scholarly journals Strength analysis of warship hull’s bottom loaded by the pressure wave from a non-contact explosion of sea mine explosion of sea mine

2021 ◽  
Vol 2130 (1) ◽  
pp. 012008
Author(s):  
B Szturomski ◽  
R Kiciński
Keyword(s):  
Pressure Wave ◽  
High Speed ◽  
Strength Analysis ◽  
Stress And Strain ◽  
Flat Bottom ◽  
Contact Explosion ◽  
Calculated Stress ◽  
Concentrated Masses ◽  
The Impact ◽  
Spherical Pressure

Abstract The study was based on the analysis of stamina of steel flat bottom section of transport warships, burdened by the spherical pressure wave from the non-contact explosion of TNT at a distance of 20 m under the keel. This study aims to determine the TNT mass required to break the hull. The task was solved by finite element method (FEM) explicite using CAE program [1], in which the hull’s bottom was modelled as thin shell space. The hull’s burden with pressure wave was modelled as a pressure impulse specified by the formula introduced by T.L. Geers, K.S. Hunter and R.S. Price [2]. To describe the material properties, considering high-speed strain, the Johnson-Cook model was used [3]. Therefore, the main goal of the hereby paper is to present how to correctly model the impact of large, concentrated masses of the ship’s equipment on its hull. The study presents the results of the calculated stress and strain states of the analysed section of the construction of the hull.

Transient Bending of a Large Elastic Plate by an Incident Spherical Pressure Wave

1974 ◽  
Vol 41 (3) ◽  
pp. 772-776 ◽  
Author(s):  
H. Huang
Keyword(s):  
Wave Front ◽  
Incident Wave ◽  
Elastic Plate ◽  
Pressure Wave ◽  
Early Time ◽  
Hankel Transform ◽  
Bending Stress ◽  
The Impact ◽  
Interaction Problem ◽  
Spherical Pressure

The transient response of a large elastic plate to the impact of an incident spherical pressure wave is studied. The interaction problem is formulated with the aid of the Laplace and Hankel transform techniques and the inverse transform is asymptotically evaluated by the method of Laplace. The transient solution for early time immediately after the impact is obtained. It demonstrates that the convex incident wave front could cause bending stress at the plate many times higher than the incident wave front pressure.

Axial Impact Performance of Aluminium Thin Cylindrical Tube

2013 ◽  
Vol 315 ◽  
pp. 1-5 ◽  
Author(s):  
Perowansa Paruka ◽  
Waluyo Adi Siswanto
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Cylindrical Tube ◽  
Numerical Approach ◽  
Stress And Strain ◽  
Axial Impact ◽  
Cylindrical Structure ◽  
Impact Performance ◽  
Impact Simulation ◽  
The Impact

One of the important objectives in this research is investigating the behavior on the cylindrical tube structure via computer simulations. When a thin cylindrical structure is experienced an impact loading, the crushing process on impact can only be observed by a high speed camera. Recording the stress and strain data is also not possible experimentally. A numerical approach implementing finite element method with a dynamic-explicit code is an effective solution to observe the crushing process. A thin cylindrical structure found in aluminium can is modeled. A finite element impact simulation is then performed to observe the crushing process sequence and the stress and strain development history on axial impact employing IMPACT application program. An experimental of thin cylindrical structure on axial impact is conducted. The final crushing pattern after the impact is then compared with that from simulation. The result shows that final crushing pattern is in a good agreement with that shown in experiment. The stress and strain histories can be observed from the simulation.

Study on the AZ31B Magnesium Alloy in the Application on High-Speed Trains

2012 ◽  
Vol 535-537 ◽  
pp. 875-879 ◽  
Author(s):  
Jia Zhen Liu ◽  
Yan Hui Zhao ◽  
Lei Song ◽  
Zhong Xia Xiang
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
High Speed ◽  
Equivalent Stress ◽  
Strength Analysis ◽  
Az31b Magnesium Alloy ◽  
High Speed Trains ◽  
6063 Aluminum Alloy ◽  
The Impact

6063 aluminum alloys are used as the luggage rack’s material on high-speed trains recently. The study on the AZ31B magnesium alloy is aimed to demonstrate the feasibility of the magnesium alloy’s application as the material of the luggage rack on high-speed trains. First, the mechanical properties of the AZ31B magnesium was obtained after a series of experimental tests on basic mechanical properties of the AZ31B magnesium alloy. The results show that the strength of the magnesium alloy is 1.25 times of the 6063 aluminum alloy and the impact toughness of the AZ31B magnesium alloy is twice as much as the 6063 aluminum alloy. Second, the stress distribution and the maximum value of the equivalent stress in given loading conditions was obtained by finite element strength analysis on the structure of the aluminum alloy luggage rack on high-speed trains. And the FE analysis results indicate that if the AZ31B magnesium alloy is used as the material of the luggage rack instead of the 6063 aluminum alloy, it will have a weight loss of the luggage rack for approximately 33%. In addition, the application of AZ31B magnesium alloy has more advantages in energy-saving, environmental protection and safety control.

