Issue No: 1 Doc No: VSSC:MVIT:ASMG:MDAD:DR:110:2016

Date : 28 – 07 – 2016 Security Classification:

Restricted

Copy No: Control Status:

Universal launcher for ATVP- Preliminary Design Document

Aerospace Mechanisms Group

Mechanisms & Vehicle Integration Testing Entity

Vikram Sarabhai Space Centre

Thiruvananthapuram

Prepared by Task Team

Approved by

Chairman, Task Team

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Document control sheet

01 Security Classification: Restricted 02 Distribution: Limited

03

Report status:

Uncontrolled

04 Series: 05 Report type: Technical

06 Report No: VSSC-MVIT-

ASMG- MDAD-DR-110-16

07 Part No./

Vol.No. 1

08 Contract No:

09 Title and subtitle: Universal launcher for ATVP- Preliminary design document

10 Collation: Pages : 46

Figures : 34

11 Project No:

12 Personal author (s) : Task Team

13 Affiliation of author (s): MDAD, ASMG

Vikram Sarabhai Space Centre,

Thiruvananthapuram – 695 547

14 Corporate author (s) : Nil

15 Originating unit : Vikram Sarabhai Space Centre,

Thiruvananthapuram – 695 022

16 Sponsor(s): Name: Vikram Sarabhai Space Centre

Type: Government

17 Date of preparation:

18-07-2016

18 Date of publication:

28-07-2016

19 Publisher/Distributor: ASMG, VSSC.

20 Form of distribution: Hard copy

21 Language of text: English 22 Language of summary: English

23 No. of reference(s): 12 24 Gives data on: ATVP Launcher

25

Abstract: This document presents the design/procurement specification of

Universal launcher for RH 200 and RH 300 rockets.

26

Keywords: Universal Launcher, specifications, design, Boom, Elevation drive,

azimuth drive, motor, gearbox, slewing bearing, servo motor, encoder, control

system, brake, launcher rails, finite element analysis, wind loads

27 Class No: 28 Supplementary elements:

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Distribution List

Copy No. Copy to Report Status

01 DD, MVIT Uncontrolled

02 PD, ATVP Controlled

03 Chairman, Task team / GD, ASMG Controlled

04 - 15 Members, Task team Controlled

16 DGM, Control Centre Controlled

17 GD, QRMG Uncontrolled

18 Head, SDED/STR Uncontrolled

19 Head, MDAD/ASMG Uncontrolled

20 Documentation, Library Uncontrolled

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Change History

Issue

No.

Issue

Date

Rev

No.

Rev

Date

Changed

Pages

Nature of Change Signature Of

the approving

authority

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CONTENTS

1.0 Introduction

2.0 Applicable documents

3.0 Rohini Sounding Rockets

3.1 RH200 vehicle description

3.2 RH 300 vehicle description

4.0 Universal launcher

4.1 Functional requirements

4.2 Design requirements

4.3 General requirements

5.0 Universal launcher Configuration

6.0 Design of Launcher subsystems

6.1 Boom

6.2 Elevation drive system

6.2.1. Gearbox specifications

6.2.2. Motor and control system specifications

6.2.3. Sample calculation

6.2.4 Shaft

6.2.5 Spline selection

6.2.6 Brake Specifications

6.2.7 Elevation drive bearings selection

6.3 Pedestal/ Support system

6.3.1. Shaft support/Plummer block assembly

6.3.2. Load capability of Plummer block housings

6.3.3. Pedestal support system

6.4 Azimuth drive system

6.4.1. Base Plate

6.4.2. Slewing bearings

6.4.3. Estimation of torque demand

6.4.4. Slew drive

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6.4.5. Motor and control system for azimuth drive

6.4.6 Azimuth brake specifications

7.0 Modal Analysis

8.0 Instrumentation

9.0 Surface protection

10.0 Foundation

11.0 Thermal Analysis

12.0 Acceptance Tests

12.1 Load Tests

12.2 Frequency measurement

12.3 Acceptance Trials

12.4 Brake trials

12.5 Safety Systems

12.6 Calibration

12.7 Alignment Checks

13.0 Summary

14.0 References

Appendix

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LIST OF FIGURES

Figure 1a RH 200 vehicle configuration

Figure 1b RH 300 Mk II vehicle configuration

Figure 2a RH 200 vehicle attachment to Launcher boom

Figure 2b RH 300 vehicle attachment to Launcher boom

Figure 3a Side view of launcher with RH200 in position

Figure 3b Launcher with RH200 at launch elevation

Figure 3c Side view of launcher with RH300 in position

Figure 3d Launcher with RH300 at launch elevation

Figure 4a, 4b Launcher subsystems

Figure 5 Boom Assembly

Figure 6a Tip deflection of launcher boom

Figure 6b von Mises stress plot of launcher boom

Figure 7a Mode shape of launcher boom (1st mode)

Figure 7b Mode shape of launcher boom (2nd mode)

