Topology Optimization Applied to Part Constructed Via FDM (Fused Deposition Modelling) for an Unmanned Aerial Vehicle
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The document discusses the Italian regulations and classifications of remotely piloted aircraft (sapr), which are divided into two categories based on weight. It outlines the PBK project, focusing on the development of a multi-rotor UAV designed to optimize weight using additive manufacturing techniques, and it details various testing phases and results, including stress analysis and prototypes. The project aims to integrate multiple components into a single part to improve functionality while minimizing mass, with next steps including further material evaluations and simulations.
![Pbk project: material characterization
• Choosing process of the micro
tensile specimens via DOE to
evaluate also the
manufacturing constraints (min
wall thickness, maximum angle
without support etc.)
• Construction of 96 micro-tensile
specimens to extimate the
ϭbrake nd the elongation at
roupture
• Experiment design and post
processing carried out with
hyperstudy
Displacement [mm]
Load[N]](https://image.slidesharecdn.com/eatc2015pdtferro-151113103904-lva1-app6891/85/Topology-Optimization-Applied-to-Part-Constructed-Via-FDM-Fused-Deposition-Modelling-for-an-Unmanned-Aerial-Vehicle-8-320.jpg)
Topology Optimization Applied to Part Constructed Via FDM (Fused Deposition Modelling) for an Unmanned Aerial Vehicle
- 2. SAPR, UAV: Definition and Italian Regulamentation • ENAC: a SAPR is a aircraft remotely piloted without people on board not used for recreational use • The UAV or SAPR used in special operations or in experimental activities constitutes the system of aircraft remotely piloted and are submitted to the air law (ICAO) • The aircraft modelling ARE NOT considered aircraft and are not submitted to the air law codex. Indeed they can’t be used in aerial work or in other application except the recreational use in special areas. SAPR.. ..UAV.. ..APR..
- 3. SAPR, UAV: Italian Classification SAPR are divided into two main categories: • MTOW < 25Kg • MTOW > 25Kg No critical operations, no densely inhabited areas, no controlled ATZ, AutoRoute, rail station etc. V70 flight space (50 m minimum distance from people, 70 m maximum height over soil, 200 m maximum operative radius from the pilot, VLOS link) Only daytime operations. Project PBK
- 4. Progetto PBK, il velivolo Attempt to establish a world record! • Multi rotor aircraft (8 Propellers); • Long range / time of flight (more than 3 h); • Patented power generation system • High resistance / low weight structure designed using aluminum alloys, carbon fiber and additive manufactured abs parts in the interfaces: • Carbon pipe – electric motor; • Carbon pipe – aluminum frame.
- 5. SAPR & ADDITIVE MANUFACTURING Additive layer manufacturing (ALM) could bring great potentials to the design of SAPR due to: • Great demand of weight reduction to match the requirements; • Small series pieces that doesn’t require shells special tooling etc.; • Demand to vary the design of the parts customizing the aircraft • Time to market as short as possible
- 6. Additivemanufacturing:scoutingofpotentialtechnologies • Powder bed (SLM, EBM, DMLS): useful technology to build metal andplastic part. At the time to expensive for the UAV market both for machine cost and part produced via external service. • Stereo lithography: a photopolymer is hardened via a selective coherent light deflected in a x-y plane by movable mirrors. 3DSystem was the first to introduce this technology and is now the leader. Optimal mechanical properties and dimensional tolerances but cost still unaffordable for the SAPR market. • FDM (material extruder): is the most diffused technology on earth and outside (the machine installed on ISS bt NASA). All derives from the open source project RepRap. • More than 21000 printers sold only in 2012 by Stratasys.
- 7. Progetto PBK: Work Stream Evaluation of the results Weights, stress, deformation Modal frequencies etc FEM analysis with Optistruct Stress, strain modal Redesign Preliminar optimization with Inspire Objective min mass Boundary constraint max stress and model frequencies Design of the rough model design space non-design space Material characterization at tension / compression Construction of microtensile specimen Testing Evaluation of material properties
- 8. Pbk project: material characterization • Choosing process of the micro tensile specimens via DOE to evaluate also the manufacturing constraints (min wall thickness, maximum angle without support etc.) • Construction of 96 micro-tensile specimens to extimate the ϭbrake nd the elongation at roupture • Experiment design and post processing carried out with hyperstudy Displacement [mm] Load[N]
- 9. Paretodiagramandmaineffectfortheloadatrouptureand theYoungmodulus* *growth direction perpendicular to the plate*growth direction parallel to the plate
- 10. Pbk project: choosing of the parts to be constructed Two components were selected to be built with FDM: • Interface between motor and carbon pipe • Interface between carbon pipe and aluminum alloy structure This two components have been selected due to the high solicitation and because of the simplification of the gluing process. The original version of the two parts were in 7075 alloy with a weight of 34,5 grams, the other 31,1 grams Total weight: 773 grams
- 11. Pbk project: design and optimization • Non design space: connections with the pipe and with the screws of the motor • Design space volume: gross space usable • Objective function: min of the mass • Constraint : max stress and first 10th modal greater than 250 Hz.
- 12. Pbk project: results obtained • Boundary constraint satisficed • Need to add some other manufacturing constraint orientation angle, removal of the support tooling space etc.)
- 13. Pbk project: re design of the parts
- 14. Pbk project: validation analysis • Analysis post the redesign phase: stresses and strain are under the limit. The first 10 modal are over than 250 Hz. • Motor support optimized weight 10,2grams • Pipe support post opt 6,7 grams • Total weight of the parts: 189,2 versus 773 grams
- 15. Progetto PBK: Costruction and testing Both the prototypes were tested statically in laboratory to verify the displacement with good comparison with the expected results
- 16. ProgettoPBKNextsteps:integrationofmorecomponentina singlepartshockabsorber • Task: obtain one multifunctional component bult in a single part (shock absorber and motor support); • Minimum mass; • Constructed with FDM • Both statical and dynamical simulation with large displacements(shock simulation executed with RADIOSS) • Experimental verification on October 2015 1 2 3
- 17. Risultati preliminari • Weight: 90.46g • Good printability results with FDM • Scale version 1:2 printed for the preliminary statical test CAD model Prototype Static Test
- 18. ProgettoPBK:Sviluppifuturi,integrazionepiùcomponenti, shockabsorber • Evaluation of other material properties (PLA); • Testing with hybrid filaments(carbon fiber); • Study on the fatigue of ABS built specimens via FDM; • Introduction of the optimization concepts also to other parts of the UAV • Numerical simulation and experimental testing of the vehicle in take off and heavy landing.