Analytical Study on Low Compressive Strength of Composite Laminates with Impact Damage

Transcription

1 Analytical Stuy on Low Compressive Strength of Composite Laminates with Impact Damage Hiroshi Suemasu, Makoto Ichiki, Grauate Stuent, an Yuichiro Aoki, JAXA UK-Japan Workshop, Bristol, March 4-7, 03 /7

2 Backgroun Composite Materials High Specific Strength an Specific Stiffness BUT Insufficient toughness Complex amage state an growth to failure Evaluation of Material Strength Consiering its Damage Tolerant Performance Compression After Impact (CAI) Strength = A measure of amage tolerant performance UK-Japan Workshop, Bristol, March 4-7, 03 /7

3 Experiment mm & Finite Element Analysis UK-Japan Workshop, Bristol, March 4-7, 03 3/7

4 CAI strength Damage size an interlaminar toughness CAI Strength (MPa) T800H/39 T800H/3900-B IM600/33 T700/ Fracture Toughness GIIc (kj/m) UK-Japan Workshop, Bristol, March 4-7, 03 4/7

5 Deflection T700/#500 (Impact energy= 5.05 J/mm) 6ply 3ply 64ply Courtesy of Dr. Y. Aoki (JAXA) 5/7

6 Analytical moel Delamination Impact sie Impact point Top Layer Bottom Layer Back sie Transverse ack UK-Japan Workshop, Bristol, March 4-7, 03 6/7

7 Circular multiple elamination moel an Double spiral amage moel 64ply 3ply Local buckling loa of 30 mm amage 6ply UK-Japan Workshop, Bristol, March 4-7, 03 7/7

8 Loa Out of plane isplacement: SP30S Global buckling Local through thickness buckling Intact laminate Local surface buckling UK-Japan Workshop, Bristol, March 4-7, 03 8/7

9 Applie loa an maximum energy release rate at the outsie eges Fracture Toughness & Energy Release rate (kj/m ) G IIC of IM600/#33 FEM (=40mm) G IIC of T800/#500 FEM (=30mm) Compressive Stress (MPa) To know the energy release rate is one way to unerstan the characteristic of CAI strength. UK-Japan Workshop, Bristol, March 4-7, 03 9/7

10 Unit amage an iealize annular plate. UK-Japan Workshop, Bristol, March 4-7, 03 0/7

11 Comparison of Energy Release Rate Distributions P=40 kn ( = 9 MPa) Double spiral amage moel Present theory (=33mm) P=70 kn ( = 354 MPa) Annular elamination moel UK-Japan Workshop, Bristol, March 4-7, 03 /7

12 What is CAI failure? Final failure occurs at the stage of throughthickness local buckling. Small ajustment of amage configurations by partial elamination growth occurs before unstable growth of whole amage into transverse irection. The energy release rate of multiple circular amage moel can be a measure of the final failure It enables the preiction of the failure loa to know the energy release rate as a function of applie loa an amage size. G(P )=G /7

13 Analytical Stuy to get close form solution UK-Japan Workshop, Bristol, March 4-7, 03 3/7

14 Assemble plate moel y b 3 3 Inplane stiffness eease ue to buckling of amage portion ' O a x Inplane stiffness is maintaine UK-Japan Workshop, Bristol, March 4-7, 03 4/7

15 Inplane stiffness of amage portion y, v ' x, u y b 3 3 ' O a x Out of plane eflection is constraine Bounary conitions of amage portion u / v / at at x y UK-Japan Workshop, Bristol, March 4-7, 03 5/7

16 Postbuckling Loa an En-Shortening E f when when t k E Relationship between normalize loa an en-shortening is inepenent of unit size ' when /' is constant 3 3 UK-Japan Workshop, Bristol, March 4-7, 03 6/7

17 Multiple circular amage y, v ' x, u m = '/ =.0 f B B B = B = 0.35 k =.88 t k E UK-Japan Workshop, Bristol, March 4-7, 03 7/7

18 Multiple elamination moel ' ' m = '/ =. f B B B = 0.35 B = 0. k = B = B = 0.35 k =.88 t k E UK-Japan Workshop, Bristol, March 4-7, 03 Normalize compressive loa Normalize en shortening 8/7

19 Rule of Mixtures b Intact portion Damage portion ' a Moel b Intact portion Moel Intact portion b a Damage portion Damage portion a b a Reuss moel Moel 4 Voigt moel Intact portion 0 Intact Damage portion portion b' 0 ' ' a' a Series rule UK-Japan Workshop, Bristol, March 4-7, 03 Parallel moel 9/7

20 Moel : = in all portions Upper boun Moel : = in all portions Lower boun Moel 3: series moel b= ' + (b'), = a= ' + (a'), = Moel 4: parallel moel a= ' + (a'), = b= ' + (b'), = UK-Japan Workshop, Bristol, March 4-7, 03 0/7

21 Relationship between Loa an En- Shortening of assemble plate p pf s f p=s for Moel p = for Moel p = + s for Moel 3 p = s for Moel 4 UK-Japan Workshop, Bristol, March 4-7, 03 /7

22 /7 UK-Japan Workshop, Bristol, March 4-7, 03 Total Strain Energy = /b, = /a F pf t k Em Eabt pf F s pf Eabt pf f s pf Eabt pf f s pf Eabt a bt Pu U u f F

23 3/7 UK-Japan Workshop, Bristol, March 4-7, 03 Average energy release rate G f p p F f t Em n n F pf t m Ek n n U n n U U n n G const const const

24 Compliance Inease Normalize Compliance Inease 0 / 0 / (=40 mm) Present analysis moel moel moel 3 moel 4 Finite element analysis MCD moel DSD moel Normalize Applie Displacement 0 / UK-Japan Workshop, Bristol, March 4-7, 03 4/7

25 Average Energy Release Rate (kj/m ) Present analysis moel moel moel 3 moel 4 FEM (=30 mm) MDM SDM Applie Loa (kn) UK-Japan Workshop, Bristol, March 4-7, 03 5/7

26 Average Energy Release Rate Average Energy Release Rate (kj/m ) Present analysis moel moel moel 3 moel 4 FEM (=40 mm) MSD moel SPD moel = Applie Loa (kn) UK-Japan Workshop, Bristol, March 4-7, 03 6/7

27 Applie Loa & Average EER Moe II itical EER global buckling loa of intact plate UK-Japan Workshop, Bristol, March 4-7, 03 7/7

28 CONCLUSIONS An explicit form of energy release rate base on simplifie moel is propose. The solution give a quite goo estimate of energy release rate. The solution explains the effect of various parameters on the CAI strength. G n Em t n p f 4F p f 4 p pf s f UK-Japan Workshop, Bristol, March 4-7, 03 8/7