Research on Attenuation of Shock Induced Stress Wave in Multi-Layered Thin Cylindrical Rods

2018 ◽  
Vol 878 ◽  
pp. 35-40
Author(s):  
Fei Peng ◽  
Zhi Guang Yang ◽  
Li Peng Wang
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Layered Media ◽  
One Dimension ◽  
Stress Wave Propagation ◽  
Propagation Theory ◽  
Induced Stress ◽  
The One ◽  
Wave Induced

The attenuation of stress wave induced by impact load in multi-layered thin cylindrical rods has been investigated and analyzed. Firstly, based on stress wave propagation theory, the one dimension solution of the response of stress wave in three-layered media has been given. Secondly, a three-layered thin cylindrical rod has been established through FEM, and the propagation and attenuation of stress wave in it has been analyzed. The analytical and numerical results showed that the stress wave attenuation could be achieved by using multi-layered media.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

scholarly journals Wave-induced stress and breaking of sea ice in a coupled hydrodynamic–discrete-element wave–ice model

2017 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Wave Model ◽  
Discrete Element ◽  
Two Dimensions ◽  
Particle Model ◽  
Time Step ◽  
Bonded Particle Model ◽  
Induced Stress ◽  
Wave Induced

Abstract. In this paper, a coupled sea ice–wave model is developed and used to analyze the variability of wave-induced stress and breaking in sea ice. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid "grains" floating on the water surface that can be connected to their neighbors by elastic "joints". The joints may break if instantaneous stresses acting on them exceed their strength. The wave part is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two parts are coupled with proper boundary conditions for pressure and velocity, exchanged at every time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

Elasto-Viscoplastic Dispersive Waves in Silicon Wafers

2007 ◽  
Author(s):  
Li Liu ◽  
C. Steve Suh
Keyword(s):  
Stress Wave ◽  
High Temperatures ◽  
Nonlinear Function ◽  
Low Frequency ◽  
Propagation Model ◽  
Constitutive Law ◽  
Stress Wave Propagation ◽  
Thickness Variation ◽  
Low Frequencies ◽  
Induced Stress

This paper provides the required knowledge base for establishing Laser Induced Stress Wave Thermometry (LISWT) as a viable alternative to current infrared technologies for temperature measurement up to 1000°C with ±1°C resolution. A stress wave propagation model having a complex, temperature-dependent elasto-viscoplastic constitutive law is developed. Investigated results show that wave group velocity is a nonlinear function of temperature. Nonlinearity becomes more prominent at high temperatures and low frequencies. As such, for LISWT to achieve better thermal resolution at high temperatures, low frequency components of the induced stress wave should be exploited. The results also show that the influence of temperature on attenuation is relatively small. It is not recommended to use attenuation for resolving temperature variation as small as several degrees Celsius. In addition to temperature, geometry also is found to have an impact on wave dispersion and attenuation. The influence of thickness on wave velocity is significant, thus suggesting that for LISWT to achieve high temperature resolution, wafer thickness must be accurately calibrated in order to eliminate all possible errors introduced by thickness variation.

Numerical Simulation Analysis of the Effect on the One-Dimension Assumption in Different Diameter SHPB Pressure Bar by Two Kinds of Loading Waveform

2013 ◽  
Vol 787 ◽  
pp. 759-764
Author(s):  
Sheng Zhang ◽  
Xiang Hao Yang ◽  
Xin Wen Li
Keyword(s):  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Simulation Analysis ◽  
Sine Wave ◽  
Stress Waves ◽  
One Dimension ◽  
Hopkinson Pressure Bar ◽  
Finite Element Software ◽  
The One ◽  
Pressure Bar

t is one of precondition of determining rock material dynamic parameters for one-dimension assumption of the elastic pressure bar. In order to analyze its effect by loading wave type, the dynamic stress was simulated with Ls-dynamic finite element software, when SHPB(Split Hopkinson Pressure Bar) pressure bar with diameter of 50 mm, 75 mm and 100 mm were impacted respectively by a cycle rectangular loading wave and half sine loading wave. The stress waves of cross section in different diameter pressure bar and the different distance with pressure bar end were compared and analyzed. The results indicated that the dispersion of stress waves was very serious and the matching ability of stress wave at different distances in pressure bar was poor when the rectangular wave was loaded. However, the dispersion of stress wave was not obvious with the increase of the diameter of pressure bar and the change of pressure bar when the half sine wave was loaded. The half sine loading wave which can strictly meet the one-dimension assumption is one of the ideal loading waveforms of the rocky heterogeneous materials.

