作者: X.C. You, Zhuo Zhuang, T. Tang, Y.R. Feng, Chun Yong Huo, C.J. Zhuang
381
作者: Hyung Seop Shin, Ki Hyun Kim, Young Jin Jung, Dong Kyun Ko
摘要: The impact fracture behavior of Zr-based bulk metallic glass was investigated by an
instrumented impact tester using subsize Charpy specimens. Influences of loading rate and notch shape on the fracture behavior of amorphous Zr-Al-Ni-Cu alloy were examined. As a result, the maximum load and absorbed fracture energy under impact loading were lower than those under quasi-static loading. A large part of the absorbed fracture energy in the Zr-based BMG was consumed in the process for crack initiation and not for crack propagation. In addition, fractographic characteristics of BMGs were investigated. Fractured surfaces under impact loading are smoother than those under quasi-static loading. The absorbed fracture energy appeared differently depending on the appearance of the shear bands developed. It can be found that the fracture energy and fracture toughness of Zr-based BMG are closely related with the extent of shear bands developed during fracture.
1356
作者: Yasuhito Takashima, Mitsuru Ohata, Fumiyoshi Minami
61
作者: Ivo Dlouhý, Ladislav Jurášek, Miloslav Holzmann
摘要: In pearlitic steels the fracture initiation of pre-cracked specimens is strongly affected by
Lüders’ flow and higher strength properties. There is a gap in fracture toughness data of pre-cracked
Charpy (PC) and compact tension (CT) specimens between 60 and 90 MPam1/2 due to plastic hinge
formation. The distribution of maximum principal stress ahead of the crack tip in PC specimen
loaded into fully plastic regime was found to be identical with that of reference stress-strain field in
plane-strain SSY condition. 3D FEM simulations have also shown that there is no constraint loss in
PC specimens.
413
作者: Ruben Cuamatzi-Melendez, J.R. Yates
摘要: Little work has been published concerning the transferability of Gurson’s ductile damage model parameters in specimens tested at different strain rates and in the rolling direction of a Grade A ship plate steel. In order to investigate the transferability of the damage model parameters of Gurson’s model, tensile specimens with different constraint level and impact Charpy specimens were simulated to investigate the effect of the strain rate on the damage model parameters of Gurson model. The simulations were performed with the finite element program ABAQUS Explicit [1]. ABAQUS Explicit is ideally suited for the solution of complex nonlinear dynamic and quasi–static problems [2], especially those involving impact and other highly discontinuous events. ABAQUS Explicit supports not only stress–displacement analyses but also fully coupled transient dynamic temperature, displacement, acoustic and coupled acoustic–structural analyses. This makes the program very suitable for modelling fracture initiation and propagation. In ABAQUS Explicit, the element deletion technique is provided, so the damaged or dead elements are removed from the analysis once the failure criterion is locally reached. This simulates crack growth through the microstructure. It was found that the variation of the strain rate affects slightly the value of the damage model parameters of Gurson model.
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