Abstract
The nominal strength of structures made of quasibrittle materials shows a noticeable decrease or increase in brittleness with respect to the increase in structure dimension; this is the well-known size effect on strength. The present study aims to analyze and experimentally validate the size effect on laminate composite glass fibers using cohesive laws. This work not only correlates the nominal strength with the size of the failure processing zone but also relates the size of the failure processing zone at failure load to the specimen dimension and geometry. Our study provides a useful tool that enables engineers to obtain a set of design charts that relate the nominal strength of the structure to the size and shape of the specimen. Moreover, it aims to apply a new method to study the effect of structure size on the tensile strength of fiber polymer composite. The results of nominal strength are validated using a matrix of experimental work, and they agree very well with the experimental data. The other fracture properties are compared using an extended finite element method. The output of the analysis is a valuable graph that gives the nominal strength of the open-hole specimen.
Similar content being viewed by others
Abbreviations
- \({\rho_{{\rm{Cr}}}^{{\rm{theoretical}}}}\) :
-
Calculated relative specimen size
- β w :
-
Normalized hole radius or hole width ratio, geometric factor
- β i :
-
Parameter \({\beta_{i} =-\frac{2}{\pi}\left[{\sin ^{-1}\left( {\frac{C_{i}}{d}}\right)-\sin^{-1}\left({\frac{b_{i}}{d}}\right)}\right]\frac{F_{3} F_{4}}{F_{1} F_{2}}}\)
- K t :
-
Stress concentration factor
- σ n :
-
The nominal applied stress, mean stress at failure plane
- σ u :
-
Un-notch strength
- \({\overline{\rho}_{{\rm{Cr}}}}\) :
-
Transformation function
- \({\overline{\sigma}_{{\rm{C}}}}\) :
-
Normalized cohesive law
- ℓ Cr :
-
Irwin’s characteristic length
- ℓ FPZ :
-
Crack length ahead of the hole radius
- \({\rho_{{\rm{Cr}}}^{{\rm{Experimental}}}}\) :
-
Experimental relative specimen size
- \({\overline{{w}}}\) :
-
Normalized crack opening
- σ Zero :
-
Residual stress at maximum crack opening displacement
- \({{b}_{{i,j}} ,{C}_{{i,j}}}\) :
-
Dimension for partially loaded cracks, i, j = 1,2
- d :
-
Half length of crack (hole) pulse FPZ
- E :
-
Laminate’s Young’s modulus
- F 1 :
-
Hole correction factor
- F 2 :
-
Width correction factor
- F 3 :
-
Partially loaded hole correction factor
- F 4 :
-
Partially loaded width correction factor
- f i :
-
Operator functions \({f_{ij} =\frac{2}{E}\sqrt{d^{2}-x_{i}}F_1 F_2}\)
- f ij , G(x i , x j ):
-
Influence functions that are independent of the crack geometry and loading conditions
- G IC :
-
Mode I surface release energy
- Ks:
-
Stress intensity factor due to remote stress
- K σ :
-
Stress intensity factor due to crack face stress
- R :
-
Hole radius
- S :
-
Remote applied stress
- S n :
-
Normalized nominal strength
- W :
-
Specimen width
- w c :
-
Critical crack opening
- W i :
-
Unite crack opening displacement
- X i,j :
-
Coordinate locates for element (i) or (j)
- α ij :
-
Operator vector
- θ ℓ :
-
Dimensionless length of (ℓ fpz), mm
- λ :
-
Normalized crack length (normalized hole radius)
- ρ CR :
-
Relative specimen size
- σ ij :
-
Cauchy stresses
- ξ :
-
Material type correction factor
References
Guinea G.V., Planas J., Elices M.: A general bilinear fit for the softening curve of concrete. Mater. Struct. 27(2), 99–105 (1994)
Bazânt Z.P.: Size effect. Int. J. Solid Struct. 37, 69–80 (2000)
Bazânt, Z.P., Planas, J.: Fracture and Size Effect in Concrete and Other Quasi-brittle Materials, CRC Press, Boca Raton (1998)
