A numerical simulation method for multi-layer soft tissue flexibility interaction based on Abaqus / CAE

Abstract

The present invention discloses a multi-layer soft tissue flexible interactive numerical simulation method based on Abaqus / CAE, which relates to the field of acupuncture and moxibustion, and specifically includes S1: establishing a simplified three-dimensional model and an assembly; S2: importing the model into Abaqus / CAE; S3: setting cross-section properties and material properties for the needles, skin layer, fat layer and muscle layer in step S1; S4: assembling components and setting analysis steps; S5: contact setting and partial rigidification; S6: completing boundary conditions and loading conditions through a boundary condition manager, layering the Euler body according to step S2, selecting the air layer Void, the skin layer, the fat layer and the muscle layer to complete the assignment; S7: meshing the needles and the Euler body; S8: setting a solution model; S9: post-processing and analyzing and evaluating the simulation results. The present invention adopts the above-mentioned simulation method to establish a multi-layer soft tissue model of skin, fat and muscle, avoids the single three-dimensional model from being unable to correctly characterize the mechanical properties of the acupuncture process, and improves the simulation accuracy.

Description

Technical Field

[0001] The invention relates to the field of acupuncture simulation, and in particular to an Abaqus / CAE-based multi-layer soft tissue flexible interactive numerical simulation method. Background Art

[0002] Flexible interactive numerical simulation methods for multi-layer soft tissues are widely used in biomedical engineering, virtual reality, animation production and other fields. However, the current traditional simulation methods have the following disadvantages:

[0003] The mechanical properties of soft tissues are complex and vary greatly between individuals, making it very difficult to construct an accurate mechanical model. In multi-layer soft tissue simulation, accurately setting boundary conditions and handling the contact between different tissues are critical, but they can also easily introduce errors.

[0004] The existing technologies all use the default Lagrangian mesh in the meshing stage when simulating and analyzing soft tissue models with acupuncture. However, the simulation accuracy of this model is low when simulating models with large material fluidity, high uncertainty, and mesh distortion or distortion. In addition, on three-dimensional models, the existing technologies all use a single model and assign a single material, which cannot better simulate the mechanical properties of the needle penetrating the skin tissue and then entering the muscle tissue during acupuncture.

[0005] Therefore, it is necessary to provide a multi-layer soft tissue flexibility interaction numerical simulation method based on Abaqus / CAE to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-layer soft tissue flexible interactive numerical simulation method based on Abaqus / CAE, establish a multi-layer soft tissue model of skin, fat and muscle, avoid the single three-dimensional model can not correctly characterize the mechanical properties of the acupuncture process, apply the same motion load as the actual acupuncture technique, simulate the lifting, insertion, twisting and other actions in acupuncture, so that the simulation results are more scientific and accurate.

[0007] To achieve the above object, the present invention provides a multi-layer soft tissue flexibility interaction numerical simulation method based on Abaqus / CAE, comprising the following steps:

[0008] S1: Establish a finite element model of the three layers of skin, fat and muscle, determine the geometric dimensions of the needles, skin layer, fat layer and muscle layer, and the air layer Void required for setting the Euler body in Abaqus, and convert the assembly into .step format for export after completion;

[0009] S2: Import the model into Abaqus / CAE and start simulation, specifically including importing the assembly obtained in step S1 into the component function module and cutting the milli-needle and Euler body;

[0010] S3: setting cross-sectional properties and material properties for the needles, skin layer, fat layer and muscle layer in step S1;

[0011] S4: Assemble the two components of the needle and the Euler body, and set the type and analysis step time length through the analysis step manager;

[0012] S5: Set the contact properties through the interaction property manager and set the rear half of the needle as a rigid body through the constraint manager;

[0013] S6: Complete the boundary conditions and loading conditions through the boundary condition manager, layer the Euler body according to step S2, select the air layer Void, skin layer, fat layer and muscle layer in turn, and complete the assignment;

[0014] S7: Meshing of the needles and the Euler body;

[0015] S8: Set up the solution model;

[0016] S9: Post-processing analyzes and evaluates the simulation results.

[0017] Preferably, in step S1, the geometric dimensions include the thickness of the needle body and the thickness of each layer. The geometric model is established using Solidworks, and when Abaqus is used to establish the assembly, the needle is inserted into the air layer but does not contact the skin layer.

[0018] Preferably, in step S2, a cutting surface is set on the fine needle at 3 / 8 of the distance from the end; the Euler body includes three cutting surfaces, corresponding to the air layer and the skin layer, the skin layer and the fat layer, and the fat layer and the muscle layer, respectively. The cutting surfaces are set at corresponding positions at a distance of 3 / 8, 7 / 16, and 23 / 32 of the thickness of the Euler body from the upper surface of the Euler body, i.e., the upper surface of the air layer.

