scholarly journals Probing the Impact Energy Release Behavior of Al/Ni-Based Reactive Metals with Experimental and Numerical Methods

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 499 ◽  
Author(s):  
Kerong Ren ◽  
Rong Chen ◽  
Yuliang Lin ◽  
Shun Li ◽  
Xianfeng Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Energy Release ◽  
Chemical Reaction ◽  
Impact Energy ◽  
Testing Machine ◽  
Strong Impact ◽  
Release Behavior ◽  
The Impact ◽  
Reactive Metals

Reactive metals (RMs) are a new class of material that can withstand mechanical loads and chemically react to release large amounts of heat under strong impact loading. They are gradually becoming widely used in defense and military fields, including for high-efficiency warheads and reactive armor. For the numerical simulation method considering the combined mechanical-thermo-chemical process for the impact energy release behavior of the RMs, the Al/Ni-based RMs were investigated in this work by combining experiments, theoretical calculations and a numerical simulation. Three kinds of Al/Ni-based RMs (Al-Ni, Al-Ni-CuO and Al-Ni-MoO3), were prepared using the hot-pressing forming process. Firstly, the compressive behavior and the parameters of the Johnson-Cook constitutive model were obtained using a mechanical testing machine and split Hopkinson pressure bars (SHPB). Secondly, the parameters of the equation of state (EOS) under the medium and low pressure conditions of the Al/Ni-based RMs, which were was seen as porous mixtures with high theoretical material density percentages (TMD%), were calculated based on the cold-energy superposition theory and the Wu-Jing method. Third, the impact energy release behaviors of the three RMs were studied with direct ballistic tests. The shock temperatures at different impact velocities were calculated based on the existing shock-induced chemical reaction thermo-chemical model while considering the chemical reaction efficiency, the relationship between the shock temperature and the extent of the chemical reaction was established, and the parameters of the relevant chemical kinetic equations were fitted. Finally, the user’s subroutines defining the material model were implemented to update the stresses in the solids elements in LS-DYNA. The model was based on the Johnson-Cook constitutive model with consideration of the mechanical-thermo-chemical coupling effect, which was verified by the experimental results. The results show that the constitutive model developed in this work can describe the impact energy release behavior of the Al/Ni-based RMs.

scholarly journals Modelling on Shock-Induced Energy Release Behavior of Reactive Materials considering Mechanical-Thermal-Chemical Coupled Effect

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baoyue Guo ◽  
Kerong Ren ◽  
Zhibin Li ◽  
Rong Chen
Keyword(s):  
Numerical Simulation ◽  
Energy Release ◽  
Simulation Approach ◽  
Release Behavior ◽  
Reactive Material ◽  
Reactive Materials ◽  
Coupled Effect ◽  
Macro Scale ◽  
The Military ◽  
The Impact

Reactive material (RM) is a new type of energetic material, which is widely used in the military technology fields such as fragmentation warheads and shaped charge warheads. Violent chemical reactions take place in the impact process of reactive materials, and how to realize the macro numerical simulation of shock-induced energy release behavior of reactive materials is one of the most urgent problems to be solved for its future military applications. In this study, a numerical simulation approach and procedure is proposed, which can simulate the shock-induced energy release behavior of reactive materials on a macro scale. Firstly, program implementation of the mechanical-thermal-chemical coupled effect model for RM is realized in the second-development interface of LS-DYNA software. Then, the adaptive simulated annealing algorithm is used to fit the chemical reaction kinetic parameters of RM using the direct ballistics test data. Finally, the simulation calculation of the fragment penetrating upon steel plate is carried out to expand the applicability of the numerical simulation approach proposed in this study. The results show that the numerical simulation approach proposed in this study can reproduce the results of the direct ballistics test more accurately, which assumes practical significance for the engineering application of reactive materials in the military field in the future.

scholarly journals Study of the Impact Energy Releasing Characteristics of Al/PTFE/W Energetic Jets

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Fuhai Li ◽  
Hantao Liu ◽  
Yanwen Xiao
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Energy Release ◽  
Impact Energy ◽  
Energetic Materials ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
Pressure Peak ◽  
The Impact

