Publications

Hydraulic synchronous motors are widely used in synchronous control of the hydraulic system,and the control precision is much higher than any other timing modes.The structural classifications and features of hydraulic synchronous motors were introduced.Taking the 12 flow synchronous motors in hydraulic system of cold frame of strand caster in a certain corporation as an example,the function implement of hydraulic synchronous motors was introduced,the main factors influencing the synchronization accuracy of the hydraulic synchronous motors were discussed,and corresponding solutions were proposed.

The Grey relationship degree of NEPE solid propellant sensitivities was calculated by numerical method,including impact sensitivities,friction sensitivities,flame sensitivities and other sensitivities from composing and granularities.The results indict that plasticization ratio is the main influence factors of friction sensitiity and regional thermal sensitiity.The contants of HMX is the main influence factors of Shock sensitivity and 5 s explosion temperature,S is the main influence factors of impact sensitivity electrostatic spark sensitivity and flame sensitivity.Granularities result indict that particle size of Al is the main influence factors of friction sensitiity,5 s explosion temperature and flame sensitivity.The particle size of AP is the main influence factors of regional thermal sensitiity and electrostatic spark sensitivity,particle size of HMX is the main influence factors of impact sensitivity.

A novel resonance sound absorber, whose resonant frequency characteristic can be varied by turning the external magnetic field, is constructed based on micro-perforated magnetorheological elastomer (MP-MRE). The influence of parameters, such as porosity, thickness, curing agent weight ratio and magnetic field intensity, are investigated to analyze the magneto-acoustic coupling property of MP-MRE sound absorber. By increasing the magnetic flux density, the resonant frequency of resonance sound absorber moves toward high frequency region. It is found the magnetic field-induced deformation of the MP-MRE and its pores affected the resonant frequency. When the magnetic flux density was increased from 0 to 132 mT, the maximum variation of the resonant frequency reached 304 Hz. Finally, originated from this unique magnetic controllability, the MP-MRE sound absorber shows broad potential in the tunable sound absorber at middle and low frequency range.

<p>The key fatigue failure modes of rib-to-deck welded joints in orthotropic steel bridge deck (OSD) are fatigue cracks that initiate from toe and root and propagate toward the deck plate. To enhance the fatigue durability of rib-to-deck welded joints, an innovative rib-to-deck joint in OSD with both- side fillet welded joints was proposed. Fatigue performance of the proposed detail was evaluated by the effective notch stress approach, which was compared with the fatigue performance of conventional single-side welding with partial penetration weld detail. The stress range of different penetration rates of both-side fillet welded joints was discussed by finite-element method. The analytical results indicate that both-side fillet welded joints can reduce the maximum effective notch stress amplitude of the weld root and improve the fatigue resistance of rib-to-deck welded joints significantly. Compared with single-side welded joints initiating from weld root, the dominant fatigue failure mode of both-side welded joints is the crack initiating from the weld toe and propagating to deck plate. The results of parametric study indicate the fatigue resistance of novel rib-to-deck welded joints was not distinctly improved by increasing weld penetration ratio.</p>

Abstract In offshore drilling operations, most water-base mud (WBM) and synthetic-based mud (SBM)-associated cuttings are discharged to the seabed whenever feasible. Although SBM is less toxic and biodegrade in marine sediments faster than oil-base mud, discharge of SBM associated with cuttings is still an environmental concern. It is highly desirable to know where the drill cuttings go during and after offshore well drilling. This paper presents an analytical method to predict the transport and settling of drill cuttings in seawater. Starting from Newton’s second law of motion, a mathematical model has been developed in this study to predict the transport and settling of drill cuttings in seawater. It can forecast the location, configuration, and characteristics of cuttings piles in flowing seawater. Factors affecting the cuttings transport include water depth, current velocity, cuttings properties (size distribution, density, and sphericity), and water properties (density and viscosity). This mathematical model has been computerized. It provides a useful tool for predicting the characteristics of cuttings piles that can be used for evaluating the potential impact of drill cuttings on subsea environment.

This paper proposes a data-driven damage detection method based on fixed moving principal component analysis (FMPCA) to analyze structural dynamic responses and monitor the bridge operational condition and the damage occurrence. The damage indices based on principal components (PCs) and eigenvalues can be calculated continuously by applying a fixed moving window. The length of the moving window is determined by using a new criterion based on the convergent spectrum of cumulative contribution ratio. Numerical simulations and experimental tests in the laboratory on beam bridge models subjected to stochastic loads are conducted to investigate the accuracy and effectiveness of the proposed approach. Both simulation and experimental results indicate that using the FMPCA can well analyze the dynamic vibration data to detect damage or abnormal vibration behavior during the operational condition. It can be used to accurately monitor the time instant of damage occurrence, which is very important in long-term monitoring of civil engineering structures. The proposed method is successfully applied to analyze the data recorded during an incident that a real large-scale suspension bridge was slightly scraped by the mast of a sand ship, which further verifies the effectiveness and feasibility of this method in engineering applications. The results also indicate that the bridge was not damaged after the incident but presented a short time abnormal vibration behavior owing to the impact of the ship mast.

Mindfulness is a specific way to perceive,Live in the presentAnd don't judge. In recent dec-ades, mindfulness has become one of the hot issues in research. In the field of exercise psychology, applying its theory and therapy to the field of physical exercise can provide theoretical reference and new ideas for teenagers to relieve psychological pressure. This paper uses the methods of literature review and inductive analysis to study and analyze mindfulness in the field of physical exercise. Alt-hough the concept of mindfulness is still controversial, some studies have found that mindfulness practice can promote people's physical and mental health. By combing the research status of mind-fulness and physical exercise, this study comprehensively analyzes the mechanism and function of mindfulness in physical exercise and healthy behavior, and puts forward some suggestions for future research and practice on the basis of existing research.