scholarly journals A Novel Design of Rescue Capsule considering the Pressure Characteristics and Thermal Dynamic Response with Thermomechanical Coupling Action Subjected to Gas Explosion Load

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaowei Zhai ◽  
Shibo Wu ◽  
Kai Wang ◽  
Xiaokun Chen ◽  
Haitao Li
Keyword(s):  
Dynamic Response ◽  
Coal Mine ◽  
Coupling Effect ◽  
Design Method ◽  
Thermomechanical Coupling ◽  
Structural Safety ◽  
Coupling Mechanism ◽  
Gas Explosion ◽  
Explosion Load ◽  
Mine Rescue

To ensure the structural safety and reliability of coal mine rescue capsule in disastrous surroundings after gas explosion, in this paper, the thermomechanical coupling effect on a certain structure subjected to gas explosion was analyzed, and then a novel rescue capsule with a combination of radius and square features was designed according to the underground surroundings and relevant regulations on mine rescue devices. Foremost, the coupling mechanism of thermal-fluid-solid interaction between gas explosion shock wave and rescue capsule and the thermal dynamic response of the capsule subjected to explosion load of gas/air mixture was investigated and revealed by employing LS-DYNA. The variation laws and characteristics of stress field, displacement field, and temperature field of the capsule were analyzed based on the simulation results. Results show that the structural safety, tightness, and reliability of the capsule meet the requirements of the national safety regulations. The design method presented in this work provides a new thought for design of coal mine rescue capsule.

Solution of Gas Explosion Load and Simulation of Dynamic Response of Multilayer Structures

2012 ◽  
Vol 557-559 ◽  
pp. 2401-2405
Author(s):  
Hua Dong Liu ◽  
Wei Qiang Wang
Keyword(s):  
Dynamic Response ◽  
Multilayer Structure ◽  
Radial Direction ◽  
Burst Pressure ◽  
Multilayer Structures ◽  
Gas Explosion ◽  
Explosion Pressure ◽  
Structure Strength ◽  
Explosion Load ◽  
Chemical Explosion

Chemical explosion may occur in urea reactor. The explosion load and the dynamic response of the multilayer structure are analyzed. Based on Russel model, the maximum explosion loads were calculated by thermodynamic methods. Dynamic response was simulated by Ls-dyna software. The result shows that the explosion pressure is smaller than the burst pressure; the stress distribution along the radial direction and the effective stress history are obtained and they both show some new features. The results may offer some reference significance for similar structure strength design and safe protection.

Optimum Design of Journal Bearings Dimensions for Rotating Machines

2020 ◽  
Vol 38 (10A) ◽  
pp. 1481-1488
Author(s):  
Tariq M. Hammza ◽  
Ehab N. Abas ◽  
Nassear R. Hmoad
Keyword(s):  
Aspect Ratio ◽  
Dynamic Response ◽  
Numerical Solution ◽  
Critical Speed ◽  
Design Method ◽  
Considerable Effect ◽  
Journal Bearings ◽  
Rotating Machines ◽  
Bearing Clearance ◽  
Study Results

The values of Many parameters which involve in the design of fluid film journal bearings mainly depend on the bearing applied load when using the conventional design method to design the journal bearings, in this study, as well as applied bearing load, the dynamic response and critical speed have been used to calculate the dimensions of journal bearings. In the field of rotating machine, especially a heavy-duty rotating machines, the critical speed and response are the main parameters that specify bearing dimensions. The bearing aspect ratio (bearing length to bore diameter) and bearing clearance have been determined based on rotor maximum critical speed and minimum response displacement. The analytical solution of rotor Eq. of motion was verified by numerical solution via using ANSYS Mechanical APDL 18.0 and by comparing the numerical solution with the preceding study. The final study results clearly showed that the bearing aspect ratio has little effect on the critical speed, but it has a high effect on the dynamic response also the bearing clearance has little effect on the critical speed and considerable effect on the dynamic response. The study showed that the more accurate values of bearing aspect ratio to make the response of rotor as low as possible are about 0.65 - 1 and bearing percent clearance is about 0.15 - 0.2 for different rotor dimensions.

scholarly journals Sartre as prosecutor of occupational murder: notes from a People's Tribunal in a French mine (1970)

2021 ◽  
Vol 99 ◽  
pp. 167-176
Author(s):  
Pascal Marichalar ◽  
Gerald Markowitz ◽  
David Rosner
Keyword(s):  
Coal Mine ◽  
Public Prosecutor ◽  
Gas Explosion ◽  
The Public ◽  
Northern France ◽  
Publicly Owned

On February 4, 1970, in the Fouquières-lès-Lens coal mine in northern France, sixteen miners were killed in a gas explosion (“firedamp,” grisou in French). This was an accident like many others before it, yet with a relatively high number of fatalities. The public prosecutor concluded, as usual, that there was no case against the publicly owned mine. No investigation was to be carried out. The accident had been the work of fate, of bad luck.

