The Effect of Manufacturing Induced Defects on Performance of Composite Laminates

Transcription

1 The Effect of Manufacturing Induced Defects on Performance of Composite Laminates Date 27 th February 2013 Presenter Wayne Van Rooyen, Materials Technologist Composites Slides 17 Event SAMPE Seminar, Advanced Composites: The Engine for Growth Location Cranfield University, UK The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of Rolls-Royce plc. This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary or associated companies.

2 Contents 2 Introduction Why Composites Rolls-Royce Composite Capability Development Composite Manufacturing Technology (AFP) Background to Features & Defects Testing Findings & Technical Summary Conclusions

3 Introduction Wayne Van Rooyen Present Advanced Technologist for Organic Matrix Composites at Rolls-Royce plc, Derby Professional Excellence Operations Engineering Graduate Trainee Scheme at Rolls-Royce plc, including secondments in Derby, Bristol & Indianapolis (USA) Early Engineering Professional Development Program (EEPDP) in conjunction with University of Bristol - Aerospace Engineering & Management, Bristol MEng Aerospace Materials Degree, Imperial College London, South Kensington Campus Providing support to design, manufacturing engineering and purchasing in the form of design data and specifications for composite materials used in Rolls- Royce product. Support for composite issues on all in-service civil fleet engines, representing the Department both internally and externally to Rolls-Royce Professional Graduate Member of the Institute of Materials (ProfGradIMMM) and an Associate Member of the Royal Aeronautical Society (AMRAeS)

4 Strength Thermal Capability Composites: What & Why? In its most basic form a composite material is one which is composed of at least two elements working together to produce material properties that are different to those elements on their own Consist of a bulk material the matrix, and a reinforcement of some kind, added primarily to increase the strength and stiffness of the matrix. FIBRE COMPOSITE SYSTEM MATRIX 4 Glass Fibre E-Glass S-Glass Para-aramid Fibre Carbon Fibre -High Modulus -Intermediate modulus Matrix (Thermoset) Polyester Vinyl Ester Epoxy Phenolic Benzoxazine Cyanate Ester Bismaleimide Polyamideimide Polyimide Pthalonitrile Polysiloxane Matrix (Thermoplastic) Polyamides PolyPhenylineSulphide (PPS) PolyEtherEtherKetone (PEEK) PolyEtherImide (PEI) Polyesters 80 to 100 C Epoxies -55 to 120 C Bismaleimides Max. ~ 180 C Polyimides ~260 C

5 Rolls-Royce Composite Capability Development 5 Civil Aerospace Defence Aerospace Marine Energy

6 OMCs in Aero Engines FAN BLADE. WEIGHT ANNULUS FILLER REDUCTION ACOUSTIC LINERS NOSE SPINNER FAN OGV (HYBRID) FAN CASING Advanced Composite Manufacturing Technologies INCREASED PROPULSIVE EFFICIENCY 6 REDUCED FUEL BURN REDUCED CO 2 Advanced composite materials have been available in the market since the late 1960 s and have substantially displaced the use of light alloys in the most recent civil airframe applications Where and why are these materials used in current engine applications? How is Rolls- Royce developing its capability to develop, specify and procure low risk competitive composite products and services that satisfy market needs?

7 Composite Manufacturing Technology 7 1. Strategic requirement to develop OMC Fan Blade and Containment system 2. Automated Fibre Placed (AFP) technology being developed for composite fan blade OPPORTUNITY Reduce blade lay-up time from >80 hours (hand-lay) to < 4 hours Automated Fibre Placed What about laminate quality? Cannot be sacrificed for increased rate...

