ROHACELL. Unique lightweight solutions for the Aerospace Industry. Ron R. van Hoorn. May Sicomp Conference Linköping

Transcription

1 ROHACELL Unique lightweight solutions for the Aerospace Industry Ron R. van Hoorn May Sicomp Conference Linköping

2 1. Evonik supports the composite market 2. The advantages of using PMI foam 3. A new ductile PMI product development - HERO 4. Testing of HERO to fulfill structural requirements 5. Conclusion

3 Evonik worldwide North America 3,709 Middle and South America 611 Worldwide 33,241 employees Europe (incl. Russia) 24,176 Middle East, Africa 125 Asia-Pacific 4,620 Status as of

4 Products and expertise in almost all composite sub-components Composite sandwich system schematic view Thermoplastics VESTAKEEP VESTAMID HTplus VESTAMID L TROGAMID Foam cores ROHACELL Additives/rheological modifier AEROSIL Dynasylan TEGOMER Matrix Interface Fiber Foam Core Adhesive / Sealant Thermosets COMPIMIDE CALIDUR Crosslinker VESTAMIN VESTANAT JAYHAWK Dianhydrides VISIOMER Thermoset modifier NANOPOX ALBIPOX ALBIDUR P84 Understanding all aspects of a complex system is important.

5 Production sides Positioned to serve a global market Darmstadt Mobile Shanghai Mobile, Alabama (USA) Production: Foaming Cutting Shaping Sandwich Technology Center Darmstadt (Germany) Production: Casting Foaming Cutting Shaping Sandwich Technology Center Shanghai (China) Production: Cutting Shaping Sandwich Technology Center

6 Production of ROHACELL 6. Sandwich structure Customer 5. Net-Shaped cores 4. Cut-to-Size Foam Sheets 3. Raw Foam Block 2. Co-Polymer Sheet 1. Liquid Monomer Solution

7 1. Evonik supports the composite market 2. The advantages of using PMI foam 3. A new ductile PMI product development - HERO 4. Testing of HERO to fulfill structural requirements 5. Conclusion

8 Get the best performance out of a sandwich part by using ROHACELL HERO Design Design freedom: complex, integral, light, strong Processing Quick curing (fast, one shot co-curing) Stable process with high yield, no core stabilization cycle Logistics Fewer parts, no secondary bonding, ready-to-use In Service Performance Excellent fatigue, impact visibility and bird strike behavior Low finished part weight Multiple function e.g. isolation

9 1. Evonik supports the composite market 2. The advantages of using PMI foam 3. A new ductile PMI product development - HERO 4. Testing of HERO to fulfill structural requirements 5. Conclusion

10 The ROHACELL HERO development challenge: Improve a proven, high performing foam sandwich core product for use in Class A and B parts. Add: With: Keep: Result: High damage tolerance & visibility Greatly improved elongation at break All existing advantages Reduced finished part costs

11 Increased elongation at break is key to meeting the damage requirement Tension Standard ROHACELL grades 3-4% 9-10% HERO offers the highest elongation at break of any ROHACELL grades Elongation

12 1. Evonik supports the composite market 2. The advantages of using PMI foam 3. A new ductile PMI product development - HERO 4. Testing of HERO to fulfill structural requirements 5. Conclusion

13 Mechanical performance - standard tests Compressive strength Shear Strength Tensile Strength Test Chamber

14 Impact damage visibility test ROHACELL HERO Sandwich Density 75 kg/m³ NOMEX Honeycomb Sandwich Density 48 kg/m³ - Cell size 3.2 mm Objective: Prove that a ROHACELL HERO sandwich provides the same damage visibility after an impact as a honeycomb sandwich.

15 Impact-Depth [mm] Test at -55 C Impact depth after 48 hours Foam-Sandwich after 48h Honeycomb-Sandwich after 48h 4,0 3,0 2,0 1,0 BVID (DVI) > 0.3 mm 0, Impact-Energy [J]

16 Impact 10J at 23 C Foam Sandwich X-cut specimen Honeycomb Sandwich

17 Impact 35J at -55 C Foam Sandwich X-cut specimen Honeycomb Sandwich

18 Fatigue testing Test procedure (ASTM C393)

19 max / UL [-] HERO outperforms Honeycomb in comparison 1,00 0,80 Cycled fatigue specimens failed due to core shear cracking 0,60 ~ +52% 0,40 0,20 CFRP/71HERO Sandwich CFRP/71WF Sandwich** CFRP/NOMEX ECA 3.2/48 L* CFRP/NOMEX ECA 3.2/48 W* 0,00 1,E+00 1,E+01 1,E+02 1,E+03 1,E+04 1,E+05 1,E+06 1,E+07 Load cycles [-] * Fatigue Crack Initiation and Propagation in Sandwich Structures, Magnus Burmann, Report No , 1998, KTH **Burman M. and Zenkert D., Fatigue of Foam Core Sandwich Beams, Part 2: Damaged Specimens International Journal of Fatigue, Vol. 19, No. 7, pp , 1997

20 Shear strength [Mpa] Residual strength test 71 HERO 1,5 1,2 1,19 1,0 0,5 0,0 uncycled 55% UL, after 5 Mio. cycles Fatigue loaded specimen of 55% UL with 5 Mio. load cycles failed in the same force range as the uncycled specimen (= quasi-static test)!

