Automated Fiber Placement Composites for Improved Structural Efficiency of Aircrafts

Transcription

1 1 Automated Fiber Placement Composites for Improved Structural Efficiency of Aircrafts Kazem Fayazbakhsh & Damiano Pasini Pasini Lab Mechanical Engineering McGill University May 16 th, 2013 UTIAS National Colloquium on Sustainable Aviation

2 Outline 2 Introduction A sustainable aircraft : Boeing 787 Composite design concepts Automated Fiber Placement Talk objectives Research expertise of the Lab Concluding remarks

3 3 A sustainable aircraft : Boeing 787 Fuel use reduced Automated manufacturing technologies Emissions cut Quieter take-offs and landings Point-to-point travel enabled End-of-life recycling A life cycle approach

4 4 Boeing 787 (a sustainable aircraft) Fuel use reduced Automated manufacturing technologies Emissions cut Quieter take-offs and landings Point-to-point travel enabled End-of-life recycling A life cycle approach

5 5 Boeing 787 (a sustainable aircraft) Fuel use reduced Increased use of light weight composite materials New engines More-efficient system applications Modern aerodynamics Advanced manufacturing technologies Automated Fiber Placement

6 6 Boeing 787 (a sustainable aircraft) Fuel use reduced Increased use of light weight composite materials New engines More-efficient system applications Modern aerodynamics Advanced manufacturing technologies Automated Fiber Placement

7 7 Composite design concepts Constant stiffness (CS) Traditional composite design Keeping the fiber angle constant within each layer Variable stiffness (VS) Allowing fibers to follow curvilinear paths More favorable stress distribution Constant stiffness variable stiffness

8 8 Automated Fiber Placement machine (AFP) Robotic arm which places strips of material side-by-side to create a band Lays down bands to create the laminate Pros: High manufacturing flexibility Fully automated process Speeds up the layup time Ideal for large structures Cons: Defects produced during the manufacturing Source: Coriolis website.

9 9

10 10 Automated Fiber Placement machine (AFP) Robotic arm which places strips of material side-by-side to create a band Lays down bands to create the laminate Pros: High manufacturing flexibility Fully automated process Speeds up the layup time Ideal for large structures Cons: Defects produced during the manufacturing Source: Coriolis website.

11 Variable stiffness defects 11 Defects can be categorized as gaps and overlaps Gaps Overlaps

12 Talk objectives 12 Exploiting variable stiffness design to improve mechanical efficiency of lightweight laminate composites Development of a simulation toolbox to capture the mechanical impact of AFP defects Incorporating the effect of defects in the analysis and optimization of variable stiffness composite laminates

13 Lab Expertise 13 Microarchitectured Materials

14 Lab Expertise 14 Biomechanics Multiscale Mechanics Microarchitectured Materials Design Optimization Biomimetics

15 Lab Expertise 15 Biomechanics Multiscale Mechanics Biomedical Devices Microarchitectured Materials Design Optimization Aerospace Structures Biomimetics

16 Current Projects 16 Multiphysics of lattice materials AFP variable stiffness laminate composites Ultralightweight lattice panels via additive manufacturing Cellular hip replacement implants Lattice stent-like devices Plant cellular tissue inspired materials

17 Talk objectives 17 Exploiting variable stiffness design to improve mechanical efficiency of lightweight laminate composites Development of a simulation toolbox to capture the mechanical impact of AFP defects Incorporating the effect of defects in the analysis and optimization of variable stiffness composite laminates

18 Talk objectives 18 Exploiting variable stiffness design to improve mechanical efficiency of lightweight laminate composites Development of a simulation toolbox to capture the mechanical impact of AFP defects Incorporating the effect of defects in the analysis and optimization of variable stiffness composite laminates

19 Curvilinear fiber path 19 Constant curvature fiber path is used as the reference fiber path* T 0 y T 1 The reference fiber path is shifted to manufacture the whole laminate T 1 ρ x O [ T T T ] x 16 in plate is considered as a case study Free Free *Blom et al., Journal of Composite Materials (2009).

