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In this paper, a dynamic simulation analysis model was established for CMGB (control moment gyroscope bearing) under the conditions of time-varying moment. The influences of the moment's response time, axial preload, and working temperature on the dynamic characteristics and friction torque of CMGB were analyzed, and the relevant verification tests were conducted. The results show that the friction torque fluctuation of CMGB directly corresponds to the dynamic characteristics. The faster the response time of the time-varying moment, the larger the friction torque fluctuation of CMGB. The larger preload minimizes the difference in the ball's loading state, which is the actual reason for reducing the friction torque fluctuation. Moreover, as the working temperature increases, the friction torque fluctuation of CMGB decreases. [ABSTRACT FROM AUTHOR]

The transition point of the crack length to a microstructurally small crack is necessary for predicting crack extension behavior. The conventional criterion is the crack length smaller than the grain size and is a probabilistic criterion. This criterion does not consider the metal's crystallite plasticity property discrepancy (CPPD). However, CPPD determines crack extension behavior for recently developed advanced materials with complex microstructures. Therefore, the authors propose a deterministic judgment method for microstructurally small cracks considering crystallite plasticity based on a physics‐based crystal plasticity finite element model with strain localization. The proposed method is based on the difference value of the crack tip opening displacement varying with the ratio between the crack length and grain size with the change in the grain orientation ahead of the crack tip. A case study for copper is performed, and the results show that the novel method can be applied to define the microstructurally small crack. [ABSTRACT FROM AUTHOR]

Our previous study demonstrated that, in a cracked single‐crystal subjected to remote tensile stress, the interactions among material behavior, strain localization, mechanical behavior, and strain concentration caused the formation of a strain field was quite different from the HRR singularity introduced in the homogeneous continuum. Moreover, to quantify strain localization ability for metals, a material index for strain localization susceptibility (SLS) was proposed. However, the effectiveness and availability of that index were not examined in detail. In this study, a Cu‐based single crystal was examined using the crystal‐plasticity finite element method (CPFEM) model. This model incorporates the strain localization mechanism from the non‐crystallographic shear band. Additionally, a new material index for SLS was introduced. The results showed that the new material index could reflect the SLS of the material. Meanwhile, a critical material index value based on strain localization was determined for predicting the crack behavior. This study also discusses the plastic deformation behavior near the crack tip with different material indices for SLS. Highlights: Crystal plasticity finite element model for crack with strain localization.A new material index for strain localization susceptibility.Deformation behavior near the crack tip for material with different strain localization susceptibility. [ABSTRACT FROM AUTHOR]

Well-dispersed silica-coated FeCo nanocubes are mass prepared using the polyol process and are then amine-functionalized with 1,6-diaminohexane. Further, the almost "matrix-free" soft magnetic nanocomposites (SMNCs) are fabricated using the FeCo nanocubes as bricks, which are cross-linked by epoxy monomers in which the nanoparticles are well separated. These SMNCs exhibit a dense microstructure and extremely high resistivity that limit the eddy current loss, thereby allowing excellent high-frequency inductance performance in a few hundred megahertz and extending the cutoff frequency to 2–7 GHz. The permeability is approximately 8.0 with excellent high-frequency stability at 1 GHz. The quality factor of the nanocomposites exceeds 200 in the 100 MHz range and 500 in the few megahertz range that corresponds to the 36 and 13 nm silica-coating samples, respectively. Furthermore, they exhibit a novel microwave absorbing property with an extremely thin thickness. The absorption approaches − 46.5 dB at 2.41 GHz with only a 1.75 mm nanocomposite absorbing layer. This SMNC presents great potential as multifunction components to satisfy the urgent requirement of wide bandgap semiconductor power in the megahertz range and microwave devices in the gigahertz range. [ABSTRACT FROM AUTHOR]

