Dura mater cutting simulation method based on fracture mechanics, storage medium and computer

Abstract

The present invention relates to the field of virtual reality technology, and provides a simulation method for dura mater cutting based on fracture mechanics, a storage medium, and a computer. The dura mater tissue model is obtained according to position dynamics, and the cutting influence unit body is obtained by using the nodes therein as the tetrahedron vertices. Mechanical analysis is performed on each cutting influence unit body to obtain the von Mises equivalent stress of each cutting influence unit body. Furthermore, the state of each cutting influence unit body can be accurately judged according to the von Mises equivalent stress, improving the judgment accuracy of whether a cut is formed and enhancing the simulation effect. Moreover, different analysis methods can be adopted for the cutting influence unit bodies in the elastic deformation state, plastic damage state, and fragmentation state, reducing the demand for computing power and improving the simulation real-time performance. The present invention can effectively improve the cutting simulation effect of the dura mater tissue model, providing convenience for the application of dura mater cutting simulation.

Description

Technical Field

[0001] The present invention relates to the technical field of virtual reality, and particularly relates to a method for simulating dural incision based on fracture mechanics, a storage medium, and a computer. Background Art

[0002] The dura mater is a tough connective tissue membrane attached to the inner surface of the skull, composed of glial fibers and elastic fibers, and continues with the spinal dura mater at the foramen magnum. Dural incision surgery is a key technical link in neurosurgery, skull base surgery, and spinal surgery. Its purpose is to expose the soft tissues of the brain for further operations. The surgery requires high precision, and surgeons need sufficient training to ensure surgical safety.

[0003] Traditional surgical training relies on cadaver dissection, animal experiments, or real surgical operations under the supervision of a tutor, which has ethical controversies, biosafety risks (such as infection), and patient safety pressure. With the development of technology, the application of virtual reality technology in neurosurgical simulation has gradually become an important supplement to traditional surgical training methods, which can effectively improve the training effect.

[0004] In the prior art, common virtual cutting simulation techniques include the finite element method (FEM), the particle spring model (MSM), the meshless method, and the position-based dynamics (PBD) method. Among them, the PBD method has high computational performance and good real-time performance compared with other methods and is widely used in dural tissue models. However, it updates the model state in cutting simulation based on geometric constraints, and its simulation ability for actual physical rupture behavior is insufficient, resulting in insufficient simulation authenticity and difficulty in meeting the precision requirements of neurosurgical operations, which is not conducive to the practical application of virtual cutting simulation technology. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a method for simulating dural incision based on fracture mechanics, a storage medium, and a computer, so as to solve the problem that the dural tissue model constructed based on position-based dynamics has insufficient simulation ability for actual physical rupture behavior, resulting in insufficient simulation authenticity and difficulty in meeting the precision requirements of neurosurgical operations.

[0006] One aspect of the present invention provides a method for simulating dural incision based on fracture mechanics, including:

[0007] Obtaining a dural tissue model according to position-based dynamics, and performing collision detection based on the dural tissue model and an instrument model to obtain a cutting influence area of the dural tissue model, and obtaining cutting influence nodes according to the cutting influence area;

[0008] Obtain cutting influence unit cells based on the cutting influence nodes, and perform mechanical analysis on each of the cutting influence unit cells to obtain the von Mises equivalent stress of each of the cutting influence unit cells;

[0009] Judge the state of each of the cutting influence unit cells according to the von Mises equivalent stress, and update the dura mater tissue model according to the state of each of the cutting influence unit cells and the corresponding analysis method;

[0010] Among them, the states of the cutting influence unit cells include elastic deformation state, plastic damage state and fragmentation state, and the cutting influence unit cells are tetrahedrons.

[0011] Optionally, the steps of updating the dura mater tissue model according to the state of each of the cutting influence unit cells and the corresponding analysis method include:

[0012] Perform elastic deformation analysis based on position dynamics on the cutting influence unit cells in the elastic deformation state to update the vertex positions of the corresponding cutting influence unit cells, and further update the dura mater tissue model;

[0013] Perform stiffness analysis on the cutting influence unit cells in the plastic damage state to update the dura mater tissue model according to the stiffness change information of the corresponding cutting influence unit cells;

[0014] Delete the cutting influence unit cells in the fragmentation state, define the nodes whose connected unit cells are all deleted as invalid nodes, and define other nodes as valid nodes;

[0015] Delete the invalid nodes, and distribute the mass of the invalid nodes to the adjacent valid nodes;

[0016] Perform incision smoothing on the remaining valid nodes on the newly added incision surface to update the dura mater tissue model.

