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Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Considering the real stress and deformation state of impeller during the operation of centrifugal pump, the fluid-structure coupling numerical simulation of impeller of centrifugal pump model was carried out based on the software platform of Ansys Workbench and the computational fluid dynamics analysis software CFX. The strength of impeller of centrifugal pump under the combined action of centrifugal force and CFD pressure load was calculated. The position of the maximum stress on the impeller under the action of cyclic alternating stress during rotation is determined. Finally, nCode Designlife software was used to predict the fatigue life of the impeller. The results show that the maximum stress is located at the interface between the blade outlet edge and the cover plate, and the cyclic cyclic stress is the main cause of the fatigue damage of the impeller. The impeller meets the design of infinite life fatigue strength, and the impeller has no risk of fatigue failure. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the evolution law of precursor information of water and mud breakout on faults by taking the construction of drainage roadway through the fracture zone of Julong copper mine in Tibet as the engineering background. Method: Through numerical simulation, we investigated the changing rules of displacement, stress, plastic zone, and seepage field of surrounding rock during the construction of drainage roadway to the crushed zone under the effect of fluid-solid coupling, and analyzed the evolution law of premonitory information of water and mud breakout in the roadway through the crushed zone of the fault. Result: The results show that when the roadway is excavated to the fracture zone, the displacement of the palm face increases abruptly. At the same time, stress disturbance occurs in the fracture zone. The plastic zone of the surrounding rock expands in the direction of the crushing zone, and the rock body in the crushing zone undergoes plastic deformation, which is connected with the plastic zone of the palm face. When the roadway is excavated to the crushing zone, the seepage field in the surrounding rock changes obviously, the exposed crushing zone forms a drainage outlet, the water pressure of the surrounding rock decreases suddenly, and the roadway is prone to sudden water and mud accidents. Significance: The results of this paper provide a theoretical reference for the construction of Julong drainage road through the crushed zone. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ureteral pain caused by kidney stones has long tormented humans and seriously affected their quality of life. However, currently, in clinical practice, due to the lack of quantitative analysis of the interaction between kidney stones and ureters, urologists are unable to develop precise personalized treatment and pain relief plans for different patients. In response to this issue, small-sized kidney stones were taken as an example and to analyze the interaction behavior between small-sized kidney stones entering the ureteral lumen and the ureter with a fluid-structure coupling finite element method based on the coupled Eulerian-Lagrangian (CEL) algorithm. With the established ureteral pain model, the ureteral pain caused by small-sized kidney stones was quantitatively studied. The finite element analysis results indicate that, when the stone diameter is smaller than the inner diameter of the ureter, the stone will dynamically contact the ureter under peristalsis of the ureter wall, causing dynamic stress on the inner wall of the ureter. The stone moving speed will increase with the peristaltic amplitude of the ureteral wall, but the contacting probability between the stone and the ureter will decrease, and the contacting stress on the ureteral wall will decrease as well. The stress results were input into the ureteral pain model to calculate the corresponding central transmission neuron cell membrane potential. The model results show that, the change in the pain level over time was similar to the trend of dynamic stresses over time. In the case of alternating stress changes, the pain level would not decrease below the pain threshold as the stress drops to 0, showing inconformity between the pain level and the stress level. The results can be combined with existing medical imaging technologies in clinical practices, as well as big data and artificial intelligence technologies in the field of computer science. The research provides a theoretical basis for personalized and accurate diagnosis of the condition of stone patients, quantitative evaluation of patient pain levels, and the development of personalized treatment plans for precise medical clinical strategies. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The cutting force suffered by the machine tool in the cutting process can be assumed to be the combined force of the steady state force and the dynamic disturbing force.In order to investigate the dynamic characteristics of electric spindle system supported by gas bearings,sine wave was used as dynamic disturbance loading form,and the dynamic characteristics of a simplified model of a gas bearing rotor system were studied by combining the harmonic excitation method with the bidirectional fluid-structure coupling numerical simulation. The dynamic stiffness and damping coefficients were identified. Through modal analysis,the system vibration modes and natural frequencies of the rotor under different steady-state forces were obtained. The results show that with the increase of steady-state force,the growth rate of Kyy of the lower radial bearing is greater than that of Kxx,while the cross stiffness and cross damping are almost unchanged.The main stiffness of the lower radial bearing is greater than the cross stiffness,and the main damping is greater than the cross damping. When the steady-state force ranges from 50 N to 200 N,the y-shift at the lower end of the rotor first increases and then decreases with the increase of dynamic disturbance frequency. The resonance frequency of the system increases with the increase of the steady-state force. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wind turbine blade pitch fault is easy to cause unstable ultra-high load, which can lead to structural failure and damage. Firstly, the aerodynamic characteristics of NREL 5 MW wind turbine blades with pitch fault/success were analyzed based on the computational fluid dynamics method. Then, the two-way strong fluid-structure coupling and bending analysis were used to study the state of blades with pitch fault under typical azimuths. The results show that average flapwise torque of the blade with pitch fault under the cut-out wind speed is 13. 8 times that of the blade with successful pitch, and the flow field wake of the former is more obvious. The fluctuation range of blade flapwise torque under two-way strong fluid-structure coupling is significantly wider than that without fluid-structure coupling, and the maximum tip displacement of the blade with pitch fault is 14. 1 times that of the blade with successful pitch. For the four typical azimuth angles of 0°, 60°, 120°, and 180°, the bending moment, tip displacement, bending degree, end effect, wake range and strength of the blade with pitch fault gradually decrease with the increase of the angle. Buckling analysis reveals that the buckling factor increases with the enlargement of azimuth angle, and the first-order buckling factor of 180°azimuth is 20.2% higher than that of 0° azimuth.

