CN-115270539-B - Method for creating multiple pelvis upper bone needle distribution optimization finite element models at one time

Abstract

A method for creating multiple pelvis upper spicule distribution optimization finite element models at one time comprises the steps of creating a three-dimensional model of damaged pelvis musculature and spicules, secondarily developing an ABAQUS script file for creating a plurality of finite element models at one time by adopting ABAQUS/Python software, and reading the script file by the ABAQUS software to create n pelvis musculature finite element models containing spicules at one time. The method is based on ABAQUS/Python software, develops a script file secondarily, is used for creating a plurality of finite element models of pelvic skeletal muscle tissues containing bone needles at one time, can avoid repetitive work of finite element modeling, and effectively improves the creation efficiency of the models.

Inventors

• LEI JINGTAO
• WEI YIMIN

Assignees

• 上海大学
• 上海大学

Dates

Publication Date

20260421

Application Date

20220525

Priority Date

20220525

Claims (3)

1. 1. A method for one-time creation of a plurality of optimized finite element models of the distribution of bone needles on pelvis, comprising the following three steps: (1) Creating a three-dimensional model of skeletal muscle tissue and bone needles of the damaged pelvis; (2) Secondarily developing a script file capable of creating a plurality of finite element models based on ABAQUS/Python software, wherein the script file comprises the following components: a) Programming Python language to calculate the spatial pose of n groups of spicules on pelvis and storing in CSV file; b) Reading the spatial pose of n groups of spicules, and creating hole elements of the spicules on a pelvic skeletal muscle tissue model; c) Assembling pelvic skeletal muscle tissue with two bone needles; d) Generating an ABAQUS script file capable of creating n finite element models at one time; (3) The ABAQUS software reads the script file and creates n pelvis bone muscle tissue finite element models containing bone needles at one time; the step (2) comprises the following 4 points: the key point 1 is that Python language programming calculates the space pose vector of the bone needle on the pelvis and stores the space pose vector in a CSV file; aiming at two spicules needing to be placed into the damaged pelvis, the spatial pose of the 1 st spicule is determined according to the fracture type and clinical experience of the damaged pelvis, and the spatial pose of the 2 nd spicule is specifically calculated as follows: The needle point and the needle tail point of the 2 nd bone needle are respectively 、 Wherein Respectively, the two points are in the pelvis coordinate system If the three coordinate components in the model are included, the spatial position and the gesture of the bone needle are uniquely determined by the two points; needle point coordinates of bone setting needle In the pelvic coordinate system The change interval along the three directions of x, y and z is , , Coordinates of needle point of bone needle The point coordinates of the needle points of the kth group of bone needle pose are determined in a uniform way in the interval Where k= (1, 2,., n) is the kth set of spicule tip point coordinates, n is the total number of spicule tips; Coordinates of needle tail point of bone needle Along the pelvic coordinate system The change interval along the three directions of x, y and z is , , The coordinates of the needle tail points of the bone needles are calculated as above, namely the coordinates of the needle tail points of the bone needles of the kth group are calculated as Where k= (1, 2,., n) is the k-th set of spicule tail point coordinates, n is the total number of spicule tail points; From the needle point of the k-th group With the kth needle tail point Can calculate the coordinate of the kth group of spicules in the model coordinate system by combining the length L 0 of the spicules Three azimuth angles in (3) I.e. , , ; Calculating the spatial pose of all the spicules according to the three azimuth angles of the spicule point coordinates and the spicule vectors, and storing the calculation results of the spatial pose of the spicules in a CSV file; The key point 2 is that the pose information of n groups of spicules is read, and the hole elements of the spicules are created on the skeletal muscle tissue model of the pelvis: In software ABAQUS, according to the space pose of n groups of spicules, creating hole elements to be placed into spicules on a skeletal muscle tissue three-dimensional model of pelvis; assembling pelvic skeletal muscle tissue and two bone needle models; After the spicule hole elements in the pelvis model are created, two spicule parts are imported from the Part module through an Assembly module interface, at the moment, the imported pose of the spicule is an initial pose vector, coordinate displacement and angle rotation of the initial pose vector and the target pose vector of the two spicules are determined through Python programming calculation, and the pelvis musculature and the two spicule models are assembled; Generating an ABAQUS script file capable of creating n finite element models at one time; Combining script sentences for reading the space pose of the bone needle, creating fracture hole elements on the pelvis model and assembling the pelvis and the bone needle model together to generate an ABAQUS script file capable of creating n finite element models at one time; the method for creating the spicule hole element in the key point 2 specifically comprises the following steps: Determining auxiliary points on the cylindrical surface of the bone needle according to the read pose of the bone needle, defining three datum points P1, P2 and P3 by using a function DatumPointByCoordinate from the start point, the end point and the auxiliary points of the bone needle vector, creating an auxiliary datum axis by using a function DatumAxisByTwoPoint from the datum points P1 and P2, creating an auxiliary datum plane by using a function DatumPlaneByThreePoints from the datum points P1, P2 and P3, constructing a cross-section sketch of the bone needle on the auxiliary datum plane according to the size parameter of the bone needle, and constructing hole elements needing to be placed into the bone needle on the pelvis model by using a function CutRevolve from the created auxiliary datum axis and the auxiliary datum plane.
2. 2. A method for one-time creation of a plurality of optimized finite element models of bone pin distribution on pelvis according to claim 1, wherein said step (1) specifically comprises: The three-dimensional digital model of the bone muscle tissue of the damaged pelvis is reversely rebuilt by adopting medical image processing software Mimics and reverse engineering software Geomagic Studio, the three-dimensional digital model of the bone muscle tissue of the damaged pelvis is imported from SolidWorks software in a Part module in software ABAQUS, the file expansion name is x_t, a three-dimensional model of a spicule is newly built, and the three-dimensional model of the bone muscle tissue of the damaged pelvis and the spicule is built, wherein the coordinate system of the damaged pelvis is that 。
3. 3. A method for one-time creation of a plurality of optimized finite element models of bone pin distribution on pelvis according to claim 1, wherein said step (3) specifically comprises: and 2, running a Script program in a PDE module in the ABAQUS software, clicking a Run Script under a File menu bar in the ABAQUS, switching a catalog to a storage position of the Script File generated in the selection step 2, selecting the Script File, clicking OK for confirmation, reading the Script File, and creating n finite element models at one time, wherein the n finite element models are three-dimensional finite element models formed by integrating pelvic skeletal muscle tissues and bone needles in different space poses.