[0017] Optionally, the steps of performing incision smoothing on the remaining valid nodes on the newly added incision surface include:

[0018] Obtain the cutting plane and the maximum cutting width according to the movement characteristics of the instrument model;

[0019] Define the valid nodes that make up the incision as incision nodes, obtain the current distance from the incision nodes to the cutting plane according to the cutting plane, and obtain the ideal distance from the incision nodes to the cutting plane according to the maximum cutting width;

[0020] Obtain the normal deviation according to the difference between the ideal distance and the current distance, and update the positions of the incision nodes in combination with the position change amount obtained by the elastic deformation analysis of the incision nodes based on position dynamics.

[0021] Optionally, the step of performing position dynamics elastic deformation analysis to update the vertex positions of the corresponding cutting influence unit cells includes:

[0022] Update the position information of each node according to the positions of the nodes to update the model;

[0023] Correct the updated position information according to the position constraint model, distance constraint model, and volume preservation model so that the distances between the nodes are consistent with the desired distances and the volumes of the unit cells are kept constant.

[0024] Optionally, it further includes: obtaining a cutting stiffness force according to the normal component of the Cauchy stress tensor in the dura mater tissue model, and obtaining a cutting force by combining the friction force between the dura mater tissue model and the instrument model.

[0025] Optionally, the step of performing collision detection according to the dura mater tissue model and the instrument model to obtain the cutting influence area of the dura mater tissue model, and obtaining the cutting influence nodes according to the cutting influence area includes:

[0026] Before performing collision detection, divide the simulation space into cubes;

[0027] And during collision detection, mark the cube where the contact point between the dura mater tissue model and the instrument model is located and the adjacent cubes as the cutting influence area;

[0028] Take all the nodes of the unit cells in the dura mater tissue model associated with the cutting influence area as the cutting influence nodes.

[0029] Optionally, the step of performing mechanical analysis on each of the cutting influence unit cells to obtain the von Mises equivalent stress of each of the cutting influence unit cells includes:

[0030] Obtain the first Piola-Kirchhoff stress tensor of the cutting influence unit cell according to the strain energy density function;

[0031] Obtain the Cauchy stress tensor of the cutting influence unit cell according to the first Piola-Kirchhoff stress tensor;

[0032] Obtain the von Mises equivalent stress of the cutting influence unit cell according to the Cauchy stress tensor.

[0033] Optionally, the step of judging the state of each of the cutting influence unit cells according to the von Mises equivalent stress includes:

[0034] Mark the state of the cutting influence unit cell with a von Mises equivalent stress less than the damage stress threshold as the elastic deformation state;

[0035] Mark the state of the cutting influence element with the von Mises equivalent stress greater than the fracture stress threshold as the fractured state;

[0036] Mark the state of the cutting influence element with the von Mises equivalent stress in the closed interval from the damage stress threshold to the fracture stress threshold as the plastic damage state.

[0037] On the other hand, the present invention provides a storage medium, which is a computer-readable storage medium. A computer program is stored in the computer-readable storage medium. When the computer program is read and run by a processor, the above-mentioned dural mater cutting simulation method based on fracture mechanics can be realized.

[0038] The present invention also provides a computer. A computer program is stored in the computer. When the computer program is read and run by a processor, the above-mentioned dural mater cutting simulation method based on fracture mechanics can be realized.

[0039] The dural mater cutting simulation method based on fracture mechanics provided by the present invention obtains a dural mater tissue model according to position dynamics, and uses the nodes therein as the vertices of tetrahedrons to obtain cutting influence elements. Mechanical analysis is performed on each cutting influence element to obtain the von Mises equivalent stress of each cutting influence element; furthermore, the state of each cutting influence element can be accurately judged according to the von Mises equivalent stress. By distinguishing the state transition, the judgment accuracy of the rupture position and the fracture timing can be improved, the judgment accuracy of whether a cut is formed can be improved, and the simulation effect can be improved; moreover, different analysis methods can be adopted for the cutting influence elements in the elastic deformation state, plastic damage state and fractured state, reducing the demand for computing power, improving the real-time update of the dural mater tissue model state, further improving the simulation effect, and facilitating the application of dural mater cutting simulation. Description of the Drawings

[0040] Figure 1 It is a schematic diagram of the main process of the dural mater cutting simulation method based on fracture mechanics in the embodiment of the present invention.