The marine net cage is an essential facility and equipment for deep-water aquaculture in China, and its hydrodynamic characteristics are directly related to its operational stability. This paper established a finite element model for a marine net cage with three-layer and employed a fluid-structure interaction method to simulate the hydrodynamic characteristics of the net cage under the frontal flow conditions of a level 17 typhoon. Furthermore, a comparative analysis of the variation patterns in the hydrodynamic characteristics of the net cage with and without a netting structure was conducted. The results showed that under the frontal flow of the typhoon, the main areas of stress concentration in the net cage were the lateral support points of the bait chamber, the upmost walkway board connecting pipes on the windward side, and the cross-points of the mid-level load-bearing structure. When the net cage was equipped with a netting structure, the pendulum distance decreased, but the yawing motion intensified. In other words, the netting structure contributed to the vertical stability of the net cage but increased its yawing motion intensity. With the inclusion of the netting structure, due to the improved vertical stability of the frame, the maximum stress at the lateral support points of the bait chamber, the upmost walkway board connecting pipes on the windward side, decreased by 5.1% and 3.2% respectively, while the maximum stress at the cross-points of the mid-level load-bearing structure exhibited little change. However, the maximum stress on the windward side of the mid-lower level connecting pipes decreased by 8.7%.

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The classical groundwater seepage theory was established on the basis of the principle of water equilibrium, which cannot explain the phenomenon of well water level change caused by natural seismic activities and other external loads, and is not conducive to the in-depth understanding of the role of groundwater seepage movement in various environmental geological disasters. To solve this problem, a mathematical model of pore pressure change of a confined aquifer driven by seismic wave stress is constructed based on the fluid-structure coupling dynamic theory. The numerical verification of the model is realized by using the software Comsol. The change characteristics of well water level are inversely performed by using the Cooper theory, and the results are compared with the change characteristics of well water level caused by strong earthquakes in the Sichian-Yunnan region. The influencing factors of seepage movement of a confined aquifer under earthquake are studied by changing the simulation parameters. The results show that when seismic wave loads act on the confined aquifers, pore pressure oscillates in the same period as the seismic waves, and the amplitude, frequency and hydraulic slope of the seismic waves have significant effects on the pore pressure, while the coefficient of permeability and porosity have little effect on the change characteristics. At the initial stage of seismic wave loading, pore pressure increases rapidly, and then part of the water in the aquifer is slowly discharged. The load pressure gradually transfers to the granular framework, and the rate of change of pore pressure slows down and tends to reach a new equilibrium. The variation characteristics of well water level are closely related to pore pressure, and the oscillation period and variation pattern are consistent with pore pressure, but the amplitude is different. Generally, the oscillation rises and tends to be stable, which is basically the same with the variation pattern of well water level observed in the Sichuan-Yunnan region. The results are of valuable exploration significance for the establishment and improvement of groundwater seepage theory under stress, and can enrich and expand the research ideas and application fields of traditional groundwater dynamics and classical fluid-structure coupling theory.

