d'andrea - srm materials&process_final

Colleferro 8th of July 2011 All information contained in this document is property of Avio SpA.

@ Copyright All rights reserved

1212thth edition CVA Summer Schooledition CVA Summer School

SOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSSOLID ROCKET MOTORSMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSESMATERIALS AND PROCESSES

Bruno Bruno Bruno Bruno Bruno Bruno Bruno Bruno DDDDDDDD’’’’’’’’AndreaAndreaAndreaAndreaAndreaAndreaAndreaAndrea




CONTENTS CONTENTS CONTENTS CONTENTS CONTENTS CONTENTS CONTENTS CONTENTS

• The SRM Structure and Components

• Motor Case

• Thermal Insulation

• The Bonding

• Solid Propellant

• Non Destructive Tests and Proof

• Igniter

• Nozzle




GETTING STARTGETTING STARTGETTING STARTGETTING STARTGETTING STARTGETTING STARTGETTING STARTGETTING START……………………

FROM THE ENDFROM THE ENDFROM THE ENDFROM THE ENDFROM THE ENDFROM THE ENDFROM THE ENDFROM THE END




……OUR TARGETOUR TARGET




THE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTORTHE SOLID ROCKET MOTOR

Structure and ComponentsStructure and ComponentsStructure and ComponentsStructure and ComponentsStructure and ComponentsStructure and ComponentsStructure and ComponentsStructure and Components




Motor Case

Thermal Insulation

Solid Propellant

Nozzle

Metallic

Composite (Carbon-Epoxy)

External Thermal Insulation(opt)

Filled Rubber

Reinforced Rubber

Polyurethane

Ammonium Perchlorate

Aluminum

Filled Rubber

Carbon-Carbon

Carbon-Phenolic

IgniterStanding

Consumable

COMPONENT MAIN TECHNOLOGY




VEGA LAUNCHER ARCHITECTURE

-Structural Ratio

1500Reference mission performance [kg]

136811Mass at Lift-off [kg]

2.6002.600Fairing diameter [m]

3.005Maximum diameter [m]

30.152Height [m]Payload Payload

CompositeComposite

AVUM AVUM

& &

IS34IS34

Z9 SRMZ9 SRM Z23 SRMZ23 SRM

P80 SRMP80 SRM

IS 12IS 12

IS 23IS 23IS 01IS 01




THE MOTOR CASETHE MOTOR CASETHE MOTOR CASETHE MOTOR CASETHE MOTOR CASETHE MOTOR CASETHE MOTOR CASETHE MOTOR CASE




Solid Rocket Motor CaseSolid Rocket Motor Case

The Motor Case can be:

• Metallic

– The thermal Insulation are applied on the inner surface and bonded by vulcanization

• Composite

– The Thermal Insulation are manufactured together with the case

– The carbon-epoxy material is winded on the thermal insulation

– The rubber can be vulcanized before the filament winding or co-cured

• In any case, some thermal insulation parts are vulcanized separately and bonded successively





3 - SANDBLASTING

2 - DEGREASING

1- CASE INCOMING

4 - ADHESIVES APPLICATION5 - UNCURED T.I. DEPOSITION

6 . MANUAL DEPOSITION

9 - MACHINING10-FINAL APPLICATION

11-SHIPPING

8 - ULTRASOUND CHECK

7 - VULCANIIZATION

METALLIC CASE MAIN STEPSMETALLIC CASE MAIN STEPS

KOUROU (GUY-F)




Solid Rocket Motor CaseSolid Rocket Motor Case METALLIC CASE MAIN STEPSMETALLIC CASE MAIN STEPS

DEGREASING

AUTOCLAVESANDBLASTING

VERTICAL LATHE

U.S. EQUIPMENT

UNCURED T.I. DEPOSITION




Solid Rocket Motor CaseSolid Rocket Motor Case METALLIC CASE INNER SURFACEMETALLIC CASE INNER SURFACE

AUTOMATIC UNCURED THERMAL INSULATION DEPOSITION AND MANUAL APPLICATION OF SOME PARTS : WORKING INSIDE THE MOTOR




Solid Rocket Motor CaseSolid Rocket Motor Case COMPOSITE CASE MAIN STEPSCOMPOSITE CASE MAIN STEPS