[0041] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0042] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0043] It should be noted that when an element is referred to as "fixedly provided on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are only for the purpose of illustration.

[0044] Unless otherwise defined, all technical and scientific terms used in this article have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the description of this invention in this article are only for the purpose of describing specific embodiments and are not intended to limit this invention. The term "and / or" used in this article includes any and all combinations of one or more of the related listed items.

[0045] To solve the problem that the simulation ability of the dura mater tissue model constructed based on position dynamics for actual physical rupture behavior is insufficient, resulting in insufficient simulation authenticity and difficulty in meeting the accuracy requirements of neurosurgery. The present invention provides a dura mater cutting simulation method based on fracture mechanics. Based on the dura mater tissue model obtained according to position dynamics, the cutting influence unit body is obtained by using the nodes therein as the vertices of the tetrahedron, and mechanical analysis is performed on each cutting influence unit body to obtain the von Mises equivalent stress of each cutting influence unit body; furthermore, the state of each cutting influence unit body can be accurately judged according to the von Mises equivalent stress, improving the judgment accuracy of whether an incision is formed and the simulation effect; and different analysis methods can be adopted for the cutting influence unit bodies in the elastic deformation state, plastic damage state and broken state, reducing the demand for computing power, improving the real-time update of the state of the dura mater tissue model, further improving the simulation effect, and providing convenience for the application of dura mater cutting simulation.

[0046] Specifically, as Figure 1 shown, it is a schematic diagram of the main process of the dura mater cutting simulation method based on fracture mechanics in this embodiment, including:

[0047] Step S01: Obtain the dura mater tissue model according to position dynamics, and perform collision detection according to the dura mater tissue model and the instrument model to obtain the cutting influence area of the dura mater tissue model, and obtain the cutting influence nodes according to the cutting influence area;

[0048] Step S02: Obtain the cutting influence unit bodies according to the cutting influence nodes, and perform mechanical analysis on each cutting influence unit body to obtain the von Mises equivalent stress of each cutting influence unit body;

[0049] Step S03: Determine the states of the respective cutting-affected unit cells according to the von Mises equivalent stress, and update the dura mater tissue model according to the states of the respective cutting-affected unit cells and the corresponding analysis methods.

[0050] Among them, the states of the cutting-affected unit cells include elastic deformation state, plastic damage state, and fragmentation state, and the cutting-affected unit cells are tetrahedrons.

[0051] In step S01, multiple tetrahedral unit cells are also divided with the nodes of the dura mater tissue model as vertices. To reduce computing power, step S01 specifically includes: before performing collision detection, dividing the simulation space into cubes; and when collision detection occurs, marking the cube where the contact point between the dura mater tissue model and the instrument model is located and its adjacent cubes as the cutting-affected area; taking all the nodes of the unit cells in the dura mater tissue model associated with the cutting-affected area as the cutting-affected nodes.

[0052] Among them, the simulation space can completely accommodate the dura mater tissue model and the instrument model, and there is an activity space for the instrument model to move. The size of the cube is calibrated according to the actual cutting-affected area, and specific data thereof is not particularly limited in this application. Through the division of the cube, the cutting-affected nodes can be quickly located, avoiding global analysis, thereby reducing the amount of data processing and improving the simulation response speed.

[0053] The association between the unit cells of the dura mater tissue model and the cutting-affected area mainly includes two cases: the unit cell is included in the cutting-affected area and the unit cell intersects with the cutting-affected area.

[0054] In step S02, the mechanical analysis includes: obtaining the first Piola-Kirchhoff stress tensor of the cutting-affected unit cell according to the strain energy density function, obtaining the Cauchy stress tensor of the cutting-affected unit cell according to the first Piola-Kirchhoff stress tensor, and obtaining the von Mises equivalent stress of the cutting-affected unit cell according to the Cauchy stress tensor.

[0055] Among them, the designed calculation formulas include:

[0056] ;

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] Among them, W is the strain energy density, and the Lamé parameters determined by the Young's modulus and Poisson's ratio of the material respectively, F is the deformation gradient, X is the initial vertex position matrix, x is the current vertex position matrix, is the transpose of F, is the transpose of the inverse matrix of F, is the trace operator, J is the volume change ratio, P is the first Piola-Kirchhoff stress tensor, σ is the Cauchy stress tensor, is the von Mises equivalent stress (vm is its subscript for identification), are the components of the Cauchy stress tensor (i, j take values in 1, 2, 3).

