An Electromagnetic Payload Launcher for Marine Applications Chris Watts, Technology Acquisition Lead, Babcock DST
Strictly Private and Confidential Introduction • Electromagnetic launch – using Linear Induction Motors (LIMs) to launch a payload • Ability to launch a range of different payloads • Adaptable to varying launch requirements and conditions • Specific focus on EM fields generated in the payload area – modelled and verified with experimental testing • Test rig designed and built to demonstrate performance and compliance to applicable standards • Simulation and FEA model used for design and performance prediction 2 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential EM Launch Benefits Simple – control system uses COTS components, DOL or standard motor drives Low maintenance – minimal to zero requirement, with no high pressure systems Adaptable – can be scaled to launch payloads of varying size and mass High reliability – only one moving part coupled with mature linear motor technology Controllable – exit speed and acceleration can be controlled to suit the specific payload and conditions 3 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Underwater Defence Applications • Torpedo launch • Mine launch • Acoustic countermeasures • Submerged signal ejectors • UUV launch • Special forces deployment 4 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Safe Energy Density Levels Applicable standards: • MIL-HDBK-240A (HERO) • BR2924 (surface & underwater) • DEF Stan 59-411 • JSP 482 Edition 4 • STANAG 4234 BR2924 identified as worst-case 5 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Test Rig Launcher: Launch payload at Catcher: Arresting the payload required exit velocity after launch Features: Linear motors, DC Features: High friction rails, brake, low friction rails modular structure Payload: Dummy payload to represent lightweight torpedo Features: Accelerometer mounted externally • Full scale test rig used to launch a dummy payload of identical dimensions and mass to a lightweight torpedo • Aim to demonstrate electromagnetic compliance with applicable standards, specifically BR2924, using EM field measurement equipment on the test rig over multiple launches 6 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell FEA Model 7 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell Performance Prediction 8 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell Flux Density Areas 1. LIM teeth 2. Back iron 3. C beams housing the LIMs 4. Airgap 5. Actuation fin 6. Payload 7. Payload internal volume 9 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell Flux Density Magnitude 10 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell Flux Density Plots 11 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Ansys Maxwell Flux Density Plots 12 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Launch Video 13 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com www.babcockinternational.com
Strictly Private and Confidential Measured Launch Parameters Measured parameters Current, Acceleration, Velocity Simulated parameters Current, Acceleration, Velocity 14 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Measuring EM Fields Test rig reconfigured for EM fields measurement • Bespoke method of measuring fields using off-the-shelf equipment • Pusher bracket on actuation fin turned around • Payload positioned in front of the fin instead of above it • Field probes placed above the LIMs and the fin where payload would normally be This enables a full-load launch with measurement of EM fields in the area of interest 15 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Analysis of EM Fields Data Measured fields in comparison to limit based on BR2924 16 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Conclusions • Proven ability to launch payload at specified exit speed • Demonstrated consistent and reliable operation – over 100 launches completed with no maintenance • Impact on power supply determined by overall system level capabilities (energy storage could be provided) • Proven adaptability for various payloads and launch requirements. i.e. torpedo variants, UUVs • Ability to accurately predict performance using FEA model and simulation techniques • Demonstrated that EM fields generated by the launcher are below threshold of applicable standards 17 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
Strictly Private and Confidential Further Work • Continue to improve the model and simulation techniques to aid with further development and accurately predict performance characteristics • Investigate alternative interface and release mechanisms for a wide range of payloads • Investigate system application under water using modelling techniques to simulate submerged LIMs • Develop roadmap for underwater concept design, considering a range of possible payloads (e.g. heavyweight torpedoes, mines, countermeasures, UUV) 18 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
19 An Electromagnetic Payload Launcher for Marine Applications www.babcockinternational.com
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