july 2010 snl blade workshop

8/7/2019 July 2010 SNL Blade Workshop

1/38

Program: Recent Results

Montana State University

July 20-22, 2010


2/38

Thanks

To Sandia/DOE for support since 1989


3/38

Research Group

CoPI Research Engineer: Daniel Samborsky,

Post Doc: Aaron Sears FEA Adhesives

Grad Student: Tiok Agastra Processing, Complex Structure Coupon Testing and FEA

Undergraduate Assistants: Patrick Flahertyand David Buswell

Sandia PIs: Tom Ashwill, Josh Paquette


4/38

Standard laminates re resentin s ars skins

Fatigue Topics

and webs

Adhesive joints

Core/sandwich areas Damage growth at flaws

Ply delamination at details like ply drops and

joints, and near adhesive joints, , , ,

Processing effects

Loading conditions/

Sandwich Panel


5/38

Public Database

at gue ata ase(SNL Website or MSU program

/composites/) Over 190 Materials 11,500+ test results

Updates each March ren s ana yze n pu ca ons

and contractor reports onwebsite; Draft of current

contractor report


6/38

More Detailsontractor reports an pu cat ons onwww.coe.montana.edu/composites/; additional informationincluding resins, adhesives, fabrics, etc.

Contact: [email protected].

on rac or epor an ecen apers on e s e:1. 2010 Sandia Contractor Report (Draft), Mandell, et al.

2. 2010 Sandia Blade Workshop Presentation, Mandell.. , , , ,

Samborsky, paper and presentation, program overview.4. SAMPE 2010, Seattle, paper 398, Agastra and Mandell, Complex StructuredCoupons.

- -. , , , , ,Laminates.6. AIAA SDM 2010, Orlando, paper AIAA-2010-2821, Sears, et al, Adhesives.

7. ACS 2010, Cocoa Beach, Selection of Blade Materials, Mandell, Presentation.


7/38

Presentation Topics

Summary of recent results:

1. Standard laminate fati ue:

fabric and resin effects.. ,

complex structured coupons

-

structures).

. .


8/38

Standard Laminate Fatigue

, = .1. Glass fiber laminates mostsensitive to tensile part offatigue cycles2. Clean failure modesfor materials com arisons

R = Min Stress/Max Stress

Ref. 1


9/38

MSU resin infusion process with hard mold on one side

(panels also supplied by industry)

Ref. 1


10/38

VectorplyELT5500Fabric,FrontandBackViews

a r c , gsm

Ref. 5


11/38

PPG-Devold L1200/G50-E07 (MSU Fabric H, 1261 gsm)

Front ac


12/38

Strain-cycles trends for eight MD laminates, UD fabrics1200-2400 gsm, Hybon 2026 sized strands, filament

, , .

Studies involving systematic fabricvariation with Devold and OCV in progress


13/38

Data Representation

on yc e

Strain Parameter,Power Law Exponent,

- ,Polyester (UP) vs

Epoxy (EP)

MultidirectionalLaminates;TT: Database Laminate

Note: Strains shown onfigures are Initial Strainsfrom extensometer in

[45/0/45/0/45]the first few fatigue

cyclesRef. 1, 5


14/38

Resin Comparison, Same Fabrics

Vinyl esters: intermediatepDCPD (Materia): similar to epoxy


15/38

UP and EP resins with and w/out 90-strands removedin gage section before infusion, UD laminates

Significant effect only for UP resin laminates

epoxy

polyester


16/38

Typical Infused Laminate Property RatiosPolyester (UP) to Epoxy (EP)*

Property Ratio UP/EP

Axial Tensile Modulus (UD) 1.0

.

Axial (UD) Static Tensile Strength 0.90Axial (MD) Static Tensile Strength 0.95

ransverse tat c ens e rac ngStrain

0.42

Axial (UD) 106 Cycle Strain (R = 0.1) 0.51Axial (MD) 106 Cycle Strain (R = 0.1) 0.65

Axial (MD) 106 Cycle Stress (R = 0.1) 0.61

Axial (Biax) 106 Cycle strain (R = 0.1) 0.91

Interlaminar GIc (0-0 interface) 0.55

Interlaminar GIIc (0-0 interface) 0.48

,Threshold Fatigue Strain (R = -1)

.