[0062] Based on the research data, the ultimate tensile strength of the dura mater of patients who need surgery is generally 7.01 ± 0.77 MPa. That is, when the von Mises equivalent stress is less than 7.01 - 0.77 = 6.24 MPa, the dura mater will not be damaged and only elastic deformation occurs; when the von Mises equivalent stress is greater than 7.01 + 0.77 = 7.78 MPa, the dura mater breaks and can be cut; when the von Mises equivalent stress is in the closed interval of 6.24 MPa to 7.78 MPa, plastic damage occurs.

[0063] According to the ultimate tensile strength of the dura mater, the damage stress threshold and the fracture stress threshold can be confirmed. Furthermore, the state of the cutting influence element with the von Mises equivalent stress less than the damage stress threshold can be marked as the elastic deformation state; the state of the cutting influence element with the von Mises equivalent stress greater than the fracture stress threshold can be marked as the fracture state; the state of the cutting influence element with the von Mises equivalent stress in the closed interval from the damage stress threshold to the fracture stress threshold can be marked as the plastic damage state. Among them, the specific value of the ultimate tensile strength of the dura mater generally varies according to the patient's age, tissue lesion situation, etc. According to its variation range, the number of data samples in the database can be increased to improve the simulation coverage of various actual surgical situations.

[0064] For different states, different analysis methods can be selected to improve the analysis speed and the accuracy of the simulation state change. Specifically, in step S03, it includes:

[0065] For the cutting influence element in the elastic deformation state, perform elastic deformation analysis based on position dynamics to update the vertex position of the corresponding cutting influence element, and then update the dura mater tissue model;

[0066] For the cutting influence element in the plastic damage state, perform stiffness analysis to update the dura mater tissue model according to the stiffness change information of the corresponding cutting influence element;

[0067] Delete the cutting influence unit bodies in a broken state, define the nodes where all connected unit bodies are deleted as invalid nodes, and define other nodes as valid nodes; delete the invalid nodes, and distribute the mass of the invalid nodes to adjacent valid nodes; perform incision smoothing on the remaining valid nodes on the newly added incision surface to update the model and update the dura mater tissue model.

[0068] Specifically, the elastic deformation analysis based on position dynamics includes: updating the position information of each node according to the positions of the nodes to update the model; correcting the updated position information according to the position constraint model, distance constraint model, and volume preservation model so that the distances between the nodes are consistent with the expected distances and the volumes of the unit bodies remain constant. Among them, the involved calculation formulas include:

[0069] ;

[0070] ;

[0071] ;

[0072] ;

[0073] ;

[0074] Among them, represents the position of node at time step , represents the position of node at time step , represents the velocity of node i at time step , is the time step size, is the position change of node , s is the offset used to adjust the node position, is the weight of node i, is the mass of node i, C is the constraint function, ∇ is the gradient operator, is the gradient of the constraint, representing the direction and amplitude that node i needs to move, is the distance constraint function between node i and node j of the vector, and are the positions of node i and node j, is the expected distance between node i and node j, is the current distance between node i and node j, is the vertex position of the tetrahedral element, is the volume constraint function of the tetrahedral element, and V is the maintained volume of the tetrahedral element.

[0075] The calculation formulas involved in the stiffness analysis include:

[0076] ;

[0077] ;

[0078] ;

[0079] Among them, D is the damage variable, is the damage stress threshold, is the fracture stress threshold, is the normal equivalent stress, n is the stiffness loss rate control parameter, k is the stiffness coefficient, is the gradient of the constraint, max() is the maximum value operator, and min() is the minimum value operator.

[0080] The calculation formulas for distributing the mass of the invalid node to the adjacent valid nodes include:

[0081] ;

[0082] Among them, represents the mass increment of the valid node j adjacent to the invalid node, m is the mass of the invalid node, and N is the number of valid nodes j adjacent to the invalid node.

