A fragment identification method based on SPH algorithm of LS-DYNA

Abstract

The present invention discloses a fragment identification method of an SPH algorithm based on LS-DYNA. First, based on the LS-DYNA calculation results, the main data information of the particles is output, and the data information matrix of all SPH particles is established. Then, the data information matrix of all SPH particles is mirrored according to the actual situation. Next, a non-independent matrix representing the interaction between particles is constructed through the data information matrix of all SPH particles. Then, all fragments are screened through the non-independent matrix. Finally, the physical quantities such as the mass, volume, velocity component and center of mass coordinates of each fragment are sorted out and output as a text file. The fragment identification and information statistics method of the SPH algorithm based on LS-DYNA proposed by the present invention can accurately identify fragments of any size, material and type of the SPH algorithm calculation results of the LS-DYNA solver.

Description

Technical Field

[0001] The present invention belongs to the field of finite element numerical simulation technology, and specifically relates to a fragment identification method based on LS-DYNA SPH algorithm Background Art

[0002] Under high-speed / ultra-high-speed (1.5-11.0 km / s) impact conditions, a large number of fragments will be generated during the collision between objects. During the explosion of the lethal warhead, many fragments of different sizes will be formed and scattered in all directions. During the penetration of the target plate by the warhead, extremely lethal behind-the-target fragments will be generated on the back of the target plate. Taking the behind-the-target fragments as an example, the behind-the-target fragments are also called secondary fragments. This highly dispersed fragment cloud is composed of warhead fragments and target plate collapse fragments. The distribution characteristics of the secondary fragment cloud under high-speed collision are studied. At present, the more active fields include spherical projectiles hitting the target plate, long-rod projectiles hitting the target plate, shaped energy jets penetrating the target plate, and EFP penetrating the target plate. In these fields, the parameters of the secondary fragment power field that are discussed include the target plate penetration diameter, the front expansion speed of the fragment cloud, the lateral expansion speed, the maximum flying angle, and the mass and spatial distribution, which are of great reference value for damage assessment and target vulnerability analysis.

[0003] In recent years, with the development of secondary fragment research, numerical simulation technology has been widely used in the simulation calculation of secondary fragments. Compared with traditional analytical methods and empirical methods, numerical simulation can not only simulate the complex interaction between media, but also characterize special processes such as deformation and fracture, and obtain clear and continuously changing physical images and the changing laws of various physical quantities. Traditional Lagrange algorithm, Euler algorithm, etc. are commonly used numerical simulation algorithms in the field of computational solid mechanics. However, in the process of high-speed collision, the material deforms greatly in an instant, and even the target plate is punctured and ruptured. The particles of the projectile and target materials splash to form a fragment cloud. The processing of the contact interface and the loss of calculation accuracy caused by the large deformation of the grid and even the interruption of the calculation are difficult problems in the calculation method. The SPH (Smoothed Particle Hydrodynamics) algorithm is a typical Lagrange meshless numerical simulation method developed in the late 1970s. It uses discrete nodes with mass, momentum, energy, etc. to form a calculation domain. Nodes of different materials naturally form interfaces, and the interaction between materials can be naturally simulated by the interaction between nodes. At the same time, since this method does not require a grid, it is particularly suitable for simulating large deformation problems. The strong shock waves in hypervelocity impacts make the material behave like fluids, accompanied by large deformation or even breakage of the material. Traditional grid methods are difficult to solve, but the SPH algorithm based on the fluid dynamics control equations is very applicable.

[0004] With the deepening of secondary fragment research, the research scope has begun to expand from the relevant parameters of macroscopic fragment clouds to the relevant parameters of microscopic fragment individuals, such as the number of fragments, fragment mass, fragment velocity, fragment coordinates, fragment volume and other physical quantities. Among the current mainstream damage simulation calculation software, AUTODYN software, as a highly integrated software with pre- and post-processing and solvers, can automatically count various physical quantities of non-failed fragments. However, the solver calculation time of this software is too long, and some algorithms have obvious limitations. In addition, its SPH algorithm function is relatively single, and the method of filling SPH particles according to geometric shapes is difficult to meet the needs of the current mainstream damage simulation calculation software. In contrast, the LS-DYNA solver has a much higher calculation speed and its SPH algorithm is very powerful. As its pre- and post-processing software, LS-PREPOST provides a variety of filling methods. At the same time, the grid filling method makes it easy to build complex models using SPH particles. However, LS-PREPOST lacks the function of automatically counting the physical quantities related to secondary fragments like AUTODYN. When faced with the need to study the relevant parameters of microscopic fragments involving the SPH algorithm, AUTODYN is still the preferred tool. At present, in order to solve such defects, publication number CN103455669B proposes an automatic statistical method for quantitative information of fragments based on LS-DYNA calculation results. This method reconstructs the fragment field in ANSYS by exporting the LS-DYNA calculation results, and then counts the quantitative information such as mass, velocity and volume of the fragments by retrieving all the units connected to a certain unit and assigning material numbers. However, the process of reconstructing the fragment field in this method depends on the secondary input of the ANSYS software, lacks statistics on the coordinates of the fragments, and does not take into account the fragment superposition process of the symmetrical calculation model. Finally, the statistics of the fragment velocity are based on the direct average of the node velocity, which cannot cope with the situation of mixed SPH particle fragments of different materials and sizes. Summary of the invention

[0005] The purpose of the present invention is to provide a fragment information statistics method based on the SPH algorithm calculation results for the LS-DYNA solver, in view of the significant defects in the LS-DYNA post-processing program and the existing LS-DYNA fragmentation results quantitative information statistics method for fragment information based on the SPH algorithm calculation results. The method can obtain the physical quantities such as the number, mass, volume, velocity, coordinates, etc. of all fragments in the SPH algorithm calculation results, and can directly output them as text files for quantitative statistics of fragment information, so as to provide assistance for numerical calculation work in the field of damage assessment and secondary damage.

