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MDA/CERF: Durability Study Fatigue Task Group. John J. Lesko Kenneth L. Reifsnider Stephan P. Phifer Charles E. Bakis Anthony Nanni Clem Heil ASME 2000 International Mechanical Engineering Congress & Exposition, November 2000. Fatigue Issue Not Covered in This Talk. ?.
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MDA/CERF: Durability StudyFatigue Task Group John J. Lesko Kenneth L. Reifsnider Stephan P. Phifer Charles E. Bakis Anthony Nanni Clem Heil ASME 2000 International Mechanical Engineering Congress & Exposition, November 2000
Fatigue Failure Mechanisms Fatigue-Life Diagram proposed by Talreja
Failure Mechanisms Fiber Matrix Residual Cure Stress Interface - Sizing Laminate Processing Fatigue - Overview • Material & Processing Effects • Environmental & Testing Effects • Frequency/Creep • Hygrothermal • Temperature • Acid/Base/Electrolyte • Interactive Effects
Material Effects • Fatigue Failure Mechanisms • Fiber • E-glass, carbon/graphite, Kevlar • Matrix • Brittle, toughened • Interface • Compatible and non-compatible sizings • Laminate • Woven, stitched, and unidirectional • Stacking sequence - 0°, ±45 °, 90° plies • Processing Type
FIBERS - (0/90°)s • Gathercole, Reiter,Adam, Harris 1994, IJ of Fatigue, v. 16, no. 8, p.523.
FIBERS - Tensile Stress Fatigue E-Glass • Demers, Cornelia. E. 1997 The National Seminar on Advanced Composite Material Bridges, May 5-7.
Normalized Fatigue Performance of Glass/Vinyl Ester F. McBagonluri, K. Garcia, M. Hayes, N. Verghese, & J. J. Lesko, "Characterization of Fatigue and Combined Environment on Durability Performance of Glass/Vinyl Ester Composite for Infrastructure Applications" International Journal of Fatigue, Vol. 22, Issue 1, 2000, pp. 53-64.
Glass Composite Fatigue 1. Unidirectional glass/epoxy, vf=0.5 2. Unidirectional glass/epoxy, vf=0.33 3. Unidirectional glass/epoxy, vf=0.16 4. 0°/90° glass 5. 30-40% glass in poly(hexamethylene adipamide), injection molded 6. 30-40% glass in polycarbonate injection molded 7. 30-40% glass in polyphenylenesulfide injection molded 8. 30-40% glass in poly(amide-imide) injection molded 9. Chopped-strand mat polyester 10. Sheet molding compound (smc) of rubber-modified epoxy 11. SMC, rubber-modified epoxy 12. SMC, r50 13. 0°/±45 ° /90° glass/epoxy 14. Chopped-strand mat polyester Mandell, J. F., 1978, “Fatigue Behavior of Fibre-Resin Composites,” Developments in Reinforced Plastics 2, Properties of Laminates, Ed. G. Pritchard.
Mechanism: Fatigue of Glass Composites • Crack growth in the fiber dominates the failure process • Accumulation of damage is accounted for in crack growth that takes place based on the fractional time spent at a damaging stress level Glass fiber remaining strength given a s (t)
Fatigue Simulation & Experiment UCFR - unidirectional continuous fiber/epoxy UCMFR - unidirectional & continuous strand mat fiber/vinyl ester S-N Slope (%UTS/decade) Data: 10.2 and 13 Predictions: 12 to 14 F. McBagonluri, G. Foster, S. Case, W. Curtin, & J. Lesko, “ Simulation Of Fatigue Performance Of Polymeric Composites For Infrastructure Applications,” Simulation of Fatigue Performance of Polymeric Composites for Infrastructure Applications ASME IMECE 98, Anaheim CA, Nov 1998
Matrix Effects - S-N Curves for E-glass Laminates • Konur & Matthews 1989, Composites, V.20, No. 4, July 1989.
Sizing & Matrix Toughening Effects • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Sizing Effects • EP - Epoxy Sizing • MP - Multi-pupose sizing • Epoxy Resin • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Pultruded AS-4/Derakane 411-35 LI: Sizing Effect Input: R=0.1 Unidirectional Fatigue Data
Process Type Effects • FW - Filament Winding • PMC - Prepreg Press Molding • P - Pultrusion • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Process & Laminate Effects - Pultruded CP, Prepreg CP & Woven Laminated Stitched or Woven • Phifer 1998, Thesis Virginia Tech. http://scholar.lib.vt.edu/theses/available/etd-013199-185939
Testing & Environmental Effects • Testing • Mean Stress & R - Ratio • Frequency • Environmental • Hygrothermal • Temperature • pH Effects
Static vs. Dynamic Fatigue • Mandell & Meier 1983 ASTM STP 813 p.60
Test Effects: R - ratio • Gathercole, Reiter, Adam, Harris 1994, IJ of Fatigue, v. 16, no. 8, p.523.