[0083] The steps for smoothing the remaining valid nodes on the newly added incision surface include: obtaining the cutting plane and the maximum cutting width according to the movement characteristics of the appliance model; defining the valid nodes that form the incision as incision nodes, obtaining the current distance from the incision nodes to the cutting plane according to the cutting plane, and obtaining the ideal distance from the incision nodes to the cutting plane according to the maximum cutting width; obtaining the normal deviation according to the difference between the ideal distance and the current distance, and updating the positions of the incision nodes in combination with the position changes obtained by the position dynamics elastic deformation analysis of the incision nodes. Among them, the calculation formulas involved include:

[0084] ;

[0085] ;

[0086] ;

[0087] ;

[0088] ;

[0089] Among them, is the adjustment amount of the incision node in the normal vector direction of the cutting plane, is the position adjustment amount of the incision node, is the ideal distance from the incision node to the cutting plane obtained according to the maximum cutting width, is the distance from the incision node to the cutting plane, is the normal vector of the cutting plane; is the reference point on the cutting plane, which means the position vector of a fixed reference point on the cutting plane; is the velocity direction of the appliance model, is the unit vector perpendicular to the upper surface of the dura mater tissue model and downward. is the position vector of the incision node in the dura mater tissue model at time t representing the coordinates of the node in three-dimensional space. is the final position adjustment amount of the incision node i, and × is the cross product operator of vectors, is the maximum cutting width, and the variable R represents the smaller one of the ratios of the distances from the projection points of the boundary nodes on the cutting surface to the cutting start point and the end point.

[0090] Among them, in a specific example, when then ; when then ; when then .

[0091] To obtain the cutting force, in this embodiment, it includes: obtaining the cutting stiffness force according to the normal component of the Cauchy stress tensor in the dura mater tissue model, and combining the friction force between the dura mater tissue model and the appliance model to obtain the cutting force. Among them, the involved calculation formulas include:

[0092] ;

[0093] ;

[0094] ;

[0095] Among them, is the cutting force, is the stiffness force, is the friction force between the appliance model and the dura mater tissue model, is the contact area between the appliance model and the dura mater tissue model, is the normal component of the Cauchy stress tensor along the path direction of the appliance model, reflecting the normal stress per unit area, is the friction coefficient, It is the normal contact force at the contact surface between the instrument model and the dura mater tissue model.

[0096] The present invention also provides a storage medium, which is a computer-readable storage medium. A computer program is stored in the computer-readable storage medium. When the computer program is read and run by a processor, the above-mentioned dural mater cutting simulation method based on fracture mechanics can be realized.

[0097] Those skilled in the art can understand that the logic or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable storage medium for use by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus or device and execute the instructions), or in combination with these instruction execution systems, apparatus or devices. For the purposes of this specification, a "computer-readable storage medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus or device.

[0098] More specific examples (non-exhaustive list) of computer-readable storage media include the following: an electrical connection part (electronic device) having one or more wirings, a portable computer disk cartridge (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, a computer-readable storage medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, then editing, interpreting, or otherwise processing it as appropriate, and then storing it in a computer memory.

[0099] The present invention also provides a computer. A computer program is stored in the computer. When the computer program is read and run by a processor, the above-mentioned dural mater cutting simulation method based on fracture mechanics can be realized.

[0100] The dural incision simulation method based on fracture mechanics provided by the present invention obtains a dural tissue model according to position dynamics, and uses the nodes therein as the vertices of tetrahedrons to obtain cutting influence unit bodies, and performs mechanical analysis on each cutting influence unit body to obtain the von Mises equivalent stress of each cutting influence unit body; furthermore, the state of each cutting influence unit body can be accurately judged according to the von Mises equivalent stress, improving the judgment accuracy of whether an incision is formed and the simulation effect; and different analysis methods can be adopted for the cutting influence unit bodies in the elastic deformation state, plastic damage state and fragmentation state. While ensuring the incision judgment accuracy, the demand for computing power can be reduced, the real-time performance of the dural tissue model state update can be improved, and the simulation effect can be further improved, providing convenience for the application of dural incision simulation.

[0101] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0102] The above-described embodiments only represent several specific implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as a limitation on the scope of the invention patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent of the present invention should be subject to the appended claims.

