The 4th International Conference on Hydrogen Safety September 18th, 2011 Influence of Pressure and Temperature on the Fatigue Strength of Type-3 Compressed-Hydrogen Tanks for Vehicles Jun-ichi TOMIOKA , Kazuhiro KIGUCHI, Yohsuke TAMURA, Hiroyuki MITSUISHI, Japan Automobile Research Institute
The 4th International Conference on Hydrogen Safety September 18th, 2011. Influence of Pressure and Temperature on the Fatigue Strength of Type-3 Compressed-Hydrogen Tanks for Vehicles. Jun-ichi TOMIOKA , Kazuhiro KIGUCHI, Yohsuke TAMURA, Hiroyuki MITSUISHI , - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The 4th International Conference on Hydrogen Safety September 18th, 2011Influence of Pressure and
Temperature on the Fatigue Strength of Type-3 Compressed-Hydrogen Tanks for
Because of differences in thermal expansion rates in aluminum alloy and CFRP
15
①Stress due to Internal Pressure
Strain gauge on the liner
Hydraulic
system
Hydraulic pressure
Measuring method for strain due to internal pressure
The inner surface of the liner
Strain gauges were attached to the inner surface of the liner
Applying pressure to the tank
Measuring the strain due to internal pressure
Caluculate the stress based on the measured strain.
16
①Stress due to Internal Pressure
Relationship between pressure and stress of the liner
Relationship between pressure and stress of the liner was linear-proportion.
0 10 20 30 40 500
50100150200250300350400450
circumferential stressaxial stress
Pressure [MPa]
Lin
er
str
ess [
MP
a]
17
②Residual Stress
Measuring method for residual strain
A, B : Outer surface of CFRPa, b : Inner surface of liner
BA
Strain gauges
Cut 1 Cut 2
a
b
Strain gauges
Cut 3 : Separate CFRP and LinerCFRP
Liner
AabB
In all tanks after the pressure-cycle test, strain gauges attached to the outer surface of the CFRP and the inner surface of the liner
Cutting the tank at room temperature (15°C) to release the residual strain
Measuring the residual strain Caluculate the stress based on the measured strain.
18
②Residual Stress (Measured results)
Residual stress of the liner after pressure-cycle test at HT was smaller than the others.
Usageenvironment
Liner circumferential
stress
LT : -40°C -256MPa
RT : 15°C -239MPa
HT : 85°C -126MPa
Residual stress of Liner
Axialstrain
Circumferentialstrain
CFRP 0.097% 0.034%
Liner -0.134% -0.265%
Residual strain of the tank after the pressure-cycle test
at RT
Tensile strain resided in the CFRP and compressive stress resided in the liner.
19
③Thermal StressThermostatic
Chamber
Aluminum tube
-40°C ~ 85°CThermocouple
Strain gauge
εts = ε1 - ε2
εts: Strain due to the thermal stressε1 : Strain of the liner
ε2 : Strain of the aluminum tube
ε1 ε2
Strain gauges and thermocouples were attached to the inner surface of the liner and the aluminum tube
Changes in the temperature ranging from -40°C to +85°C(①15°C→②-40°C→③15°C→④85°C→⑤15°C )
Measuring the thermal strain Caluculate the stress based on the measured strain.
Measuring method for thermal strain
Thermocouple
Strain gauge
20
-50 0 50 100 -400
-300
-200
-100
0
Temperature [°C]
Lin
er
Str
ess [
MP
a]
Relationship between temperature and circumferential stress of the liner
In high-temperature and low-pressure, the liner was loaded with residual compressive stress and compressive stress due to the thermal stress.→The liner was deforemd plastically in high-temperature and low-pressure.
plastic deformation(yield stress: 300MPa)
③Thermal Stress
21
Liner Stress (hydraulic cycle)
-50 -30 -10 10 30 50 70 90-400
-300
-200
-100
0
100
200
SOC0%
SOC100%
SOC125% at 20°C
Temperature [°C]
Lin
er
Str
ess [
MP
a]
Relationship between temperature and circumferential stress of the liner
Tensile stress at AT (SOC125%) exceeds that under any SOC100% condition.
⇒The pressure-cycle test under AT can ensure the safety of a Type-3 tank against fatigue life.
plastic deformation(yield stress: 300MPa)
LT -40°C,28MPa HT
85°C,44MPa
AT ( 15~25°C, 44MPa )
RT15°C,35MP
a
22
-50 -30 -10 10 30 50 70 90-400
-300
-200
-100
0
100
200
SOC0%
SOC100%
inferred SOC100% in gas cycle
Temperature [°C]
Lin
er
Str
ess [
MP
a]
Liner Stress (gas cycle)
Relationship between temperature and circumferential stress of the liner
gas cycle
at -40°Cgas
cycleat 15°C
the gas cycle is the repetition of a low-temperature and low-pressure condition and a high-temperature and high-pressure condition.
→The liner will be not deforemd plastically in gas cycle.
23
-50 -30 -10 10 30 50 70 90-400
-300
-200
-100
0
100
200
SOC0%
SOC100%
inferred SOC100% in gas cycle
Temperature [°C]
Lin
er
Str
ess [
MP
a]
Liner Stress (hydraulic and gas)
Relationship between temperature and circumferential stress of the liner
gas cycle
at 15°C
The stress range during gas cycles is smaller than during hydraulic cycles.
⇒Hydraulic cycles are more severe than gas cycles.
LT -40°C
HT85°C
RT15°C
gas cycle
at -40°C
24
5. SUMMARY
25
Summary
Pressure cycle tests assuming SOC 100% in type-3 tanks revealed that The fatigue life assuming SOC 100% is longer
than the room temp. pressure cycle test (AT,SOC125%).
The room temp. pressure cycle test (AT,SOC125%) can ensure the safety of a Type-3 tank against fatigue.
Stress range during gas cycles is smaller than during hydraulic cycles, so the hydraulic-cycle tests are more severe than gas-cycle tests.
26
THANK YOU
This study is summarizes part of the results of "Establishment of Codes & Standards for Hydrogen Economy Society - Research and Development Concerning Standardization of Hydrogen and Fuel Cell Vehicles" consigned by the New Energy and Industrial Technology Development Organization (NEDO).