Improved Correlation Between Accelerated Board Level Reliability (BLR) Testing and Customer BLR Results Using a Hybrid Closed-Form/Finite Element Methodology

2019 ◽  
Author(s):  
Maxim Serebreni ◽  
Natalie Hernandez ◽  
Gil Sharon ◽  
Nathan Blattau ◽  
Craig Hillman ◽  
...  
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Board Level ◽  
Board Level Reliability ◽  
Finite Element Methodology

Board Level Reliability of Automotive Grade WLCSP for Radar Applications

2020 ◽  
Author(s):  
Nishant Lakhera ◽  
Burt Carpenter ◽  
Trung Duong ◽  
Mollie Benson ◽  
Andrew J Mawer
Keyword(s):  
Radar Applications ◽  
Board Level ◽  
Board Level Reliability

Board-Level Reliability of Pb-Free Surface Mounted Assemblies during Thermal Shock Testing

2006 ◽  
Vol 15-17 ◽  
pp. 633-638 ◽  
Author(s):  
Jong Woong Kim ◽  
Hyun Suk Chun ◽  
Sang Su Ha ◽  
Jong Hyuck Chae ◽  
Jin Ho Joo ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Solder Joints ◽  
Lead Frame ◽  
Shear Forces ◽  
Microstructural Investigation ◽  
Shock Testing ◽  
Ceramic Capacitor ◽  
Board Level ◽  
Board Level Reliability ◽  
Thermal Shocks

Board-level reliability of conventional Sn-37Pb and Pb-free Sn-3.0Ag-0.5Cu solder joints was evaluated using thermal shock testing. In the microstructural investigation of the solder joints, the formation of Cu6Sn5 intermetallic compound (IMC) layer was observed between both solders and Cu lead frame, but any crack or newly introduced defect cannot be found even after 2000 cycles of thermal shocks. Shear test of the multi layer ceramic capacitor (MLCC) joints were also conducted to investigate the effect of microstructural variations on the bonding strength of the solder joints. Shear forces of the both solder joints decreased with increasing thermal shock cycles. The reason to the decrease in shear force was discussed with fracture surfaces of the shear tested solder joints.

scholarly journals Buckling of regular, chiral and hierarchical honeycombs under a general macroscopic stress state

2014 ◽  
Vol 470 (2167) ◽  
pp. 20130856 ◽  
Author(s):  
Babak Haghpanah ◽  
Jim Papadopoulos ◽  
Davood Mousanezhad ◽  
Hamid Nayeb-Hashemi ◽  
Ashkan Vaziri
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Closed Form ◽  
Plane Stress ◽  
Plane Stress State ◽  
Cellular Structures ◽  
Two Dimensional ◽  
Buckling Strength ◽  
Macroscopic Stress ◽  
Unit Cells

An approach to obtain analytical closed-form expressions for the macroscopic ‘buckling strength’ of various two-dimensional cellular structures is presented. The method is based on classical beam-column end-moment behaviour expressed in a matrix form. It is applied to sample honeycombs with square, triangular and hexagonal unit cells to determine their buckling strength under a general macroscopic in-plane stress state. The results were verified using finite-element Eigenvalue analysis.

Validation of Nitinol SMA Characteristics Using Finite Element Analysis and Closed Form Solutions

2013 ◽  
Vol 856 ◽  
pp. 147-152
Author(s):  
S.H. Adarsh ◽  
U.S. Mallikarjun
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fe Analysis ◽  
Element Analysis ◽  
Complex Behaviour ◽  
Closed Form Solutions

Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

Analysis of tunnels in shaly rock considering three-dimensional stress effects on swelling

2005 ◽  
Vol 42 (1) ◽  
pp. 1-12 ◽  
Author(s):  
B C Hawlader ◽  
K Y Lo ◽  
I D Moore
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Cold Water ◽  
Principal Direction ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Time Dependent ◽  
Stress Effect ◽  
Stress Effects ◽  
Laboratory Test Results

Underground structures in shales or shaly rocks endure time-dependent swelling effects. Laboratory test results show that the swelling of these shales is dependent on three-dimensional stresses; an external stress on a specimen in one principal direction reduces the swelling not only in that direction but also perpendicularly. The effectiveness of a time-dependent swelling model that considers the three-dimensional stress effect is presented in this paper. A finite element algorithm incorporating the new constitutive model is used for a numerical analysis. The finite element program is used to analyze two tunnels in southern Ontario: the Heart Lake storm sewer tunnel, and the Darlington cold-water intake tunnel. The predicted results agree well with the records of field performance of these tunnels. The comparison between present analyses and the existing closed-form solution shows that the existing solution overestimates the time-dependent swelling effects. The three-dimensional stress effects on swelling are not considered in the closed-form solutions and are the cause of this discrepancy. The pseudo-Poisson's effect is a key parameter for modelling the observed time-dependent swelling. The use of these solutions in design is discussed.Key words: time-dependent swelling, shale, modelling, three-dimensional stress effect, finite element method, tunnel.

A Dynamic Bending Method for PoP Package Board Level Reliability Validation

2018 ◽  
Author(s):  
Jeffrey Lee ◽  
Cheng-Chih Chen ◽  
Lane Brown ◽  
Esme Mehretu ◽  
Thomas Obrien ◽  
...  
Keyword(s):  
Dynamic Bending ◽  
Board Level ◽  
Board Level Reliability

Board Level Reliability of Solder Joint with a Low CTE PCB

2019 ◽  
Vol 44 (1) ◽  
pp. 975-983 ◽  
Author(s):  
Kyoungmoo Harr ◽  
Chang-Bae Lee ◽  
Yoon-Su Kim ◽  
Seungwook Park ◽  
Jin-Gu Kim ◽  
...  
Keyword(s):  
Solder Joint ◽  
Board Level ◽  
Board Level Reliability
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