21 Compressive creep [%] Proven stability at high temperatures and pressures Compressive Creep 180 C/ 0.7 MPa 130 C/ 0.5 MPa Curing conditions (2h) Out-time investigation at 23 C / 50% RF and 27 C / 70% RF is running.

22 HERO outperforms honeycomb 4 - Superior 3 - Excellent 2 - Very good 1 - Good 0 - Unacceptable Damage visibility 4 3 Honeycomb HERO Part cost 2 Water ingress 1 0 Surface quality Part weight Design freedom

23 Demonstrator and evaluation part: Nose Landing Gear Door (NLGD) Foam / Infusion This foam sandwich part was originally constructed as a 71/200 WF core in infusion technique for Do728. All qualification steps were made. Now, it was optimized for 71 HERO with dry fabrics to stay in infusion manufacturing technique. Honeycomb / Prepreg Baseline for the comparison is an NLG door similar to the A320 design and a process using Nomex honeycomb (64 kg/m³ - 4,8 mm) and prepreg (Fibredux 913C %). Foam / Prepreg Additionally, we compare the foam with an Autoclave (Prepreg) process in a situation where honeycomb is replaced by foam, but the process stays the same (180 C / 50psi).

24 Time for each step [h] The time advantage: Where are the main differences? 10 Comparison of time by process step 8 6 Core handling 2 shot curing Prepreg instead of infusion Honeycomb/Prepreg Foam/Prepreg 4 Core handling Foam/Infusion 2 0

25 Cost share [%] Cost advantage results: Save % using foam! 100 Cost comparison NLG door 100 Labor: 55 /h Machine and Labor: 85 /h Honeycomb/Prepreg Foam/Infusion Foam/Prepreg 0 Material cost Labor and Machine cost Total cost

26 Weight [%] Weight advantage results: Save 19 % using foam! Weight comparison NLG door Honeycomb/Prepreg 50 No adhesive film Foam/Prepreg No need for potting Foam/Infusion 25 0

27 Design, analyze and test steps for the NLG-demonstrator at a low cost Building block approach at a low cost Conducted same main load test as original part Bird strike test by DLR Stuttgart: m= 1.9kg and speed= 143m/s First NLG door passes the test Weight and cost analysis by CTC and evaluation part build (by INVENT) Load introduction for hinges, standard potting for HC and weight optimized for foam (by CTC) Details according to HC standard (A320) and foam solution as used in aircraft design, e.g. no need for potting with foam (by CTC) Detailed testing to compare impact, mechanical performance and fatigue, 48kg/m³ HC and 75kg/m³ HERO (by AIRBUS, IWM and Evonik)

28 Main load case: Bird Strike test details The main structural load case for an NLG door is the bird strike test. To prove the weight and cost optimization, the part must pass a typical bird strike test (1.8kg bird strike / speed of 540 km/h). Part in the test rig at DLR Stuttgart A bird strike is most critical when the NLGD is closed during the landing approach!

29 Main load case: Bird Strike test results Condition of the part after bird strike testing Test parameters: 1.9 kg gel bird / speed: 515 km/h Evaluation: Local delamination, but the part is still working and can withstand all required aerodynamic loads. Even without any rivets on the structure! The NLGD passes the test!

30 Main load case: Bird Strike test results what s a presentation without a video?

31 1. Evonik supports the composite market 2. The advantages of using PMI foam 3. A new ductile PMI product development - HERO 4. Testing of HERO to fulfill structural requirements 5. Conclusion

32 Lay-up / process / part cost Easy handling Lower part cost and weight (up to -25%) Stable curing process Fewer production steps Ready-to-use parts

33 Conclusion Solve Honeycomb problems No water problem, better fit to CRFP Efficient part production Reduce manufacturing costs Robust damage behavior Excellent mechanical properties and fatigue behavior Meet industry requirements for damage tolerance and visibility Produce reliable structural components with long service life ROHACELL HERO Qualification AIRBUS Spec. and MIL-PRF-46194a are in progress

34 We re making the WORLD lighter! ROHACELL The Core of Sandwich Solutions Evonik Resource Efficiency