Li Y.N., Bazânt Z.P.: Eigen-value analysis of size effect for cohesive crack model. Int. J. Fract. 66(3), 213–226 (1994)
Wisnom M.R.: Size effects in the testing of fiber-composite materials. Compos. Sci. Technol. 59, 1937–1957 (1999)
Wisnom M.R., Khan B., Hallet S.R.: Size effects in un-notched tensile strength of unidirectional and quasi-isotropic carbon/epoxy composites. Compos. Struct. 84, 21–28 (2008)
Bullock R.E.: Strength ratios of composite materials in flexure and in tension. J. Compos. Mater. 8, 200–206 (1974)
Hitchon J.W., Phillips D.C.: The effect of specimen size on the strength of CFRP. Composites 9, 119–124 (1978)
Jackson, K.E., Kellas, S.: Effect of specimen size on the tensile strength of geometrically scaled [+θ n /−θ n /902n ] S composite laminates. In: US Army Symposium on Solid Mechanics, Plymouth, August (1993)
Wisnom M.R., Atkinson J.A.: Reduction in tensile and flexural strength of unidirectional glass fiber-epoxy with increasing specimen size. Compos. Struct. 38, 405–412 (1997)
Jackson, K.E., Kellas, S., Morton, J.: Scale effects in the response and failure of fiber reinforced composite laminates loaded in tension and in flexure. J. Compos. Mater. 26(18), 2674–2705 (1992)
Cunningham, M.E., Schoulz, S.V., Toth, J.M.: Effect of the end tab design on tension specimen stress concentrations. In: Recent advances in composites in the United States and Japan. ASTM STP 864, pp. 263–262 (1985)
Hojo M., Sawada Y., Miyairi H.: Influence of clamping method on tensile properties of unidirectional CFRP in 0° and 90° directions - round robin activity for international standardization in Japan. Composites 25, 786–796 (1994)
Wisnom, M.R., Maheri, M.R.: Tensile strength of unidirectional carbon fiber-epoxy from tapered specimens. In: Second European Conference on Composites Testing and Standardization, Hamburg, pp 239–247 (1994)
Bing Q., Sun C.T.: Specimen size effect in off-axis compression tests of fiber composites. Compos. Part B Eng. 39, 20–26 (2008)
Soutis C., Lee J.: Scaling effects in notched carbon fiber/epoxy composites loaded in compression. J. Mater. Sci. 43(20), 6593–6598 (2008)
Lee J., Soutis C.: Measuring the notched compressive strength of composite laminates: specimen size effects. Compos. Sci. Technol. 68(12), 2359–2366 (2008)
Wisnom M.R., Hallet S.R., Soutis C.: Scaling effects in notched composites. J. Compos. Mater. 44(2), 195–210 (2010)
Bazânt, Z.P., Daniel, I.M., Li, Z.: Size effect and fracture characteristics of composite laminates. J. Eng. Mater. Technol. 118(3), 317–324 (1996)
Bayldon, J., Bazânt, Z.P., Daniel, I.M., Q. Yu: Size effect on compressive strength of sandwich panels with fracture of woven laminate facesheet. J. Eng. Mater. Technol. 128/169 (2006)
Zi G., Bazânt Z.P.: Eigenvalue method for computing size effect of cohesive cracks with residual stress, with application to kink-bands in composites. Int. J. Eng. Sci. 41, 1519–1534 (2003)
Planas J., Bazânt Z.P., Jirasek M.: Reinterpretation of Karihaloo’s size effect analysis for notched Quasibrittle structures. Int. J. Fract. 111, 17–28 (2001)
Füssl J. et al.: Failure modes and effective strength of two-phase materials determined by means of numerical limit analysis. Acta Mech. 195.1–4, 185–202 (2008)
Theocaris P.S.: Failure criteria for weak-axis quasi-orthotropic woven fabric composites. Acta Mech. 95(1–4), 69–86 (1992)
Theocaris P.S.: Failure modes of woven fabric composites loaded in the transverse isotropic plane. Acta Mech. 103(1–4), 157–175 (1994)
Camanho P.P., Maimi P., Davila C.G.: Prediction of size effects in notched laminates using continuum damage mechanics. Compos. Sci. Technol. 67, 2715–2727 (2007)