[0006] The technical solution to achieve the purpose of the present invention is: a fragment identification method based on the SPH algorithm of LS-DYNA, the steps are as follows:

[0007] Step S1, according to the fragmentation simulation containing the SPH algorithm, LS-DYNA is used to calculate and obtain the SPH particle influence radius, mass, volume, velocity and coordinate data information of the whole process, and then the data information matrix of the whole SPH particle is established. The data information matrix of the whole SPH particle includes the influence radius information matrix, mass information matrix, volume information matrix, velocity information matrix and coordinate information matrix, and then proceeds to step S2.

[0008] Step S2, according to the actual situation, respectively mirror the influence radius information matrix, mass information matrix, volume information matrix, velocity information matrix and coordinate information matrix to obtain the influence radius mirror matrix, mass mirror matrix, volume mirror matrix, velocity mirror matrix and coordinate mirror matrix, then reassign the influence radius mirror matrix, mass mirror matrix, volume mirror matrix, velocity mirror matrix and coordinate mirror matrix to obtain the influence radius value matrix, mass value matrix, volume value matrix, velocity value matrix and coordinate value matrix, and then proceed to step S3.

[0009] Step S3, construct a non-independent matrix characterizing the interaction between particles based on the influence radius assignment matrix, mass assignment matrix, volume assignment matrix, velocity assignment matrix and coordinate assignment matrix, and then proceed to step S4.

[0010] Step S4, screen all broken pieces through the non-independent matrix and proceed to step S5.

[0011] Step S5, obtain the number of fragments, the mass of each fragment, the volume of the fragment, the speed of the fragment along the X, Y, and Z directions, the total speed of the fragment, and the center of mass coordinates of the fragment along the X, Y, and Z directions, and output them.

[0012] Compared with the prior art, the present invention has the following significant advantages: the present invention can accurately identify and count the fragments of the SPH algorithm calculation results of the LS-DYNA solver, regardless of the particle size and material, including but not limited to warhead fragments, secondary fragments, collision fragments and other fragment types, thereby overcoming the problem that it is difficult to count the fragments under the SPH algorithm calculation results of the LS-DYNA solver. The overall idea is concise and clear, and the implementation difficulty is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Flow chart of the method of the present invention.

[0014] Figure 2 This is a flow chart of fragment screening of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0016] Combination Figure 1 andFigure 2 , a fragment identification method based on SPH algorithm of LS-DYNA, the steps are as follows:

[0017] Step S1, according to the fragmentation simulation containing the SPH algorithm, the SPH particle influence radius, mass, volume, speed and coordinate data information of the components composed of SPH particles in the whole process are obtained by LS-DYNA calculation, according to the SPH particle influence radius, mass, volume, speed and coordinate data information of the whole process, the particle influence radius, mass, volume, speed and coordinate data information of the moment of interest are extracted, and the output is a txt text file, and the non-digital information in the txt text file is removed to establish the whole SPH particle data information matrix, that is, the influence radius information matrix, the mass information matrix, the volume information matrix, the speed information matrix and the coordinate information matrix, the influence radius information matrix, the mass information matrix and the volume information matrix have 2 columns, the first column is the SPH particle serial number, and the second column corresponds to the influence radius, mass and speed of the SPH particle respectively. The speed information matrix has 4 columns, the first column is the SPH particle serial number, and the second to fourth columns are the speed component values ​​of the SPH particles along the X, Y, and Z directions respectively. The number of columns of the coordinate information matrix is ​​4, the first column is the SPH particle number, and the second to fourth columns are the coordinate component values ​​of the SPH particles along the X, Y, and Z directions respectively, and then proceed to step S2.

[0018] Step S2: According to the actual situation, the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix are mirrored respectively to obtain the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix, and then the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix are reassigned to obtain the influence radius value matrix, the mass value matrix, the volume value matrix, the velocity value matrix and the coordinate value matrix, as follows:

[0019] Step S2-1, determine whether the data information matrix of all SPH particles is actually obtained based on a complete model or a symmetric model: If the data information matrix of all SPH particles is obtained based on a complete model, reassign the first column of the influence radius information matrix, mass information matrix, volume information matrix, velocity information matrix and coordinate information matrix from 1 to obtain the data assignment matrix of all SPH particles, and proceed to step S3. If the data information matrix of all SPH particles is obtained based on a symmetric model, proceed to step S2-2.

[0020] Step S2-2, invert the particle coordinate component value of the coordinate information matrix about the normal direction of the symmetry plane of the symmetry model, and keep the coordinate component values ​​in other directions unchanged. Exclude duplicate particles located at the symmetry plane according to the coordinates, and connect the obtained coordinate mirror matrix in turn under the coordinate information matrix to obtain the coordinate splicing matrix, and then go to step S2-3.

[0021] Step S2-3, invert the particle velocity component value of the velocity information matrix about the normal direction of the symmetry plane of the symmetry model, and keep the velocity component values ​​in other directions unchanged. According to the SPH particle number in the first column, exclude the duplicate particles located at the symmetry plane, and connect the obtained velocity mirror matrix in sequence under the velocity information matrix to obtain the velocity splicing matrix, and then go to step S2-4.