Figure 8a Spline shaft details

Figure 8b Spline shaft attachment details

Figure 9a, 9b Brake for Elevation Drive

Figure 10 Spherical roller bearing

Figure 11 Plummer block housing

Figure 12 Plummer block housing mounting Details

Figure 13 Load capability of Plummer block housings

Figure 14 Pedestal support system (Pillar)

Figure 15 Base Plate details

Figure 16a Deflection plot of base plate

Figure 16b Stress plot of base plate

Figure 17a, 17b Slewing Bearing Load Capability

Figure 18a, 18b Brake for Azimuth Drive

Figure 19a, 19b Mode shape of launcher Assembly

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1. Introduction

The existing launcher used for launching RH300 and RH 200 rockets has been

on service for a long period and is due for replacement. Due to aging of current

launcher, it is proposed to realize a new universal launcher. Accordingly a new

compact launcher is designed to launch RH-200 and RH-300 MK-II.

This report presents the preliminary concept and design of the rocket

launcher capable of launching Rohini Series rockets RH 200 and RH300. The

launcher is configured based on the inputs obtained from ATVP Project and the Task

Team.

2. Applicable documents

1. Design Report of Rohini Launcher, VSSC-TERLS-DR-04-83, Issue-01 dt. June 1983

2. Design guide to Rocket launchers, ISRO-SHAR-TR-09-066-91, Issue-01 dt. July 1991

3. Design of new launcher for RH560 variants, ISRO-SHAR-09-DR-110-2009 dt. Sept 2009

3. Rohini Sounding Rockets The sounding rockets planned to launch from this launcher are uncontrolled

and unguided. They are spun from the beginning to reduce the dispersion of the

flight trajectory. Also, they are initially guided using rails in the launcher, till the

rocket attains 30-35m/s velocity.

3.1. RH200 vehicle description: RH 200 is a two stage solid propellant rocket with overall length of 3590.6mm

and takeoff weight of 110kg. RH-200 rocket with 10.3 kg payload is capable of

reaching an apogee altitude of 70 km at 75 deg. launch elevation. The Vehicle

configuration is given in Fig. (1a). The details of RH 200 are given below

a. Nominal elevation: 750

b. CG from base: 1259.0 mm

c. Diameter of booster: 207mm

d. Diameter of second stage: 125 mm

e. Distance between fore-end and rear end launch lugs: 1082 mm

f. Span of the launch lugs: 130 mm

g. Length of guide rails: 6000 mm.

h. Gap between fins (booster): 460 mm, 4 Nos. fins at 900

i. Gap between fins (2nd stage): 261 mm

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3.2. RH300 vehicle description:

RH300-MkII is a single stage spinning and fin stabilised rocket with overall

length of 6284mm, diameter 305mm and takeoff weight of 510±10 kg. Two spin

rockets are mounted on one set of opposite fins (Fins 1 & 3). Initial spin at launcher

exit is provided by these spin-rockets. The spin rockets are ejected out from fins

after its function. The vehicle configuration ref. Fig. (1b)

a. Nominal elevation: 820

b. CG from base: 2270 mm

c. Distance between fore-end and rear end launch lugs: 3572 mm

d. Span of the launch lugs: 221 mm

e. Length of guide rails: 13000 mm.

f. Gap between fins (booster): 708 mm, 4 Nos. fins at 900

3.3. Rocket Assembly to launcher

Both RH200 and RH 300 are attached to the launcher rails using two lugs and

the details are given in figures 2a and 2b. The launch lugs at aft end and forward end

will be sliding on the rails.

4. Universal launcher

4.1. Functional requirements

a. Should be able to launch RH-200 and RH-300

b. RH300 loading on launcher shall be of under slung type.

c. Guided launch for both rockets; RH200-6m & RH300-13m

d. The nozzle exit shall have a minimum clearance of 3D along the vehicle axis

e. Desirable working height: 1. 5m for RH-300, 2.2m for RH-200

f. Elevation range: -30 to 900

Nominal operation speed 45 deg/min

Accuracy and least count of angle = 0.01 deg (or better)

g. Azimuth range: 0 to ±900 (1800 range)

Nominal operation speed 90 deg/min

Accuracy and least count of angle = 0.01 deg (or better)

h. Operational cycles: ~ 100 per year

i. Operation of launcher shall be in manual mode at launch pad and remote

mode from terminal room as well as from Block House(100 m from launch pad)

j. Launcher boom shall be firmly held in position during launch and parking

using brakes.

k. All functional elements shall be protected from plumes using cowlings.

