Search

Objective Based on the virtual simulation fatigue test technology, fatigue life analysis and reliability evaluation of the bogie arm positioning node of a certain type of vehicle are carried out to improve the vehicle stability and guarantee the train operation safety. Method ABAQUS software is used to establish a finite element model of the arm positioning node and obtain the stress and strain data. FE-SAFE software is used to set the fatigue parameters of rubber material, simulate and analyze its fatigue life. Graph test method is used to test the distribution hypothesis of pseudo-failure fatigue life and to select the optimal life distribution. The relation between the life distribution parameters and the stress level is used to fit a proper functional relation and evaluate the reliability of the arm positioning node fatigue life under normal stress level. Result & Conclusion Under normal stress level, only the rubber bushing in arm positioning node will have fatigue damage. The bottom end of the rubber bushing is the area with the lowest pseudo-failure fatigue life value, and is also the area where the damage occurs first. On-site test and fatigue simulation results verify the accuracy of the finite element model of arm positioning node. The optimal normal life distribution is determined. Under normal stress level, the number of fatigue life cycles is about 210,000 when the reliability of the arm positioning node is 0.9.

The thermal runaway issue represents a long‐standing obstacle that retards large‐scale applications of lithium metal batteries. Various approaches to inhibit thermal runaway suffer from some intrinsic drawbacks, either being irreversible or delayed thermal protection. Herein, this work has explored thermo‐responsive lower critical solution temperature (LCST) ionic liquid‐based electrolytes, which provides reversible overheating protection for batteries with warning and shut‐down stages, well corresponding to an initial stage of thermal runaway process. The batteries could function stably below 70 °C as a working mode, while demonstrating a warning mode above 80 °C with a noticeable reduction in specific capacitance to delay temperature increase of batteries. In terms of 110 °C as a critically dangerous temperature, a shut‐down mode is designed to minimize the thermal energy releasing as the batteries are barely chargeable and dischargeable. Dynamically growing polymeric particles above LCST contributed to such an intelligent and mild control on specific capacitance. Larger size will occupy larger surfaces of electrodes and close more pores of separators, enabling a gradual suppressing of Li+ transfer and reactions. The present work demonstrated a scientific design of thermoresponsive LCST electrolytes with a superiorly precise and intelligent control of electrochemical performances to achieve self‐adapted overheating protections. [ABSTRACT FROM AUTHOR]

Magnetic responsive ionic liquid (MIL) demonstrated an advanced photomobility in confined narrow spaces through the doping of photoresponsive azobenzene by the interplay of supramolecular π–cations. Moreover, reversible physisorption/desorption of CO2 was achieved based on the photocontrolled solid–liquid transitions of the mixtures. Our approach opens opportunities to obtain multi-stimuli response through the coordinated supramolecular interplay of each responsive component. [ABSTRACT FROM AUTHOR]

Due to the advantages of parallel architecture and low power consumption, a field-programmable gate array (FPGA) is typically utilized as the hardware for convolutional neural network (CNN) accelerators. However, SRAM-based FPGA devices are extremely susceptible to single-event upsets (SEUs) induced by space radiation. In this paper, a fault tolerance analysis and fault injection experiments are applied to a CNN accelerator, and the overall results show that SEUs occurring in a control unit (CTRL) lead to the highest system error rate, which is over 70%. After that, a hybrid hardening strategy consisting of a finite state machine error-correcting circuit (FSM-ECC) and a triple modular redundancy automatic hardening technique (TMR-AHT) is proposed in this paper to achieve a tradeoff between radiation reliability and design overhead. Moreover, the proposed methodology has very small workload and good migration ability. Finally, by full exploiting the fault tolerance property of CNNs, a highly reliable CNN accelerator with the proposed hybrid hardening strategy is implemented with Xilinx Zynq-7035. When BER is 2 × 10−6, the proposed hybrid hardening strategy reduces the whole system error rate by 78.95% with the overhead of an extra 20.7% of look-up tables (LUTs) and 20.9% of flip-flops (FFs). [ABSTRACT FROM AUTHOR]

The air film pressure field (AFPF) of aerostatic thrust bearings significantly determines the working performance of the bearings, and the characteristics of AFPF are closely related to the bearing structure parameters. This study carried out the structure optimization of aerostatic thrust bearing based on the analysis of the AFPF characteristics. The influence law of the number, distribution and the outlet shape of the orifices, as well as the bearing diameter on the static performance of the bearing was investigated. The relationship between bearing structural parameters, AFPF characteristics and bearing static performance was established and effectively used for the structure optimization of aerostatic thrust bearing. The simulation results were verified by the experiment. The results show that the static performance analysis of the aerostatic thrust bearing based on the AFPF characteristics can effectively provide a theoretical basis for the design and optimization of the bearing structure, and improve the bearing performance. [ABSTRACT FROM AUTHOR]

The real-time in situ detection and quantitative analysis of atmospheric methane have always been challenging work. In this study, a promising detection-analysis system and a calibration method for methane quantitative detection in the atmosphere were developed using laser-induced breakdown spectroscopy (LIBS) and a multidimensional entropy weight empirical based on the spectral competition equation (MEWE-SC equation), which is proposed for the first time. Static methane under normal air conditions was detected with carbon and hydrogen in the spectrum being contrastively analyzed. Then, the dynamic methane spectrum was detected by controlling the gradient change in methane concentration. The dynamic methane spectrum illustrated the change law of line C I and CN band. Afterwards, the Lomakin–Scheibe empirical equation was adopted to build the quantitative model. Having considered the C I and CN line competitions, a multidimensional entropy weight empirical based on the spectral competition equation was developed, realizing the high accuracy of quantitative fitness. The innovative method derived from LIBS and line competition theory is fast and in situ, showing far-reaching application prospects in the real-time quantitative detection of methane and some other gases containing carbon. [ABSTRACT FROM AUTHOR]