[0022] Step S2-4, directly repeat the matrix information of the influence radius information matrix, the mass information matrix and the volume information matrix, exclude the repeated particles located at the symmetry plane according to the SPH particle number in the first column, and the obtained influence radius mirror matrix, mass mirror matrix and volume mirror matrix are connected in sequence under the influence radius information matrix, mass information matrix and volume information matrix, and the influence radius splicing matrix, mass splicing matrix and volume splicing matrix are obtained respectively, and then go to step S2-5.

[0023] Step S2-5, reassign the first column of the coordinate splicing matrix, velocity splicing matrix, influence radius splicing matrix, mass splicing matrix and volume splicing matrix starting from 1 to obtain the coordinate assignment matrix, velocity assignment matrix, influence radius assignment matrix, mass assignment matrix and volume assignment matrix.

[0024] Step S3, construct a distance matrix according to the influence radius assignment matrix, then use the distance matrix as the subtracted matrix, the particle influence radius matrix as the subtraction matrix, the comparison matrix as the difference matrix, set the diagonal elements of the comparison matrix to 0, and finally extract the row numbers and column numbers corresponding to all values ​​less than 0 to generate a non-independent matrix. The row numbers and column numbers of the influence radius assignment matrix correspond to the particle numbers, respectively, and the elements of the influence radius assignment matrix represent the maximum influence radius value among the particles corresponding to the row numbers and the particles corresponding to the column numbers. The row numbers and column numbers of the distance matrix correspond to the particle numbers, respectively, and the elements of the distance matrix represent the distance between the particles corresponding to the row numbers and the particles corresponding to the column numbers. The number of columns of the non-independent matrix is ​​2, the first column is the row number of the comparison matrix, the second column is the column number of the comparison matrix, and the column numbers are sorted from small to large.

[0025] Step S4: Screen all the fragments through the non-independent matrix to obtain the number of fragments, as follows:

[0026] Step S4-1, for the non-independent matrix M, take out all the elements in the second column, remove the repeated elements with the same serial number shown therein, and form an array, named the non-independent array Ms, where i represents the subscript of the matrix and j represents the subscript of the array. Initialize it and set i=1, j=0, and go to step S4-2.

[0027] Step S4-2, select the first element E of the non-independent array Ms, and go to step S4-3.

[0028] Step S4-3, search the first column of the non-independent matrix M for the element set P that has the same sequence number as the element E i , go to step S4-4,

[0029] Step S4-4, search the second column of the non-independent matrix M for the element set Q that has the same sequence number as the element set Pi i , go to step S4-5.

[0030] Step S4-5, search the first column of the non-independent matrix M for the element Q i The set P of elements with the same sequence number i+1 , go to step S4-6,

[0031] Step S4-6, searching the second column of the non-independent matrix M for the element set P i+1 The set Q of elements with the same sequence number i+1 , go to step S4-7.

[0032] Step S4-7, let i=i+1, repeat steps S4-5 to S4-6 until the element set Q i If it is an empty set, go to step S4-8.

[0033] Step S4-8, element E, all element sets P i 、The set of all elements Q i The serial numbers of all elements are listed in an array S j , and remove the array S j If there is a repeated sequence number, go to step S4-9.

[0034] Step S4-9, let j=j+1, in the dependent array Ms, remove the j The same elements in the array are used to obtain a new non-independent array Ms. j , go to step S4-10.

[0035] Step S4-10, for the new dependent array Ms j , repeat steps S4-2 to S4-9 until the new non-independent array Ms j Is empty, get J arrays S j, j ranges from 1 to J, and the process goes to step S4-11.

[0036] Step S4-11, all row numbers of the particle comparison matrix are formed into an array, and after removing the same numbers in the array as those in the dependent array Ms, an independent array P is obtained, which contains K elements.

[0037] Step S5, determine the fragment mass, fragment volume, fragment velocity along the X, Y, and Z directions, fragment combined velocity, and center of mass coordinates of the fragment along the X, Y, and Z directions corresponding to each fragment, and output them, as follows:

[0038] Step S5-1, compare the first column numbers of the mass assignment matrix, volume assignment matrix, velocity assignment matrix and coordinate assignment matrix with the first column numbers of the array S j All rows corresponding to the elements with the same sequence number in are included in a mass information sub-matrix, a volume information sub-matrix, a velocity information sub-matrix and a coordinate information sub-matrix in turn. The non-independent array S j A subscript of corresponds to a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and then the rows corresponding to the elements with the same sequence numbers in the first column of the mass assignment matrix, the volume assignment matrix, the velocity assignment matrix, and the coordinate assignment matrix are separately listed in turn into a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix. An element in the independent array P corresponds to a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and a total of J+K mass information submatrices, J+K volume information submatrices, J+K velocity information submatrices, and J+K coordinate information submatrices are obtained. U is used to represent the sequence numbers of the mass information submatrix, the volume information submatrix, the velocity information submatrix, and the coordinate information submatrix. Then the u-th mass information submatrix, the u-th volume information submatrix, the u-th velocity information submatrix, and the u-th coordinate information submatrix have the same number of rows num u , each mass information submatrix represents the mass information of the particles contained in a fragment, each volume information submatrix represents the volume information of the particles contained in a fragment, each velocity information submatrix represents the velocity information of the particles contained in a fragment, and each coordinate information submatrix represents the coordinate information of the particles contained in a fragment, and then proceed to step S5-2.