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of East China University of Science & Technology is the property of Journal of East China University of Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The flutter of the linear compressor valve plate is the main factor that affects the working life and performance of the compressor. Because the flutter of the valve plate will aggravate the fatigue failure of the valve plate and affect the stability of the mass flow through the valve plate. In order to study this problem, this paper uses a three-dimensional fluid-structure interaction (FSI) model to simulate the opening and closing process of the exhaust valve of a linear compressor. This method can effectively predict valve plate flutter and valve plate reflux. Based on the FSI model, the influence of compressor working pressure ratio and piston operating frequency on valve flap vibration period and valve flap return was studied. According to the simulation results, an empirical correlation between the predicted valve plate flutter period and the piston operating frequency is obtained. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the wind turbine data provided by the American National Renewable Energy Laboratory (NREL), the manuscript was used ProE to establish a 5 MW offshore semi-submersible wind turbine model. A two-way fluid-structure coupling simulation through simulation software was conducted. The research was based on the deformation and equivalent stress of the two-way fluid-structure coupling semi-submersible wind turbine blade during the coupling action. The shutdown state of the wind turbine and the operation of the wind turbine under different wind and wave conditions were analyzed. The analysis shows that the blade is the most important part of the wind turbine. As the speed of impeller increases, the deformation increases, and the peak value shifts to the left. The maximum equivalent stress of the wind wheel appears in the initial stage of operation. As time goes by, the stress finally stabilizes within a certain range. The degree of deformation of the blade increases with the increase of wind speed. During the operation of the wind turbine, the mooring line moves periodically with the float foundation. This research provides a reference for the safe and stable operation of offshore semi-submersible wind turbines, and at the same time provides a reference for the design of offshore semi-submersible wind turbines.

The Daguangbao landslide is the largest co-seismic landslide with a volume of approximately 12×108 m3, which triggered by the Wenchuan earthquake (Ms 8.0) occurred on May 12, 2008. The slide zone is located in the Paleozoic carbonate strata and it is an interlayer structural dislocation zone with a depth of 400 m and a maximum thickness of 5 m inside the slope. A previous study concluded that the shear failure of the Daguangbao landslide developed within the bedding fault. Our latest investigation showed that this bedding fault was under the water table, and its rock mass was saturated before the landslide. To reveal the initiation mechanism of the Daguangbao landslide related to the groundwater, a simplified model of a hard carbonate slope with an inter-weak layer is given. The response characteristics of the model are stimulated by a fluid-structure coupling algorithm using the FLAC3D. The results show that significant differences in deformation patterns during the earthquake, such as response time, wave shape, and amplitude exist between the upper and lower hard layers. Three uncoordinated deformation patterns, i.e., tension, compress, and shearing coming from the upper layer to the weak layer, are identified. The deformation pattern results in the amplification of compress and shear forces within the weak layer. The stress amplification subsequently induces excess pore water pressure with instant amplification and accumulation features. It is reasonably inferred that the excess pore water pressure essentially reduces the effective stress of the bedding fault. Our simulation confirms that the excess pore-water pressure can be generated within a saturated bedding fault deep situated in a slope during a strong earthquake. We propose that the excess pore water pressure within the saturated fault at 400 m underground is the cause of the Daguangbao landslide.