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4.2. Design Requirements Input data for the design of the launcher is given below.

a. Boom length shall be 13m to accommodate the guide rails

b. Shall withstand the static & dynamic loads during prelaunch and launch

conditions

c. Rail length shall be minimum 6 m on top and 13m below

d. Mass shall be minimum with CG location close to hinge point

e. Natural frequency of boom shall be greater than 5 Hz and overall frequency shall

be greater than the existing launcher frequency of 2.25 Hz.

f. Boom tip deflection shall be less than 14.4 mm( L/900 criteria, Ref: 3)

g. Redundancy shall be planned in drives and brakes

h. Shall have mechanical stops for elevation and azimuth drive

4.3. General Requirements a. Protective coatings for sea shore environment.

b. Drive motors and controls shall be of flame-proof construction

c. Ease of maintenance and disassembly of mechanical systems

d. Digital display systems for azimuth and elevation angles of the launcher shall be

provided at launch pad and blockhouse.

e. Provision for failure detection in the drives and shall give warning

messages/alarms.

f. Cable carriers shall be provided for all electrical routings

5. Universal Launcher- Configuration

The system consists of a boom of 13 m length, hinged on a trunnion with

balancing mass on the aft end. A drive shaft is integrated to the boom through

splined coupling and is driven by close-loop controlled A/C servo motors through

gearbox to get the launch elevation. The whole boom assembly is fixed on a rotating

platform, supported on slewing bearing of 2.8 meter diameter which is also driven

for obtaining the required azimuth angle and the details are given in Figures 3a to

3d.

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The Launcher consists of the following sub systems. (Refer Fig. (4a & 4b))

a) Boom assembly with counter mass:-

To support the guide rails and rocket

b) Elevation drive with gearbox and closed loop control system:-

To achieve the required launch elevation angle

c) Pedestal/ support system:-

To support the entire boom mass, gear box, bearings

d) Azimuth system with gearbox and closed loop control system:-

To achieve the required launch azimuth angle

e) Bearings for azimuth and elevation drive:-

For smooth and effortless rotation

f) Brakes for azimuth and elevation drive:-

To firmly hold the launcher in the desired position

g) Electrical interfaces:- For flight instrumentation h) Foundation:- To support the entire system

6. Design of Launcher subsystems

6.1. Boom

Boom is a tapered box structure fabricated from standard structural Steel

plates. The length of boom is 13 m from the hinge. The box cross section is 600mm

(w) X 800mm (h) at the hinge with taper on the top and lateral sides from 600x800

to 400x400 upto 6m length and uniform 400mm X 400mm section from 6m till the

tip. The plate thickness is 40mm upto 4 m from hinge, 15mm thickness for 4 to 8m

length and 5mm thickness for 8 to 13m length (Fig. (5)). Rail supports are provided

at the bottom and top faces of boom in order to avoid rocket fin interference with

the boom. Guide rails are bolted to the bottom and top faces of rail supports to

attach RH-300 and RH-200 rockets respectively. With the present configuration the

minimum clearance between rocket fins and the Boom are 22 mm for RH 200 and 31

mm for RH 300. A shaft is attached to the boom at the hinge location through splined

coupling for driving to the required elevation angle and is arrested laterally using

the coupling to take care of lateral loads. The rear side of the boom hinge is filled

with balancing mass in order to reduce the driving torque of elevation drive system.

By operating elevation drive system, suspension boom can be oriented at any

elevation angle between -5O and 93O.The boom has a minimum clearance of 100mm

each with the pedestal and 100mm with the base. The working height for RH-300

assembly is 1500mm from ground and for RH-200 assembly is 2200mm when boom

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is in horizontal condition. The working height for RH200 can be brought to 1.7

meters by tilting the boom by 2.50 towards ground using the elevation drive. The

overall length of boom with counter mass is 14.6m. The top and bottom surfaces of

the boom shall be machined for attaching the guide rails and the other surfaces to be

sandblasted.

Boom specifications:

Material : Structural steel

Length : 14.6 m (overall)

13 m working length (from hinge)

Working height from ground level : 1. 5m (RH-300), 2.2m (RH-200)

Size: : 600X800 at hinge tapered to 400X400 till

6m; 400X400 uniform from 6m to boom

tip (13m)

With cutouts for maintenance and weight

reduction, 240X150 ‘C’ section machined

and ground rail supports at top and

bottom (Fig 5).

Qty : 01 No.

The boom configuration is modelled using Autodesk Inventor® and the following

properties are derived

Mass : ~21000 + 520 kg (RH-300 mass)

Moment of inertia (1.45 X 105 + 7503 (RH-200)) =1.525x105

kg.m2 about hinge axis

CG : ~ (0,0,0) from hinge point (with counter

mass)

The above properties are for boom inclusive of rails, spline shaft, and Boom-shaft

coupling elements.

FE analysis

The boom is analysed using FEM using shell elements with fixed BC at Hinge

section and free at the tip. The deflection plot is given in Fig. 6a and von Mises stress

plot is given in Fig. 6b. The results are summarised below.

Tip deflection : 13.3 mm (due to self weight and rocket weight at the tip)

Maximum stress : 44.1 MPa

Natural frequency (Cantilever BC) : 5.5 Hz (lateral), 7.6 Hz (vertical).

Mode shapes are given in Fig. 7a and Fig. 7b.

