FAA sUAS COE Task A3 UAS Airborne Collision Hazard ... · Fixed wing is expected to introduce more...

www. ASSUREuas.org1

FAA sUAS COE Task A3UAS Airborne Collision

Hazard Severity Evaluation

Gerardo Olivares Ph.D. | November 2017 | Washington D.C.

www. ASSUREuas.org2

UAS Airborne Collision Hazard Severity Research

Purpose Inclusion of large numbers of sUAS into the National Airspace System (NAS) may pose unique

hazards to other aircraft sharing the NAS. It is necessary to determine potential severity of sUAS mid-air collisions with aircraft in order to define

an Equivalent Level of Safety to manned aviation.

Research Questions What is the severity of a UAS collision with a manned aircraft? What are the hazard severity criteria for a UAS mid-air collision (weight, kinetic energy, etc.)? How can the design of a UAS minimize potential damage during a mid-air collision? Can we classify a UAS impact similar to a bird strike? What particular characteristics of a UAS are required to avoid so it will not be a risk to a manned

aircraft? Can we categorize the severity of a UAS mid-air collision with an aircraft based on the UAS and what

would those categories look like?

Approach Develop high-fidelity computer models supported by component level tests to evaluate the severity of

sUAS collisions with manned aircraft (commercial transports, business jets)

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sUAS Airborne Collision Hazard Severity Evaluation – ASSURE Research TeamASSURE Principal Investigator (PI): Gerardo Olivares Ph.D., Director Computational Mechanics and Crash Dynamics Laboratories, National Institute for Aviation Research –Wichita State University, [email protected] . 316-9787273Other ASSURE Performers PI’s:

Wichita State University - NIARTom AldagJaime Espinosa de los MonterosChandresh ZinzuwadiaAdrian GomezRussel BaldridgeLuis GomezStudents: Armando Barriga, Hoa Ly, Rodrigo Marco, Sameer Naukudkar, and NathanielJ. Baum

Mississippi State UniversityThomas E. Lacy Jr. Ph.D. (co-PI)Students: Kalyan Raj Kota, Nimesh Jayakody, and Trent Ricks

Montana State UniversityDoug Cairns Ph.D. (co-PI)Mike EdensStudents: Graham Johnson and Forrest Arnold

Ohio State UniversityKiran D'Souza Ph.D. (co-PI)James Gregory Ph.D.Students: Troy Lyons

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Research Program OverviewDescription of Activity Quarterly Report

Research Plan Definition

WPI .UAS Class Definition

WPII. TargetAircraft Definition

WPIII. (a) sUAS Type I Projectile Development

WPIII.(b) sUAS Type II Projectile Development

WPIV.(a)NarrowBodyTransportModel Dev.

WPIV.(b)Business Jet Model Development

WPV.(a) Business Jet Safety Evaluation

WPV.(b) Narrow Body Safety Evaluation

WPV.(c) EngineModel Safety Evaluation

WPVI.Aircraft Draft Recommendations

WPVII. UAS Draft RecommendationsPeer Review

On Track Milestone

Completed Milestone

TBD Milestone

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Research Approach : Why did we use Simulation?

14 month research effort plus a 3 month peer review process.

Over 140 scenarios were analyzed: Two different sUAS configurations(QuadCopter and Fixed-

Wing) Two different Airplane Targets (Single Aisle Commercial

and Business Jet) with eight different impact locations (Wing leading edge, Horizontal Stabilizer, Vertical Stabilizer, and Windshield).

Impact velocities from 100 knots to 365 knots. Comparison with 2.68, 4, and 8 lb bird strike impacts. sUAS

masses 2.68, 4, and 8 lb. configurations. Engine ingestion configurations: Take-off, Cruise, Landing

This will have not been possible through Full Scale Physical Testing [Prohibitive costs and time, sourcing of test articles, control of accurate impact conditions, etc.]

Simulation allows for quick changes on impact conditions (Orientation, Velocity, Impact location, Mass)

Simulation allows for repeatability between tests and appropriated comparisons between impact scenarios.

Simulation allows for further evaluations with minimal costs.

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sUAS Models Development Process

sUAS Selection•Market Study

•Model Selection

sUAS Preparation•UAS Disassemble

•Component Mass Measurement

Reverse Engineering•Cloud Point Generation

•CAD Modeling•Material Identification

•Sanity Checks

FE Modeling•Discretization•Material Definitions

•Connections•Contact Modeling •Mass and CG Check

Validation (Building Block)•Coupon•Component•Full Scale

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Simulation Methodology – Physics Based Modeling – Material Level

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Drop Tower Test - Material Validation –ISO View - Kinematics

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Simulation Methodology – Physics Based Modeling – Motor Component Level

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Motor Component Test - 250knots -Side View - Kinematics


Motor Component Test - 250knots -ISO View - Kinematics


Simulation Methodology – Physics Based Modeling – Battery Component Level


Battery Component Test - 250knots -ISO View - Kinematics


Simulation Methodology – Physics Based Modeling – sUAS Quad Assembly


sUAS Quad Assembly – Kinematics

t = 0.001 s t = 0.002 s t = 0.003 s


Aircraft Target Models


Severity Level and Risk of Post Impact Battery Fire Classification


Quadcopter Vertical Stabilizer and Fixed-Wing Horizontal Stabilizer - 250knots


Quadcopter Vertical Stabilizer -250knots - Kinematics


Fixed-Wing Horizontal Stabilizer -250knots - Kinematics


What is the Severity of a sUAS Midair Collision with a Narrow Body Aircraft?