PROOF TEST

MANDREL

INTEGRATION

EXTERNAL HOOP WINDING

THERMAL PROTECTION APPLICATION

ONTO THE MANDREL

CURE CYCLE

MANDREL

ESTRACTION

HELICAL WINDING

PTS© : Reinforced Thermal Protections (Avio patent)

To be winded by the same machine of the prepreg filament winding

Vulcanization

Machining

Skirt Mandrels




HOW DOES THE CURING WORK?HOW DOES THE CURING WORK?

• At the cycle startup, the resin flows through the composite thickness, following the temperature � decreasing of viscosity for temperature raising

• After the gel time, the curing reaction dominates the resin rheology � increasing of

viscosity for temperature raising

• It is important not to harden the composite before the maximum mandrel expansion

RHEOLOGYRHEOLOGY





HOW DOES THE CURING WORK?HOW DOES THE CURING WORK?

GLASS TRANSITIONGLASS TRANSITION






VEGA-

Zefiro 9 - DM00

Insulated Case

manufacturing

Winding

mandrel

PTS deposition

Vacuum bag applicationVulcanization in autoclave





Zefiro 23 DM00 FW production campaign




Solid Rocket Motor CaseSolid Rocket Motor Case COMPOSITE CASE FILAMENT WINDINGCOMPOSITE CASE FILAMENT WINDING




THE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATIONTHE THERMAL INSULATION




The Thermal InsulationThe Thermal Insulation

The Thermal Insulation are composite materials:

• Base rubber

– The most common is EPDM : Ethylene-Propylene-Diene Copolymer, stable until 290°C

• Anti-flame Filler

– Can be silica-based, heavy metals oxides or cyclic hydro carbide, stable until275°C

• Structural Reinforce / Filler

– Can be anisotropic (spherical), tyxotropic, chop (fiber orientation during manufacturing) or structural as for PTS (fabric), in general selected to be stable until 500°C

• Additives

– Plasticizer, vulcanization agents (commonly peroxides)




Thermal InsulationThermal Insulation

THE VULCANIZATIONTHE VULCANIZATION

• The vulcanization creates cross-links inside the polymeric chain of the rubber matrix

• The reactivity can be studied by rheology, to optimize the vulcanization cycle (take care the scale up effect)

• The final thermal insulation shows mechanical properties to be measured for fitting the requirement and check the good vulcanization:

– Hardness (shoreA)

– Tensile strength

– Shear strength

– Compression strength




Thermal InsulationThermal Insulation HOW DOES IT WORK?HOW DOES IT WORK?

• The Thermal Insulation shows low thermal conductivity and high specific heat

• The Thermal Insulation has a endothermic thermal decomposition under non oxidative environment �

small contribution for heat absorption

• At the steady state, the multiple layer of : charred – decomposing – neat material ensure to keep the insulation

ABLATIVE EFFECTABLATIVE EFFECT

CHARRED

DECOMPOSING

NEAT

Thermal Insulation

COMBUSTION GASES

TGA analysis

Thermal Conductivity

analysis




Mixing by means: Open mixer or Bambury

Components weighting

Calender phase

Deposition or

Loose part shapingVulcanization

Sheets of differentthickness

Bobbins

Thermal InsulationThermal Insulation MATERIAL MANUFACTURING MAIN STEPSMATERIAL MANUFACTURING MAIN STEPS




THE BONDINGTHE BONDINGTHE BONDINGTHE BONDINGTHE BONDINGTHE BONDINGTHE BONDINGTHE BONDING




The Bonding The Bonding -- 11

Almost everything inside the Solid Rocket Motor is bonded, creating several interfaces:

• Thermal Insulation to Case

• Propellant to Thermal Insulation

• Nozzle parts (c-c to carbon-phenolic or c-ph to c-ph)

• Nozzle to case (igniter)

• External Thermal Insulation to case

• Harness to SRM External Surface




The Bonding The Bonding -- 22The base principles of a good bonding are:

• Surfaces preparation

– Suitable Roughness (sandblasting or sandpaper)