[0039] Step S5-2: Remove the first column of all quality information sub-matrices, and accumulate the quality information sub-matrices to obtain a number representing the quality of the fragments. num u Indicates the number of rows of the u-th quality information submatrix, mass vu is the vth row of the uth quality information submatrix, Mass u is the mass of the uth fragment.

[0040] Remove the first column of all volume information sub-matrices, and accumulate the volume information sub-matrices to get a number representing the fragment volume num u Indicates the number of rows of the u-th volume information submatrix, vol vu is the vth row of the uth volume information submatrix, Vol u is the volume of the u-th fragment.

[0041] Remove the first column of all velocity information submatrices, perform mass-weighted average calculation on the first column of the velocity information submatrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num u Indicates the number of rows of the u-th velocity information submatrix, xvel vu is the 1st column and the vth row of the uth velocity information submatrix, XVel u is the velocity of the uth fragment along the X direction.

[0042] The mass-weighted average calculation is performed on the second column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th velocity information submatrix, yvel vu YVel is the 2nd column and the vth row of the uth velocity information submatrix. u is the velocity of the uth fragment along the Y direction.

[0043] The mass-weighted average calculation is performed on the third column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th velocity information submatrix, zvel vu is the 3rd column and the vth row of the uth velocity information submatrix, ZVel u is the velocity of the uth fragment along the Z direction.

[0044] Remove the first column of all coordinate information sub-matrices, perform mass-weighted average calculation on the first column of the coordinate information sub-matrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num u Indicates the number of rows of the u-th coordinate information submatrix, xcoor vu is the 1st column and the vth row of the uth coordinate information submatrix, XCoor u is the coordinate of the uth fragment along the X direction.

[0045] The mass-weighted average calculation is performed on the second column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th coordinate information submatrix, ycoor vu is the 2nd column and the vth row of the uth coordinate information submatrix, YCoor u is the coordinate of the u-th fragment along the Y direction.

[0046] The mass-weighted average calculation is performed on the third column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th coordinate information submatrix, zcoor vu is the 3rd column and the vth row of the uth coordinate information submatrix, ZCoor u is the coordinate of the u-th fragment along the Z direction.

[0047] The fragment number, mass, three-dimensional velocity, total velocity, and three-dimensional coordinates are output to the result matrix. The total velocity is the modulus of the vector sum of the three-dimensional velocity. Vel u is the total velocity of the u-th fragment. The first column of the result matrix is ​​the fragment serial number. The number of fragments can be known through the serial number. The second column is the mass of the fragment. The third column is the volume of the fragment. The fourth to sixth columns are the speeds of the fragments along the X, Y, and Z directions. The seventh column is the total velocity of the fragments. The eighth to eleventh columns are the coordinates of the center of mass of the fragments along the X, Y, and Z directions. Go to step S5-3.

[0048] Step S5-3: Output the result matrix as a text file.

[0049] By following the above steps, the SPH algorithm fragments of LS-DYNA can be accurately identified and counted.

[0050] Example

[0051] Combination Figure 1 and Figure 2 The fragment identification method of the SPH algorithm based on LS-DYNA described in the present invention comprises the following steps:

[0052] First, set up the example: establish a calculation example of a spherical projectile penetrating a target plate in the LS-PREPOST software, based on the 1 / 4 model calculation, the projectile and the target plate are both SPH algorithms, the projectile speed is along the positive direction of the X-axis, the magnitude is 2000m / s, and the input is LS-DYNA solver to calculate to 100us.

[0053] Step S1, according to the fragmentation simulation containing the SPH algorithm, the SPH particle influence radius, mass, volume, speed and coordinate data information of the components composed of SPH particles in the whole process are obtained by LS-DYNA calculation, according to the SPH particle influence radius, mass, volume, speed and coordinate data information of the whole process, the particle influence radius, mass, volume, speed and coordinate data information of the moment of interest are extracted, and the output is a txt text file, and the non-digital information in the txt text file is removed to establish the whole SPH particle data information matrix, that is, the influence radius information matrix, the mass information matrix, the volume information matrix, the speed information matrix and the coordinate information matrix, the influence radius information matrix, the mass information matrix and the volume information matrix have 2 columns, the first column is the SPH particle serial number, and the second column corresponds to the influence radius, mass and speed of the SPH particle respectively. The speed information matrix has 4 columns, the first column is the SPH particle serial number, and the second to fourth columns are the speed component values ​​of the SPH particles along the X, Y, and Z directions respectively. The number of columns of the coordinate information matrix is ​​4, the first column is the SPH particle number, and the second to fourth columns are the coordinate component values ​​of the SPH particles along the X, Y, and Z directions respectively, and then proceed to step S2.

[0054] Step S2: According to the actual situation, the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix are mirrored respectively to obtain the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix, and then the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix are reassigned to obtain the influence radius value matrix, the mass value matrix, the volume value matrix, the velocity value matrix and the coordinate value matrix, as follows:

[0055] Step S2-1: Since the calculation model is a symmetric model, proceed to step S2-2.

[0056] Step S2-2, invert the particle coordinate component value of the coordinate information matrix about the normal direction of the symmetry plane of the symmetry model, and keep the coordinate component values ​​in other directions unchanged. Exclude duplicate particles located at the symmetry plane according to the coordinates, and connect the obtained coordinate mirror matrix in turn under the coordinate information matrix to obtain the coordinate splicing matrix, and then go to step S2-3.