Soutis C., Fleck N.A., Smith P.A.: Failure prediction technique for compression loaded carbon fiber-epoxy laminate with open holes. J. Compos. Mater. 25(11), 1476–1498 (1991)
Soutis C.A.: Fibremicrobuckling model for predicting the notched compressive strength of composite sandwich panels. Mech. Compos. Mater. 43(1), 51–58 (2007)
Soutis C., Curtis P.T., Fleck N.A.: Compressive failure of notched carbon fiber composites. Proc. R. Soc. Lond. A 440, 241–256 (1993)
Soutis C., Curtis P.T.: A method for predicting the fracture toughness of CFRP laminates failing by fibermicrobuckling. Compos. Part A 31, 733–740 (2000)
Hassan, M.K., Mohammed, Y., Salem, T.M., Hashem, A.M.: Prediction of nominal strength of composite structure open hole specimen through cohesive laws. Int. J. Mech. Mech. Eng. IJMME-IJENS 12:1–9
Maimi p., Trias D., Gonzalez E.V., Renart J.: Nominal strength of Quasibrittle open hole specimens. Compos. Sci. Technol. 72, 1203–1208 (2012)
Dugdale D.S.: Yielding of steel sheets containing slits. J. Mech. Phys. Solids 8(2), 100–104 (1960)
Barenblatt G.I.: The mathematical theory of equilibrium cracks in brittle fracture. Adv. Appl. Mech. 7, 55–129 (1962)
Bao G., Suo Z.: Remarks on crack-bridging concepts. Appl. Mech. Rev. 45(8), 355–366 (1992)
He M.Y., Wu B., Suo Z.: Notch-sensitivity and shear bands in brittle matrix composites. Acta Metall. Mater. 42(9), 3065–3070 (1994)
Suo Z., Ho S., Gong X.: Notch ductile-to-brittle transition due to localized inelastic band. J. Eng. Mater. Technol. 115(3), 319–326 (1993)
Williams T.N., Newman J.C. Jr., Gullett P.M.: Crack-surface displacements for cracks emanating from a circular hole under various loading conditions. Fatigue Fract. Eng. Mater. Struct. 34(4), 250–259 (2011)
Bazânt, Z.P., Li, Z.: Zero-brittleness size-effect method for one-size fracture test of concrete. J. Eng. Mech. 122(5), 458–468 (1996)
Khashaba U.A.: In-plane shear properties of cross-ply composite laminates with different off-axis angles. Compos. Struct. 65(2), 167–177 (2004)
Stander test method constituent of composite material, ASTM D 3171-99. American Society for Testing and Materials (ASTM) (1999)
Davis J.R.: Tensile Testing. ASM International, Ohio (2004)
Standard test method for tensile properties of polymer matrix composite materials, ASTM D 3039/D 3039M-00. American Society for Testing and Materials (ASTM), West Conshohocken (PA), USA (2000)
ASTM D3518: “Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test of a±45° Laminate.” W. American Society for Testing and Materials, Conshohocken, PA (2001)
Standard Method of Test for Plane Strain Fracture Toughness in Metallic Materials, ASTM E399-81, American Society for Testing and Materials, Philadelphia (1981)
Standard, A.S.T.M.: D638M-93, Standard Test Method for Tensile Properties of Plastics (Metric). Ann. Book ASTM Stand. Part 8, 59–67 (1993)
Jones R.M.: Mechanics of Composite Materials. Taylor & Francis, London (1999)
Mallick P.K.: Fiber-Reinforced Composites, 2nd edn. Marcel Dekker Press, New York (1993)
Gibson R.F.: Principles of Composite Material Mechanics. CRC Press, Boca Raton (2011)
Green B.G., Wisnom M.R., Hallet S.R.: An experimental investigation into the tensile strength scaling of notched composite. Compos. Part A 38, 867–878 (2007)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Mohammed, Y., Hassan, M.K., El-Ainin, H.A. et al. Size effect analysis of open-hole glass fiber composite laminate using two-parameter cohesive laws. Acta Mech 226, 1027–1044 (2015). https://doi.org/10.1007/s00707-014-1150-0
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00707-014-1150-0