[0019] Preferably, in step S3, setting the material properties specifically includes the following steps:

[0020] S30: Open the material manager, click Create, and set parameters including density, Young's modulus, Poisson's ratio, and failure criterion of the material;

[0021] Setting section properties includes the following steps:

[0022] S31: Open the Section Manager, click Create, and set the needle to solid and homogeneous sections, and the Euler body to Euler type sections;

[0023] S32: Open the section assignment manager, click Create, and assign the material set in step S30 to the section in step S31.

[0024] Preferably, step S4 specifically includes the following steps:

[0025] S41: Click Create Instance, select the two parts of the needle and the Euler body for assembly;

[0026] S42: Open the analysis step manager, click Create, select "Dynamic, Explicit" as the type, turn on "Geometric Nonlinearity", and set the analysis step time length;

[0027] S43: Comprehensively consider the numerical simulation calculation efficiency and calculation accuracy, and make appropriate mass scaling settings;

[0028] S44: Open the field output request manager and the process output request manager, and check the required simulation data.

[0029] Preferably, step S5 specifically includes the following steps:

[0030] S51: Open the Interaction Properties Manager, click Create, select the "Contact" type, and set the contact properties;

[0031] S52: Open the interaction manager, select "General Contact Explicit" as the type, and select the contact properties set in step S51 as the attribute assignment;

[0032] S53: Open the constraint manager, click Create, select "Rigid Body" as the type, select the back half of the needle as the "Region Type", and set the reference point to the center of the plane at the end of the needle.

[0033] Preferably, in step S6, the following steps are specifically included:

[0034] S61: Open the boundary condition manager and create boundary conditions:

[0035] Condition 1: Select the "Symmetric / Antisymmetric / Completely Fixed" type and set the bottom surface of the Euler body to be completely fixed;

[0036] Condition 2: Select the "Displacement / Rotation" type and set the X-direction displacement of the front and back faces to 0;

[0037] Condition 3: Select the "Displacement / Rotation" type and set the Y-direction displacement of the left and right faces to 0;

[0038] S62: The loading condition is set as the linear velocity of the reference point at the end of the needle along the Z direction and the angular velocity of the needle around the Z axis;

[0039] S63: setting the speed amplitude curve of the loading condition to simulate the lifting, inserting and twisting movements during acupuncture;

[0040] S64: Open the predefined field manager, click Create, select "Initial" for the analysis step, select "Material Assignment" for the type, and according to the stratification of the Euler body in step S2, select the air layer Void, skin layer, fat layer, and muscle layer in turn to complete the assignment.

[0041] Preferably, in step S7, the "tetrahedron, free" mesh property is selected for the acupuncture needles; the "hexahedron, swept" mesh property is selected for the Euler body, and the generated mesh units are regular and uniform.

[0042] Preferably, in step S8, the following steps are specifically included:

[0043] S81: Open the job manager, click Create, enter a name and select Continue;

[0044] S82: Click "Parallel", check "Use multiple processors", and enter the number of processors suitable for the computer;

[0045] S83: Click "Precision", set the "Abaqus / Explicit Precision" option to "Both - Analysis + Packager" and confirm.

[0046] Preferably, in step S9, the following steps are specifically included:

[0047] S91: Open the job manager, select the simulation job to be viewed, and view the results;

[0048] S92: Open the general drawing options, check the visible edge option as "free edge", click "Draw cloud map on deformation map", click the field output dialog box, select "SVAVG" and "Mises", and through the view section manager, check "X-Plane" to view the stress cloud map of the skin layer and muscle layer;

[0049] S93: In the field output dialog box, select "U" or "U2" to check the deformation of the acupuncture needle.

[0050] Therefore, the present invention adopts the above-mentioned Abaqus / CAE-based multi-layer soft tissue flexible interactive numerical simulation method, which has the following beneficial effects:

[0051] (1) The present invention establishes a finite element model of three layers of skin, fat and muscle tissue, replacing the single-layer three-dimensional model solution of the previous technology; using the Coupled Eulerian-Lagrangian (CEL) method, a simulation model with higher simulation accuracy is provided, which is more consistent with the acupuncture process. At the same time, repeated up and down and rotational movements are applied to the needle to simulate actions such as lifting, insertion, and twisting, which can better simulate the mechanical response of the needle entering the human body and provide a scientific basis for clinical practice.