[0057] Step S2-3, invert the particle velocity component value of the velocity information matrix about the normal direction of the symmetry plane of the symmetry model, and keep the velocity component values ​​in other directions unchanged. According to the SPH particle number in the first column, exclude the duplicate particles located at the symmetry plane, and connect the obtained velocity mirror matrix in sequence under the velocity information matrix to obtain the velocity splicing matrix, and then go to step S2-4.

[0058] Step S2-4, directly repeat the matrix information of the influence radius information matrix, the mass information matrix and the volume information matrix, exclude the repeated particles located at the symmetry plane according to the SPH particle number in the first column, and the obtained influence radius mirror matrix, mass mirror matrix and volume mirror matrix are connected in sequence under the influence radius information matrix, mass information matrix and volume information matrix, and the influence radius splicing matrix, mass splicing matrix and volume splicing matrix are obtained respectively, and then go to step S2-5.

[0059] Step S2-5, reassign the first column of the coordinate splicing matrix, velocity splicing matrix, influence radius splicing matrix, mass splicing matrix and volume splicing matrix starting from 1 to obtain the coordinate assignment matrix, velocity assignment matrix, influence radius assignment matrix, mass assignment matrix and volume assignment matrix.

[0060] Step S3, construct a distance matrix according to the influence radius assignment matrix, then use the distance matrix as the subtracted matrix, the particle influence radius matrix as the subtraction matrix, the comparison matrix as the difference matrix, set the diagonal elements of the comparison matrix to 0, and finally extract the row numbers and column numbers corresponding to all values ​​less than 0 to generate a non-independent matrix. The row numbers and column numbers of the influence radius assignment matrix correspond to the particle numbers, respectively, and the elements of the influence radius assignment matrix represent the maximum influence radius value among the particles corresponding to the row numbers and the particles corresponding to the column numbers. The row numbers and column numbers of the distance matrix correspond to the particle numbers, respectively, and the elements of the distance matrix represent the distance between the particles corresponding to the row numbers and the particles corresponding to the column numbers. The number of columns of the non-independent matrix is ​​2, the first column is the row number of the comparison matrix, the second column is the column number of the comparison matrix, and the column numbers are sorted from small to large.

[0061] Step S4: Screen all the fragments through the non-independent matrix to obtain the number of fragments, as follows:

[0062] Step S4-1, for the non-independent matrix M, take out all the elements in the second column, remove the repeated elements with the same serial number shown therein, and form an array, named the non-independent array Ms, where i represents the subscript of the matrix and j represents the subscript of the array. Initialize it and set i=1, j=0, and go to step S4-2.

[0063] Step S4-2, select the first element E of the non-independent array Ms, and go to step S4-3.

[0064] Step S4-3, search the first column of the non-independent matrix M for the element set P that has the same sequence number as the element E i , go to step S4-4,

[0065] Step S4-4, search the second column of the non-independent matrix M for the element set Q that has the same sequence number as the element set Pi i , go to step S4-5.

[0066] Step S4-5, search the first column of the non-independent matrix M for the element Q i The set P of elements with the same sequence number i+1 , go to step S4-6,

[0067] Step S4-6, searching the second column of the non-independent matrix M for the element set P i+1 The set Q of elements with the same sequence number i+1 , go to step S4-7.

[0068] Step S4-7, let i=i+1, repeat steps S4-5 to S4-6 until the element set Q i If it is an empty set, go to step S4-8.

[0069] Step S4-8, element E, all element sets P i 、The set of all elements Q i The serial numbers of all elements are listed in an array S j , and remove the array S j If there is a repeated sequence number, go to step S4-9.

[0070] Step S4-9, let j=j+1, in the dependent array Ms, remove the j The same elements in the array are used to obtain a new non-independent array Ms. j , go to step S4-10.

[0071] Step S4-10, for the new dependent array Ms j , repeat steps S4-2 to S4-9 until the new non-independent array Ms j Is empty, get J arrays S j , j takes a value of 1 to 169, and goes to step S4-11.

[0072] Step S4-11, all row numbers of the particle comparison matrix are formed into an array, and after removing the same numbers in the array as those in the dependent array Ms, an independent array P is obtained, which contains 22 elements.

[0073] Step S5, determine the fragment mass, fragment volume, fragment velocity along the X, Y, and Z directions, fragment combined velocity, and fragment center coordinates along the X, Y, and Z directions corresponding to each fragment, and output them.

[0074] Step S5-1, compare the first column numbers of the mass assignment matrix, volume assignment matrix, velocity assignment matrix and coordinate assignment matrix with the first column numbers of the array S jAll rows corresponding to the elements with the same sequence number in are included in a mass information sub-matrix, a volume information sub-matrix, a velocity information sub-matrix and a coordinate information sub-matrix in turn. The non-independent array S j A subscript of corresponds to a quality information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and then the rows corresponding to the elements with the same sequence numbers in the first column of the mass assignment matrix, the volume assignment matrix, the velocity assignment matrix, and the coordinate assignment matrix are separately listed in turn into a quality information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix. One element in the independent array P corresponds to a quality information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and a total of 191 quality information submatrices, 191 volume information submatrices, 191 velocity information submatrices, and 191 coordinate information submatrices are obtained. U is used to represent the sequence numbers of the quality information submatrix, the volume information submatrix, the velocity information submatrix, and the coordinate information submatrix. The u-th quality information submatrix, the u-th volume information submatrix, the u-th velocity information submatrix, and the u-th coordinate information submatrix have the same number of rows num u , each mass information submatrix represents the mass information of the particles contained in a fragment, each volume information submatrix represents the volume information of the particles contained in a fragment, each velocity information submatrix represents the velocity information of the particles contained in a fragment, and each coordinate information submatrix represents the coordinate information of the particles contained in a fragment, and then proceed to step S5-2.