20 Multi-objective optimization 20 Simultaneously optimization of [±<T 1 T 0 T 1 >] 4s for In-plane Stiffness Buckling Load Eeq ( x), 1 Ncr ( x) x T0 T1 0 1 & 25, min ;, x s. t. T, T [0,90 ] R in T N cr /N Quasi-isotropic The effect of defects is ignored E eq /E Quasi-isotropic

21 Performance of VS design without defects 21 Normalized buckling load (N cr ) Design 2: Maximum Buckling Load Design 1 QI (baseline) Design 3: Same Stiffness and Higher Buckling Load Normalized stiffness (E eq ) Design 4: Same Buckling Load and Higher Stiffness Design 5: Max. Stiffness 5 N cr = 1.56 E eq = 0.60 N cr = 1 E eq = 1.30 N cr = 1.33 E eq = N cr = 0.42 E eq = 2.62

22 Variable stiffness defects 22 Defects can be categorized as gaps and overlaps Gaps Overlaps

23 Talk objectives 23 Exploiting variable stiffness design to improve mechanical efficiency of lightweight laminate composites Development of a simulation toolbox to capture the mechanical impact of AFP defects Incorporating the effect of defects in the analysis and optimization of variable stiffness composite laminates

24 AFP defects analysis toolbox 24 A lamina with gaps Mesh generation Stress in y-direction

25 25 The effect of defects on VS laminates performance Normalized buckling load Design 2 Design 3 Ignoring gaps/overlaps Overlaps Gaps Normalized buckling load Normalized Stiffness Normalized buckling load Normalized buckling load Design Design

26 Talk objectives 26 Exploiting variable stiffness design to improve mechanical efficiency of lightweight laminate composites Development of a simulation toolbox to capture the mechanical impact of AFP defects Incorporating the effect of defects in the analysis and optimization of variable stiffness composite laminates

27 Multi-objective optimization including defects 27 Simultaneously maximize objectives of [±<T 1 T 0 T 1 >] 4s : In-plane Stiffness. Buckling Load. 1 Eeq ( x), 1 Ncr ( x) x T0 T1 0 1 & 25, min ;, x s. t. T, T [0,90 ] R in T The effect of defects is considered during the optimization process. Defect layer method is used.

28 Impact on the mechanical properties 28 Normalized buckling load Ignoring defects Gaps Overlaps Normalized in-plane stiffness

29 Impact on the optimum fiber paths Normalized buckling load Ignoring defects Gaps Overlaps # Design 1 [±< >] 4s 2 [±< >] 4s [±< >] 4s Normalized in-plane stiffness

30 Work underway: manufacturing and testing 30

31 Work underway: manufacturing and testing 31 Design 2: highest buckling load compared to the baseline

32 32 Concluding remarks Exploiting variable stiffness design to improve mechanical efficiency : 56% improvement in buckling load Development of a simulation toolbox to capture the mechanical impact of AFP defects: 88% improvement in buckling load for laminates with overlaps 40% improvement in buckling load for laminates with gaps Optimization of variable stiffness composite laminates including defects

33 33 Concluding remarks Exploiting variable stiffness design to improve mechanical efficiency : 56% improvement in buckling load Development of a simulation toolbox to capture the mechanical impact of AFP defects: 88% improvement in buckling load for laminates with overlaps 40% improvement in buckling load for laminates with gaps Optimization of variable stiffness composite laminates including defects A lighter structure, more fuel efficient and sustainable

34 34 Questions?

35 Current Projects 35 Multiphysics of lattice materials AFP variable stiffness laminate composites Ultralightweight lattice panels via additive manufacturing Cellular hip replacement implants Lattice stent-like devices Plant cellular tissue inspired materials

36 Overlap-modified defect element 36 A single layer [0] T laminate. An overlap is at the plate center and along fiber direction. Material and strength properties are the same as regular composite material. The effective element thickness is the average of the thickness in the element. y y x x

37 Superiority of defect element approach 37 The element length is half of the tow width. The FE model for [+< >] layer: Real gap distribution Gap distribution in FE model Existing approach in the literature Defect element approach

38 FE model for capturing defects (module 3) 38 A novel approach, defect layer, is proposed to capture defects precisely. Gap-modified defect layer. Overlap-modified defect layer. Each element may contain any defect area percentage. Fiber orientation at the element midpoint is calculated and used as the element fiber orientation.

39 39 Gap-modified defect element A single layer [0] T laminate is considered. y Gap is at the plate center and along the fiber direction. x Test simulations are used to find material and strength properties E x E y G

40 Gap width Modified material and strength properties 40 Gap area percentage is varied with the gap width. The graphs are used in APDL codes to calculate properties of a defect element with any defect area percentage. y x Normalized material properties Ex Ey G 0.0 0% 20% 40% 60% 80% 100% Gap area percentage (%)

41 Stress distribution 41 The stress in y-direction for [+< >] layer in Design (A) with gaps Free Free y x 0 Real gap distribution Stress in y-direction