽  
Structural Integrity ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Living Systems ◽  
Bragg Grating ◽  
Physical Parameters ◽  
Engineering Systems

Today, no one doubts that fiber Bragg gratings (FBGs) have become the most used tool for measuring various physical parameters, the structural integrity of engineering systems, and the biological activity of living systems [...]

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