Numerical simulation on response characteristics of coal ignition under the disturbance of fluctuating heat

2022 ◽  
Vol 237 ◽  
pp. 111870
Author(s):  
Xueqiang Shi ◽  
Yutao Zhang ◽  
Xiaokun Chen ◽  
Yuanbo Zhang ◽  
Liu Rui ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Response Characteristics

scholarly journals Numerical Simulation of Transient Electromagnetic Response of Unfavorable Geological Body in Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 37-40 ◽  
Author(s):  
Lu Bo Meng ◽  
Tian Bin Li ◽  
Zheng Duan
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Electromagnetic Field ◽  
Electromagnetic Response ◽  
Detection Distance ◽  
Geological Body ◽  
Response Characteristics ◽  
Finite Element Software ◽  
Transient Electromagnetic ◽  
Field Decay

To investigate the transient electromagnetic method of response characteristics in the tunnel geological prediction, the finite element numerical simulation of unfavorable geological body of different location, different resistivity sizes, different shapes, and different volume size were carried out by ANSYS finite element software. The results show that secondary electromagnetic field of different location of unfavorable geological body have same decay rate, when detection distance from 30m to 70m, transient electromagnetic responses are strongest, followed distance from 10m to 30m and from 70m to 90m. The shape, volume and resistivity of unfavorable geological body have strong influence on transient electromagnetic response, unfavorable geological body more sleek, the greater the volume and the smaller the resistivity of unfavorable geological body, the secondary electromagnetic field decay slower.

scholarly journals Study on Mechanical Properties of Submunition’s Ribbon Straightening Section

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Dong-ze Qin ◽  
Wei Zhang ◽  
Shu-Yun Zhang ◽  
Tian-Ji Guo ◽  
Shui-Yuan Pei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Force ◽  
Physical Structure ◽  
Simulation Software ◽  
Tension Test ◽  
Response Characteristics ◽  
Experimental Scheme ◽  
Drop Velocity ◽  
Simulation Results

The humanitarian damage caused by the unexploded submunitions is one of the hot issues of concern to the international community at present. A portion of the submunition that did not explode was caused by a break at the connection between the ribbon riveting and the fuze. According to the physical structure of the submunition and the trajectory into which it was ejected, we analyzed the forces of the submunition in flight, deduced the related mathematical models, and clarify the key elements of the mechanics. In this paper, the commercial simulation software was used to calculate the mechanical properties of the ribbon. And the variation regularity between drop velocity and straightening force of ribbon are revealed. And the response characteristics of different material ribbon with different sizes of riveting holes and riveting joints under tensile action were simulated. The simulation results show that, in the trajectory environment with 30 m/s~55 m/s typical stream speed, the tensile force of the ribbon is less than 300 N, and the application concentration of the connecting parts of the riveting joint and the ribbon will not cause the failure of the kevlar ribbon, but it will cause the failure of the nylon ribbon. In order to verify the variation of the tension of kevlar ribbons in different trajectory environments, we designed the experimental scheme of tension test of the ribbon straightening section of submunition and conducted experiments. Experimental results and numerical simulation results revealed the same law. This paper provides effective technical support for solving the problem of unexploded submunitions.

Methods and Prospects of Seismic Research on Subway Structures

2014 ◽  
Vol 638-640 ◽  
pp. 1961-1966
Author(s):  
Deng Zhou Quan ◽  
Yan Dai ◽  
Hong Jie Guan
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Seismic Design ◽  
Research Method ◽  
Space Exploration ◽  
Rapid Development ◽  
Underground Space ◽  
Development History ◽  
Response Characteristics ◽  
History Of

With the rapid development of underground space exploration in Chinese cities, the construction scale of underground subway structures expands continuously. This thesis elaborates the development history of seismic research on underground subway structures, summaries the seismic response characteristics of the structures, and analyzes the seismic research methods of underground subway structures including the prototype observation, theoretical analysis, numerical simulation and experimental research and discusses the characteristics and usages of each research method. At last, several important problems have been proposed for seismic research and seismic design of underground subway structures in China.

