Maximum mean principal stress criterion for three-dimensional brittle fracture

A novel fixture for mixed mode I/II/III fracture testing of brittle materials

“…It can be stated that the main reason of this discrepancy is the nonlinear behavior of the load‐displacement curve of the epoxy resin under out‐of‐plane loading, which is not considered by the mentioned fracture criteria. This discrepancy was also reported by various researchers such as Ayatollahi and Saboori, Wang et al, and Richard et al…”

“…Furthre explanations about the mentioned criteria have been presented in Wang et al The fracture limit surfaces illustrated based on the different criteria are shown in Figure . If the total SIF related to a cracked sample reaches this fracture limit, unstable crack growth will immediately occur.…”

“…Fracture criteria are usually used in order to validate the results experimentally obtained . In the recent years, investigators have developed various three‐dimensional fracture criteria for brittle materials.…”

“…Then, this criterion was extended for the mixed mode I/II/III fracture problems. GMERR; Zhao showed that the maximum energy release rate (MERR) can be used to estimate the 3‐D crack growth initiation. This criterion expresses that the crack propagates as the energy release rate reaches its maximum value. MPERR; this criterion proposed by Chang et al is a modified version of the GMERR. MMPS; Wang et al presented a 3‐D brittle fracture criterion based on the maximum mean principal stress (MMPS). MTSED; the maximum tangential strain energy density fracture criterion was extended by Ayatollahi and Saboori for the samples subjected to the mixed mode I/II/III loading condition. Richard; a practical‐based criterion was developed by Richard et al The classical stress hypotheses were used to predict the crack growth initiation.…”

Impact of MURR LEU Conversion on Beryllium Reflector Lifetime

“…Despite the lack of complete information on the properties, an attempt is made to use limited available data to assess the relative strength of the analyzed reflectors with this approach. It must be noted that the crack propagation theories for the multi-dimensional state of stress are under constant development and there is no consensus on which one of them should generally be used [94], especially for materials as rarely used as beryllium. It is worth noting that the FE analysis in COMSOL does not rely on UTS and UCS.…”