Jwl equation of state contains parameters determined by the cylinder expansion test. During modeling of detonation characteristics of explosives in simulations, joneswilkinslee jwl equation of state eos is widely used. Therefore, the common practice is to resort to empirical or semiempirical equations of state eoss describing the detonation properties of explosives. The joneswilkinslee or jwl equation of state models the pressure generated by the release of chemical energy in an explosive.
Equation 1 expresses the pressure of the detonation products as a. This process, when applied to a large range of explosives, seems to show that the exponent increases with increasing energy density and is grouped based on ideality. Overdriven detonation waves with shock pressures higher than cj are created by highvelocity impacts or converging detonation waves. Adjustment of parameters in the jwl equation changes the expansion profile of the cylinder wall in hydrocode simulations. In physics and thermodynamics, an equation of state is a thermodynamic equation relating state variables which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature pvt, or internal energy. These initial sets of parameters are then used as starting points for simulations of the cylinder expansion tests with the explicit fem code lsdyna. The dsd model is used in conjunction with experimental cylinder test data to obtain the jwl equation of state eos for edc35. Determination of properties for emulsion explosives using. Beckerkistiakowskiwilson bkw and joneswilkinslee jwl are among the most widely used eos.
Theory and calibration of jwl and jwlb thermodynamic. Theory and calibration of jwl and jwlb thermodynamic equations. Equation of state the empirically based jwl eos was fitted to the data in conjunction with the thermochemistry code, cheetah, fried et al. Jwl equation of state coefficients for high explosives. It describes in a correct manner the behaviour of detonation products within the whole range of pressure changes and becomes an equation of an ideal gas for small densities. The physical processes involved in a detonation phenomenon, though, are extremely complex. Reflection from highimpedance materials, multiple shock. The steadystate detonation velocity, including its. Note that the constant r is different for each gas. Pdf theory and calibration of jwl and jwlb thermodynamic. The joneswilkinslee jwl equation of state is an empirical model useful in describing the thermodynamic properties i. Pdf structure geometric configuration and response can be strongly coupled to. The jwl constants found in the literature is only suit for sample of a certain density, while it is simple to have slight density differences in application.
The jwl equation of state describing the adiabatic expansion of detonation products is revisited to complete the description of the principal eigenvalue, to reset the secondary eigenvalue to produce a wellbehaved adiabatic gamma profile, and to normalize the characteristic equation of state in terms of conventional parameters having a clear experimental interpretation. Equations of state are useful in describing the properties of fluids, mixtures of fluids, solids, and the interior of stars. Jwl bauation of state coefficients for high explosives. The jwlmiller equation of state 14 fordescribing the detonation product of aluminized explosives are adopted as p a1. Pdf the jwl eos is widely used in different forms two, three terms according to the level of accuracy in the pressurevolume domain that. The jwl equation of state 14 was used for high explosives and the williamsburg equation of state 15 coded into abaqus software was used for the anfo mixture.
The jwl equation of state, ubiquitous in the field of explosivemetal interactions, is examined. Equation of state from wikipedia, the free encyclopedia in physics and thermodynamics, an equation of stateis a relation between state variables. The analysis of experimental cylinder test data to generate a jwl equation of state and gurney energy is described and the results compared with other published data. Weggel department of civil and environmental engineering, unc charlotte, usa abstract two separate blast tests were conducted inside a conventional, unreinforced, brick building scheduled to be demolished. The model relies on analysis of the metal cylinder expansion by detonation products. The most popular equation of state used in numerical codes is the semiempirical joneswilkinslee jwl equation, which can be easily applied in numerical algorithms. The equation of state needs to be represented for each of the reaction states. For blast applications, it is vital that the total work output from the detonation state to high expansion of the detonation.
Equation of state eos for the detonation products via hydrocode modelling 1. However, the jwl equation of state has proven itself to be a very useful for engin eering calculations, and is very widely used. A new derivation of jwl eos is proposed, using a less restrictive assumption for the gruneisen coefficient suggested by. A study of the jwl equation of state parameters of. A study of the jwl equation of state parameters of dynamite for use in airblast models b. Jwl equation of state for expansion of detonating products after explosion has been studied for several high explosives and simplified approach with p v. Comparison of bkw and jwl equations of state for explosion simulations. The general expression for the free energy of a crystal can be written in terms of three functions where x vjv plp, is the dimensionless volume rela tive to the volume at normal conditions and 8 is a charac. From this code, both the parameters of the jwl equation of state of a given compositi. On exact conservation for the euler equations with complex. The equation of state of the detonation product of aluminized explosives should be able to establish the essential relationship among pressure, density, internal energy and the reaction process variable. An analytic cylinder test model that uses jwl or jwlb equations of state has.