6.2. Elevation drive system

Elevation drive system consists of a driving shaft with two synchronised drive systems (one on each side as redundant) and each drive unit consists of a

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planetary reduction gearbox with worm gearbox for inherent self-locking, plummer block for housing the bearings, flame proof AC servo motor with closed loop control and built-in fail safe brake .

Estimation of torque demand:

Normal rotation speed = 450/min. = 0.013rad/s =0.125 rpm [90O in 2 min]

Acceleration time = 10 s

ω = ω 0 + α t where ω 0 = 0 rad/sec

Angular acceleration (α) = ω/t

Angular acceleration (α) = 0.0013 rad/sec2

Torque due to acceleration = 1.525 x105 kg-m2 x 0.0013 rad/sec2

= 198.25 Nm

Torque due to friction

Friction coefficient, µ = 0.0018 [for spherical roller bearings, SKF catalogue Pg: 98, Ref: 8]

Radial load on bearings, F = 21 tons = 210000 N

d = bearing bore diameter = 220 mm

Frictional torque = 0.5µFd = 0.5 x 0.0018 x 210000 x 0.22 = 41.6 Nm

Torque due to wind (25 m/s) = 12290 Nm (Refer Appendix: A)

Torque required to rotate the boom with rocket =520*9.81*2.27=11.579 kNm (for RH-300 elevation) & 7.984 kNm for RH 200 elevation Total torque required for

rotating the boom = acceleration torque + frictional torque+ wind

torque + torque due to rocket weight

= 198+41.6+12290+11579 = 24108.6 Nm

Assuming a factor of 2, Torque = 48217.2 Nm (say 50 kNm x2 Nos)

6.2.1. Gearbox specifications: A combination of planetary and worm gear box is used for elevation drive system. Gear Ratio Required Input speed (Motor speed) = 1500 rpm Output speed required = 450/min = 0.125 rpm Gear Ratio Required = 1500/0.125 = 12000

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Stage – I (Worm Gearbox) Gear Ratio = 70 Motor speed = 1500 rpm Output speed of gearbox = 1500/70 = 21.43 rpm Stage – II (Planetary Gearbox) Gear Ratio = 180 Output speed of gearbox = 21.43/180 = 0.119 rpm = 430/min Torque Calculations Torque requirement = 50000 Nm Input torque required at Stage – II gearbox = 50000/180 = 278 Nm Assuming a gearbox efficiency of 70%, the output torque required for Stage – I Gearbox is 397 Nm Input torque required at Stage – I gearbox = 397/70 = 5.67 Nm Assuming a gearbox efficiency of 40%, the motor output torque required is 14.2 Nm. Assuming a driver efficiency of 70%, the motor torque required is 20.25 Nm at 1500 rpm.

Gearbox Size : ~ 400 X 700 X 700 mm (Stage – I (Worm Gearbox) : ~Dia 600 X 1000 mm (Stage – II (Planetary Gearbox)

Weight : <700 kg (for two stages)

Rated torque for Stage – I : >2000 Nm (for 10000 rpm-hours life)

Rated torque for Stage – II : >50000 Nm (for 10000 rpm-hours life)

Design criteria : AGMA standards / DIN

Tolerance : DIN 4 or better

Qty : 02 Nos

Interfaces:

Mounting: Foot mounted Planetary and Worm gear box with

Output: Splined shaft preferred

Input : Splined shaft preferred

6.2.2. Motor and Control system Specifications 1. Category : Programmable A/C Servo motor (Siemens

make) with position and speed feedback, with brake 2. Make : Siemens

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3. Rated Power : 3.3 kW 4. Rated Speed : 1500 rpm 5. Rated Torque : 24.5 Nm 6. Static Torque : 27 Nm 7. Mass : 27.5 kg (without brake) 8. Margin on Torque = (27/20.25) -1=0.3 9. Qty : 02 Nos

Control system:

1. Type: Servo control system with programmable position, speed and acceleration meeting the accuracy requirements specified in Section 4

2. Programmable from a remote PC 3. Final drive position sensor (optical encoder of accuracy 0.5 arc minute or

better). It is preferred to have the feedback sensor on the boom for better positioning accuracy.

6.2.3. Shaft A cylindrical stepped shaft of dia 260 mm is firmly attached to the boom at the hinge location through splines (Fig.8a). The maximum stress observed is 203MPa and the angular deflection is 0.164deg. The sag observed due to the weight of the boom is 0.313 mm. The boom is laterally restrained using a coupling as shown in fig. 8b. Shape: Dia 260mm with spline at boom location, reduced to Dia 240 stepped down

to dia 220 at bearing locations and interfaces for gearbox coupling

Material : 15CDV6 steel

Qty : 01 No

Attachment details : Ref Fig 8b

6.2.4. Spline Selection

Involute sided splines of 300 pressure angle is selected for the application. The spline selection is carried out as per IS standard 3665 The configuration of spline arrived at is 260x244x31x 7HE / 7he IS:3665