[0052] (2) The present invention adopts the Euler-Lagrange coupling method (CEL method) to perform multi-physical field coupling, thereby ensuring the accuracy of finite element numerical simulation results.

[0053] (3) The present invention applies the same motion load as the actual acupuncture technique to simulate the lifting, inserting, twisting and other movements in acupuncture, making the simulation results more scientific and accurate.

[0054] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a flow chart of a multi-layer soft tissue flexible interactive numerical simulation method based on Abaqus / CAE of the present invention;

[0056] Figure 2 It is a schematic diagram of CEL simulation analysis in the present invention;

[0057] Figure 3 It is a three-dimensional model diagram established in the present invention;

[0058] Figure 4 is a material property setting diagram in an embodiment of the present invention;

[0059] Figure 5 is a diagram of the Euler domain setting in an embodiment of the present invention;

[0060] Figure 6 is a cross-section attribute setting diagram in an embodiment of the present invention;

[0061] Figure 7 is an interface diagram of an analysis step manager in an embodiment of the present invention;

[0062] Figure 8 This is a diagram of the rigidification of the filiform needle portion in an embodiment of the present invention;

[0063] Fig. 9 is a boundary condition setting diagram in an embodiment of the present invention;

[0064] Fig.10 is a grid division diagram in an embodiment of the present invention;

[0065] Fig.11 This is the bending deformation result of the filiform needle in the embodiment of the present invention;

[0066] Fig.12 It is a stress cloud diagram of the Euler body in the embodiment of the present invention. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0068] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0069] The words "include" or "comprises" and the like used in the present invention mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The orientation or position relationship indicated by the terms "inside", "outside", "upper", "lower", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. When the absolute position of the described object changes, the relative position relationship may also change accordingly. In the present invention, unless otherwise clearly specified and limited, the terms "attachment" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] Example

[0071] like Figure 1-Figure 12 As shown, the present invention provides a multi-layer soft tissue flexible interaction numerical simulation method based on Abaqus / CAE, comprising the following steps:

[0072] S1: Establish a finite element model of the three layers of skin, fat and muscle tissue, determine the geometric dimensions of the needle, skin layer, fat layer and muscle layer and the air layer Void required for setting the Euler body in Abaqus, and convert it into .step format for export after completing the establishment of the assembly; in step S1, the geometric dimensions include the thickness of the needle body and the thickness of each layer. Solidworks is used to establish the geometric model. When Abaqus establishes the assembly, the needle is inserted into the air layer but does not touch the skin layer.

[0073] Therefore, the Abaqus / CAE-based multi-layer soft tissue flexible interactive numerical simulation method for acupuncture process establishes a finite element model of three layers of skin, fat and muscle tissue, and uses the Coupled Eulerian-Lagrangian method (CEL method) to provide a simulation with higher accuracy and a simulation model that is more consistent with the acupuncture process. At the same time, repeated up and down and rotational movements are applied to the needle to simulate actions such as lifting, insertion, and twisting, which can better simulate the mechanical response of the needle entering the human body and provide a scientific basis for clinical practice.

[0074] S2: Import the model into Abaqus / CAE and start simulation, which specifically includes importing the assembly obtained in step S1 into the component function module and cutting the filiform needle and the Euler body; in step S2, the filiform needle sets a cutting surface at 3 / 8 of the distance from the end; the Euler body includes three sections, corresponding to the air layer and the skin layer, the skin layer and the fat layer, and the fat layer and the muscle layer, and the cutting surfaces are set at corresponding positions at 3 / 8, 7 / 16, and 23 / 32 of the thickness of the Euler body, respectively, at a distance from the upper surface of the Euler body, i.e., the upper surface of the air layer.

[0075] S3: Setting cross-sectional properties and material properties for the needles, skin layer, fat layer, and muscle layer in step S1; in step S3, setting material properties specifically includes the following steps:

[0076] S30: Open the material manager, click Create, and set parameters including density, Young's modulus, Poisson's ratio, and failure criterion of the material;

[0077] Setting section properties includes the following steps:

[0078] S31: Open the Section Manager, click Create, and set the needle to solid and homogeneous sections, and the Euler body to Euler type sections;

[0079] S32: Open the section assignment manager, click Create, and assign the material set in step S30 to the section in step S31.

[0080] S4: Assemble the two components of the needle and the Euler body, and set the type and the length of the analysis step time through the analysis step manager; step S4 specifically includes the following steps:

[0081] S41: Click Create Instance, select the two parts of the needle and the Euler body for assembly;

[0082] S42: Open the analysis step manager, click Create, select "Dynamic, Explicit" as the type, turn on "Geometric Nonlinearity", and set the analysis step time length;

[0083] S43: Comprehensively consider the numerical simulation calculation efficiency and calculation accuracy, and make appropriate mass scaling settings;

[0084] S44: Open the field output request manager and the process output request manager, and check the required simulation data.