Claims

1. A simulation method for dural incision based on fracture mechanics, characterized in that Including: Obtain a dura mater tissue model according to position dynamics, perform collision detection based on the dura mater tissue model and an instrument model to obtain a cutting influence area of the dura mater tissue model, and obtain cutting influence nodes according to the cutting influence area; Obtain cutting influence unit cells according to the cutting influence nodes, and perform mechanical analysis on each of the cutting influence unit cells to obtain the von Mises equivalent stress of each of the cutting influence unit cells; Judge the states of each of the cutting influence unit cells according to the von Mises equivalent stress, and update the dura mater tissue model according to the states of each of the cutting influence unit cells and corresponding analysis methods; Wherein, the states of the cutting influence unit cells include an elastic deformation state, a plastic damage state, and a fragmentation state, the cutting influence unit cells are tetrahedrons, and the steps of updating the dura mater tissue model according to the states of each of the cutting influence unit cells and corresponding analysis methods include: Perform elastic deformation analysis based on position dynamics on the cutting influence unit cells in the elastic deformation state to update the vertex positions of the corresponding cutting influence unit cells, and further update the dura mater tissue model; Perform stiffness analysis on the cutting influence unit cells in the plastic damage state to update the dura mater tissue model according to the stiffness change information of the corresponding cutting influence unit cells; Delete the cutting influence unit cells in the fragmentation state, define the nodes whose connected unit cells are all deleted as invalid nodes, and define other nodes as valid nodes; Delete the invalid nodes, and distribute the mass of the invalid nodes to the adjacent valid nodes; Perform incision smoothing on the remaining valid nodes on the newly added incision surface to update the dura mater tissue model.

2. The method for simulating dural incision based on fracture mechanics according to claim 1, wherein The steps of performing incision smoothing on the remaining valid nodes on the newly added incision surface include: Obtain a cutting plane and a maximum cutting width according to the movement characteristics of the instrument model; Define the valid nodes constituting the incision as incision nodes, obtain the current distance from the incision nodes to the cutting plane according to the cutting plane, and obtain the ideal distance from the incision nodes to the cutting plane according to the maximum cutting width; Obtain a normal deviation according to the difference between the ideal distance and the current distance, and update the positions of the incision nodes in combination with the position change amounts obtained by the elastic deformation analysis of the incision nodes based on position dynamics.

3. The method for simulating the dural incision based on fracture mechanics according to claim 2, wherein The steps of performing elastic deformation analysis based on position dynamics to update the vertex positions of the corresponding cutting influence unit cells include: Update the position information of each node according to the position of the node to update the model; Correct the updated position information according to a position constraint model, a distance constraint model, and a volume conservation model so that the distances between the nodes are consistent with the expected distances and the volumes of the unit cells are kept constant.

4. The method for simulating dural incision based on fracture mechanics according to claim 1, characterized in that, Also including: Obtain a cutting stiffness force according to the normal component of the Cauchy stress tensor in the dura mater tissue model, and obtain a cutting force in combination with the frictional force between the dura mater tissue model and the instrument model.

5. The method for simulating dural incision based on fracture mechanics according to claim 1, wherein Collision detection is performed based on the dura mater tissue model and the instrument model to obtain the cutting influence area of the dura mater tissue model. The steps of obtaining the cutting influence nodes according to the cutting influence area include: Before performing collision detection, the simulation space is divided into cubes; When collision detection occurs, the cube where the contact point of the dura mater tissue model and the instrument model is located and its adjacent cubes are marked as the cutting influence area; All nodes of the unit cells in the dura mater tissue model associated with the cutting influence area are used as the cutting influence nodes.

6. The method for simulating dural incision based on fracture mechanics according to claim 5, characterized in that, The steps of performing mechanical analysis on each of the cutting influence unit cells to obtain the von Mises equivalent stress of each of the cutting influence unit cells include: Obtaining the first Piola-Kirchhoff stress tensor of the cutting influence unit cell according to the strain energy density function; Obtaining the Cauchy stress tensor of the cutting influence unit cell according to the first Piola-Kirchhoff stress tensor; Obtaining the von Mises equivalent stress of the cutting influence unit cell according to the Cauchy stress tensor.

7. The method for simulating dural incision based on fracture mechanics according to claim 6, wherein, The steps of judging the state of each of the cutting influence unit cells according to the von Mises equivalent stress include: Marking the state of the cutting influence unit cell with a von Mises equivalent stress less than the damage stress threshold as the elastic deformation state; Marking the state of the cutting influence unit cell with a von Mises equivalent stress greater than the fracture stress threshold as the fracture state; Marking the state of the cutting influence unit cell with a von Mises equivalent stress in the closed interval from the damage stress threshold to the fracture stress threshold as the plastic damage state.

8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored in the computer-readable storage medium. When the computer program is read and run by a processor, the method for simulating dura mater cutting based on fracture mechanics according to any one of claims 1 to 7 can be implemented.

9. A computer, characterized in that, A computer program is stored in the computer. When the computer program is read and run by a processor, the method for simulating dura mater cutting based on fracture mechanics according to any one of claims 1 to 7 can be implemented.

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