In the construction of water-rich tunnels, the curtain grouting method is often used to reinforce the surrounding rock for water blocking. Therefore, the displacement and stress fields of the surrounding rock of the tunnel after being reinforced by the curtain grouting method for a deep buried tunnel with rich water should be accurately described. Based on the theory of fluid-solid coupling, a mechanical model of the tunnel curtain grouting is established, and the displacement and effective stress of the surrounding rock are deduced. Then, with a deep-buried tunnel on the Dali-Ruili Railway as the engineering background, six reinforcement schemes are calculated using the established mechanical model, and the influence of the shear modulus and elastic coefficient of the surrounding rock on the field change of displacement and stress are discussed. The accuracy of the mechanical model is verified by comparing with the results of numerical simulation and field monitoring. The research results show that the mechanical model can be used to calculate the displacement and effective stress of the surrounding rock of the tunnel constructed by the curtain grouting method; the larger shear modulus and elastic coefficient can restrain the displacement of the surrounding rock, but will increase the radial and circumferential directions of the surrounding rock effective stress. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The lubrication condition of angular contact ball bearings in operation is crucial，and the lubricant directly affects the contact state of rolling bearings. In order to analyze the lubrication condition of angular contact ball bearings and the mechanical characteristics of bearings considering lubrication，based on finite element method and Lattice-Boltzmann method， the bidirectional fluid-structure coupling simulation model of bearings is established. The dynamics finite element simulation and lubricating fluid simulation of angular contact ball bearings are carried out，and the results are compared with the calculation results of bearing quasi-static theory to verify the accuracy of the model. The results show that the cage is in contact with the ball and hits，the oil film pressure is the largest in the bearing cavity，and the contact areas of the ball with the inner ring and the outer ring raceway are the second and third largest oil film pressure areas respectively. The lubricating oil is affected by the revolution of the ball and flows along the direction of rotation of the ball to achieve lubrication between the ball and inner ring，outer ring and cage. The simulation results of ball motion and maximum contact stress are consistent with the solution results of bearing quasi-static theory，that is，the fluid-structure coupling simulation model has high accuracy in calculating the mechanical characteristics of bearings.

Diffuser is a key component of aero-engine compressor, which has an important impact on its performance, efficiency and operating conditions. In order to solve the problem of poor rigidity and easy deformation of insulating sleeve structure in the process of electrochemical trepanning, the optimization method of insulating sleeve rigidity is proposed, strengthening rib is designed at the free end of insulating sleeve, and the fluid structure coupling simulation comparative study under different strengthening rib shapes and sizes is carried out. When the two ends of strengthening rib are round, the width b = 2 mm and the distance from the bottom h = 6 mm, the maximum deformation is reduced by 88.3% compared with the structure without strengthening rib. The experimental research of electrolytic machining is carried out. The stable machining with cathode feed rate of 1.4 mm/min is realized, and the machining stability and efficiency are significantly improved. The effectiveness of the rigidity optimization method of insulating sleeve is verified. [ABSTRACT FROM AUTHOR]

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the natural vibration characteristics and vibration modes of different types of gates under the fluidstructure coupling effect with different openings, the plane escape gate and a radial gate in spillway tunnel are taken as the research objects, the finite element analysis software ANSYS is used to establish the modal and carry out modal analysis. The results show that due to the influence of additional mass, the natural frequencies of the plane gate and the radial gate decrease compared with the waterless condition and gradually increase with the gate opening process, but change oppositely with the modal order; the low-order frequencies of the radial gate are closer to the main frequency of the flow fluctuation resulting in high probability of resonance compared with that of the plane gate; the upper and lower structures of plane gate are easy to obviously vibrate while the lower structures and the arms of radial gate are easy to obviously vibrate. [ABSTRACT FROM AUTHOR]

The nonlinear dynamics of the drilling string system is studied, and the fluid-structure coupling dynamic equation of the drilling string system is established. With the Galerkin truncation method, a set of partial differential equations are diverted into ordinary differential equations. Numerical simulation is carried out by using the Runge-Kutta integration method and the effects of parameters such as pulsating frequency, pulsation amplitude and mass ratio on the dynamic characteristics of the drilling string system are investigated. The results show that there are various dynamic behaviors for the model in different parametric excitation such as periodic motion, quasiperiodic motion, chaotic motion and jump discontinuous phenomenon. Besides, the path from chaotic motion to periodic motion is in the form of period-doubling inverse bifurcation, and the support stiffness can cause a certain change in the inherent characteristics of the system, which has a complex impact on the nonlinear dynamic behavior of the system. [ABSTRACT FROM AUTHOR]

Aiming at analyzing the influence of thermal load and mechanical load on the vibration characteristics and fatigue life of the exhaust system,the finite element model and modal test were conducted by modal analysis. The temperature field distribution of the exhaust system was obtained via CFD analysis. Finally,a frequency-domain called Dirlik was applied to analyze the vibration thermal fatigue life of this exhaust system. The results show that the structural modal frequency decreases under the temperature field distribution,and the fatigue life of the exhaust system considering temperature field distribution is 90. 8% lower than that not considering temperature distribution. Therefore,the temperature field distribution has significant effects on the fatigue life of the exhaust system,and it can’t be ignored during the development process.