Test Effects: R - ratio • Adams, Fernando, Dickson, Reiter & Harris. 1989, IJ of Fatigue, V. 11, no. 4, p.233.
Enviro-mechanical Fatigue of Glass/Vinyl Ester F. McBagonluri, K. Garcia, M. Hayes, N. Verghese, & J. J. Lesko, "Characterization of Fatigue and Combined Environment on Durability Performance of Glass/Vinyl Ester Composite for Infrastructure Applications" International Journal of Fatigue, Vol. 22, Issue 1, 2000, pp. 53-64.
Temperature Effects - S-N Curves • Branco, Ferreira, Fael & Richardson 1995 Int. J. Fatigue, V. 18, No. 4, p. 255
Effect of Temperature Effect on E-Glass FRP Fatigue Pultruded E-Glass/Vinyl Ester 4 °C 30 °C 65 °C
So Where Are the Gaps? • Combined Conditions • Creep & Fatigue • Temperature & Fatigue • Temp, Moisture & Fatigue • Chemistry & Fatigue • Spectrum loadings (stress and environment) • Tools • Generalization of Glass Fatigue • Remaining strength representations for combined loading
Remaining Strength N Stress on Critical Element Estimating Remaining Strength Degradation Processes • Cycle dependent damage • Kinetic • Chemical • Thermodynamic Geometry Constitutive Initial Strength Stress or Strength Life Reifsnider & Stinchcomb, “A Critical Element Model of the Residual Strength and Life of Fatigue-loaded Composite Coupons,” ASTM STP 907, 1986
AMERICAN SOCIETY FOR COMPOSITES 16th Annual Technical Conference CALL FOR PAPERS September 9-12, 2001Virginia Tech, Blacksburg, VADonaldson Brown Hotel & Conference Center Abstracts should be submitted no later than January 31, 2001. M.W. Hyer by e-mail as a pdf file to asc16@vt.edu http://www.esm.vt.edu/ASC/
Ranking of Importance of Data for Fatigue Effects Key:A composite B composite/substrate interface; adhesive (if any) C substrate Rank 5: Critical, cannot go forward without it 3: Important 1: Good to have
Ranking of Availability of Data for Fatigue Effects Key:A composite B composite/substrate interface; adhesive (if any) C substrate Rank1: Widely available and validated 3: Sparse and/or questionable 5: Not available
Overall Ranking of Gaps for Fatigue Effects Key:A composite B composite/substrate interface; adhesive (if any) C substrate Rank2: Widely available and validated 6: Sparse and/or questionable 10: Not available
Fiber Effects Mandell, J. F. 1982
Material Effects - Kevlar Fibers - (0/90°) • Jones, Dickson, Adam, Reiter, Harris 1983, Composites, V. 14, No.3, July KFRP
Material Effects - E-Glass Fibers - (0/90°) • Jones, Dickson, Adam, Reiter, Harris 1983, Composites, V. 14, No.3, July GRP
Material Effects - Carbon Fibers - (0/90°) • Gathercole, Reiter,Adam, Harris 1994, IJ of Fatigue, v. 16, no. 8, p.523. CFRP
Tensile Fatigue Damage Mechanism • Kim & Ebert 1978, J. of Composite Matl., V. 12, April .
Manufacturing Effects • S-N curves are dependent upon manufacturing process( P-pultrusion, FW-Filament Winding, PMC-Press Molding of Prepreg) • Variations in resin and fiber sizing. Curve fit to • eo & log(N10)eo process related
Sizing & Matrix Toughening Effects • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Sizing Effects • EP - Epoxy Sizing • MP - Multi-pupose sizing • Epoxy Resin • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Process Effects • FW - Filament Winding • PMC - Prepreg Press Molding • P - Pultrusion • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Sizing & Matrix Toughening Effects • Salvia, Fiore, Fournier & Vincent I.J. of Fatigue, 1997,V.19 No.3, p. 253.
Summary from Salvia et al. • Pultrusion yields lower durabilility composites than Filament wound or press molded • Resin and sizing strongly affect both A and B of • eo was directly related to accoustic emission threshold. eo(pultrusion) = 0.0me
Tensile Strain Fatigue • Harris 1977 Composites Oct. p. 214.
Tensile Stress Fatigue • Harris 1977 Composites Oct. p. 214.
Material Effects - Shear Fatigue - Mean Stress • Bevan 1977 Composites Oct. p. 277.