Compared with traditional jets, energetic jets have more efficient damage effects. To study the reaction characteristics of polytetrafluoroethylene- (PTFE-) based energetic jets under impact loading, the static mechanical properties of Al/PTFE/W composite energetic materials are studied by using a universal testing machine at a strain rate of 0.01 s−1, and the dynamic mechanical properties are tested on a slip Hopkinson pressure bar (SHPB) system at a strain rate of 1000∼5500 s−1. A dynamic energy acquisition system is established to quantify the energy generated by the response of the Al/PTFE/W energetic jets to impact targets. The effects of the material proportion and impact energy on the mechanical and energy release properties of the Al/PTFE/W energetic jets are analyzed. The results show that the Al/PTFE/W composite has an obvious strain rate effect. As the W content in the composite increases, the yield strength and compressive strength of the material increase gradually, but the strain at break decreases. When the W content is 45%, the peak pressure, total release energy, pressure platform duration, and total pressure duration of the Al/PTFE/W energetic jets are the highest. As the impact energy increases, the pressure peak and energy release values of the energetic jets increase. At an impact energy threshold of 106.1 MJ/m2, the chemical reaction of the Al/PTFE/W (45%) energetic jets is saturated. The results provide a theoretical and experimental basis for the application of energetic jets.

scholarly journals Modeling of Impact Energy Release of PTFE/Al Reactive Material

2021 ◽  
Vol 11 (19) ◽  
pp. 8910
Author(s):  
Xuan Zou ◽  
Jingyuan Zhou ◽  
Wenhui Tang ◽  
Yiting Wu ◽  
Pengwan Chen ◽  
...  
Keyword(s):  
Energy Release ◽  
Impact Energy ◽  
Chemical Kinetic ◽  
State Equation ◽  
Release Behavior ◽  
Hugoniot Curve ◽  
Reactive Material ◽  
Simulation Parameters ◽  
The Hill ◽  
The Impact

Many scholars have used experimental research methods to conduct extensive research on the impact energy release behavior of Polytetrafluoroethylene(PTFE)/Al reactive materials. However, in numerical simulation, PTFE/Al still lacks the calculation parameters of impact energy release behavior. In order to obtain the simulation parameters of PTFE/Al impact ignition, the Hill mixture law was used to calculate the material parameters of PTFE/Al (mass ratio 73.5/26.5), and according to the Hugoniot curve of PTFE/Al and the γ state equation, the JWL equation of state of a PTFE/Al unreacted substance and reaction product was fitted with a genetic algorithm. According to the PTFE/Al impact energy release experiment, the parameters of the PTFE/Al chemical kinetic equation were determined, and the parameters of the trinomial reaction rate equation were fitted. The obtained parameters were used in the simulation calculation in LS-dyna to predict the damage of the aluminum target plate under the impact of the PTFE/Al reactive fragments.

scholarly journals Effect of impact energy on wear behavior of high chromium white iron produced by liquid die forging

2018 ◽  
Vol 207 ◽  
pp. 03011
Author(s):  
B Qiu ◽  
S M Xing ◽  
Q Dong ◽  
H Liu
Keyword(s):  
Abrasive Wear ◽  
Impact Energy ◽  
Wear Behavior ◽  
Testing Machine ◽  
Wear Testing ◽  
Volume Loss ◽  
White Iron ◽  
High Chromium ◽  
Die Forging ◽  
The Impact

Impact abrasive wear behavior of high chromium white iron (HCWI) produced by liquid die forging process were investigated. the wear tests were performed with the MLD-10 abrasive wear testing machine, using SiO2 abrasive and with four impact energies of 1.5 J, 2.5 J, 3.5 J and 4.5 J for 120 min. The results indicated that the cumulative volume loss of HCWI sample increases with the growth of impact energy, and exhibits best wear resistance under low impact condition. For given impact energy, the volume loss increases with the increasing of wear time, which shown an approximately liner tendency. The macro-morphologies, SEM images of worn surface and cross-sectional images of wear samples were observed by optical microscope and SEM, and the wear mechanism and characteristics were analyzed. Results shown that the wear characteristics is mainly based on the shallow ploughing and accompanied by plastic deformation under lower impact energy, while the fatigue peeling and embedded abrasive become the most significant characteristics when the impact energy is higher.

