A non-destructive characterization method for explosive small component particle migration distribution based on mu CT

Abstract

The application provides a nondestructive characterization method of explosive small component particle migration distribution based on mu CT, and the method comprises the following steps: step one, establishing a coordinate system for describing the position of component particles; step two, determining the position of a single particle; step three, describing the position of the single particle in different states; and step four, constructing a migration distribution characterization model. The method of the application establishes a position description system of explosive component particles by taking mu CT as a technical means, determines a single particle position description method, and constructs a component migration distribution characterization model by describing the position of different components and different particles under different conditions, so that the migration distribution change of explosive grain internal small component particles is nondestructively and finely characterized, and a foundation is laid for migration mechanism research.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of explosives and relates to small component migration in explosive grain, in particular to a nondestructive characterization method for small component particle migration distribution of explosives based on μCT. BACKGROUND

[0002] In order to improve the performance of explosives, small components such as binders, plasticizers and desensitizers need to be added on the basis of energetic ingredients to improve mechanical properties, process properties and safety performance. In the long-term storage process, small molecular components with low melting point in the explosive formula will produce phase change and dissolution due to temperature and aging effect, and will produce "surface-seeking" migration under the push of concentration difference or pressure difference, and crystal precipitation and oil seepage may occur on the surface of the explosive grain. Due to the migration and seepage of small components of explosives, pores may be produced in the interior of the explosive grain, making the explosive locally loose and brittle, affecting the structural integrity and mechanical properties of the explosive grain, and the migration and seepage of desensitizer small components will also cause the sensitization of explosives and increase the sensitivity, thereby increasing the use risk. Therefore, it is necessary to carry out research on the characterization method of component migration to provide technical support for safety failure analysis, formula design, safe and reliable use and the like of explosive charging.

[0003] At present, the migration distribution of small components in the interior of explosive grain in the field of explosives is mainly characterized by destruction, that is, the explosive grain in different aging processes is radially sliced or turned into powder with a certain thickness, and the content of each range is analyzed by using HPLC and other technical means, and then the migration distribution change is reconstructed according to the content of different parts. The disadvantages of this destructive migration distribution characterization method are as follows: 1. The same explosive grain cannot be subjected to complete cycle migration distribution research because the explosive grain is destroyed; 2. The sampling points are few due to the slicing or turning with a certain thickness, resulting in low distribution detection precision; 3. The distribution change path or other details of the component particles cannot be analyzed because only the whole analysis of the sliced pieces or turned powder can be carried out. Therefore, a nondestructive characterization method for the migration distribution of small component particles in the interior of explosive grain is needed. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a nondestructive characterization method for the migration distribution of small component particles of explosives based on μCT, so as to solve the technical problem that there is no nondestructive, full-cycle and intuitive particle migration distribution characterization method in the field of explosives in the prior art.

[0005] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0006] A nondestructive characterization method for the migration distribution of small component particles of explosives based on μCT, which comprises the following steps:

[0007] Step 1: Establish a coordinate system for describing the position of component particles:

[0008] A coordinate system is established with the straight line where the initial test position of the grain column is located and the bottom surface of the grain column.

[0009] Step two, determine the single particle position:

[0010] On the μCT image, the number of different components N and the number of particles M corresponding to a component n are determined according to the gray value range, and the space region corresponding to a particle m is obtained, that is, a image containing particle m is determined; in the a image containing particle m, the image a with the largest particle area is selected x is the target image, and a x The center position of the particle area in the image is defined as the position L of the particle in the grain column n-m .

[0011] Step three, describe the position of the single particle in different states:

[0012] The positions of the particles of the component in the initial state and in different aging temperature, aging humidity and aging time ranges are described.

[0013] Step four, construct a migration distribution characterization model:

[0014] The migration distribution characterization model is constructed for the components prone to migration by selecting particles with different depths and different volume sizes as the modeling objects; and the migration distribution characterization model of the particles in the component under different conditions is fitted according to the position data obtained under different temperature, humidity and time conditions.

[0015] The present application also has the following technical features:

[0016] In step one, the straight line where the initial test position of the grain column is located is taken as the Z axis, and the bottom surface of the grain column is taken as the X-Y plane, wherein the straight line passing through the center point of the grain column is taken as the Y axis, and the straight line perpendicular to the Y axis and the Z axis is taken as the X axis.

[0017] In step three, the initial position of the mth particle of the component n is defined as The particle position under different aging temperatures is The particle position under different aging humidities is defined as The particle position under different aging times is defined as

[0018]

[0019] In step four, the number of components prone to migration is N' (N ′ ∈[1,N]), and the number of particles of a component n with modeling characteristics is M' (M ′ ∈[1,M]) ; the aging test includes T' temperature test points, H' humidity test points and t' time test points.

