development of a new vibro-acoustic qualification philosophy for … 06... · 2020-02-10 ·...
TRANSCRIPT
Development of a new vibro-acoustic qualification philosophy for
Argentinian missions
Sosa Visconti, Ariel – Roggero, Edgardo Luis
[email protected] – [email protected]
2nd IAA Latin American Symposium on Small Satellites
Analyses TestsPhysical models
Math. models
Test / Model Philo.
2/19
1. Introduction
The definition of the set of analyses, tests and models
–physical and/or mathematical – for the test phase is
acknowledged as Test/Model Philosophy.
1.1. Main test/model philosophies
3/19
Pro
toty
pe p
hilo
so
ph
y • 1+ prototypes & flight model
• Qualification tests over prototypes
• Acceptance tests over FM
• < Risks
• > Costs
Pro
tofl
igh
tp
hilo
so
ph
y • 1 model (protoflight)
• Qualification tests over PFM
• > Risks
• < Costs
Hyb
rid
ph
ilo
so
ph
y • PFM centred
• Qualification tests over critical elements
• Risks ↔ Costs
SAC-B
• ThM
• SM
• FM
SAC-C
• ThM
• SM
• FM
SAC-D / Aquarius
• SM
• PFM
1.2. Argentinian model philosophy
evolution
4/19
1.3. Current
process
5/19
2. Main objectives
❑Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
❑Reduce the overall cost of the test program.
❑Keep the same risk levels.
6/19
3. New philosophy proposal
7/19
3.1. FEM-STR adjustment
8/19
Low level sinusoidal test over flight STR (lower damping)
Stablish conservative relationship from previous missions tests results
Add equipment masses to convert the FEM-STR to FEM-PFM
Starting point for future projects
3.2. Critical elements qualification
Follow the Hybrid Philosophy, qualify through tests only
the structural elements considered critical for the
mission.
Every project would have to consider:
❑ Equivalent dynamic effect to account for lower mass
❑ Failure modes of the tested element
❑Most convenient test to apply
❑ Qualification by similarity
❑ Qualification by analysis
❑ Qualification when PFM available
9/19
3.3. Objectives achieved
✓Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
❑Reduce the overall cost of the test program.
❑Keep the same risk levels.
Objectives achieved
❑Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
❑Reduce the overall cost of the test program.
❑Keep the same risk levels.
10/19
4. Impact analyses – Factors of
safety
To keep the risks at the minimum level:
• Qualification by tests, lower FS
• Qualification by analyses, higher FS
• Proposal, intermediate FS
TypeQualification
by tests
Intermediate
proposal
Qualification
by analyses
Yield factor 1,25 1,6 2,0
Ultimate factor 1,4 2,0 2,6
11/19
4.1. Mass increment
Considering a 500 kg satellite using 1 m by 1 m
honeycomb panels.
Factor of safety 1,25 1,625 2,0
Equivalent acceleration 100% 130% 160%
Increment by longitudinal loads 0% 0,2% 0,4%
Increment by lateral loads 0% 0,7% 1,4%
Total mass increment 0% 0,9% 1,8%
Satellite final mass 500 kg 504,7 kg 509 kg
12/19
4.2. Costs
analysisSM + PFM Only PFM
New Philosophy
Structural analyses USD 60.000 USD 60.000 USD 60.000
Dummies analyses USD 22.500
Additional analyses USD 30.000 USD 20.000
Subtotal USD 112.500 USD 60.000 USD 80.000
Structural design USD 50.000 USD 50.000 USD 50.000
Dummies design USD 22.500
Additional designs USD 30.000 USD 15.000
Subtotal USD 102.500 USD 50.000 USD 65.000
STR fabrication USD 260.000 USD 260.000 USD 260.000
STR-SM fabrication USD 190.000
Dummies fabrication USD 7.500
Integration USD 25.000 USD 10.000
Subtotal USD 482.500 USD 260.000 USD 270.000
Tests USD 60.000 USD 28.000
Facilities USD 200.000 USD 80.000
Launch vehicle USD 180.000 USD 90.000
Total USD 957.500 USD 550.000 USD 613.000
Difference with SM USD - USD 407.500 USD 344.500
Percentage 0% 43% 36%
13/19
3.3. Objectives achieved
✓Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
✓Reduce the overall cost of the test program.
❑Keep the same risk levels.
Objectives achieved
❑Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
❑Reduce the overall cost of the test program.
❑Keep the same risk levels.
14/19
4.3. Risks assessment
❖ The flight STR, as the primary element of the overall
dynamic response, is used to empirically and
conservatively estimate the damping
❖ Anticipated structural qualification of critical
elements or use of higher factors of safety.
❖ Subsystems tests levels obtained by analyses over
the already conservatively adjusted FEM.
15/19
3.3. Objectives achieved
✓Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
✓Reduce the overall cost of the test program.
✓Keep the same risk levels.
Objectives achieved
❑Accomplish the same objectives as the current
philosophy, which are:
▪ Adjust and verify the structural mathematical model of the
satellite (FEM-PFM).
▪ Qualify the primary and secondary structures.
❑Reduce the overall cost of the test program.
❑Keep the same risk levels.
16/19
5. Conclusions
✓Replacing the SM with the flight STR reduces costs.
✓Launching costs can be reduced further by taking
lower factors of safety.
✓Test campaign overall schedule reduced.
✓Conservative adjustment of the FEM allows for a
confident CLA.
✓Critical elements qualified as by current philosophy.
✓New philosophy keeps the same overall risks levels.
17/19
Literature
• GSFC-STD-7000A
• NASA-STD-7001B
• NASA-STD-7002B
• NASA-HDBK-7005
• NASA-HDBK-7008
• NASA-STD-5001A
• NASA-STD-5002
• ECSS-E-ST-10-02C
• ECSS-E-ST-10-03C
• ECSS-E-HB-10-02A
• Spacecraft Structures
• Structural Dynamics and
Vibration in Practice, An
Engineering Handbook
• Vibration Monitoring, Testing,
and Instrumentation
• The Standard Deviation of
Launch Vehicle Environments
• Método de auxílio à concepcao
de plataformas aplicadas à
família de satélites
18/19
Backup Slides
15/14
Sine sweep response
Top
Panel
+Y
Aluminium
frame
Bottom panel with
adapter ring
-Y
Lateral
Panel
-X
Lateral
Panel
+Z
Lateral
Panel
-Z
Lateral
Panel
+X
Cube model structure – 500 kg