scholarly journals Experimental Study on the Energy-Release Characteristics of Fine-Grained Fe/Al Energetic Jets under Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3317
Author(s):  
Li ◽  
Du
Keyword(s):  
Experimental Data ◽  
Energy Release ◽  
Impact Energy ◽  
Impact Loading ◽  
Energetic Materials ◽  
Chemical Properties ◽  
Microscopic Analysis ◽  
Specific Content ◽  
Fine Grained ◽  
The Impact

The energy released by the active metal phase in fine-grained Fe/Al energetic materials enables the replacement of conventional materials in new types of weapons. This paper describes an experiment designed to study the energy-release characteristics of fine-grained Fe/Al energetic jets under impact loading. By means of dynamic mechanical properties analysis, the physical and chemical properties of Fe/Al energetic materials with specific content are studied, and the preparation process is determined. The energy-release properties of fine-grained Fe/Al jets subject to different impact conditions are studied based on experimental data, and energy-release differences are discussed. The results show that for fine-grained Fe/Al energetic materials to remain active and exhibit high strength, the highest sintering temperature is 550 °C. With increasing impact energy, the energy release of fine-grained Fe/Al energetic jets increases. At an impact-energy threshold of 121.1 J/mm2, the chemical reaction of the fine-grained Fe/Al energetic jets is saturated. The experimental data and microscopic analysis show that when the impact energy reaches the threshold, the energy efficiency ratio of Fe/Al energetic jets can reach 95.3%.

The Impact Analysis of Ground Stability Caused by Exploiting Underground Coal

2011 ◽  
Vol 243-249 ◽  
pp. 3147-3150
Author(s):  
Shu Xian Liu ◽  
Xiao Gang Wei ◽  
Shu Hui Liu ◽  
Li Ping Lv
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Impact Analysis ◽  
Shear Failure ◽  
Failure Process ◽  
Wall Rock ◽  
Strong Impact ◽  
Element Analysis ◽  
Deformation And Failure ◽  
The Impact

Disaster caused by exploiting underground coal is due to original mechanical equilibrium of underground rock has been destroyed when underground coal is exploited. And Stress redistribution and stress concentration of wall rock in the goaf happened too. As many complex factors exist such as complex structures of ground, multivariate stope boundary conditions, many stochastic mining factors and so on, it is difficult to evaluate the damage of the geological environment caused the excavation by surrounding underground coal accurately. Besides that, the coexistence of continuous and discontinuous of deformation and failure of wall rock make a strong impact on the ground, and the co-exist of tension, compression and shear failure also pay a great deal contribution to the destroy. Due to the mechanical property and deformation mechanism of goaf are complex , changeable, nonlinear and probabilistic, which changes with in space and time dynamically, it can not be studied analytically by the classical mathematical model and the theory of mechanics computation. Through finite element analysis software ABAQUS, a numerical simulation of the process of underground coal mining have been made. After make a research of the simulation process, it shows the change process of stress environment of wall rock and deformation and failure process of rock mass during the process of coal mining. The numerical simulation of the process can provide theoretical basis and technical support to the protection and reinforcement of laneway the process of coal excavation. Besides that, it also provides a scientific basis and has a great significance to reasonable Excavation and control of mind-out area.

scholarly journals Experimental and numerical impact models of protection fences

2019 ◽  
Vol 11 (1) ◽  
pp. 90-108
Author(s):  
Trung Tran Le Hoang ◽  
Hiroshi Masuya ◽  
Yoichi Nishita ◽  
Taichi Ishii
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Impact Energy ◽  
Mountainous Areas ◽  
Contact Conditions ◽  
Wire Ropes ◽  
Energy Absorbers ◽  
Full Scale Tests ◽  
The Impact ◽  
Impact Models