*Vf = 0.5 to 0.6, UD Fabrics D and H, Biax Fabrics M and P


17/38

Complex Coupons With Ply Drops

Thi kn T rin

Ref. 4


18/38

Delamination TestinMixed Mode Delamination Testing, Different Resins

Ref. 1, 5


19/38

Complex Structured Coupons with Ply

,Purpose: Mini-substructuretest. Sim lified less costl

approach to substructuretesting. Efficient comparisonsof resins, fabrics, geometric

details in structural context..coupons represent morerealistic internal (infused) blade

standard laminate tests

Ref. 1, 4


20/38

Complex Structured Coupon with Ply Drops(See 2009 SDM, AIAA-2009-2411; and 2010 SAMPE paper 398)

Damage

ComponentsAlternate Geometries

Ref. 1, 4


21/38


22/38

Damage Growth Curves

Static Fatigue, R = 0.1

Damage Growth with DifferentResins Correlates withInterlaminar G G

Simulation

Ref. 4


23/38

1 PD = 1.3 mmat gue

(R=0.1, Pmax=55.6 kN)a c

2 PD = 2.6 mm

4 PD = 5.2 mm Ref. 1, 4


24/38

THRESHOLDS

-results for three resins:epoxy (EP-1), polyester (UP-1)and pDCPD; R = -1.

Near threshold results (5-mm delamination length L1 in 106 cycles), R = -1,

ResinMax. Force, kN, and thin

side average strain (%)

Force Change

From EpoxyObserved Damage

wo p es roppe a one pos on.

Epoxy EP-1 19 (0.18%) ___ L1, L2, crack at ply ends

Polyester UP-1 14 (0.13%) -26%L1, L2, biax cracking, crack at

ply ends

p . , crac a p y en s


25/38

Blade

Initial Test Parameters

Characterize Nominally Good Quality Joints(Most Contain Significant Porosity)

Range of Uniaxial Loading Conditions (R-values)

ange o rac o e x y I II Failure Modes; Crack initiation and Growth

Strength-lifetime or Fracture Mechanics-da/dN


26/38

Strength-Lifetime Lap Shear Test

es ve - , yc es e , yc es r g(Non-symmetrical Specimen Clamped in Hydraulic Grips)

Ref. 1, 6


27/38

Simulated blade joint study, see AIAA paper AIAA-2009-1510

Joint strength statistics and criticalflaws; failure modes; eometr

Fatigue exponentsPorosity modeling

Ref. 1, 6


28/38

,

Test,

Mixed Mode I and II Cracked Lap Sheares


29/38

Adhesives and GIc from DCB Test

Designation Adhesive Cure temp GIc, J/m2

ADH-1Hexion

ADH-5 Rhino 405 70 938

ADH-6 3M W1100 70 1626

DCB Test


30/38

CLS Adhesive Fracture S ecimens

Ref. 6


31/38

Std. 50 mm 100 mm w/steel

50 mm w/steel G-Calibrations of CLS Specimens

at 4.45 kN Tension LoadStd. 50 mm

50 mmw/steel

100 mmw/steel


32/38

Adhesive Thickness Effect on Mode Mixit

0.80

shortgeometry(2"lap)3.8mm,steel

0.60

0.70

0.5mm1mm2mm

3.8mm(testedgeom)

0.5 mm

0.40

0.50

2/

GT

8mm 2 mm

0.20

0.30

8 mm

0.00

0.10

0 5 10 15 20 25 30 35 40

cracklength(mm)


33/38

Maximum GT (tension half of cycle) vs da/dN, R = -1

Ref. 6

ADH 1 Adh i R 0 1 d 1 t d b M d


34/38

ADH-1 Adhesive, R = 0.1 and -1, separated by ModeMixity Range (reversed loading 10X higher crack velocity)

R = 0.1 R = -1


35/38

PreliminaryIn Progress:

Define static Gc andfatigue crack growth

range of modes (GI/GII)and R-values experienced

(data for ADH-1).

C k P th (N l t C k Di ti )


36/38

CLS Crack Paths on Section Normal to Crack

Crack Path (Normal to Crack Direction)

Direction Near Adhesive / Laminate Interface

CRACK PATH:

A. Cohesive in adhesiveB. Cohesive along peel surfaceC. Adhesive along strand surface

Expanded View of Path B


37/38

CLS, ADH-1, laminate side CLS, ADH-1, adhesive side

Peel Surface CLS, ADH-5, laminate side


38/38

, ,

Environment

o e ng

Further Test Development

july 2010 snl blade workshop

Documents