Analysis of Pile-Soil Interaction by Computer Simulation

2006 ◽  
Vol 326-328 ◽  
pp. 1531-1534 ◽  
Author(s):  
Guang Zhang ◽  
Dong Zi Pan ◽  
Jing Xi Chen ◽  
Ai Fang Zhou
Keyword(s):  
Computer Simulation ◽  
Numerical Model ◽  
Stress Wave ◽  
Dynamic Test ◽  
Wave Theory ◽  
One Dimension ◽  
Concrete Piles ◽  
The One ◽  
Reflection Characteristics

In this paper, a numerical model to simulate the interaction of pile-soil based on the one-dimension stress wave theory is established, which can provide the propagating process and reflection characteristics of stress wave under impulsed load in concrete piles. The simulation is carried on about the stress wave in integrated pile and defective pile, which provide all kinds of the propagating characteristics. It can enhance the accuracy of dynamic test. The validity of this approach is verified through the comparison of the measured curve and the simulated curve.

scholarly journals Analysis of Dynamic Response Behavior of Crack under Impact Stress Wave

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1920
Author(s):  
Yan Peng ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Fracture Mechanics ◽  
Dynamic Response ◽  
Stress Wave ◽  
Dynamic Fracture ◽  
Impact Load ◽  
Stress Wave Propagation ◽  
Failure Behavior ◽  
Stress And Strain ◽  
Response Behavior ◽  
Shock Stress

The structural parts of construction machinery mostly fail due to impact load, but current research on the failure behavior of the impact load has not established a complete theoretical system. Based on wave theory and fracture mechanics, this paper analyzed the wave behavior of shock stress waves and established a model of shock stress wave propagation. Given the dynamic response behavior of the stress and strain field at the crack tip, dynamic fracture mechanics theory was used to solve the dynamic fracture strength stress factor and evaluate the dynamic fracture performance of the structure with crack damage under shock waves. Through dynamic response analysis and numerical calculation of the typical SHPB (split Hopkinson pressure bar) test standard compact tension (CT) specimens under the short-term strong shock stress wave, the stress and strain evolution law of the material under the shock wave was analyzed, and the correlation of the shock stress wave was verified. This research work can meet the requirements of engineering design and has practical engineering significance, playing an important role in material safety design.

Study of Stress Wave Propagation in SHPB with NHDMOC

2013 ◽  
Vol 444-445 ◽  
pp. 158-162
Author(s):  
Ming Li Xu ◽  
Guang Ying Zhang ◽  
Ruo Qi Zhang
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Elastic Stress ◽  
Constitutive Relationship ◽  
Stress Wave Propagation ◽  
One Dimensional ◽  
Elastic Bar ◽  
The One ◽  
Dispersion And Attenuation ◽  
Elastic Stress Wave

In this paper the NHDMOC method which succeeded in studying stress wave propagation with one dimensional strain was applied to study the one-dimensional stress wave propagation. In this paper, the ZWT nonlinear visco-elastic constitutive relationship with 7 parameters to NHDMOC, and corresponding equations were deduced The equations was verified from the comparison of elastic stress wave propagation in SHPB with elastic bar and visco-elastic bar respectively. Finally the dispersion and attenuation of stress wave in SHPB with visco-elastic bar was studied.

scholarly journals Subsection Forward Modeling Method of Blasting Stress Wave Underground

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Bo Yan ◽  
Xinwu Zeng ◽  
Yuan Li
Keyword(s):  
Finite Element ◽  
Stress Wave ◽  
Source Region ◽  
Stress Waves ◽  
Nonlinear Finite Element ◽  
Stress Wave Propagation ◽  
Local Structures ◽  
Nonlinear Responses ◽  
Induced Stress ◽  
Material Nonlinear

The generation of stress waves induced by explosions underground is governed by material nonlinear responses of materials surrounding explosions and affected by source region mediums and local structures. A nonlinear finite element (NFE) method can simulate the generation efficiently. However, the calculation using the NFE to observational distances, where motions are elastic, is computationally challenging. In order to tackle this problem, we present a subsection numerical simulating method for forward modelling the generation and propagation of stress waves with a hybrid method coupling the NFE and a linear finite element (LFE). The subsection idea is developed based on previous works; calculating steps of the subsection method as well as techniques of passing motions from a source region to an elastic region are discussed. 3D numerical simulations of stress wave propagation in rock generated by decoupled explosion underground with two methods for comparison are carried out. The accuracy of the subsection method is demonstrated with simulated results. The demand of PC memory and the calculating time are investigated. The subsection method provides another approach for modeling and understanding the generation and propagation of explosion-induced stress waves, though, currently, studies are preliminary.

scholarly journals Wave-induced stress and breaking of sea ice in a coupled hydrodynamic discrete-element wave–ice model

2017 ◽  
Vol 11 (6) ◽  
pp. 2711-2725 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Wave Model ◽  
Discrete Element ◽  
Two Dimensions ◽  
Particle Model ◽  
Time Step ◽  
Bonded Particle Model ◽  
Induced Stress ◽  
Wave Induced

Abstract. In this paper, a coupled sea ice–wave model is developed and used to analyze wave-induced stress and breaking in sea ice for a range of wave and ice conditions. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid grains floating on the water surface that can be connected to their neighbors by elastic joints. The joints may break if instantaneous stresses acting on them exceed their strength. The wave module is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two modules are coupled with proper boundary conditions for pressure and velocity, exchanged at every wave model time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

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