Major dia of Internal Spline : 260mm

Minor dia of Internal Spline : 244mm

Major dia of External Spline : 258.4mm

Minor dia of External Spline : 242.4mm

Module : 08

No of Teeth : 31

Length of Spline : 200 mm on each side

Design Margin (Stress based) :835/160 – 1 = 4.2

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6.2.5. Brake specifications:

From Section 6.2 the torque required to hold the boom in position is estimated as 23869 Nm at the boom location. Since it is difficult to accommodate a brake with 23869 Nm braking torque in the proposed configuration, it is decided to keep the brake at the worm gearbox output shaft. A normally closed (fail safe) heavy duty disc brake is preferred. From literature it is found that heavy duty disc brakes are available and typical specifications are given in figures 9a and 9b.

Holding capacity of brake required = 23869/180

= 133 Nm

Type : Disc Brake, NORMALLY ENGAGED, electrically released (with manual release option)

Manufacturer : Pintsch Bubenzer (Or equivalent)

Supply : 3 Phase AC

Power : 450 W

Current : 0.8 A at 400V

Disc Dia : 630 mm

Braking torque : 2200 Nm

Mass : 110 Kg

Margin on Braking Torque : (2200 X 2/133) - 1 = 32

Two disc brakes on either side of boom is provided

6.2.6. Elevation drive bearings selection

Spherical roller bearings have two rows of rollers, a common sphered outer ring raceway and two inner ring raceways inclined at an angle to the bearing axis is considered. The centre point of the sphere in the outer ring raceway is at the bearing axis. Therefore, the bearings are self-aligning and insensitive to misalignment of the shaft relative to the housing, which can be caused, say, by shaft deflection. Spherical roller bearings are designed to accommodate heavy radial loads, as well as heavy axial loads in both directions.

Based on the load ratings, SKF Part No: 23044 CC/W33 (Spherical roller

bearings with cylindrical bore) is selected

The load ratings and dimensions of the selected spherical roller bearing part number are highlighted in the catalogue reproduced in Fig. 10. Design Checks Weight on bearings = 21+0.5/2 =10.75 tons = 107 kN Load due to Thrust misalignment (30) = 3.382 kN

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Radial load expected = 107 + 3.382 = 110.38 kN Margin on radial load = 1220/110.38 - 1 = 10 Axial Load expected (due to 25m/s wind) = 2.72kN (Appendix: A) Speed =0.125rpm (limit 2000rpm) Qty = 02 Nos Hence the bearing selected is safe for operations 6.3. Pedestal / Support system

6.3.1. Shaft Support/Plummer block assembly:

The boom shaft is supported on 2 spherical roller bearings each of which is assembled on plummer block housing. The plummer block selected is a SKF standard part with part no: SNL 3044 G which suits the selected spherical roller bearings (SKF Part No: 23044 CC/W33). The important housing dimensions and its associated components of the selected part are highlighted in the catalogue reproduced in figures 11 and 12. The assembly details are shown in figure 8b. 6.3.2. Load capability of Plummer block housings

The load capability of housing and attachment bolts are highlighted in the catalogue reproduced in Fig. 13. Radial load acting on plummer block housing (P00)= (210000+5050)/2 + thrust misalignment(3.38kN) = 110.9 kN Axial load acting on plummer block housing = 2.72 kN [Wind Load- refer appendix: A] Margin of safety on radial load = 520/110.9 -1 = 3.68 Margin of safety on axial load = 168/2.72 -1 = 60 Tensile load on housing (on bolts) (without preload) = 2.72+3.38=6.1kN (Upward wind load+ thrust misalignment) Load capability for cap bolts (M24 x 4Nos) (1800 load) = 380 kN Plummer block Qty : 02 Nos 6.3.3. Pedestal support system

The entire bearing housing, gearbox and motor is supported on a 50mm thick

plate mounted on the Pillar Fig. 14. The Pillar and Plate are designed to take care of

the axial and lateral loads of the boom and the reaction loads of the gearbox motor

assembly. A box type monocoque construction is adopted for the pillar design and

the details are given below. FE analysis were carried out using shell elements and

stress & deflection values are found to be within limits.

6.3.3.1. Loads ( with a factor of 2)

Axial a. Self weight of boom/2 + Bearing/housing + Gearbox (2) + Rocket

wt/2+ Plate wt + motor + brake :127.53x2= 255.061 kN

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b. Gearbox/Motor reaction torque : 50kNm

Lateral a. Wind Load from Boom : 2.72kN

Overall size : 1.5mX1.35mX0.7m box made of 50 mm thick plates (Fig 14)

Material : Structural Steel

Stress : 16.7 MPa

Deflection : 0.137 mm.

Interfaces : Plate to Pillar M24 Bolts (16+ 12 Nos) (hole locations are shown in fig 14)

: Pillar welded to Base Plate.