[0075] Step S5-2: Remove the first column of all quality information sub-matrices, and accumulate the quality information sub-matrices to obtain a number representing the quality of the fragments. num u Indicates the number of rows of the u-th quality information submatrix, mass vu is the vth row of the uth quality information submatrix, Mass u is the mass of the uth fragment.

[0076] Remove the first column of all volume information sub-matrices, and accumulate the volume information sub-matrices to get a number representing the fragment volume num u Indicates the number of rows of the u-th volume information submatrix, vol vu is the vth row of the uth volume information submatrix, Vol u is the volume of the u-th fragment.

[0077] Remove the first column of all velocity information submatrices, perform mass-weighted average calculation on the first column of the velocity information submatrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num uIndicates the number of rows of the u-th velocity information submatrix, xvel vu is the 1st column and the vth row of the uth velocity information submatrix, XVel u is the velocity of the uth fragment along the X direction.

[0078] The mass-weighted average calculation is performed on the second column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th velocity information submatrix, yvel vu YVel is the 2nd column and the vth row of the uth velocity information submatrix. u is the velocity of the uth fragment along the Y direction.

[0079] The mass-weighted average calculation is performed on the third column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th velocity information submatrix, zvel vu is the 3rd column and the vth row of the uth velocity information submatrix, ZVel u is the velocity of the uth fragment along the Z direction.

[0080] Remove the first column of all coordinate information sub-matrices, perform mass-weighted average calculation on the first column of the coordinate information sub-matrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num u Indicates the number of rows of the u-th coordinate information submatrix, xcoor vu is the 1st column and the vth row of the uth coordinate information submatrix, XCoor u is the coordinate of the uth fragment along the X direction.

[0081] The mass-weighted average calculation is performed on the second column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th coordinate information submatrix, ycoor vu is the 2nd column and the vth row of the uth coordinate information submatrix, YCoor u is the coordinate of the u-th fragment along the Y direction.

[0082] The mass-weighted average calculation is performed on the third column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th coordinate information submatrix, zcoor vuis the 3rd column and the vth row of the uth coordinate information submatrix, ZCoor u is the coordinate of the u-th fragment along the Z direction.

[0083] The fragment number, mass, three-dimensional velocity, total velocity, and three-dimensional coordinates are output to the result matrix. The total velocity is the modulus of the vector sum of the three-dimensional velocity. Vel u is the total velocity of the u-th fragment. The first column of the result matrix is ​​the fragment serial number. The number of fragments can be known through the serial number. The second column is the mass of the fragment. The third column is the volume of the fragment. The fourth to sixth columns are the speeds of the fragments along the X, Y, and Z directions. The seventh column is the total velocity of the fragments. The eighth to eleventh columns are the coordinates of the center of mass of the fragments along the X, Y, and Z directions. Go to step S5-3.

[0084] Step S5-3: Output the result matrix as a text file.

Claims

1. A fragment identification method based on SPH algorithm of LS-DYNA, It is characterized in that The specific steps are as follows: Step S1, according to the fragmentation simulation containing the SPH algorithm, LS-DYNA is used to calculate and obtain the SPH particle influence radius, mass, volume, velocity and coordinate data information of the whole process, and then the whole SPH particle data information matrix is ​​established. The whole SPH particle data information matrix includes the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix, and then the process goes to step S2; Step S2, according to the actual situation, respectively mirror the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix to obtain the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix, and then re-assign the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix to obtain the influence radius value matrix, the mass value matrix, the volume value matrix, the velocity value matrix and the coordinate value matrix, and then proceed to step S3; Step S3, constructing a non-independent matrix representing the interaction between particles according to the influence radius assignment matrix, the mass assignment matrix, the volume assignment matrix, the velocity assignment matrix and the coordinate assignment matrix, and then proceeding to step S4; Step S4, screening all fragments through the non-independent matrix to obtain the number of fragments, as follows: Step S4-1, for the non-independent matrix M, take out all the elements in the second column, remove the repeated elements with the same sequence number, form an array, named as the non-independent array Ms, where i represents the subscript of the matrix and j represents the subscript of the array, initialize, set i=1, j=0, and go to step S4-2; Step S4-2, select the first element E of the non-independent array Ms, and go to step S4-3; Step S4-3, search the first column of the non-independent matrix M for the element set P that has the same sequence number as the element E i , go to step S4-4, Step S4-4, search the second column of the non-independent matrix M for the element set Q that has the same sequence number as the element set Pi i , go to step S4-5; Step S4-5, search the first column of the non-independent matrix M for the element Q i The set P of elements with the same sequence number i+1 , go to step S4-6, Step S4-6, searching the second column of the non-independent matrix M for the element set P i+1 The set Q of elements with the same sequence number i+1 , go to step S4-7; Step S4-7, let i=i+1, repeat steps S4-5 to S4-6 until the element set Q i If it is an empty set, go to step S4-8; Step S4-8, element E, all element sets P i 、The set of all elements Q i The serial numbers of all elements are listed in an array S j , and remove the array S j If the sequence number is repeated, go to step S4-9; Step S4-9, let j=j+1, in the dependent array Ms, remove the j The same elements in the array are used to obtain a new non-independent array Ms. j , go to step S4-10; Step S4-10, for the new dependent array Ms j , repeat steps S4-2 to S4-9 until the new non-independent array Ms j Is empty, get J arrays S j , j takes a value of 1 to J, and goes to step S4-11; Step S4-11, forming an array with all row numbers of the particle comparison matrix, removing the same numbers in the array as those in the dependent array Ms, and obtaining an independent array P, which contains K elements; Go to step S5; Step S5, determining the fragment mass, fragment volume, fragment velocity along the X, Y, and Z directions, fragment combined velocity, and center of mass coordinates of the fragment along the X, Y, and Z directions corresponding to each fragment, and outputting them.