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objectives] To study the coating effects on structures subjected to near-field underwater explosion, [Methods] the coupling Runge-Kutta Discontinuous Galerkin Method, Boundary Element Method and Finite Element Method are developed in this paper to solve a rubber coating circular plate subjected to near-field underwater explosion. The results are compared with experimentally obtained wet face pressure and bubble shape to verify the method, and the explosion bubble response to the flexible boundary is discussed. [Results] The results indicate that the rubber coating plate will shorten the pulse width of the shockwave, but the cavitation collapse will occur more easily. In addition, solid rubber coating has little effect on the deformation of the explosion bubble. [Conclusions] This research can provide a theoretical basis and technical support for the coating design and optimization of warships subjected to near-field underwater explosion.

Assisted airflow can cause the deformation of canopy leaf for the wide transport channel of droplets in the air-assisted spray. The uniformity of droplet deposition can be enhanced in the crop canopy. In this study, a mathematical model of cotton leaf deformation was established under the action of assisted airflow using fluid-structure coupling and parameter identification. Firstly, the petiole and leaf surface samples of cotton were collected to obtain the size parameters. A three-point bending was selected to calculate the elastic modulus of petiole and leaf surface. The moisture content of the petiole and leaf surface was measured during drying at 105 ℃. The results showed that the median elastic modulus of leaf surface was 46.5 MPa, where 95% confidence interval was [28.5, 64.5] MPa, whereas the median elastic modulus of petiole was 244.6 MPa, where 95% confidence interval was [215.5, 273.69] MPa, while the average moisture content of petiole was 87.2%, where 95% confidence interval was [82.5%, 91.9%], and the average moisture content of leaf surface was 80.7%, where 95% confidence interval was [72.3%, 89.1%]. Then, a bidirectional fluid-structure coupling model was established to characterize the deformation process of cotton leaf. The deflection data were obtained in four monitoring points, including the middle and end of the petiole, as well as the center and tip of leaf surface. A high-speed camera was used to carry out the deformation test of cotton leaf with assisted airflow. The deflection test data of monitoring points were captured to verify the coupling model with the maximum simulation error of 9.9%. Furthermore, an orthogonal test was performed on experimental factors, including the assisted airflow speed, leaf inclination angle, elastic moduli of petiole and leaf. A significant order of experimental factors was obtained: wind speed, elastic modulus, leaf inclination angle. Finally, a mathematical model of cotton leaf deformation was constructed using the nonlinear least square. A trust-region iterative was used to obtain the identification parameters. A systematic evaluation was made on the performance of the mathematical model for cotton leaf deformation. The mean absolute percentage error (MAPE) of petiole deflection was 5.13%, and the MAPE of main vein deflection was 10.43%. It was found that the bending deformation of cotton leaf mainly occurred at the junction of petiole and leaf surface in the assisted airflow, where the leaf surface basically kept flat with the relatively small curvature. A quantitative analysis was made to obtain the initial parameters of blade inclination and dynamic variation in the frontal area of cotton leaf at different airflow speeds. The frontal area of cotton leaf decreased monotonously with the increase of airflow speed, when the inclination angles of cotton leaf were 0° and 10°. At the inclination angles of 20° and 30°, the frontal area of cotton leaf increased first and then decreased as the airflow speed increased. It infers that the canopy density can increase under the inappropriate assisted airflow. This finding can provide a sound reference to understanding the dynamic changes of cotton canopy density, further optimizing spraying parameters in the air-assisted spray [ABSTRACT FROM AUTHOR]

