This document summarizes accelerated testing methods for assessing the reliability of components over a simulated 2-year storage period. It discusses using thermal cycling and constant temperature exposure to accelerate aging, and references statistical models for analyzing the results, including the Arrhenius model. Graphs show data from tests of current draw over thermal cycling cycles and time at elevated temperature, with over 98% of components meeting specifications after the simulated 2-year period.

1. Accelerated Testing
for 2-year Storage
Fred Schenkelberg
OPS A LA CARTE
990 Richard Avenue, Santa Clara 95054
(408)710-8248
fms@opsalacarte.com
RAMS 2013

3. cylindar
block
Epoxy

4. cylinder
block
Activation
Energy?
Epoxy

6. Low
Medium
High
Arrhenius model and
Inverse power law model
Temperature-Nonthermal Weibull model

7. cylinder
block
Plate

8. cylinder
block
Plate

10. Histogram of average daily temperatures
5 years of California Data
*data from different study
1500 90th’ile = 31°C
1000
500
0 10 20 30 40
°C

11. Histogram of daily temperature range
5 years of California Data
6000
*data from different study
5000 90th’ile = 20.6°C
4000
3000
2000
1000
5 10 15 20 25 30
°C

12. Sample size & test design Sample size & test design
for thermal cycling– using for temperature – using
Wasserman Success Testing Meeker Hahn monograph

13. Current Draw, TP1,2,3,4,5,6
Thermal Cycling Results
60
55
50
Current Draw (mA)
Current Draw over 2 years thermal cycling
45
60
40
55
35
50
Current Draw (mA)
30
45
1 2 3 4 5 6
Test Points 40
35
30
500 1000 1500 2000
Hours
Intercept no significantly different than zero

14. 98.3% within specification after 2 years
with 95% confidence

15. Current Draw 45°C Samples
Temperature only data
60
Aged at 45°C Current Draw
50
60
40
50
Current
30
40
20
30
TP0 TP1 TP2 TP3 TP4 TP5
20
0 10 20 30 40
Days

16. 99.4% within specification after 2 years
with 95% confidence