[0085] S5: setting the contact properties through the interaction property manager, and setting the rear half of the needle as a rigid body through the constraint manager; step S5 specifically includes the following steps:

[0086] S51: Open the Interaction Properties Manager, click Create, select the "Contact" type, and set the contact properties;

[0087] S52: Open the interaction manager, select "General Contact Explicit" as the type, and select the contact properties set in step S51 as the attribute assignment;

[0088] S53: Open the constraint manager, click Create, select "Rigid Body" as the type, select the back half of the needle as the "Region Type", and set the reference point to the center of the plane at the end of the needle.

[0089] S6: completing the boundary conditions and loading conditions through the boundary condition manager, layering the Euler body according to step S2, selecting the air layer Void, the skin layer, the fat layer and the muscle layer in turn, and completing the assignment; in step S6, specifically including the following steps:

[0090] S61: Open the boundary condition manager and create boundary conditions:

[0091] Condition 1: Select the "Symmetric / Antisymmetric / Completely Fixed" type and set the bottom surface of the Euler body to be completely fixed;

[0092] Condition 2: Select the "Displacement / Rotation" type and set the X-direction displacement of the front and back faces to 0;

[0093] Condition 3: Select the "Displacement / Rotation" type and set the Y-direction displacement of the left and right faces to 0;

[0094] S62: The loading condition is set as the linear velocity of the reference point at the end of the needle along the Z direction and the angular velocity of the needle around the Z axis;

[0095] S63: setting the speed amplitude curve of the loading condition to simulate the lifting, inserting and twisting movements during acupuncture;

[0096] S64: Open the predefined field manager, click Create, select "Initial" for the analysis step, select "Material Assignment" for the type, and according to the stratification of the Euler body in step S2, select the air layer Void, skin layer, fat layer, and muscle layer in turn to complete the assignment.

[0097] S7: Mesh the acupuncture needle and the Euler body. In step S7, select the "tetrahedron, free" mesh attribute for the acupuncture needle; select the "hexahedron, swept" mesh attribute for the Euler body to generate regular and uniform mesh units.

[0098] S8: Setting a solution model; in step S8, the following steps are specifically included:

[0099] S81: Open the job manager, click Create, enter a name and select Continue;

[0100] S82: Click "Parallel", check "Use multiple processors", and enter the number of processors suitable for the computer;

[0101] S83: Click "Precision", set the "Abaqus / Explicit Precision" option to "Both - Analysis + Packager" and confirm.

[0102] S9: Post-processing analyzes and evaluates the simulation results. In step S9, the following steps are specifically included:

[0103] S91: Open the job manager, select the simulation job to be viewed, and view the results;

[0104] S92: Open the general drawing options, check the visible edge option as "free edge", click "Draw cloud map on deformation map", click the field output dialog box, select "SVAVG" and "Mises", and through the view section manager, check "X-Plane" to view the stress cloud map of the skin layer and muscle layer;

[0105] S93: In the field output dialog box, select "U" or "U2" to check the deformation of the acupuncture needle.