[0020] In step four, the migration distribution characterization model of the particles m in component n under different aging temperature, humidity and time conditions is as follows:

[0021] Compared with the prior art, the present application has the following technical effects:

[0022] (I) The method of the present application uses μCT as a technical means to establish a position description system of explosive component particles, determine a single particle position description method and the positions of different components and different particles under different conditions, construct a component migration distribution characterization model, realize non-destructive and fine characterization of the migration distribution changes of small component particles in the explosive grain, and lay a foundation for migration mechanism research.

[0023] (II) The method of the present application can realize intuitive and non-destructive characterization.

[0024] (III) The method of the present application obtains 720 images by scanning the whole grain, which greatly improves the characterization accuracy compared with the characterization methods such as turning or slicing.

[0025] (IV) The method of the present application can finely analyze the migration change process of each particle in each component. It can lay a foundation for explosive component migration mechanism research. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of a coordinate system for describing the positions of component particles.

[0027] Figure 2 It is a schematic diagram for determining the position of a single particle.

[0028] The specific content of the present application is further explained and described in detail in combination with the following examples. DETAILED DESCRIPTION

[0029] It should be noted that all the basic methods in the present application, if not specially stated, all use the known basic methods in the prior art.

[0030] μCT, full name micro-focus industrial CT, can realize non-destructive testing of internal components of propellant column based on gray value. The principle is as follows: the sample is fixed on the sample table which can rotate 360 degrees or 180 degrees, and is rotated and scanned at a set step angle; during scanning, the energy of X-rays passing through the test piece is attenuated, and the attenuated signal is received by the detector and the projection image is obtained; then according to the relationship between the linear attenuation coefficient of each point of the test piece and the X-rays, the CT gray image is converted in proportion, the image threshold segmentation method is used to divide the pixel set in the image according to the gray level, and each subset obtained forms a region corresponding to the real scene. μCT not only can obtain truly isotropic volume images with a spatial resolution of several microns, but also has a relatively fast image acquisition speed, which can meet the requirements of modern high-precision and fast testing. At present, μCT in the field of explosives mainly uses porosity to realize the characterization of the damage of propellant due to moisture loss and the internal damage evolution law, and there is no report on the method of using μCT to characterize the migration distribution of small components in explosive column.

[0031] According to the above technical solution, the specific embodiments of the present application are given below. It should be noted that the present application is not limited to the following specific embodiments, and any equivalent transformation based on the technical solution of the present application falls within the scope of protection of the present application.

[0032] Embodiment:

[0033] The present embodiment gives a non-destructive characterization method of small component particle migration distribution of explosives based on μCT. After determining the thermal aging test conditions (including temperature range, humidity range and time range), μCT working conditions (including resolution and image acquisition number), and ensuring the consistent placement position of the propellant column under different test conditions, the method includes the following steps:

[0034] Step one, establish a coordinate system describing the position of component particles:

[0035] In order to more clearly and conveniently describe the migration distribution of component particles, a coordinate system is established based on the straight line where the initial test position of the propellant column is located and the bottom surface of the propellant column.

[0036] Preferably, in step one, the straight line where the initial test position of the propellant column is located is taken as the Z axis, and the bottom surface of the propellant column is taken as the X-Y plane, wherein the straight line passing through the center point of the propellant column is taken as the Y axis, and the straight line perpendicular to the Y axis and the Z axis is taken as the X axis.

[0037] Step two, determine the position of a single particle:

[0038] In the μCT image, the number N of different components and the number M of particles corresponding to a certain component n are determined according to the gray value range, and the spatial region corresponding to a certain particle m is obtained, that is, a certain image a containing particle m is obtained. In the a image containing particle m, the image a x is selected as the target image, and ax The center position of the particle area in the image is defined as the position L of the particle in the grain n-m .

[0039] Step three, the position of a single particle in different states is described:

[0040] The position of the particles of the component in the initial state and in different aging temperature, aging humidity and aging time ranges is described.

[0041] Preferably, in step three, the initial position of the mth particle of the nth component is defined as The position of the particle in different aging temperatures is The position of the particle in different aging humidities is defined as The position of the particle in different aging times is defined as

[0042] Step four, a migration distribution characterization model is constructed:

[0043] The model of this step is only modeled for the components prone to migration. If there are many particles of the components prone to migration, particles with different depths and different sizes can be selected for modeling. According to the position data obtained under different temperature, humidity and time conditions, the migration distribution characterization model of the particles in the component under different conditions is fitted, and the distribution rules such as migration rate and trajectory of the component under different conditions are inferred. Finally, the overall migration distribution characteristics of all the components prone to migration are summarized, laying a foundation for the migration mechanism research.

[0044] Preferably, in step four, the number of components prone to migration is N'(N ′ ∈[1,N]) and the number of particles of a component n with modeling characteristics is M'(M ′ ∈[1,M]);The aging test includes T' temperature test points, H' humidity test points and t' time test points.