Qty : 02 Nos

6.4. Azimuth Drive System

6.4.1. Base Plate

The entire assembly mentioned above is supported on stiffened plate

mounted on Slewing Bearings. The Base Plate is designed to take care of the axial

and lateral loads from the Pedestal assembly and the reaction loads of the azimuth

drive gearbox. A skin stiffened construction is adopted for the Base Plate design and

the details are given below (refer Fig. 15). FE analysis was carried out using shell

elements and the stress & deflection values are found to be within limits.

Loads

Axial a. Loads from Pedestal assy : 373.466x2 =747 kN

(with a factor of 2) Lateral

b. Wind Load from Boom : 2.72kN c. Azimuth Gearbox/Motor reaction torque : 2.06 kNm

Overall size : Top circular plate of dia 3500 mm (30 mm thick) Fig 15

: Bottom circular plate of dia 2500 mm (20 mm thick)

: 20 Radial stiffeners and circular stiffeners (16 mm thick)

Material : Structural Steel

Stress : 44.2 MPa

Deflection : 0.504 mm.

Interfaces : Base Plate to Slewing ring M30 Bolts at 2540mm PCD 60 Nos Base Plate to Pedestal support assy - welded connection

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Qty : 01No

6.4.2. Slewing Bearings:

The entire assembly with Base Plate is assembled to Slewing Bearings for azimuth drive. The configuration selected is having an outer race with external gear and is fixed to the foundation. ROTHE ERDE make KD 600 model with external gear fixed to foundation is considered as a candidate bearing for this application.

Type: KD600

Designation : 061.50.2645.001.49.1504

Outer diameter =2892.8mm,

Inner diameter = 2474mm

Module of external gear of Slew Ring Bearing = 16

Pitch Circle Diameter (PCD) = 2848mm

Number of teeth = 178

Total Axial load : ~ 750kN (with factor of 2)

Total moment : ~4.352 kNm

Axial load/Moment capability : refer Figures 17a & 17b

6.4.3. Estimation of torque demand for azimuth drive:

Normal rotation speed = 90°/min. = 0.026rad/s = 0.25 rpm

Acceleration time = 4 s

ω =ω0 +α x t where ω 0 = 0 rad/sec

Angular acceleration (α) = ω /t

Angular acceleration (α) = 0.0065 rad/sec2

Inertia torque due to acceleration = 600000 kg-m2 x 0.0065 rad/sec2 = 3900 Nm

Wind torque = 12.29kNm (refer Appendix: A)

Friction coefficient, µ = 0.006 (for type KD 600)

Axial load on bearing, F = 747 kN (with a factor of 2)

DL = bearing race diameter = 2.647 m

Frictional torque = µFr = 0.006 x 747000x 2.647/2 = 5923 Nm

Total torque required for rotating the slewing ring bearing = acceleration torque + wind torque + frictional torque = 3900 + 12290+ 5923 = 22.11 kNm

Assuming a factor of 1.5, Torque required is 33.165 kNm

6.4.4. Slew Drive Gear box specifications:

Gearbox type : Planetary

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Input speed of geared motor : 190 rpm

Output speed : 0.25 rpm

Overall Gear ratio required : 760

Static torque required for rotating slew bearing : 33.165 kNm

To match with slewing bearing, the module and pinion teeth of Slew drive gear box is fixed as

Pinion teeth : 11

Module : 16

Reduction ratio between pinion and slewing bearing gear = 178/11 = 16.18

Torque required from the slew drive gearbox output: 33165/16.18 = 2050Nm

Gear ratio required for Slew drive gearbox = 760/16.18=46.97 Say 50

Considering slewing gear efficiency of 70% torque required is 2928 Nm

Input torque required for the gearbox : 2942/50=58.56 Nm

Considering 70% gearbox efficiency, motor output torque required = 83.66 Nm

Considering motor drive efficiency of 70% motor torque required is 119.5 Nm

Considering two drives with motor torque of 160 Nm (refer section 6.4.5)

Margin on torque = 160x2/119.5 -1 = 1.7

Approx size : dia 280 x 400 mm

Rated torque of Gearbox ≥ 4000Nm

Qty : 02Nos

Mass : 175 kg

Interface details : foot mounted planetary gearbox with a spur gear of PCD 176mm and module 16 mm at the output shaft.