The jwl equation of state eos is frequently used for the products and sometimes reactants of a high explosive he. Jwl equation of state, joneswilkinslee equation of state for explosives. Adjustment of parameters in the jwl equation changes the expansion pro. The jwl equation of state is used worldwide to describe the pressurevolumeenergy behavior of a detonating explosive. The required parameters for the constitutive equations and equation of state used for plates and explosives. Several types of equations are used for modeling the relationship among the state parameters of explosives and computer implementation is mostly needed for predicting the behavior of explosives. Joneswilkinsleebaker jwlb equation of state is an extension of the jwl.
We obtained these parameters through a method of characteristics applied to the. This paper describes research into the suitability of the explosive fox7 in the development of insensitive munitions. The joneswilkenslee or jwl equation of state models the pressure generated by the release of chemical energy in an explosive. A variety of equations of state eos have been used to represent explosives, the popular ones being the joneswilkinslee jwl form,21 the murnaghan form22 and gruneisen form. The parameters are iterated until the best match can be made between simulation and experiment. Modeling of shock wave propagation through energetic solid. An engineering method to calculating jwl constants of. The equations reflecting the cj state conditions and the measured expansion energy were solved for the jwl parameters by a nonlinear least squares scheme. Jwl standard japan light alloy wheel standard, a set of requirements for alloy wheels set by the ministry of land, infrastructure, transport and tourism japan that must be met for all passenger cars in japan. In addition, the slow release of energy poses a challenge for conventional testing methods.
Jwl equation of state coefficients for high explosives, report, january 16. Simulating underbelly blast events using abaqusexplicit cel. Parametric study of the dynamic jwleos for detonation. The jwl eos is of the miegrueneisen form with a constant grueneisen coefficient and a constants specific heat. Because there is no founding document for the jwl equation of state, there exist different interpretations of the equation, which is the source of substantial confusion. Analytical methods of determining jwl parameters from cylinder tests have. Study on jwl equation of state for the numerical simulation of near. To be truly viable as a predictive tool, a theoretical model should give accurate results for the following properties. The jwl equation of state 1, 2, 9, 14 is commonly used in explosives modelling for describing the pressurevolumeenergy relationship of the detonation products. Determination of the equation of state for the detonation. Livermore software technology corporation, livermore, ca.
Both the mechanical and thermal equations might be considered when modeling mixtures of multiple materials for example, but for this single gas case the mechanical eos is su cient. Thus the jwleos parameters can be determinedbythecylindertest. A new analytical model for determination of joneswilkinslee jwl equation of state parameters based on the cylinder test is proposed. A new method for determining the equation of state of. To avoid transcribing errors, we have computerized the. Equation of state wikimili, the best wikipedia reader. Joneswilkinslee unreacted and reaction product equations. Pdf comparison of bkw and jwl equations of state for. The above equation is called the idealgas equation of state ideal gas relation. This model is implemented in a form referred to as a programmed burn, which means that the reaction and initiation of the explosive is not determined by shock in the material. In physics and thermodynamics, an equation of state is a thermodynamic equation relating state variables which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or internal energy. Optimizing code calibration of the jwl explosive equation. State of detonation products is described by various types of equations of state. Joneswilkinslee jwl equation of state is widely used because of its simplicity.
Equations of state the equation of state of a substance gives the pressure p as a function of volume v and temperature t. Review of joneswilkinslee equation of state citeseerx. Comparison of bkw and jwl equations of state for explosion. Nearfield effects cause severe effects on the structures leading to. The jwl equation of state is calibrated for the chapmanjouguet point discussed in a section below. The joneswilkinslee jwl equation of state eos is used to calculate expansion of detonation reaction products from the chemical equilibrium chapmanjouguet cj state to large volumes. The ideal detonation code vixeni is used to obtain initial sets of parameters for the jwl equation of state for the emulsion explosives used.
Jwl equation of state parameters based on the cylinder test is proposed. Investigation of jwl equation of state for detonation products at. Determination of jwl equation of state parameters of. The potential of fox7 explosive in insensitive munition. Recent analysis of high explosives using the cylinder test has resulted in an increased understanding of the experimental uncertainty for the cylinder test.
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