Adaptive Vibration Control of a Rigid Rotor Supported by Active Magnetic Bearings

1996 ◽  
Vol 118 (4) ◽  
pp. 825-829 ◽  
Author(s):  
O. Lang ◽  
J. Wassermann ◽  
H. Springer
Keyword(s):  
Numerical Simulation ◽  
Cross Coupling ◽  
Least Square ◽  
Magnetic Bearings ◽  
Pole Placement ◽  
Rigid Rotor ◽  
Active Magnetic Bearings ◽  
Coupling Coefficients ◽  
Least Square Estimator ◽  
Response Characteristics

In this paper a digital numerical simulation is carried out in which active magnetic bearings (AMB) are applied to control nonlinear and nonsynchronous vibrations of a rigid rotor excited by nonconservative cross-coupling mechanisms. Through an adaptive control algorithm of the AMB controller, unknown cross-coupling parameters of a rotor are estimated on-line by a standard least-square estimator along with a time-varying so-called forgetting factor. The parameters of the AMB controller are adapted in order to compensate for the cross-coupling effects and to stabilize the rotor system. Transient cross-coupling response characteristics are calculated by numerical simulation of a rigid rotor supported by two active magnetic bearings. With this kind of control strategy, the stability of the system can be guaranteed for much higher values of cross-coupling coefficients than with common nonadaptive feedback controllers, designed with pole placement or least square algorithms.

Numerical simulation of the dual laterolog for carbonate cave reservoirs and response characteristics

2011 ◽  
Vol 8 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Mao-Jin Tan ◽  
Jie Gao ◽  
Xiao-Chang Wang ◽  
Song-Yang Zhang
Keyword(s):  
Numerical Simulation ◽  
Response Characteristics ◽  
Dual Laterolog

scholarly journals Shaking Table Test and Numerical Verification for Free Ground Seismic Response of Saturated Soft Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xuelei Cheng ◽  
Chunyi Cui ◽  
Zongguang Sun ◽  
Jinhong Xia ◽  
Guangbing Wang
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Effective Stress ◽  
Shaking Table Test ◽  
Soft Soil ◽  
Pressure Ratio ◽  
Free Field ◽  
Shaking Table ◽  
Response Characteristics ◽  
Fully Coupled

This paper investigates shaking table test (1g) and numerical simulation (fully coupled) of vertically propagating shear waves for saturated soft free field. A large-scale shaking table model test was performed to study seismic response characteristics of saturated soft soil free field. According to test results of seismic response features of free field system in saturated soft soil, the free field nonlinearity fully coupled numerical model of dynamical effective stress of saturated soft soil was established using OpenSEES, based on the u-p formulations of dynamic consolidation equation as well as effective stress solution method for saturated two-phase media. The numerical simulation of the free field seismic response of saturated soft soil under various test conditions was performed and the calculated results were compared with the shaking table test results. The results show the following. (1) With the increase of input ground motion intensity, the characteristic frequency of the saturated soft free ground decreases and the damping ratio increases gradually. (2) The saturated soft soil ground has short period filtering and long period amplification effect on the horizontal input seismic loads. The failure foundation takes on the isolation and shock absorption under strong ground motions. (3) The peak pore pressure ratio of the saturated soft soil ground is located in the shallow buried soil layer, and with the increase of the input ground motion intensity, the advantage of dynamic pore pressure ratio in this area is gradually weakened. (4) The numerical simulation results are consistent with the results of the shaking table test. This fully coupled effective stress numerical method can reasonably simulate the seismic response characteristics of free field in saturated soft soil, which lay the foundation for other more complex parameter extrapolation models of saturated soft soil sites. This research can provide the necessary technical experience for experimental study on non-free field.

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