6.4.5. Motor and control system for azimuth drive:

Motor:

1. Category: A/C servo motor (Siemens make) with position and speed feedback, with brake, Programmable

2. Type : SIMOTICS S-1FK7 geared servomotors (Synchronous motor)1FK7 helical geared motor

3. Rated Power : 3.18 kW 4. Rated Speed : 190 rpm 5. Rated Torque : 160 Nm 6. Weight :~ 50 kg

Control system:

1. Type: Servo control system with programmable speed and acceleration

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2. Programmable from a remote PC 3. Final drive position sensor (optical encoder of accuracy 0.5 arcminute)

6.4.6. Azimuth Brake specifications

From Section 6.4.3 the torque required to hold the azimuth sub assembly in position is estimated as 12290 Nm. A normally closed (fail safe) Heavy duty disc brake is preferred. From literature it is found that heavy duty disc brakes are available and typical specification is given below (Refer Figures 18a & 18b)

Braking torque required : 12290/16 = 768 Nm

Type : Disc Brake

Manufacturer : Pintsch Bubenzer

Supply : 3 Phase AC

Power : 450 W

Current : 0.8A at 400V

Disc Dia : 710 mm

Braking torque : 5490 Nm

Considering two brakes for redundancy

Margin on braking torque: 5490X2/768 -1= 13.3

In addition to this mechanical lock need to be provided for holding

7.0. Modal Analysis

The entire assembly is analysed for finding the modes and the first mode is 3.6 Hz. The first mode is dominated by the torsional mode of the shaft (Fig 19a). The second mode (4.8 Hz) is mainly due to the lateral bending mode of the shaft (Fig 19b).

8.0. Instrumentation

Instrumentation details will be furnished in the next release.

9.0. Surface Protection

Surface protection to be implemented as per the following standards

1. IS: 8062 (Parts I to III): Code of practice for cathodic protection of steel

structures.

2. IS:8062 (Part I)—1976, Cathodic protection signifies protection of a metal

structure from corrosion in an electrolyte by making the structure the

cathode so that direct current flows into the structure from the electrolytic

environment.

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3. In addition to the above, zinc rich primer coating is to be applied as per IS

standard.

4. ISO 12944: 1998, Paints and varnishes – Corrosion protection of steel

structures by protective paint systems.

10.0. Foundation

Foundation required for supporting the launcher will be designed by CMG.

Foundation shall embed an interface ring for assembling the slewing bearing. The

top surface shall be 150 mm above the ground surface. Conduits with cable carrier

shall be provided for cable routing, starting from the center to radially outward at

450,1350,2250,3150.

11.0. Thermal analysis

Thermal analysis of the system under exposure to rocket plumes to be carried

out to assess TPS/cowling requirements.

12.0. Acceptance Tests

After assembly and integration of all sub systems at TERLS/VSSC, the

following acceptance tests need to be carried out. Separate acceptance test

document will be brought out.

12.1. Load Tests

After satisfactory completion of installation, load test is to be conducted to

design limit load by simulating required conditions. During this test, deflection and

strain measurements of the launcher, No load currents & Full load currents of both

the motors and current values of all four brakes has to be monitored.

a. The tip deflection with RH200/RH300 in position shall be measured. It should

be less than 14.4 mm for the design limit load.

b. Twice the motor mass shall be kept at the rail tip and the launcher

survivability shall be demonstrated.

12.2. Frequency Measurement

Axial and lateral frequency of the launcher shall be measured. Acceptance

criteria are that the frequency of the overall system should be more than 2.3 Hz in

both directions.

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12.3. Acceptance Trials

The drive systems are the main elements of the launcher. After installation of

the launcher, the party shall demonstrate the working of both drive systems

12.4. Brake Trials

After installation of the launcher, effectiveness of the elevation drive and

azimuth drive brake shall be demonstrated. Brakes also shall be tested for two times

the holding capability, to verify the margin.

12.5. Safety systems

All safety interlocks and limit switches for drive systems shall be

demonstrated through various trials.

12.6. Calibration

Measurement accuracy of elevation and azimuth angle shall be within

specification. All the instrumentation systems shall be calibrated and calibration

reports shall be supplied to VSSC.

12.7. Alignment checks:

Alignment is one of the important criteria for acceptance of the total

system. In every stage of erection, alignment has to be checked for proper leveling,

angular deviations, parallelism etc with theodolite. The specifications for guiderails

alignment is given below

Straightness of each rail (Vertical & Lateral axis): ± 0.5 mm / meter and ± 1.0

mm for total length of 13 m.

Parallelism of rails: 222 + 0.0, - 0.1 mm for total length

No deviation will be accepted

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13.0. Summary The preliminary design of universal launcher for RH 200 & 300 are presented.

The subsystems required for the launcher are identified and configured. Counter

balance mass is provided to minimise the drive torque requirement. Provision for

tuning the counter mass is included to take care of the fabrication deviation.

Preliminary structural analysis is also completed and is meeting the functional

requirements. However the stiffness of the beam need to be finalised based on

dynamic analysis considering the wind conditions and clearance study while the

rocket is sliding. Efforts are taken to identify commercially available standard

components/ systems for the launcher design. Foundation design and cowlings for

the systems to be taken up in the CDR phase. Regarding the gearbox for elevation

drive a customised integrated gearbox with worm input and planetary output can be

considered.