The essential requirements for the protection of structures in mountainous areas against rockfalls have led to the development of various types of protection fences. Herein, we conducted impact tests on the protection fence by changing the heights of its posts and collision positions to evaluate adequately and precisely the absorbable capacity of the impact energy. In all experimental cases, the protection fence, which had a span of 5 m and posts with the heights of 2 and 3 m, exhibited an outstanding capacity for dissipating the impact energy of 50 kJ in accordance with a rational arrangement of energy absorbers, which caused the effective slipping of wire ropes. In addition, the simplest possible assumptions adopted in numerical simulations are presented clearly and in detail in terms of the choice of finite element shapes, constitutive laws, and contact conditions, so that the model of the numerical simulation can reproduce successfully the dynamic behavior of the protection fence. Furthermore, this numerical model can aid or replace the full-scale tests to attain an improved capacity for absorbing the energy of rockfall.

scholarly journals Experimental and Numerical Study on the Mechanical Behavior of Composite Steel Structure under Explosion Load

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 246
Author(s):  
Kai Zheng ◽  
Xiangzhao Xu
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Dynamic Response ◽  
Mechanical Behavior ◽  
Steel Structure ◽  
Parallel Program ◽  
Strong Impact ◽  
Explosion Load ◽  
The Impact ◽  
Composite Steel

Most engineering structures are composed of basic components such as plates, shells, and beams, and their dynamic characteristics under explosion load determine the impact resistance of the structure. In this paper, a three-dimensional composite steel structure was designed using a beam, plate, and other basic elements to study its mechanical behavior under explosion load. Subsequently, experiments on the composite steel structure under explosion load were carried out to study its mechanical behavior, and the failure mode and deformation data of the composite steel structure were obtained, which provided important experimental data regarding the dynamic response and mechanical behavior of the composite steel structure under explosion load. Then, we independently developed a parallel program with the coupled calculation method to solve the numerical simulation of the dynamic response and failure process of the composite steel structure under explosion load. This program adopts the Euler method as a whole, and Lagrange particles are used for materials that need to be accurately tracked. The numerical calculation results are in good agreement with the experimental data, indicating that the developed parallel program can effectively deal with the large deformation problems of multi-medium materials and the numerical simulation of the complex engineering structure failures subjected to the strong impact load.

Experimental and Numerical Investigation of Quick Closing Buffer Performance of Steam Turbine Admission Valve

2016 ◽  
Author(s):  
Lei Xiao ◽  
Sihua Xu ◽  
Jin He ◽  
Zhiqiang Hu ◽  
Xiaogang Zhou
Keyword(s):  
Numerical Simulation ◽  
Steam Turbine ◽  
Dynamic Characteristic ◽  
Impact Energy ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Buffer System ◽  
Characteristic Analysis ◽  
Cfd Numerical Simulation ◽  
The Impact

One of the main functions of the steam turbine admission valve is to provide a very fast closing to intercept the supply of mass flow rapidly from the steam entering the turbine and cause destructive overspeed. In order to quickly close the admission valve, at the beginning of the stroke the moving parts of the valve should be accelerated to a high speed; when the stroke ends, a lot of kinetic energy is converted to impact energy. To prevent damage to valve parts, a quick closing buffer system is required to absorb the most of the impact energy. The quick closing buffer system plays an important role in the admission valve as an influencing factor of the dynamic characteristics of the valve. In the past, considering the complex internal structure, the research about quick closing buffer system relied on confirmatory experimental study or analytic method to get a quick closing buffer process. This paper focus on the quick closing process of a high pressure steam admission valve of Shanghai Turbine Plant. The dynamic characteristic of the quick closing buffer system is investigated by means of method of CFD numerical simulation for the first time, in order to find a more convenient and effective way to get the key factors that affect the dynamic characteristics, and the accuracy of the of CFD numerical simulation is verified by test, which are valuable for building an accurate dynamic characteristic analysis model of steam turbine admission valve.

Sign in / Sign up

Export Citation Format

Share Document