scholarly journals Three-Dimensional J-Integral Based on a Domain Integral Method for Non-Homogeneous Solid with Residual Stresses Undergoing Large Deformation

2019 ◽  
Vol 21 (1) ◽  
pp. 10-11
Author(s):  
Hiroshi Okada ◽  
Tatsuro Ishizaka ◽  
Akira Takahashi ◽  
Koichiro Arai ◽  
Yasunori Yusa
Keyword(s):  
Residual Stresses ◽  
Large Deformation ◽  
Integral Method ◽  
Three Dimensional ◽  
J Integral ◽  
Domain Integral

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

2021 ◽  
Author(s):  
WU XU ◽  
JIANCAN DING
Keyword(s):  
Fracture Toughness ◽  
Closed Form ◽  
Large Deformation ◽  
Cantilever Beam ◽  
Integral Method ◽  
Double Cantilever Beam ◽  
J Integral ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture

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.

Mesh-independent equivalent domain integral method for J-integral evaluation

2016 ◽  
Vol 100 ◽  
pp. 308-318 ◽  
Author(s):  
G.P. Nikishkov ◽  
A.V. Vershinin ◽  
Y.G. Nikishkov
Keyword(s):  
Integral Method ◽  
J Integral ◽  
Integral Evaluation ◽  
Domain Integral

scholarly journals Integral method coefficients for the ring-core technique to evaluate non-uniform residual stresses

2018 ◽  
Vol 53 (4) ◽  
pp. 210-224 ◽  
Author(s):  
Michele Barsanti ◽  
Marco Beghini ◽  
Ciro Santus ◽  
Alessio Benincasa ◽  
Lorenzo Bertelli
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Integral Method ◽  
Three Dimensional ◽  
Element Model ◽  
Hole Drilling ◽  
Stress Distributions ◽  
Three Dimensional Model ◽  
Small Depth ◽  
Ring Core

The ring-core technique allows for the determination of non-uniform residual stresses from the surface up to relatively higher depths as compared to the hole-drilling technique. The integral method, which is usually applied to hole-drilling, can also be used for elaborating the results of the ring-core test since these two experimental techniques share the axisymmetric geometry and the 0°–45°–90° layout of the strain gage rosette. The aim of this article is to provide accurate coefficients which can be used for evaluating the residual stress distribution by the ring-core integral method. The coefficients have been obtained by elaborating the results of a very refined plane harmonic axisymmetric finite element model and verified with an independent three-dimensional model. The coefficients for small depth steps were initially provided, and then the values for multiple integer step depths were also derived by manipulating the high-resolution coefficient matrices, thus showing how the present results can be practically used for obtaining the residual stresses according to different depth sequences, even non-uniform. This analysis also allowed the evaluation of the eccentricity effect which turned out to be negligible due to the symmetry of the problem. An applicative example was reported in which the input of the experimentally measured relaxed strains was elaborated with different depth resolutions, and the obtained residual stress distributions were compared.

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