[0106] Therefore, the present invention adopts the above-mentioned multi-layer soft tissue flexible interactive numerical simulation method based on Abaqus / CAE to more accurately describe the process of simulated acupuncture, applies the CEL method for simulation, improves the simulation accuracy, and makes the result more reliable; establishes a multi-layer soft tissue model of skin, fat and muscle, avoids the single three-dimensional model from being unable to correctly characterize the mechanical properties of the acupuncture process, and provides a more scientific basis for the clinical practice of acupuncture; applies the same motion load as the actual acupuncture technique, simulates the lifting, insertion, twisting and other actions in acupuncture, and makes the simulation results more scientific and accurate.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A multi-layer soft tissue flexibility interactive numerical simulation method based on Abaqus / CAE, characterized in that: The following steps are involved: S1: Establish a simplified 3D model, determine the geometric dimensions of the needles, skin layer, fat layer and muscle layer, and the air layer Void required for setting the Euler body in Abaqus, and convert the assembly into .step format for export after completion; S2: Import the model into Abaqus / CAE and start simulation, specifically including importing the assembly obtained in step S1 into the component function module and cutting the milli-needle and Euler body; S3: setting cross-sectional properties and material properties for the needles, skin layer, fat layer and muscle layer in step S1; S4: Assemble the two components of the needle and the Euler body, and set the type and analysis step time length through the analysis step manager; S5: Set the contact properties through the interaction property manager and set the rear half of the needle as a rigid body through the constraint manager; S6: Complete the boundary conditions and loading conditions through the boundary condition manager, layer the Euler body according to step S2, select the air layer Void, skin layer, fat layer and muscle layer in turn, and complete the assignment; In step S6, the following steps are specifically included: S61: Open the boundary condition manager and create boundary conditions: Condition 1: Select the "Symmetric / Antisymmetric / Completely Fixed" type and set the bottom surface of the Euler body to be completely fixed; Condition 2: Select the "Displacement / Rotation" type and set the X-direction displacement of the front and back faces to 0; Condition 3: Select the "Displacement / Rotation" type and set the Y-direction displacement of the left and right faces to 0; S62: The loading condition is set as the linear velocity of the reference point at the end of the needle along the Z direction and the angular velocity of the needle around the Z axis; S63: setting the speed amplitude curve of the loading condition to simulate the lifting, inserting and twisting movements during acupuncture; S64: Open the predefined field manager, click Create, select "Initial" for the analysis step, select "Material Assignment" for the type, and select the air layer Void, skin layer, fat layer, and muscle layer in turn according to the stratification of the Euler body in step S2 to complete the assignment; S7: Meshing of the needles and the Euler body; S8: Set up the solution model; S9: Post-processing analyzes and evaluates the simulation results.

2. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S1, the geometric dimensions include the thickness of the needle body and the thickness of each layer. Solidworks is used to establish the geometric model. When Abaqus is used to establish the assembly, the needle is inserted into the air layer but does not contact the skin layer.

3. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S2, a cutting surface is set at 3 / 8 of the distance from the end of the needle; the Euler body includes three cutting surfaces, corresponding to the air layer and the skin layer, the skin layer and the fat layer, and the fat layer and the muscle layer, respectively. The cutting surfaces are set at corresponding positions at 3 / 8, 7 / 16, and 23 / 32 of the thickness of the Euler body at a distance from the upper surface of the Euler body, i.e., the upper surface of the air layer.

4. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S3, setting the material properties specifically includes the following steps: S30: Open the material manager, click Create, and set parameters including density, Young's modulus, Poisson's ratio, and failure criterion of the material; Setting section properties includes the following steps: S31: Open the Section Manager, click Create, and set the needle to solid and homogeneous sections, and the Euler body to Euler type sections; S32: Open the section assignment manager, click Create, and assign the material set in step S30 to the section in step S31.

5. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: Step S4 specifically includes the following steps: S41: Click Create Instance, select the two parts of the needle and the Euler body for assembly; S42: Open the analysis step manager, click Create, select "Dynamic, Explicit" for type, turn on "Geometric Nonlinearity", and set the analysis step time length; S43: Comprehensively consider the numerical simulation calculation efficiency and calculation accuracy, and make appropriate mass scaling settings; S44: Open the field output request manager and the process output request manager, and check the required simulation data.

6. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: Step S5 specifically includes the following steps: S51: Open the Interaction Properties Manager, click Create, select the "Contact" type, and set the contact properties; S52: Open the interaction manager, select "General Contact Explicit" as the type, and select the contact properties set in step S51 as the attribute assignment; S53: Open the constraint manager, click Create, select "rigid body" as the type, select the back half of the needle in "region type", and set the reference point to the center of the plane at the end of the needle.

7. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S7, the "tetrahedron, free" mesh attribute is selected for the acupuncture needles; the "hexahedron, swept" mesh attribute is selected for the Euler body to generate regular and uniform mesh units.

8. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S8, the following steps are specifically included: S81: Open the job manager, click Create, enter a name and select Continue; S82: Click "Parallel", check "Use multiple processors", and enter the number of processors suitable for the computer; S83: Click "Precision", set the "Abaqus / Explicit Precision" option to "Both - Analysis + Packager" and confirm.

9. The Abaqus / CAE-based multi-layer soft tissue flexibility interactive numerical simulation method according to claim 1, characterized in that: In step S9, the following steps are specifically included: S91: Open the job manager, select the simulation job to be viewed, and view the results; S92: Open the general drawing options, check the visible edge option as "free edge", click "Draw cloud map on deformation map", click the field output dialog box, select "SVAVG" and "Mises", and through the view section manager, check "X-Plane" to view the stress cloud map of the skin layer and muscle layer; S93: In the field output dialog box, select "U" or "U2" to check the deformation of the acupuncture needles.

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