Topology Optimisation of Tertiary Structures and Mass Savings for Satellite Structures
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Topology Optimisation of Tertiary Structures and Mass Savings for Satellite Structures Mouriaux Franck Senior Manager Engineering & Development RUAG Schweiz AG RUAG Space Münich, 26.06.2014
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For typical satellites, tertiary structure, i.e. supports for antennas, sensors and connectors, can represent up to 20-30kg. The introduction of new manufacturing processes like Additive Manufacturing combined with the topology optimisation capabilities of Optistruct allow to envisage mass savings of around 30%. The presentation shows the results of a topology optimisation performed by RUAG Space on an Antenna Support of the Sentinel-1 Spacecraft. It also shows how RUAG Space intend to implement this methodology combined with Additive Manufacturing in the development of future satellite structures.
Transcript of Topology Optimisation of Tertiary Structures and Mass Savings for Satellite Structures
Topology Optimisation of
Tertiary Structures and Mass
Savings for Satellite Structures
Mouriaux Franck
Senior Manager Engineering & Development
RUAG Schweiz AG
RUAG Space
Münich, 26.06.2014
Content
02.07.2014 │RUAG Space│ 2
Objective
Bracket
Work
Optimisation Setup
Model Size
Geometry Generation
Comparison
Summary
Improvement
Objective
02.07.2014 │RUAG Space│ 3
Design space,Loads and
ConstraintsPrinting
Designevaluation
StructuralAnalysis
Construction ManufacturingDesign space,
Loads and Constraints
Optimization
Compare current design against optimised design using ALTAIR
Optistruct
Time
Mass
Stress
Bracket
02.07.2014 │RUAG Space│ 4
Upper S-Band Antenna Support of the Sentinel-1 Satellite
Material Aluminium
Mass-Bracket 1.626kg
Mass-Antenna 0.783kg
Dimensions 385x345x115 mm
1.Eigenfrequency >70Hz
Static Load 20g / 25g
Allowable Stress 163MPa
Outer dimensions of the existing
bracket => Design space
Antenna represented as a
concentrated mass and
connected with RBE3.
Provision for attachment bolts
accessibility
02.07.2014 5 │RUAG Space│
Bracket
First optimization setup
Objective
Minimize Massfrac
Constraints
First eigenfreq. > 70Hz
v.M. stress < 163MPa
Problem
Very low and unrealistic eigenfrequencies
=> no feasible design
02.07.2014 6 │RUAG Space│
Optimisation Setup
Second optimization setup
Objective
Minimize compliance
Constraints
First eigenfreq. > 70Hz
Mass fraction < 0.4…0.05
Note
Running the optimization with different mass fraction constraints will
lead to different stress levels.
=> Multiple runs are needed to find a suitable stress level.
02.07.2014 7 │RUAG Space│
Optimisation Setup
02.07.2014 │RUAG Space│ 8
Full design space: 11.6kg.
Mass fraction: 0.09
Element size: 3mm
Model Size: 300’000 nodes.
No thin membranes possible
Model Size
Two optimization loops
02/07/2014 │RUAG Space│ 9
Meshing the
whole design
space
Loop #1
Target mass
of 4.5kg
Delete
unnecessary
elements and
remesh with
smaller
elements
Loop #2
Target mass
of 1.2kg
Model Size
02.07.2014 10 │RUAG Space│
Optimised Model
First automatic geometry generation (OSSmooth)
Further manual cleaning needed (ATOS, Geomagic)
02.07.2014 │RUAG Space│ 11
Before cleaning After cleaning
Geometry Generation
02/07/2014 │RUAG Space│ 12
Thin bridges Unnecessary parts
Geometry Generation
Geometry
02/07/2014 │RUAG Space│ 13
Comparison
Current Design Optimised Design
Time 3-4 Days 4-5 Days
Mass 1.6 kg 1.0 kg
Eigenfrequency 89 Hz 140 Hz
v.M. Stress 75 MPa ~90 MPa
02.07.2014 │RUAG Space│ 14
Summary
Mass reduced by 35%
Key Problems
Compromise between acceptable model size and element size
Effort for cleaning the geometry
Need for interpretation and manual work
02.07.2014 │RUAG Space│ 15
Improvement
Better smoothing of «big steps» by OSSmooth
Checking of unnecessary parts by OSSmooth
Automatic mesh refinement
02.07.2014 │RUAG Space│ 16
Thank you for your attention!
02.07.2014 │RUAG Space│ 17
