Workshop - Voorkomen van faling door vibraties - mechanical validation

1. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
Workshop vibration
validation experiments
30/05/2013
Davy Pissoort
Filip Vanhee
Bart Boesman

2. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
Overview
• Two testcases
1. Test run @ RMA
• Test settings
• Comparison to vibration tool
2. Second test example
• Test of the board
• Comparison with results
3. Concluding remarks

3. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
1. Vibration testing – Test @ RMA
Test settings
• Test case:
– Bare PCB
– 200 x 200 mm²
– Clamped at all 4 edges
• Classic hammer test:
– Board excited on 16 points
(4 x 4 matrix) with impulse
– Accelerometer mounted on
bottom side of the board
• Test performed December
4th, raw test results
received Jan. 24th
• Reference: board III

4. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
1. Vibration testing – Test @ RMA
Results – comparison vibration tool
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 1, FREQUENCY 191.448025(Hz), DAMPING 0.048304
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 2, FREQUENCY 401.622890(Hz), DAMPING 0.007670
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 3, FREQUENCY 409.206762(Hz), DAMPING 0.005971
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 4, FREQUENCY 606.636062(Hz), DAMPING 0.004998
f = 142.388947
f = 356.443695 f = 569.177002
f = 356.443695

5. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
1. Vibration testing – Test @ RMA
Results – comparison vibration tool
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 5, FREQUENCY 735.400370(Hz), DAMPING 0.006750
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 6, FREQUENCY 882.960090(Hz), DAMPING 0.008600
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 7, FREQUENCY 930.743356(Hz), DAMPING 0.006867
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 8, FREQUENCY 981.787996(Hz), DAMPING 0.004062
f = 713.434509
f = 925.060852
f = 925.060852

6. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
1. Vibration testing – Test @ RMA
Results – comparison vibration tool
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 9, FREQUENCY 1187.950178(Hz), DAMPING 0.005137
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 10, FREQUENCY 1395.286721(Hz), DAMPING 0.003091
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 11, FREQUENCY 1616.645765(Hz), DAMPING 0.005770
0 0.05 0.1 0.15 0.2
0
0.05
0.1
0.15
0.2
MODE NO. 12, FREQUENCY 1702.813952(Hz), DAMPING 0.010855
f = 1212.83252

7. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
2. Second testcase
7mm
Heigh
t
1 2
3
Width
X
Y
Size: Width=176mm, Height=94mm, Thickness=1.7mm
5 point supports:
4 corners (center of fixation holes at 5mm from edges)
1 in the middle of the plate
Weight = 147 gram (without connectors, which are relative light)
Heavy components (1-2-3) pulling center of gravity 7 mm to the left, but no clear shift of
center of gravity in Y-direction

8. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
2. Measurements
• Goal
– Measure resonance of the mechanical
housing and PCB
– Accelerometer positioned in top of
back-cover and 2 on the PCB
• Result
– Resonance housing ~ 150 Hz
– Resonance PCB ~180 Hz

9. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
2. Model and Parameters
31© Sirris | 9
The eigenfrenquences are calculated with our Tool , free
FEM software Calculix and Abaqus
The positions of components are not considered for this
calculation
Two sets of parameters are used for PCB without
components and PCB with components
1. Density=1885kg/m3 , E=22410Mpa, Poisson=0.12 (FR4)
2. Equivalent Density=5226kg/m3 , E=22410Mpa, Poisson=0.12 (FR4)

10. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
2. Simulation Results for the housing
Freq. 147.52 245.39 273.04
Mode 1 2 3

11. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
2. Eigen-frequency results with and
without components
Mode Tool(Hz) Calculix
(Hz)
Abaqus(Hz) Error %
(Tool-
Calculix)
1 292 278 278 5.0360
2 352 342 342 2.9240
3 406 420 420 -3.3333
4 505 505
5 643 644
Mode Tool
(Hz)
Calculix
(Hz)
Abaqus(Hz
)
Error %
(Tool-
Calculix)
1 173 165 165 4.485
2 209 203 203 2.9557
3 242 250 250 -3.2
4 300 300
5 383 383
Without components
Density = 1885 Kg/m3
With components:
Density = 5226 Kg/m3
Measured : 180 Hz

12. Flanders’ Mechatronics Engineering Centre
Laboratory for Global Reliability of Electronic Systems
http://fmec.khbo.be
3. Concluding remarks
• Experiments @ RMA
– The computed eigenfrequencies as well as the mode
shapes compare well to the measured ones
• Second test example
– The housing structure has a resonance frequency ~ 150
Hz, which is close to the FEM results of the tool
– Resonances of the PCB itself seem to occur at ~ 180 Hz,
which is close to simulated lowest frequency (173 Hz)
– However, further analysis is needed to discriminate higher
harmonics of housing resonance from PCB resonances.