AN ANALYTICAL APPROACH TO BGA COMPONENTS IN RANDOM VIBRATION ENVIRONMENTSMilan 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 Edge (6D

OF)

Connectors

Free

Edg

e

a

b

a

Boundary Conditions:

Finite Element Analysis-Hand Calcs

)1(*12*

2

3

hED

fn 3D

.75a4

2a2b2

12b4

G 2*P *Q* fn

ZRMS 9.81*Gfn2

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