– Cleaning

• Adhesives selection

– Chemical affinity with the interfaces for high strength bonding

– If interfaces are not of the same chemical nature (i.e. metal vs rubber), use substances to promoting the adhesion � primer

• Cycle

– Select to use warm or cold bonding

– Fine characterize the materials and adhesives reactivity

– Be careful to scale up from Lab to full scale

– Choose the suitable tests (U.S., X-Ray, follow up specimens or in-situ check)




The Bonding The Bonding -- 33

THERMAL INSULATION

PRIMER EPOXY ADHESIVE

METALLIC

CASE

THERMAL INSULATION

EPOXY ADHESIVE

COMPOSITE

CASE

THERMAL INSULATION

PROPELLANT

POLYURETHANE ADHESIVE

CARBON PHENOLIC

ACRILIC or EPOXY ADHESIVE

CARBON PHENOLIC

CARBON CARBON

CARBON PHENOLIC

ACRILIC or EPOXY ADHESIVE

METALLIC

CASE

COMPOSITECASE

WARM B

ONDING

COLD B

ONDIN

G




The Liner application is 3-4 weeks cycle:

• automatic cycle

– degreasing by suitable solvent

– drying

• liner batch preparation and control

• liner spray application and specimens

– liner pre-curing

– Insulated case control

• transportation to the casting pit

The Bonding The Bonding –– 44STRUCTURE PREPARATION FOR PROPELLANT CASTINGSTRUCTURE PREPARATION FOR PROPELLANT CASTING




THE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANTTHE SOLID PROPELLANT




The Solid PropellantThe Solid Propellant

The main properties are:

• Specific Impulse

– Driven by the formulation

– Imposed by the Design

• Burning Rate

– To fit the SRM combustion requirement

• Mechanical Properties

– To withstand the mechanical stress of ignition and storage

• Processability / Castability

– To be manufactured at industrial scale with no defects

– Defects are source of potential hazard and uncontrolled combustion




THE COMPOSITE PROPELLANTSARE CONSTITUTED BY:

Active ComponentsActive Components

AluminumAluminum

FUELFUEL

0% (tactics) 15 - 20%(aerospace)

amount anddiameter

influence:

BURNING RATE TUNING

SPECIFIC IMPULSE

CASTABILITY

OXIDIZER

Ammonium Perchlorate (A.P.)

65 - 80%

amount andparticle size

affect:

CASTABILITY

BURNING RATE

MECHANICAL PROPERTIES

Polymer (HTPB)Plasticizer

Curing System

Polymer (HTPB)Plasticizer

Curing System

BINDERBINDER

10 - 14%amount andcomposition

drive:

SPECIFIC IMPULSE

CASTABILITY

MECHANICAL PROPERTIES

11-14%




The Solid Propellant StructureThe Solid Propellant Structure

Propellant at time 0

HTPB cured by ISOCIANATE=

BINDER(including PLASTIFIER AND BONDING AGENT)

A.P. (200 � 4-5 µm)

Aluminum (35 to 5 µm)

Burning rate Mod. (< 3 µm)




The Solid PropellantThe Solid Propellant

The chemical reactions among the components are not completely known

Others?

Ammonium

Perchlorate

Aluminum

Ballistic

Modifiers

HTPB-

3 units

Isocianate

Plasticizer

Bonding

Agent

Curing

Catalyst

Aziridine

Ammine

Esther




The Solid Propellant The Solid Propellant –– Current TechnologyCurrent Technology

Either for the process as for the combustion, there is no modeling for completely design, tuning and characterize the solid propellant

No possible to theoretically design a propellant formulation, BUT, nevertheless, it is not a KIND OF MAGIC

EXPERIMENTAL AND CHEMISTRY ARE THE UNIQUE WAYS TO ASSESS

PERFORMANCE AND PROCESSABILITY




The Solid PropellantThe Solid Propellant ENERGETIC PERFORMANCEENERGETIC PERFORMANCE

d'andrea - srm materials&process_final

Documents

specific impulse

solid propellant

thermal insulation

colleferro

curing work

rights reserved

temperature

information