Fracture assessment of V-notched specimens with end holes made of tungsten-copper functionally graded material under mode I loading

Abstract

The present research is the first to assess fracture of V-notches with end holes (VOnotches) made of tungsten-copper functionally graded material (W-Cu FGM) under mode I both experimentally and theoretically. W-Cu FGM specimens were fabricated by powder metallurgy technique. A number of fracture tests were carried out on VOnotched W-Cu FGM specimens under mode I for various notch tip radii, notch depths, and notch opening angles.The averaged strain energy density over a well-defined control volume was employed to predict the fracture loads. A numerical approach was used to determine the outer boundary of the control volume. Besides, the effect of notch geometry (notch tip radius, notch depth, and notch opening angle) on fracture load was elaborated. This study demonstrates that SED works well on VO-notched FGM specimens under mode I loading.

Ductile Failure Prediction of U-Notched Bainitic Functionally Graded Steel Specimens Using the Equivalent Material Concept Combined with the Averaged Strain Energy Density Criterion

“…The mentioned criterion has been used in different investigations to predict the fracture of notched specimens made of functionally graded materials [32,33,31,[27][28][29][30]. However, in this study, as the notch root has been located in a very ductile region, the mentioned criterion cannot give reasonably accurate results.…”

“…Unlike homogeneous materials, in FGMs due to a gradual change in material properties, the outer boundary of control volume is no longer a circular arc, but rather an oval arc is assumed. This notion has been used in a number of previous studies on fracture of notched specimens made of FGMs [32,31,39,[27][28][29][30]. For a U-notched FGM specimen with a material variation in the xdirection under mode I, the outer boundary can be determined by a numerical approach using the following equations.…”

“…Recently, the averaged SED criterion was employed to predict the fracture of notched specimens made of different types of materials such as Polyurethane (PUR) [25,26], tungsten-copper functionally graded material [27][28][29][30][31] and functionally graded steels [32][33][34].…”

“…To predict the fracture of notched specimens made of FGMs by the averaged SED criterion, unlike homogeneous materials for which the outer boundary of the control volume is a circular arc, the strain energy density is averaged over a well-defined control volume which its outer boundary is an oval arc [27][28][29][30][31][32][33][34]. In these works, the notch depth was in brittle or semi-brittle region.…”

3D fracture behaviour of graphite specimens weakened by V- notches with end holes under mixed mode (I+II) loading

“…Recently, the SED criterion has been applied to study the static strength of functionally graded materials under mode I [26,27] and mixed mode loading [28][29][30]. Recently, the SED approach was used to investigate the fracture behavior of Tungsten-Cooper functionally graded material which has been produced by powder metallurgy technique for the first time [31][32][33][34]. The SED approach was used to investigate the static strength of sharp and rounded-tip V-notched components made of polycrystalline graphite subjected to different degrees of loading mixity, ranging from pure mode I to pure mode II [35].…”