14.0. References

1. MOM Task team 2. IS 875 (Part III): Code of practice for design loads for buildings and structures

(wind loads) 3. IS 3665: Dimensions for involute sided splines 4. IS 8062 (Parts I to III): Code of practice for cathodic protection of steel

structures 5. SKF catalogue for Rolling bearings 6. SKF catalogue for Plummer block housings 7. Rothe Erde Slewing bearings catalogue 8. SIMOTICS Servo motors catalogue, Siemens catalog PM 21 . 2013 9. Pintsch bubenzer technical catalogue

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Figure 1a: RH 200 vehicle configuration

Figure 1b: RH 300 Mk II vehicle configuration

Figure 2a: RH 200 vehicle attachment to Launcher boom

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Figure 2a: RH 300 vehicle attachment to Launcher boom

Figure 3a: Side view of launcher with RH200 in position

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Figure3b: Launcher with RH200 at launch elevation

Figure 3c: Side view of launcher with RH300 in position

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Figure3d: Launcher with RH300 at launch elevation

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Figure 4a: Launcher subsystems

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Figure 4b: Launcher subsystems

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Figure 5: Boom Assembly

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Figure 6a: Tip deflection of launcher boom

Figure 6b: von Mises stress plot of launcher boom

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Figure 7a: Mode shape of launcher boom (1st mode, Top view)

Figure 7b: Mode shape of launcher boom (2nd mode, Side view)

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Figure 8a: Spline shaft details

Figure 8b: Spline shaft attachment details

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Figure 9a: Brake for Elevation Drive

Figure 9b: Brake for Elevation Drive

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Figure 10: Spherical roller bearing

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Figure 11: Plummer block housing

Figure 12: Plummer block housing mounting Details

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Figure 13: Load capability of Plummer block housings

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Figure 14: Pedestal support system (Pillar)

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Figure 15: Base Plate details

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Figure 16a: Deflection plot of Base plate

Figure 16b: stress plot of Base plate

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Figure 17a: Slewing Bearing Load Capability

Figure 17b: Slewing Bearing Load Capability

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Figure 18a: Brake for Azimuth Drive

Figure 18b: Brake for Azimuth Drive

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Figure 19a: Mode shape of launcher Assembly (1st mode, Side view)

Figure 19b: Mode shape of launcher Assembly (2nd mode, Top view)

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APPENDIX

APPENDIX-A: WIND LOAD CALCULATIONS

Wind data:

Wind pressure data as applicable to Trivandrum region (Ref. IS-875) is used for computing wind loads. Ref: IS 875: Part 3 wind loads

Design wind speed, Vz = k1 x k2 x k3 x Vb

Where, Vb = Basic wind speed = 39 m/s (for Trivandrum)

Risk coefficient, k1 = 1.0 (for 50 years life)

Terrain, height & Structure size factor, k2 = 1.05 (Category 2, Class A, height~15 m)

Topography factor, k3 = 1.0 (for slope < 30)

Vz = 1.0 x 1.05 x 1.0 x 39 = 40.95 ~ 41 m/s

Design wind pressure, Pd = 0.6 x Vz2 = 0.6 x 412 = 1008.6 N/m2

Launcher beam area, A= 9.4 m2 (Boom in horizontal condition) & 5.8 m2 (Boom in Vertical condition)

Centre of pressure from hinge = 4.11 m (Horizontal) & 6.03 m (Vertical)

Wind load, F = (Cpe - Cpi) A Pd

Cpe = External pressure Coefficient

Cpi = Internal pressure Coefficient

Wind load in Horizontal position, FH = (0.7 - 0) x 9.4 x 1008.6 = 6.64 kN

Moment, MH = 6.64 x 4.11 = 27.28 kNm

Wind load in Vertical position, FV = (0.85 - 0) x 5.8 x 1008.6 = 4.97 kN

Moment, MV = 4.97 x 6.03 = 30 kNm

Operating Wind

Design wind speed, Vz = k1 x k2 x k3 x Vb

Where, Vb = Basic wind speed = 90 kmph = 25 m/s (for Trivandrum)

Risk coefficient, k1 = 1.0 (for 50 years life)

Terrain, height & Structure size factor, k2 = 1.05 (Category 2, Class A, height~15 m)

Topography factor, k3 = 1.0 (for slope < 30)

Vz = 1.0 x 1.05 x 1.0 x 25 = 26.25 m/s

Design wind pressure, Pd = 0.6 x Vz2 = 0.6 x 26.252 = 413.44 N/m2

Launcher beam area, A= 9.4 m2 (Boom in horizontal condition) & 5.8 m2 (Boom in Vertical condition)

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Centre of pressure from hinge = 4.11 m (Horizontal) & 6.03 m (Vertical)

Wind load, F = (Cpe - Cpi) A Pd

Cpe = External pressure Coefficient

Cpi = Internal pressure Coefficient

Wind load in Horizontal position, FH = (0.7 - 0) x 9.4 x 413.44 = 2.72 kN

Moment, MH = 2.72 x 4.11 = 11.18 kNm

Wind load in Vertical position, FV = (0.85 - 0) x 5.8 x 413.44 = 2.038 kN

Moment, MV = 2.038 x 6.03 = 12.29 kNm