Copyright of Wool Textile Journal is the property of National Wool Textile Science & Technology Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the 2D fluid-structure coupling theory, the wind-induced vibration responses of transmission lines across 2 close hills were calculated. Both the load on the wire by the mountain wind and the surface wind pressure change caused by wire vibration with its influence on the flow field were considered. Firstly, the correctness of the method was verified in comparison with the existing literature results. Then, the numerical wind tunnel model for the transmission line across 2 close hills was established. The average wind speed characteristics of the canyon and mountain pass topography as well as the distribution characteristics of the corresponding wind pressure were analyzed. The distributions of aerodynamic coefficients and vertical displacements were analyzed. The numerical results show that, in the transient wind field, the acceleration effect of the mountain pass is more significant than that of the canyon, and the acceleration ratio at the middle of the line is more important. The distribution of wind pressure around the wire is also inconsistent due to the influence of different topographic wind fields. Under the canyon topography, the distribution of wind pressure around the wire is stable with time. Under the mountain pass topography, the wind pressure around the wire fluctuates with time. The smaller the distance between the 2 hills is, the greater the variation range of the resistance coefficient time history curve will be, so is the change of wind pressure. The updraft under the mountain pass topography makes the wire subject to greater lifting force and vertical wind deviation. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The radial structural support made of epoxy FRP（ fiber reinforced plastic） of LNG fuel tank bears considerable compressive stress under impact load. However,it is hard to bear out of plane tensile stress and interlaminar shear stress. Thus,reasonable installation angle of pipes effectively guarantees the support ability of the epoxy FRP pipes. Based on it,the commercial finite element codes ANSYS with the method of fluid-structure coupling was used to stimulate the force condition of the epoxy FRP pipes,the correlation between the force of epoxy FRP pipes and installation angle of pipes was obtained. According to strength check of shear stress,radical tensile stress and the failure theory of Hoffman,the optimal installation angle of upper pipes was 30° and 60° of below the pipes. This study had an important reference value for safe operation of LNG fuel tank.

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking a centralized drive electric vehicle power train as study object,considering the influence of coolant and lubricating oil,the fluid- structure model is established. The modal and vibration response of the model is researched. First,the fluid- structure model is proved to be correct by comparing its simulation result with the experimental result. Then,other two kinds of fluid- structure model,each one of which involved one kind of fluid,are established. The different influence degree of these two kinds of fluid on the model natural frequency is analyzed through modal simulation. At last,the power train vibration response under electromagnetic excitation is obtained by simulation,and it is compared with the result of the original model. The result indicates,that various dynamics phenomenon are showed by the model which considering the fluid- structure model with coolant,lubricating oil and mechanical components and the foundation for the subsequent optimization design is provided.

The multiple scattering of sound waves and the fluid-structure interaction should be taken into account to calculate the acoustic scattering of underwater elastic corner reflectors. The scattering acoustic field of underwater elastic corner reflectors in far field is simulated by using structure finite element method(FEM)/fluid indirect coupled boundary element method(IBEM). The influences of plate material and thickness, incident angle and the type of corner reflector on target strength and the scattering mechanism are analyzed when the incident wave frequency varies from 5.0 k Hz to 20.0 kHz. The results show that the scattering acoustic field of underwater elastic corner reflectors has a strong frequency characteristic. It varies with plate material and thickness, and incident wave frequency. The multiple scattering of sound waves has important contributions to the backscattering acoustic field of corner reflectors. The simulated results are in good agreement with the experimental results. The structure design and optimization method of corner reflectors are presented. [ABSTRACT FROM AUTHOR]

It is difficult to conduct the ground separation test of large-scale rocket fairings under vacuum condition. To predict the fairing separation during extra-atmospheric flight, the established finite element (FE) model should be corrected by using the ground separation test data. The ground separation test of a large-scale flexible fairing is simulated by the coupled Eulerian-Lagrangian method. The motion characteristics and breathing deformation data of fairing separating under air resistance are obtained and agree well with the test data, which verifies the correctness of the model and the method. The separation of rocket fairing during extra-atmosphere flight is simulated with the same FE model, and the effects of air resistance and axial overload on fairing separation and deformation characteristics are analyzed. The results show that the air resistance attenuates the velocity and breathing vibration frequency of rocket fairing, but increases the amplitude of the breathing motion; the amplitude of breathing motion increases with the increasing in axial overload, meanwhile, the breathing motion of fairing is related to the first-order vibration mode. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)