CLOSED-FORM J-INTEGRAL AND ITS APPLICATIONS FOR MEASUREMENT OF MODE I INTERLAMINAR FRACTURE TOUGHNESS OF COMPOSITES

Due to the interlaminar properties of composites are low, delamination is one of the major failure modes. It threatens the safety of composite structure subjected to out-of-plane static and especially impact loadings. High interlaminar fracture toughness is demanded in the society where composite structures are widely used. However, for tough material, large deformation may occur in the determination of the interlaminar fracture toughness when using the double cantilever beam (DCB) test. Therefore, accurate determination of the fracture toughness of tough material and dynamic loading is very challenging under large deformation. J-integral is an important parameter in fracture mechanics. It’s equivalent to energy release rate under monotonic loading and widely used in the determination of interlaminar fracture toughness of composites. In this paper, it is used to determine the fracture toughness for composite DCB under large deformation and wedge-insert double cantilever beam (WDCB) test, which is widely used to determine the dynamic interlaminar fracture toughness. Exact and closed form nonlinear J-integrals are derived for the largely deformed DCB and WDCB. Compared with the alternative data reduction methods for determining interlaminar fracture toughness, the J- integral method is more accurate. In addition, the J-integral method is simple and promising, since it is unnecessary to measure the crack length in the tests.

Determination of mode I interlaminar fracture toughness of composite by a wedge-insert double cantilever beam and the nonlinear J integral

Composites Science and Technology ◽

10.1016/j.compscitech.2021.108674 ◽

2021 ◽

Vol 206 ◽

pp. 108674

Author(s):

J.C. Ding ◽

W. Xu

Keyword(s):

Fracture Toughness ◽

Cantilever Beam ◽

Double Cantilever Beam ◽

Mode I ◽

J Integral ◽

Determination of mode I interlaminar fracture toughness of C/SiC composite using taped double cantilever beam and J integral

Journal of Applied Mechanics ◽

10.1115/1.4052574 ◽

2021 ◽

pp. 1-9

Author(s):

Wu Xu ◽

J.C Ding ◽

Jingran Ge ◽

Qi Zhang

Keyword(s):

Fracture Toughness ◽

Cantilever Beam ◽

Double Cantilever Beam ◽

Ceramic Matrix Composite ◽

Mode I ◽

Complex Data ◽

J Integral ◽

Abstract Due to the low in-plane strength of C/SiC ceramic matrix composite (CMC), arm failure may occur in the classical double cantilever beam (DCB) test for determination of the mode I interlaminar fracture toughness. A taped DCB (TDCB) is proposed to avoid this undesired failure mode. Exact and explicit J integral for the TDCB is derived and applied to measure the interlaminar fracture toughness of CMC. The present TDCB and J integral are demonstrated to be simple and reliable for determining the interlaminar fracture toughness, without visual measurement of the delamination length and complex data reduction.

Determination of the Mode I Interlaminar Fracture Toughness by Using a Nonlinear Double-Cantilever Beam Specimen

Mechanics of Composite Materials ◽

10.1007/s11029-016-9587-y ◽

2016 ◽

Vol 52 (3) ◽

pp. 347-358 ◽

Cited By ~ 2

Author(s):

V. Pavelko ◽

K. Lapsa ◽

P. Pavlovskis

Keyword(s):

Fracture Toughness ◽

Cantilever Beam ◽

Double Cantilever Beam ◽

Mode I ◽

Beam Specimen ◽

Double Cantilever Beam Specimen ◽

A study of the effect of geometry on the mode I interlaminar fracture toughness; measured by width tapered double cantilever beam specimen

Journal of Materials Science Letters ◽

10.1007/bf00625000 ◽

1996 ◽

Vol 15 (17) ◽

pp. 1489-1491 ◽

Cited By ~ 2

Author(s):

Zhiyun Li ◽

Jiang Zhou ◽

Mengxian Ding ◽

Tianbai He

Keyword(s):

Fracture Toughness ◽

Cantilever Beam ◽

Double Cantilever Beam ◽

Mode I ◽

Beam Specimen ◽

Double Cantilever Beam Specimen ◽

Double Cantilever Beam Measurement and Finite Element Analysis of Cryogenic Mode I Interlaminar Fracture Toughness of Glass-Cloth/Epoxy Laminates

Journal of Engineering Materials and Technology ◽

10.1115/1.1345527 ◽

2000 ◽

Vol 123 (2) ◽

pp. 191-197 ◽

Cited By ~ 38

Author(s):

Y. Shindo ◽

K. Horiguchi ◽

R. Wang ◽

H. Kudo

Keyword(s):

Fracture Toughness ◽

Finite Element Analysis ◽

Finite Element ◽

Cantilever Beam ◽

Double Cantilever Beam ◽

Mode I ◽

Element Analysis ◽

Interlaminar Fracture ◽

Delamination Crack

An experimental and analytical investigation in cryogenic Mode I interlaminar fracture behavior and toughness of SL-E woven glass-epoxy laminates was conducted. Double cantilever beam (DCB) tests were performed at room temperature (R.T.), liquid nitrogen temperature (77 K), and liquid helium temperature (4 K) to evaluate the effect of temperature and geometrical variations on the interlaminar fracture toughness. The fracture surfaces were examined by scanning electron microscopy to verify the fracture mechanisms. A finite element model was used to perform the delamination crack analysis. Critical load levels and the geometric and material properties of the test specimens were input data for the analysis which evaluated the Mode I energy release rate at the onset of delamination crack propagation. The results of the finite element analysis are utilized to supplement the experimental data.