Influence of Initial Position of Sliding Device on Premixed Methane/air Gas Explosion Flame at Driving Face in Coal Mine

2021 ◽  
pp. 1-23
Author(s):  
Yulong Duan ◽  
Yanling Yang ◽  
Yuanbing Li ◽  
Jun Xu ◽  
Yuzhu Zhang ◽  
...  
Keyword(s):  
Coal Mine ◽  
Initial Position ◽  
Gas Explosion

Dynamic Response of Spiral Cantilever Undergoing Magnetic Coupling

2014 ◽  
Vol 14 (08) ◽  
pp. 1440021
Author(s):  
Xiaoling Bai ◽  
Yumei Wen ◽  
Ping Li ◽  
Jin Yang ◽  
Xiao Peng ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Cantilever Beam ◽  
Magnetic Force ◽  
Coupling Effect ◽  
Magnetic Coupling ◽  
Resonant Frequencies ◽  
Energy Harvesters ◽  
Magnetic Transducer ◽  
Underlying Mechanisms ◽  
Tip Mass

Cantilever beams have found intensive and extensive uses as underlying mechanisms for energy transduction in sensors as well as in energy harvesters. In magnetoelectric (ME) transduction, the underlying cantilever beam usually will undergo magnetic coupling effect. As the beam itself is either banded with magnetic transducer or magnets, the dynamic motion of the cantilever can be modified due to the magnetic force between the magnets and ME sensors. In this study, the dynamic response of a typical spiral cantilever beam with magnetic coupling is investigated. The spiral cantilever acts as the resonator of an energy harvester with a tip mass in the form of magnets, and a ME transducer is positioned in the air gap and interacts with the magnets. It is expected that this spiral configuration is capable of performing multiple vibration modes over a small frequency range and the response frequencies can be magnetically tunable. The experimental results show that the magnetic coupling between the magnets and the transducer plays a favorable role in achieving tunable resonant frequencies and reducing the frequency spacings. This will benefits the expansion of the response band of a device and is especially useful in energy harvesting.

Nonlinear Design Model for Multi-Threshold Accelerometer Utilizing Magnetic Induced Multistable Mechanisms

2018 ◽  
Author(s):  
Jian Zhao ◽  
Yu Huang ◽  
Pengbo Liu ◽  
Qifei Fang ◽  
Renjing Gao
Keyword(s):  
Inertial Sensors ◽  
Coupling Effect ◽  
Design Method ◽  
Threshold Value ◽  
Consumer Electronics ◽  
Design Model ◽  
Acceleration Pulse ◽  
Locking Mechanism ◽  
Nonlinear Design ◽  
Controlling Elements

Different from traditional accelerometer, multi-threshold acceleration switch can be triggered to different working states by external accelerations without complex auxiliary circuits and controlling elements, which has great application potentials in aerospace, vehicle safety and consumer electronics. In this paper, a novel multi-threshold acceleration switch with anti-overloading function is designed and fabricated by incorporating both magnetic multi-stable structures and compliant cantilever contacts, which also can be used to distinguish specific acceleration pulse. To enhance the contact reliability, the magnetic compliant locking mechanism is introduced to prevent bouncing back phenomenon under overload acceleration. Considering the air-damping and multi-magnetic fields coupling effect, the dynamic design model is proposed for analyzing the nonlinear switch response. Then, threshold accelerations can be determined as ac1 = 3.78g, ac2 = 10.2g and ac3 = 6.95g in one direction while threshold accelerations in opposite direction are ac4 = 4.9g, ac5 = 8.47g and ac6 = 5.6g. The switch shows excellent threshold acceleration detection capability, and the inertial switch keeps open while the external acceleration is 0.2g less than the predefined threshold value. The experimental results show that the threshold acceleration with specific pulse width can be accurately identified, and the switch can bear strong overload acceleration comparing to traditional switches. Consequently, the proposed design method provides a new way for intelligent mechanical inertial sensors.

Thermomechanical coupling effect of PVC sheet with defects

2008 ◽  
Vol 15 (S1) ◽  
pp. 568-572 ◽  
Author(s):  
Zhan-yu Yang ◽  
Ying-she Luo ◽  
Jian-xin Su ◽  
Yong-zhong Zhang ◽  
Xu-hua Deng ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Thermomechanical Coupling
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