2. According to the SPH algorithm fragment identification method based on LS-DYNA in claim 1, Features: In step S1, according to the fragmentation simulation containing the SPH algorithm, LS-DYNA is used to calculate and obtain the SPH particle influence radius, mass, volume, velocity and coordinate data information of the whole process, and then establish the data information matrix of all SPH particles. The data information matrix of all SPH particles includes the influence radius information matrix, mass information matrix, volume information matrix, velocity information matrix and coordinate information matrix, which are as follows: According to the fragmentation simulation containing the SPH algorithm, LS-DYNA is used for calculation to obtain the SPH particle influence radius, mass, volume, velocity and coordinate data information of the components composed of SPH particles in the whole process. According to the SPH particle influence radius, mass, volume, velocity and coordinate data information of the whole process, the particle influence radius, mass, volume, velocity and coordinate data information of the moment of interest are extracted and output as a txt text file. The non-digital information in the txt text file is removed to establish the data information matrix of all SPH particles, namely, the influence radius information matrix, mass information matrix, volume information matrix, velocity information matrix and coordinate information matrix.

3. According to the SPH algorithm fragment identification method based on LS-DYNA as described in claim 2, Features: The number of columns in the influence radius information matrix, mass information matrix and volume information matrix are all 2. The first column is the SPH particle number, and the second column corresponds to the influence radius, mass and velocity of the SPH particle respectively; the number of columns in the velocity information matrix is ​​4. The first column is the SPH particle number, and the second to fourth columns are the velocity component values ​​of the SPH particle along the X, Y, and Z directions respectively; the number of columns in the coordinate information matrix is ​​4. The first column is the SPH particle number, and the second to fourth columns are the coordinate component values ​​of the SPH particle along the X, Y, and Z directions respectively.

4. According to claim 3, a fragment identification method based on LS-DYNA using an SPH algorithm, Features: In step S2, according to the actual situation, the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix are mirrored respectively to obtain the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix, and then the influence radius mirror matrix, the mass mirror matrix, the volume mirror matrix, the velocity mirror matrix and the coordinate mirror matrix are reassigned to obtain the influence radius value matrix, the mass value matrix, the volume value matrix, the velocity value matrix and the coordinate value matrix, as follows: Step S2-1, judging whether the data information matrix of all SPH particles is obtained based on the complete model or the symmetric model in actual situation: if the data information matrix of all SPH particles is obtained based on the complete model, reassign the first column of the influence radius information matrix, the mass information matrix, the volume information matrix, the velocity information matrix and the coordinate information matrix from 1 to obtain the data assignment matrix of all SPH particles, and proceed to step S3; if the data information matrix of all SPH particles is obtained based on the symmetric model, proceed to step S2-2; Step S2-2, invert the particle coordinate component value of the coordinate information matrix about the normal direction of the symmetry plane of the symmetry model, and keep the coordinate component values ​​in other directions unchanged, exclude duplicate particles located at the symmetry plane according to the coordinates, and connect the obtained coordinate mirror matrix under the coordinate information matrix in sequence to obtain the coordinate splicing matrix, and then proceed to step S2-3; Step S2-3, the particle velocity component value of the velocity information matrix about the symmetry plane of the symmetry model is inverted, and the velocity component values ​​in other directions remain unchanged. According to the SPH particle number in the first column, the duplicate particles located at the symmetry plane are excluded, and the obtained velocity mirror matrix is ​​sequentially connected under the velocity information matrix to obtain the velocity splicing matrix, and then the process goes to step S2-4; Step S2-4, directly repeat the matrix information of the influence radius information matrix, the mass information matrix and the volume information matrix, exclude the repeated particles located at the symmetry plane according to the SPH particle number in the first column, and the obtained influence radius mirror matrix, mass mirror matrix and volume mirror matrix are connected to the influence radius information matrix, mass information matrix and volume information matrix in sequence, and the influence radius splicing matrix, mass splicing matrix and volume splicing matrix are obtained respectively, and then go to step S2-5; Step S2-5, reassign the first column of the coordinate splicing matrix, velocity splicing matrix, influence radius splicing matrix, mass splicing matrix and volume splicing matrix starting from 1 to obtain the coordinate assignment matrix, velocity assignment matrix, influence radius assignment matrix, mass assignment matrix and volume assignment matrix.

5. According to the SPH algorithm fragment identification method based on LS-DYNA as claimed in claim 4, Features: In step S3, a non-independent matrix characterizing the interaction between particles is constructed according to the influence radius assignment matrix, the mass assignment matrix, the volume assignment matrix, the velocity assignment matrix and the coordinate assignment matrix, as follows: A distance matrix is ​​constructed according to the influence radius assignment matrix. Next, the distance matrix is ​​used as the subtracted matrix, the particle influence radius matrix is ​​used as the subtraction matrix, and the comparison matrix is ​​used as the difference matrix. The diagonal elements of the comparison matrix are set to 0. Finally, the row and column numbers corresponding to all values ​​less than 0 are extracted and arranged to generate a non-independent matrix.