The appearance of strain localization (SL) in front of the crack tip is a factor that promotes transition toward the fatigue crack extension mode. Therefore, to predict fatigue crack extension behavior in case multiple modes occur, it is necessary to evaluate the degree of SL. In this study, the following simulations were performed on a single‐crystal twinning‐induced plasticity (TWIP) steel: (a) SL characterization by crystal plasticity finite element method (CPFEM) analysis of a smooth specimen under tension, (b) strain concentration (SC) characterization by EP‐FEM analysis of a cracked specimen under tension, and (c) characterization of interaction results between SC and SL of a cracked specimen under tension by CPFEM analysis. A comparison of the above results found that the interaction between SC and SL was large for long cracks and a significant strain field, different from the Hutchinson, Rice, Rosengren (HRR) singular field, was formed in front of the crack tip. Therefore, a parameter was proposed to quantify the SL properties in a smooth specimen. Subsequently, a fracture‐mechanics‐like method was proposed in which the results of (b) and the introduced parameters control the results of (c). Highlights: Crystal plasticity finite element model for crack with strain localization.Comparison between crystal plasticity and traditional finite element method.Strain localization affects the strain distribution around the crack tip.Strain localization changes the singularity at the crack tip. [ABSTRACT FROM AUTHOR]

Fe-based soft magnetic composites (SMCs) co-coated with Bi2O3 and silane, used as the low melting point binder and the insulating layer, respectively, were successfully prepared. The SMCs show improved mechanical strength, thermal stability, and insulation compared to other soft magnetic composite materials. The obtained SMCs exhibit a high Bm of 1.2607 T at 5000 A/m, 50 Hz, a high μmax of 497, and a low Pcm of 81.8 W/kg at 50 kHz and 50 mT for a completely homogeneous thin insulating coating. In addition, the transverse rupture strength of such materials is up to 81.2 MPa, which is extremely important for high-speed motors. Furthermore, the permeability and magnetic loss are stable under stress. Nonlinear curve fitting was used to build the loss model and then separated into the hysteresis loss, the eddy current loss, and the excess loss. The loss mechanism of SMCs with different coatings and micro-stress was explored and verified via this model. When compared to traditional SMCs, this material coated with Bi2O3 and silane shows a lower loss and a higher transverse rupture strength. This research expands the application fields of iron-based SMCs, especially in practical applications of soft magnetic components in high-speed motors. [ABSTRACT FROM AUTHOR]

Introduction: The impact of furry animal allergens on house dust mite (HDM)-induced allergic rhinitis (AR) is unclear. Objective: We aimed to investigate the co-sensitization and cross-sensitization of furry animal allergens and assess their clinical relevance with HDM-induced AR. Methods: We enrolled 268 patients with HDM-induced AR who were diagnosed with skin prick tests positive for dogs and/or cats. Specific immunoglobulin E (sIgE) for dogs (e1) and cats (e2), their components (Can f 1–5 and Fel d 1–2), and other uncommon furry animal extracts were measured. Symptoms and quality of life were assessed with a visual analog scale (VAS). Results: The VAS scores for the AR and asthma (AS; n = 166), moderate-to-severe persistent-AR (n = 132), and e1P (positive)-e2P (n = 89) groups were higher than those for single AR (n = 102), other AR classifications, and other AR sensitization profiles, respectively. The IgE positivity rates for components such as Can f 1–3 and Fel d 2 and those for rats, sheep, mice, cows, and horses were highest in e1P-e2P patients. Can f 1–4, Fel d 1, Fel d 2, or the combined allergens were positively correlated with VAS scores. AR combined with AS and sensitization to Can f 4, Fel d 1, or mice were risk factors for HDM-induced AR with VAS scores ≥5. Conclusions: Extensive cross-sensitization or co-sensitization was found between Can f 1–3, Fel d 2, or rat, sheep, mouse, cow, and horse extracts. Higher sIgE levels for Can f 1–4 and Fel d 1–2 or a higher number of furry animal allergens lead to more severe symptoms and a reduced quality of life. Combined with AS, sensitization to Can f 4, Fel d 1, or mice were risk factors for moderate-to-severe HDM-induced AR. [ABSTRACT FROM AUTHOR]