Effect of impactor radius on low-velocity impact damage of glass/epoxy composites

Abstract

With composites finding increased use as primary structures in commercial aircraft, it is necessary to understand the development of damage when a laminate is subject to low-velocity impacts from a variety of sources, which often occur during normal service operations and routine maintenance. In particular, contact with ground service equipment can present a blunt impact to the composite structure. Therefore, the effects of bluntness of an impactor are of interest as this is related to the development of any internal damage in the laminate, or even the surrounding structure, and also affects the visual detectability of an impact event. The objective of this investigation is to determine the effect of impactor radius on the impact damage resistance of composite panels. A low-velocity pendulum impactor was used to strike 200 mm² woven glass/epoxy composite plates of 3.18 and 6.35 mm thickness. Hemispherical steel impactor tips of radius 12.7, 50.8, and 152.4 mm were mounted to a piezoelectric force sensor which measures the contacting force history during the impact event. Distinct threshold energy levels defining the onset of delamination and backside fiber breakage have been measured to increase significantly with increasing impactor tip radius due to development of higher contact area.

Keywords

Woven glass/epoxy blunt impact damage resistance

Get full access to this article

View all access options for this article.

References

Abrate

. Modeling of impacts on composite structures. Compos Struct 2001; 51: 129–138.

Abrate

. Impact on composite structures , Cambridge: Cambridge University Press, 1998.

Sutherland

Guedes Soares

. Contact indentation of marine composites. Compos Struct 2005; 70: 287–294.

Mili

Necib

. Impact behavior of cross-ply laminated composite plates under low velocities. Compos Struct 2001; 51: 237–244.

Davies

GAO

Zhang

. Impact damage prediction in carbon composite structures. Int J Impact Eng 1995; 16(1): 149–170.

Davies

Hitchings

Wang

. Prediction of threshold impact energy for the onset of delamination in quasi-isotropic carbon/epoxy composite laminates under low-velocity impact. Compos Sci Technol 2000; 60: 1–7.

Zhang

. Impact damage in composite aircraft structures–experimental testing and numerical simulation. Proc Instn Mech Engrs 1998; 212: 245–259.

Choi

Chang

F-K

. A model for predicting damage in graphite/epoxy laminated composites resulting from low-velocity point impact. J Compos Mater 1992; 26(14): 2134–2169.

Sjöblom P. Simple design approach against low velocity impact damage. In: Proceedings of 32nd SAMPE Symposium, Anaheim, CA, 1987, pp. 529–539.

10.

Schoeppner

Abrate

. Delamination threshold loads for low velocity impact on composite laminates. Composites: Part A 2000; 31: 903–915.

11.

Yang

Cantwell

. Impact damage initiation in composite materials. Compos Sci Technol 2010; 70: 336–342.

12.

Cantwell

. Geometrical effects in the low velocity impact response of GFRP. Compos Sci Technol 2007; 67: 1900–1908.

13.

Tiberkak

Bachene

Rechak

. Damage prediction in composite plates subjected to low velocity impact. Compos Struct 2008; 83: 73–82.

14.

Her

S-C

Liang

Y-C

. The finite element analysis of composite laminates and shell structures subjected to low velocity impact. Compos Struct 2004; 66: 277–285.

15.

Gong

Lam

. Transient response of stiffened composite plates subjected to low velocity impact. Composite: Part B 1999; 30: 473–484.

16.

ASTM Standard D7136/D7136M-07, 2005e1. Standard test method for measuring the damage resistance of a fiber-reinforced polymer matrix composite to a drop-weight impact event. West Conshohocken, PA: ASTM International, 2005, DOI:10.1520/D7136_D7136M-07, http://www.astm.org.

17.

Finn

Y-F

Springer

. Delaminations in composite plates under transverse impact loads - Experimental results. Compos Struct 1993; 23(3): 191–204.

18.

Mitrevski

Marshall

Thomson

. The effect of impactor shape on the impact response of composite laminates. Compos Struct 2005; 67(2): 139–148.

19.

Mitrevski

Marshall

Thomson

. The influence of impactor shape on the damage to composite laminates. Compos Struct 2006; 76(1–2): 116–122.

20.

Mitrevski

Marshall

Thomson

. Low-velocity impacts on preloaded GFRP specimens with various impactor shapes. Compos Struct 2006; 76(3): 209–217.

21.

Shim

VPW

Yang

. Characterization of the residual mechanical properties of woven fabric reinforced composites after low-velocity impact. Int J Mech Sci 2005; 47(4–5): 647–665.

22.

Shyu

. Response of composite laminates to contact loads and relationship to low velocity impact. J Compos Mater 1993; 27: 1443–1464.

23.

Amaro

Reis

PNB

Magalhães

. The effect of the impactor diameter and boundary conditions on low velocity impact composites behaviour. Appl Mech Mater 2007; 7–8: 217–222.

24.

Feraboli

Kedward

. A new composite structure impact performance assessment program. Compos Sci Technol 2006; 66: 1336–1347.

25.

Siow

Shim

VPW

. An experimental study of low velocity impact damage in woven fiber composites. J Compos Mater 1998; 32: 1178–1202.