scholarly journals Numerical Analysis of the Aerodynamic Characteristics of the Open Line Intersection of Fast Freight Train with the Speed of 160 km/h

2021 ◽  
Vol 2125 (1) ◽  
pp. 012014
Author(s):  
Yue Zhang ◽  
Dongping Wang
Keyword(s):  
Pressure Wave ◽  
High Speed ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Pressure Amplitude ◽  
Freight Train ◽  
Measuring Point ◽  
Open Line ◽  
Volume Method ◽  
The Impact

Abstract With the increase of the speed of fast freight train, the aerodynamic effect of freight train in open-line intersection is more obvious. However, at present, there are many domestic researches on the aerodynamic characteristics of high-speed train open-line intersection, and almost no researches on fast freight train. Therefore, it is of great significance to study the aerodynamic characteristics of open line intersection of fast freight train in order to improve the safe operation of freight train in China. Based on the theory of computational fluid dynamics and finite volume method, uses FLUENT software to numerically calculate the three-dimensional, unsteady, compressible and turbulent flow fields in open line intersection of fast freight train at different speeds. The calculations results indicate that: when two freight trains meet, the amplitude of the pressure wave at the intersection side is the largest and the closer to the train bottom, the greater the amplitude of the pressure wave. The pressure amplitude of the bottom measuring point is 34.09% higher than that of the top measuring point. When two cars intersect at the same speed, the higher the speed, the greater the pressure amplitude and the pressure amplitude is proportional to the square of the speed. The fitting formula is: ΔP = cV2 ; When two trains intersect at different speeds, the impact on freight train with lower speed is greater than higher one.

Analysis of the aerodynamic pressure effect on the fatigue strength of the carbody of high-speed trains passing by each other in a tunnel

2018 ◽  
Vol 233 (8) ◽  
pp. 783-801
Author(s):  
Yaohui Lu ◽  
Dewen Zhang ◽  
Heyan Zheng ◽  
Chuan Lu ◽  
Tianli Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Pressure Wave ◽  
High Speed ◽  
Aerodynamic Load ◽  
Aerodynamic Loads ◽  
Aerodynamic Pressure ◽  
High Speed Trains ◽  
Short Tunnel ◽  
The Impact

When two high-speed trains pass through a tunnel, the aerodynamic changes are more complex and drastic than in open air owing to the interference of the tunnel wall and the entry effect. The impact on the carbody fatigue strength is very significant in the fatigue reliability design of the carbody. In this paper, the sequential coupling method was used for the first time to study the effect of pressure waves on the fatigue strength in a large-scale and complex carbody structure. The computational fluid dynamics method was used to calculate and analyze the aerodynamic pressure wave of the intersection of the trains in a long and short tunnel. A full-scale finite element shell model of the carbody structure was established. Then, the time integration method was used to convert the transient pressure wave into the aerodynamic loads bearing by the side wall of the carbody. The inhomogeneous stress concentrations at the restraint points were eliminated by the inertial release method; moreover, a finite element analysis of the carbody was carried out under the combined aerodynamic and mechanical loads. The Goodman fatigue strength curve of the aluminum alloy carbody was drawn. The influence of the aerodynamic load on the fatigue strength of the vehicle body was analyzed and compared under the entry effect of the short tunnel. The results show that the aerodynamic load of the short tunnel has a significant impact on the fatigue strength of the carbody owing to the train's entry effect. The safety factor of the fatigue strength is 15% less than that of the long tunnel aerodynamic load. In this paper, computational fluid dynamics and finite element method were used to analyze and evaluate the impact of the pressure wave on the fatigue strength of the carbody, which is of great reference value in the structural design of the carbody subjected to complex aerodynamic loads.

scholarly journals Analysis of structure strength for direct current high-speed switch based on flexible body theory

2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091298
Author(s):  
Mei Li ◽  
Peng Gong ◽  
Yifei Wu ◽  
Yi Wu
Keyword(s):  
Direct Current ◽  
High Speed ◽  
Dynamic Strain ◽  
Strength Analysis ◽  
Flexible Body ◽  
Stress And Strain ◽  
Operation Speed ◽  
Structure Strength ◽  
Body Theory ◽  
Opening Process

The Thomson coil actuator has an important application prospect in direct current high-speed switch due to its short respond time and fast operation speed. However, the large electromagnetic impact force during the opening process may bring the stress deformation of movable components and thus cause damage to the mechanism. Therefore, the dynamic stress and strain evaluation of the moving parts is very important for the design and optimization of direct current high-speed switch. In this article, a novel method of structure strength analysis based on the flexible body theory is established for direct current high-speed switch. The electromagnetic and buffer forces in the rapid opening process are calculated, and then the stress and strain distribution of the key components are obtained. Finally, the strain test circuit of the key components is built. By comparing the simulation and experimental results of dynamic strain, the validity of the established simulation model is verified.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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