Composite Skin Elastic Constants from Monolithic In-plane Specimens and Bonded Out-of-plane Specimens

Abstract

In this study, a full set of elastic constants (in-plane (IP) and out-of-plane (OOP)) is determined/estimated for two sandwich composite skin laminates. For the out-of-plane properties, compression and shear specimens are cut from the skin laminates and bonded together to avoid making thick laminates. This approach gives a relatively low experimental scatter for the elastic constants indicating that the measurements are not affected by the presence of the thin adhesive layers between the laminates. Finite element calculations are performed to further study the effect of the adhesive layers. It is found that the effect of the adhesive layers is minor in the range of strains used to determine the elastic constants.

Keywords

materials testing skin laminate out-of-plane elastic constants bonded specimen finite element analysis.

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References

Nielsen, S.A. and Toftegaard, H. (2000). Ultrasonic Measurement of Elastic Constants in Fiber-reinforced Polymer Composites under Influence of Absorbed Moisture, Ultrasonics, 38(1—8): 242—246.

Frederiksen, P.S. (1997). Numerical Studies for the Identification of Elastic Constants Including Transverse Shear Moduli of Thick Orthotropic Plates, European Journal of Mechanics , A/Solids, 16(1): 117—140.

Knight, M. (1982). Three-dimensional Elastic Moduli of Graphite/Epoxy Composites, Journal of Composite Materials, 16(Mar): 153—159.

Broughton, W.R. and Sims, G.D. (1994). An Overview of Through-thickness Test Methods for Polymer Matrix Composites, NPL Report DMM(A)148, National Physical Laboratory, Teddington, United Kingdom.

Broughton, W.R. , Lodeiro, M. and Sims, G.D. (1996). Experimental Validation of Shear Test Methods for Through-thickness Properties, In: Proceedings of the ECCM-7 Conference, Vol. 2, London, pp. 125—130.

Astm D 5379 (1998). Standard Test Method for Shear Properties of Composite Materials by the V-notched Beam Method.

Astm D695-02a (2000). Standard Test Method for Compressive Properties of Rigid Plastics.

ISO 527-4 Plastics — Determination of tensile properties — Part 4: Test Conditions for Isotropic and Orthotropic Fibre-reinforced Plastic Composites.

Toftegaard, H. (1999). Simulated Stiffness Determination from Simple Compression Tests on a Thick Laminate, Composites: Part A, 30(7): 849—858.

10.

Toftegaard, H. (1998). Elastic Constants from Simple Compression Tests Evaluated by Numerical Simulation, In: Proceedings of the 4th European Conference on Composites, ECCM CTS-4, Testing and Standardisation , Lisbon, Portugal, pp. 310—319.

11.

Kim, J.K. and Lee, D.G. (2002). Characteristics of Plasma Surface Treated Composite Adhesive Joints at High Environmental Temperature, Composite Structures, 57(1—4): 37—46.

12.

Xavier, J.C. , Garrido, N.M. , Oliveira, M. , Morais, J.L. , Camanho, P.P. and Pierron, F. (2004). A Comparison between the Iosipescu and Off-axis Shear Test Methods for the Characterization of Pinus Pinaster Ali, Composites: Part A, 35(7—8): 827—840.

13.

Neumeister, J.M. and Melin, L.N. (2003). A Modified Iosipescu Test for Anisotropic Composite Panels, In: Proceedings of the 14th International Conference on Composite Materials, ICCM-14, San Diego, USA.

14.

Kumosa, M. and Han, Y. (1999). Non-linear Finite Element Analysis of Iosipescu Specimens, Composites Science and Technology, 59(4): 516—573.

15.

Odegard, G. and Kumosa, M. (2000). Determination of Shear Strength of Unidirectional Composite Materials with the Iosipescu and 10 ° Off-axis Specimen, Composites Science and Technology , 60(16): 2917—2943.

16.

Chiang, M.Y.M. and He, J. (2002). An Analytical Assessment of using the Iosipescu Shear Test for Hybrid Composites, Composites: Part B, 33(6): 461—470.