[0045] Preferably, in step four, the migration distribution characterization model of the particle m in the component n under different aging temperature, humidity and time conditions is:

[0046] Application example:

[0047] The present application example gives a nondestructive characterization method of the migration distribution of small component particles of explosives based on μCT based on the above-mentioned embodiments. It is assumed in this application example that a certain explosive contains N components, n represents any component, the component n contains M particles, and n-m represents the mth particle in the component n.

[0048] The method specifically includes the following steps:

[0049] Step one, a coordinate system describing the position of the particles of the component is established:

[0050] A coordinate system is established as shown in Figure 1 , with the line where the initial test position of the propellant grain is located as the Z axis, the bottom surface of the propellant grain as the X-Y plane, and the line passing through the center point of the propellant grain as the Y axis, and the line perpendicular to the Y axis and the Z axis as the X axis.

[0051] Step two, determine the position of a single particle:

[0052] As shown in Figure 2 , the spatial region corresponding to each particle m in different components n (n ∈ [1, N]) is obtained according to the gray value range of each component in the μCT image, that is, a image containing particle m is determined. In the a image containing particle m, the image a x is selected as the target image, and the center position of the particle area in the a x image is taken as the position L of the particle in the propellant grain. n-m .

[0053] Step three, describe the position of a single particle in different states:

[0054] Step 301, initial state:

[0055] The initial position of the mth particle of component n is defined as

[0056] Step 302, different conditions:

[0057] Step 30201, different temperatures:

[0058] When the thermal aging temperature T ∈ [T1, T2], the position of the mth particle of component n is , where T1 and T2 are the upper and lower limit values of the thermal aging temperature range, respectively.

[0059] Step 30202, different humidity:

[0060] When the thermal aging humidity H ∈ [h1, h2], the position of the mth particle of component n is , where h1 and h2 are the upper and lower limit values of the thermal aging humidity range, respectively.

[0061] Step 30203, different time:

[0062] When the thermal aging time t ∈ [t1, t2], the position of the mth particle of component n is , where t1 and t2 are the upper and lower limit values of the thermal aging time range, respectively.

[0063] Step four, construct a migration distribution characterization model:

[0064] For N'(N'∈[1,N]) components prone to migration and M'(M'∈[1,M]) particles with different depths and different volume size characteristics are modeled. T' temperature test points, H' humidity test points, t' time test points can get (N'×M'×T'×H'×t') position data (including initial state position), according to the above position data, the migration distribution representation model of the mth particle in the nth component under different conditions can be fitted:

[0065]

[0066] That is, the relationship between N'×M' particle positions and aging temperature, humidity, time and initial position is fitted, and then the migration rate and trajectory distribution law of the nth component under different conditions are inferred according to M' relationships, and finally the overall migration distribution characteristics of the easily migrating component are summarized according to N' components, which lays a foundation for migration mechanism research.

Claims

1. A method for non-destructive characterization of explosive minor component particle migration distribution based on μCT, characterized in that, The method comprises the following steps: Step one, establishing a coordinate system describing the position of component particles: Establishing a coordinate system with the straight line where the initial test position of the grain is located and the bottom surface of the grain; Step two, determining the position of single particles: Determine the number of different components N and the number of particles M corresponding to a certain component n according to the gray value range on the μCT image, and obtain the spatial region corresponding to a certain particle m, i.e., determine the a-th image containing the particle m; select the image with the largest particle area in the a-th image containing the particle m The target image is taken as The center position of the particle area in the image is defined as the position of the particle in the propellant grain ; Step three, describing the position of single particles in different states: Describing the position of component particles in the initial state and in different aging temperature, humidity and time ranges; Step four, constructing a migration distribution characterization model: The migration distribution characterization model selects particles with different depths and different volume sizes for modeling for components prone to migration; according to the position data obtained under different temperature, humidity and time conditions, the migration distribution characterization model of the particles in the component under different conditions is fitted.

2. The muCT-based non-destructive characterization method of explosive sub- component particle migration distribution according to claim 1, characterized in that, In step one, the straight line where the initial test position of the grain is located is taken as the Z axis, and the bottom surface of the grain is taken as the X-Y plane, wherein the straight line passing through the center point of the grain is taken as the Y axis, and the straight line perpendicular to the Y axis and the Z axis is taken as the X axis.

3. The μCT-based non-destructive characterization method of explosive sub- component particle migration distribution according to claim 1, characterized in that, In step three, the initial position of the mth particle of component n is defined as The particle positions for different aging temperatures are defined as The particle positions for different aging humidities are defined as The particle positions for different aging times are defined as .

4. The muCT-based non-destructive characterization method of explosive sub- component particle migration distribution according to claim 1, characterized in that, In step four, the number of migration components is , , the number of particles of component n with modeling characteristics is ; the aging test includes temperature test points, humidity test points, time test points.

5. The μCT-based non-destructive characterization method of explosive sub- component particle migration distribution according to claim 1, wherein, The migration distribution characterization model of the particles m in component n under different aging temperature, humidity and time conditions in step four is: .

Images