6. According to claim 5, a fragment identification method based on LS-DYNA using an SPH algorithm, Features: The row number and column number of the influence radius assignment matrix correspond to the particle number respectively, and the element of the influence radius assignment matrix represents the maximum influence radius value among the particle corresponding to the row number and the particle corresponding to the column number; The row and column numbers of the distance matrix correspond to the particle numbers respectively, and the elements of the distance matrix represent the distance between the particle corresponding to the row number and the particle corresponding to the column number; The number of columns of the non-independent matrix is ​​2, the first column is the row number of the comparison matrix, the second column is the column number of the comparison matrix, and the column numbers are sorted from small to large.

7. The fragment identification method based on the SPH algorithm of LS-DYNA as claimed in claim 1, Features: In step S5, the number of fragments, the mass of each fragment, the volume of the fragment, the speed of the fragment along the X, Y, and Z directions, the total speed of the fragment, and the coordinates of the center of mass of the fragment along the X, Y, and Z directions are obtained and output as follows: Step S5-1, compare the first column numbers of the mass assignment matrix, volume assignment matrix, velocity assignment matrix and coordinate assignment matrix with the first column numbers of the array S j All rows corresponding to the elements with the same sequence number in are included in a mass information sub-matrix, a volume information sub-matrix, a velocity information sub-matrix and a coordinate information sub-matrix in turn. The non-independent array S j A subscript of corresponds to a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and then the rows corresponding to the elements with the same sequence numbers in the first column of the mass assignment matrix, the volume assignment matrix, the velocity assignment matrix, and the coordinate assignment matrix are separately listed in turn into a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix. An element in the independent array P corresponds to a mass information submatrix, a volume information submatrix, a velocity information submatrix, and a coordinate information submatrix, and a total of J+K mass information submatrices, J+K volume information submatrices, J+K velocity information submatrices, and J+K coordinate information submatrices are obtained. U is used to represent the sequence numbers of the mass information submatrix, the volume information submatrix, the velocity information submatrix, and the coordinate information submatrix. Then the u-th mass information submatrix, the u-th volume information submatrix, the u-th velocity information submatrix, and the u-th coordinate information submatrix have the same number of rows num u , each mass information sub-matrix represents the mass information of the particles contained in a fragment, each volume information sub-matrix represents the volume information of the particles contained in a fragment, each velocity information sub-matrix represents the velocity information of the particles contained in a fragment, and each coordinate information sub-matrix represents the coordinate information of the particles contained in a fragment, and then proceed to step S5-2; Step S5-2: Remove the first column of all quality information sub-matrices, and accumulate the quality information sub-matrices to obtain a number representing the quality of the fragments. num u Indicates the number of rows of the u-th quality information submatrix, mass vu is the vth row of the uth quality information submatrix, Mass u is the mass of the u-th fragment; Remove the first column of all volume information sub-matrices, and accumulate the volume information sub-matrices to get a number representing the fragment volume num u Indicates the number of rows of the u-th volume information submatrix, vol vu is the vth row of the uth volume information submatrix, Vol u is the volume of the uth fragment; Remove the first column of all velocity information submatrices, perform mass-weighted average calculation on the first column of the velocity information submatrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num u Indicates the number of rows of the u-th velocity information submatrix, xvel vu is the 1st column and the vth row of the uth velocity information submatrix, XVel u is the velocity of the uth fragment along the X direction; The mass-weighted average calculation is performed on the second column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th velocity information submatrix, yvel vu YVel is the 2nd column and the vth row of the uth velocity information submatrix. u is the velocity of the u-th fragment along the Y direction; The mass-weighted average calculation is performed on the third column of the velocity information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th velocity information submatrix, zvel vu is the 3rd column and the vth row of the uth velocity information submatrix, ZVel u is the velocity of the uth fragment along the Z direction; Remove the first column of all coordinate information sub-matrices, perform mass-weighted average calculation on the first column of the coordinate information sub-matrix, and obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the X direction. num u Indicates the number of rows of the u-th coordinate information submatrix, xcoor vu is the 1st column and the vth row of the uth coordinate information submatrix, XCoor u is the coordinate of the uth fragment along the X direction; The mass-weighted average calculation is performed on the second column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Y direction. num u Indicates the number of rows of the u-th coordinate information submatrix, ycoor vu is the 2nd column and the vth row of the uth coordinate information submatrix, YCoor u is the coordinate of the u-th fragment along the Y direction; The mass-weighted average calculation is performed on the third column of the coordinate information submatrix to obtain a row matrix. Each element in the row matrix represents the velocity of the fragment along the Z direction. num u Indicates the number of rows of the u-th coordinate information submatrix, zcoor vu is the 3rd column and the vth row of the uth coordinate information submatrix, ZCoor u is the coordinate of the u-th fragment along the Z direction; The fragment number, mass, three-dimensional velocity, total velocity, and three-dimensional coordinates are output to the result matrix. The total velocity is the modulus of the vector sum of the three-dimensional velocity. Vel u is the total velocity of the u-th fragment. The first column of the result matrix is ​​the fragment number, through which the number of fragments can be known. The second column is the mass of the fragment, the third column is the volume of the fragment, the fourth to sixth columns are the velocities of the fragment along the X, Y, and Z directions, the seventh column is the total velocity of the fragment, and the eighth to eleventh columns are the coordinates of the center of mass of the fragment along the X, Y, and Z directions. Go to step S5-3; Step S5-3: Output the result matrix as a text file.

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