Three-dimensional peridynamic modeling of crack initiation and propagation in bulk superconductor during field cooling magnetization

Abstract

Bulk high-temperature superconductors exhibit outstanding electromagnetic properties and are capable of trapping very large magnetic fields. However, bulk superconductors are subjected to a large Lorentz force during field cooling magnetization (FCM), which can cause crack initiation and propagation. Superconducting performance is then limited by the damage to the bulk. In this paper, we study the mechanical behavior and brittle damage of a three-dimensional (3D) bulk GdBCO superconductor during FCM. Firstly, the distribution of electromagnetic field in the bulk is obtained based on the H-formulation with a finite element model. Then, a 3D bond-based peridynamic (PD) model is used to simulate the mechanical behavior and possible brittle damage to the bulk under a given electromagnetic force. The initiation and propagation of cracks can be predicted using the 3D bond-based PD model. The effect of residual stress due to the presence of a reinforcement ring during the cooling process is also discussed. The results show that mechanical stability can be improved by reinforcing the sample.

R-z plane spatial critical current inhomogeneity-induced mechanical response of GdBCO superconducting bulks during field cooling magnetization

“…Subsequently, according to strain measurement results, Takahashi [7] and Namba [17] constructed 2D and 3D numerical models to analyze the fracture behavior of HTS bulk and further considered the effect of the real structure of the mechanical support apparatus. Recently, apart from the FEM, the extended finite element method (XFEM) [18,19], peridynamics (PDs) [20,21], and phase-field method [22,23], the theories of fracture mechanics, were also gradually employed in the structural failure analysis of bulk materials caused by crack propagation.…”

“…In addition, based on the r-z plane spatial J c inhomogeneity method, the electromagnetic-mechanical coupling behavior of many high-field bulk material application devices, such as high-gradient trapped field magnet (HG-TFM) [48], staggered-array bulk HTS undulator [30,49], nuclear magnetic resonance (NMR) spectrometer [50] and a magnetic resonance imaging (MRI) apparatus [51], and others, can be simulated more precisely. Many complex HTS bulk material structure failure simulation modes, such as fracture, crack initiation, and propagation [19,21], may also achieve better agreement with experimental phenomena.…”

Flux jump and mechanical response in inhomogeneous high-temperature superconductor under the pulsed-field magnetization

“…The magnetic-thermal characteristics and mechanical stress of an REBCO superconducting bulk material with an inhomogeneous critical current density during PFM were analyzed by Wu et al [62] and Hirano et al [63]. In addition, cracks in the bulk can propagate under complicated electromagnetic and mechanical loadings [64][65][66]. The coupled magnetic-thermal model and phase-field fracture model were proposed to simulate the flux jump and mechanical failure behaviors of bulk superconductors during PFM [67].…”

Coupled multiphysics modeling of the thermal-magnetic-mechanical instability behavior in bulk superconductors during pulsed field magnetization

“…Thus, thermomagnetic instability is coupled with mechanical failure. In the past few years, many researchers have contributed to the investigation into the mechanical stresses [40,41] and the fracture/damage [42][43][44][45] evolution within bulk superconductorsduring magnetization. However, few works [46][47][48] have been reported that investigate the fully coupled thermomagnetic-mechanical instability behavior in bulk superconductors.…”