Description

Method for creating multiple pelvis upper bone needle distribution optimization finite element models at one time Technical Field The invention relates to a finite element modeling method adopting software secondary development, in particular to a finite element modeling method adopting ABAQUS/Python software secondary development, which is used for creating a plurality of finite element models with optimized distribution of bone needles on pelvis at one time. Background ABAQUS is powerful finite element analysis software, its nonlinear analysis is powerful, and ABAQUS scripts can be developed based on powerful operation kernels. Meanwhile, the ABAQUS software has a better script interface (ASI) which is developed on the basis of Python language, and the operation on the kernel can be realized by calling the kernel by using the Python language. Pelvic fracture reduction surgery, which is usually accompanied by separation of sacroiliac joints, requires external force to guide the fracture to restore the fracture to a correct anatomical position, is mainly performed by placing a plurality of spicules on the affected side of the pelvis and reducing the fracture by moving the spicules. The working condition structure of pelvis fracture reduction is complex, traditional operation relies on experience of doctors, and the space position and posture of the distributed spicules placed in pelvis are determined according to clinical operation experience of doctors. The robot assists the reduction of the pelvis fracture, 2-3 bone needles are needed to be placed in the bone blocks at the affected side of the pelvis to stably clamp the pelvis, the bone needles are used as important elements for the transmission of the reduction force, and the spatial pose of the placed bone blocks is closely related to the stability of the clamping of the pelvis, the precision of the reduction operation and the safety. Therefore, it is necessary to perform an optimization analysis on the spatial pose of the plurality of spicules placed in the pelvis, and an optimal distribution of the plurality of spicules placed in the pelvis can be determined by using a finite element method. The pelvic bone needle space pose distribution optimization is the optimization taking the distribution uniformity of pelvic stress in operation as an objective function. Due to the nonlinear, viscoelastic and heterogeneous material characteristics of the pelvic fracture tissue, it is difficult to establish an optimized objective function for optimal analysis of the stress distribution uniformity of the pelvic fracture tissue. And when the space position of the spicule is determined by optimizing the distribution of the pelvic stress in the operation through finite element simulation software, a three-dimensional model of the pelvic bone muscle tissue containing spicules in different space positions needs to be created. Aiming at the technical difficulties, the invention aims at modeling problems of the space pose optimization of the bone needles placed in the pelvis, and relates to a method for one-time creation of a plurality of bone needle distribution optimization finite element models on the pelvis, which can avoid repetitive work of finite element modeling and effectively improve the efficiency of model creation. Disclosure of Invention Aiming at the technical problems, the invention relates to a method for creating a plurality of pelvis bone pin distribution optimization finite element models at one time, which is used for solving the complex repeatability and modeling the finite element models. The stress distribution of a plurality of spicules placed in different spaces of pelvis and damaged skeletal muscle tissues of pelvis under the action of large restoring force is studied, and the creation of a finite element model is realized by presetting the space pose information of the different spicules by adopting a method of secondarily developing ABAQUS software by Python. A method for one-time creating a plurality of pelvis bone pin distribution optimization finite element models, which specifically comprises three steps: Step 1, creating a three-dimensional model of skeletal muscle tissue and bone needles of a damaged pelvis; Step 2, adopting ABAQUS/Python software to secondarily develop an ABAQUS script file capable of creating a plurality of finite element models; and 3, the ABAQUS software reads the script file and creates n pelvis bone muscle tissue finite element models containing bone needles at one time. Step 1, three-dimensional model creation of skeletal muscle tissue and spicule of damaged pelvis 1. Three-dimensional model for reverse reconstruction injury of pelvic skeletal muscle tissue According to the CT scan data of the pelvis fracture of a patient, combining human anatomy, using medical image processing software Mimics and reverse engineering software Geomagic Studio, adopting a segmentation method of contour extraction and layer-by-layer e