2.7 lb. Quadcopter 4 lb. Fixed Wing


What is the Severity of a sUAS Midair Collision with a Business Jet Aircraft?

2.7 lb. Quadcopter 4 lb. Fixed Wing


Can a sUAS Impact be Classified Similar to a Bird Strike?


4 lb UAS vs. 4 lb Bird Strike - Vertical Stabilizer - 250knots - Kinematics


4 lb UAS vs. 4 lb Bird Strike - Horizontal Stabilizer - 250knots - Kinematics


Conclusions Airframe – sUAS Impact R&D

Comparison to Bird Strikes sUAS collisions caused greater structural damage than bird strikes for equivalent impact energy levels

(i.e. equal mass and impact velocity).

Velocity and Mass (kinetic energy) Velocities above landing speeds are considered critical for masses equal to or above 2.6lbs (1.2 kg).

Lower masses will need to be investigated in the future. Damage severity increases with increased mass and velocity

Verified through component level tests and sUAS parametric studies with simulations

Stiffness of Components Component level testing demonstrated that stiff components such as motors can produce severe

damage. Testing showed penetration of motors (2.268 oz (64 grams)) into 0.063” (1.6 mm) aluminum panels when impacted at 250 knots.

Full scale sUAS simulations confirmed that most of the damage is produced by stiffer components (battery, motor, payload, etc.)

Distribution and Connection of Masses Distribution of mass and stiffness in the design of the sUAS is critical to the energy transfer. With concentrated or aligned masses the probability of critical damage increases.

Simulations confirmed that the critical damage occurs when a majority of the masses are aligned with the impact direction.

Energy Absorption Capability sUAS designs which incorporate energy absorbing components (materials and/or structural features)

could reduce the damage to the target aircraft.


Engine Ingestion – Research Questions

Does a sUAV ingestion take out blades?

If blades are lost, are they contained?

What parameters of the ingestion event are expected to have the largest effect on the damage level? Flight condition Fan geometry Impact location and orientation Type of sUAV and sUAV

components (i.e. batteries, motors, cameras..etc.)


Engine Ingestion – Approach

Develop a generic mid-sized business jet engine model for parametric study: Capture geometric characteristics consistent with modern engines. Generic model, not specific of any particular engine in service. Define representative geometry and materials. Leverage material models developed from literature review.

Conduct ingestion simulations using LS-Dyna by setting boundary conditions to match operating conditions at key flight phases: Takeoff. Approach. Flight below 10,000 ft.


Engine Ingestion – Summary Results

Simulations focus on damage to fan, nacelle, and nosecone – downstream components such as the compressor, combustor and turbine are not included in the model.

Fixed wing is expected to introduce more damage than the quadcopter.

Stiffer components such as motors, cameras and batteries do the most damage to the fan.

Location of impact along fan is a key parameter. More damage as the impact occurs closer to the blade tip.

Takeoff scenario is the worst case because of high fan speeds.

During the peer review with various engine manufacturers [Pratt and Whitney, Rolls Royce, General Electric and Honeywell] it was recommended that further work and collaboration are required to develop and validate a representative engine model to evaluate sUAS engine ingestion impact scenarios.


Quadcopter Engine Ingestion 6000rpm -250knots - Kinematics


Conclusions ASSURE Airborne Collision Study

sUAS can introduce severe damage to aircraft structures in case of airborne collision scenarios as shown in this research.

Even non-severe structural damage levels in the Level 1 to 3 can introduce a significant economic burden to aircraft operators: due to downtime and repairs.

sUAS collisions caused greater structural damage than bird strikes for equivalent impact energy levels (i.e. equal mass and impact velocity).

sUAS hobbyist and operators need to follow the guidance provided by the FAA in Special Rule for Model Aircraft (Public Law 112-95 Section 336) and/or AC107-2 respectively.

sUAS manufacturers should adopt “detect and avoid” and/or “geo-fencing” technologies to reduce the probability of potential impacts with other aircraft in the NAS.

The data provided in this research may be used by the FAA to define future Expanded Operations and Non-segregated Operations rulemaking activities.


Future Work Phase 2 ‐ FY18 ‐ FY19

Study additional manned airframes such as rotorcraft and general aviation. Partnership with industry Original Equipment Manufacturer (OEMs) from the peer

review committee (GE, Pratt and Whitney, Rolls Royce, and Honeywell) to define a representative engine model to further research sUAS engine ingestion.

Conduct additional UAS component tests for various impact conditions (structural and rotational) as requested during the peer review with OEMS and FAA Chief Scientific Technical Advisors (CSTAS).

Phase 3 ‐ 4th Quarter FY18 ‐ FY19 Begin Testing of fan blade assembly. Develop plan and identify assets/partners/parameters/metrics for engine ingestion

testing using out of service engines; Peer review with OEMS and FAA CSTAS. Phase 4 ‐ FY20

Execute engine ingestion test using out of service engine; Peer review with OEMS and FAA CSTAS


Questions?

• Electronic copy of the presentation available at: www.ASSUREuas.org Airborne collision research contact:

Gerardo Olivares Ph.D., Director, Computational Mechanics and Crash Dynamics LaboratoriesNational Institute for Aviation Research Wichita State [email protected](316) 978-7273

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