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AN ANALYTICAL APPROACH TO BGA COMPONENTS IN RANDOM VIBRATION ENVIRONMENTS
Milan J Lucic, MANE 6980 Engineering Project
Methodology and Approach
Accurately model the ACTEL 484 PBGA with 3-D hex elements (balls and solder joint), and 2-D Shell elements (PCB and component body)
Using NX7.5 Advanced simulation for Pre-Processing and MSC PATRAN/MD NASTRAN as the post processor and solver
PATRAN Random utility to solve for frequency response (Mode Shapes), displacements, and RMS stresses
PATRAN static inertial analysis to solve for stresses of BGA’s Greatly reduce analysis time!
Using hand calculations, solve for the Miner’s Damage Index of electrical components and the high cycle fatigue of the BGA components.
Expected Outcomes
To develop a better understanding of lead vs. lead free BGA components used in common Aerospace environments
Correlate data with actual industry test data to refine future models Greatly reduce risks early in the design phase Eliminate the need for development testing of
BGA components (expensive and time consuming)
Generate plots of high cycle fatigue life for lead vs. lead-free BGA components
Project Progress-FEA Model
BGA Model ACTEL 484 PGA
Pin GridSnapshot
Solder Ball and Solder Joint FEM
Project Progress-FEA Model
Interconnect
Fixed Edge (6DOF) (Card Guide)
Fixed Edge (6DOF) (Card Guide)
Fixed E
dge (6DO
F)
Connectors
Fre
e E
dge
a
b
a
Boundary Conditions:
Finite Element Analysis-Hand Calcs
)1(*12
*2
3
hED
fn 3D
.75
a42
a2b212
b4
G 2*P *Q* fn
ZRMS 9.81*G
fn2
Plate Stiffness Factor
First Mode Natural Frequency
GRMS
Single Amplitude Displacement
Curve C Calculated Results:fn = 266.4 HzZRMS = .0018 inches
Finite Element Analysis-Normal Modes
Mode 1: 266.59 Hz
Mode 2: 341.07 Hz
Mode 3: 511.18 Hz
Finite Element Analysis-Random
Input Curve
Frequency Response
Mode 1 Mode 3Mode 2
RMS Displacement
Finite Element Analysis-Optimization
Optimized Size: 570 Elements (Quad 20)
Project Schedule
Week 1: Develop Project Definition Week 2: Preliminary Project Proposal Week 3: Project Proposal Week 4: FEA Model Development/Research Week 5: Random Analysis/Model Refinement Week 6: Random Analysis/Model Optimization Week 7: Random Analysis/Model Optimization, First Progress Report Week 8: MDI Calculations/Random Analysis Week 9: Inertial Analysis Week 10: Post Processing, Second Progress Report Week 11: Post Processing (extra time for model refinement) Week 12: Final Report Draft Week 13: Final Report Draft Week 14: Final Report