8 Blade Evolution VITAL DOVE SOAR-1 SOAR-2 FLE Increasing Fan Blade Diameter Objective: To demonstrate ability to manufacture basic composite blade and metalwork capable of withstanding standard bird strike Objective: To develop automated manufacturing processes for composite lay-up and incorporate all ancillary materials required for a flying blade Objective: To further optimise manufacturing processes and run on a flying test bed. Objective: To demonstrate capability for future FLE blade, all materials and manufacturing processes finalised 2014 start NPI programme 2019 target date for EIS

9 Pristine Background to Features & Defects testing 9 Delamination Gaps & Overlaps Porosity Phase 0 Method of fabrication & Work Instruction development Phase 1 Pilot test program to manufacture the nominal middle defect size Phase 2 Main static programme to establish the effect of different defect sizes on mechanical strength Phase 3 Fatigue programme to assess the worst case defect types at different stress levels Wrinkling Waviness Ply drops

10 Approach for down-selecting defects MANUFACTURING DEFECTS 10 Process Capability of Glass transition temperature / degc LSL USL Knock-downs in mechanical strength Literature Survey Conducted Gaps between some defects seen in manufacture but NOT reported in literature Process Data LSL 180 Target * USL 200 Sample Mean Sample N 39 StDev (Within) StDev (O v erall) O bserv ed Performance PPM < LSL 0.00 PPM > USL PPM Total Exp. Within Performance PPM < LSL 0.00 PPM > USL PPM Total Exp. O v erall Performance PPM < LSL PPM > USL PPM Total Within Overall Potential (Within) C apability C p 1.76 C PL 2.26 C PU 1.25 C pk 1.25 O v erall C apability Pp 1.00 PPL 1.29 PPU 0.72 Ppk 0.72 C pm * Probability of occurrence in manufacture Analysis & Cut-up reports of manufactured blades Statement of work for features & defects testing (specific to our requirements)

11 Testing & Modelling interaction 11 Fan blade material Test and model development Validation Sub-set Test procedures 5:1 7.5:1 10:1 12.5:1 15:1 Fan blade material Test development and results Model application to fan blade program

12 Findings & Technical Summary I 12

13 Findings & Technical Summary II 13

14 Findings & Technical Summary III 14 Porosity Laminate Test Results Measured Knockdown Porosity 0.3% n/a 1.0% 14% 3.7% 34% 7.3% 52% Defects seeded by application of reduced pressure during autoclave curing cycle NDE relationship between absorption coefficient (attenuation drop off) and measured void content attempting to be established Effect of porosity also being determined in compression testing specimens

15 Conclusions The test results give a general overview of the influence of defects on laminate behaviour under several kinds of loadings and particular laminate configuration 15 Seeded delaminations: should be treated with caution as the ETFE may not be accurately mimicking a delamination. Bending and fatigue effects need consideration In plane waviness: (amplitude / wavelength = 4mm/35mm) seeded in all 0 plies of the QI layup has shown a 23% knock-down in mean ultimate strength for compression and a 21% knock-down in mean ultimate strength for tension Out of plane wrinkling: An 8 misalignment angle has shown a 57% knockdown in mean ultimate strength for compression and a 35% knock-down in mean ultimate strength for tension. Porosity: There is a 14% knock-down in mean ILSS for <2% porosity; a 34% knock-down in mean ILSS for 2 4% porosity and a 52% knock-down in mean ILSS for >4% porosity

16 Conclusions 16 Gaps: (defect width = 2mm; gap spacing = 10mm; lay-up = 2) seeded in the -45 plies of the quasi-isotropic layup has shown a 3% knock-down in mean ultimate tensile strength and a 10% knock-down in mean ultimate compressive strength Overlaps: (defect width = 2mm; overlap spacing = 10mm; lay-up repeat = 2) seeded in the -45 plies of the quasi-isotropic layup has shown a 4% knock-down in mean ultimate tensile strength and a 11% knock-down in mean ultimate compressive strength Multiple defects should be considered in future tests and, consequently, the defect distribution will certainly become an important variable. Fatigue loading will also be considered going forward. This investigation should help to give a method to predict the performance of composite structures considering the manufacturing defects e.g. via modelling

17 Contact Details 17 Wayne Van Rooyen Materials Technologist - Organic Matrix Composites Wayne.vanrooyen@rolls-royce.com Rolls-Royce plc PO Box 31 Derby DE24 8BJ Direct: +44 (0)