A Simulation Modeling Method for Projecting the Filament Winding Trajectory of a Composite Material

Abstract

The present invention relates to a method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material. The method includes the following steps: obtaining the center point coordinates by averaging the coordinates of all nodes of the calculation unit; making a perpendicular projection point from the center point coordinates to the center lines of all tow trajectories of the currently selected ply, calculating the shortest distance from the center point to the center lines of all tow trajectories of the selected ply using the distance formula after obtaining the projection point coordinates, and selecting its tow trajectory by comparing all the above shortest distances; making a tangent to the selected tow trajectory such that the tangent passes through the projection point; calculating the dot product of the tangent vector and the ply coordinate system of the calculation unit to obtain the true ply angle of the single layer of the selected calculation unit, and replacing the theoretical ply angle of the single layer of the selected calculation unit with the true ply angle. The present invention obtains an accurate and true ply angle and can accurately simulate the structural performance of the actual automatic fiber placement.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material structure design, particularly to the field of aviation structure design, and relates to a method for simulating and modeling the projection of an automatic fiber placement path of a composite material Background Art

[0002] The automatic fiber placement manufacturing process of composite materials has the advantages of good adaptability to complex parts, high automation, high production efficiency, low labor cost, less human interference, and good consistency of part quality. With the increasing maturity of the automatic fiber placement path planning technology, manufacturing equipment, and process technology, in recent years, it has been increasingly valued by composite material design institutions and manufacturing departments worldwide, and it is a composite material technology with great vitality and application prospects

[0003] The automatic fiber placement process for manufacturing composite material parts has its unique advantages. Based on this, the design of automatic fiber placement structures has become an inevitable trend of development. Compared with traditional prepreg manual laying, the combination of automatic fiber placement structure design and process manufacturing is closer. Among them, the path planning is particularly prominent. However, the automatic fiber placement process itself has its limitations, such as the minimum turning radius, the shortest cutting distance, the gap between tows, the overlap of tows, cutting and wire breakage, etc. Considering both processability and performance requirements in the design of tow paths is the focus of research. For design, the full-laying path needs to meet the performance requirements such as structural strength, stiffness, and stability, so as to ensure the integrity of the structure and make the structure efficient; for the process, the planned path needs to meet problems such as the minimum turning radius, non-interference of the machine, full-laying, and few defects, while taking into account the design requirements for the fiber direction. There are conflicting items between the two, and they need to cooperate and coordinate with each other and iterate repeatedly to achieve the final design

[0004] Among them, after the process personnel complete the process path planning using the automatic fiber placement path design software, the automatic fiber placement composite material structure designers will obtain the automatic fiber placement path database of all design plies (the automatic fiber placement path database is stored in the automatic fiber placement path design software. Existing automatic fiber placement path design software belongs to the prior art in this field, such as VERICUT, CATFiber, etc.). How to accurately and quickly introduce the actual tow path angle change into the simulation analysis finite element model to analyze and evaluate the performance after the process full-laying planning is extremely important Summary of the Invention

[0005] Object of the Invention

[0006] Provided is a method for simulating and modeling the projection of an automatic fiber placement path of a composite material, which can accurately and quickly introduce the actual tow path angle change into the simulation analysis finite element model, so as to carry out subsequent structural integrity evaluations such as strength, stiffness, and stability, effectively improve the design quality, and shorten the design cycle

[0007] Technical solution:

[0008] The present invention provides a method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material. The method includes the following steps:

[0009] Step 1: First, establish a three-dimensional shell element finite element model for the composite material structure using the automatic fiber placement process. The size of the shell element is an integer multiple of the fiber bundle width, and the theoretical ply angles of each individual layer of each shell element are generated.

[0010] Step 2: Import all the centerlines of all fiber bundles of all individual layers from the automatic fiber placement trajectory database according to the composite material ply sequence; select the first ply.

[0011] Step 3: Select the shell elements as calculation units in sequence according to the shell element numbers.

[0012] For each selected calculation unit, the center point coordinates are obtained by averaging the coordinates of all the nodes of the calculation unit; perpendicular projection points are made from the center point coordinates to all the centerlines of the fiber bundles of the currently selected ply. After obtaining the projection point coordinates, the shortest distance from the center point to all the centerlines of the fiber bundles of the selected ply is calculated using the distance formula. By comparing all the above shortest distances, the centerline of the fiber bundle closest to the center of the calculation unit is determined, and its fiber bundle trajectory is selected; a tangent line of the selected fiber bundle trajectory is made such that the tangent line passes through the projection point, and the tangent vector of the trajectory line at the projection point is calculated using this tangent line; the dot product of the tangent vector and the ply coordinate system of the calculation unit is calculated to obtain the true ply angle of the single layer of the selected calculation unit, and the theoretical ply angle of the single layer of the selected calculation unit is replaced with the true ply angle.

[0013] Step 4: Determine whether there are any unselected plies. If so, select an unselected ply and return to Step 3. If not, end.

[0014] Further, in Step 1, the three-dimensional shell elements are automatically generated by HyperMesh as quadrilateral elements or triangular elements, which include the coordinate information of each node and the element coordinate information of the mesh generation.

[0015] Further, in Step 1, the size of the shell element is 1 to 32 times the fiber bundle width to improve efficiency.

[0016] Further, in Step 3, the selection is made in ascending order or descending order of the shell element numbers.

[0017] Further, in Step 3, the comparison of the shortest distances of all the above centerlines of the fiber bundles is obtained through a sorting method.

[0018] Technical effect:

[0019] The present invention queries the center line of the single-layer tow track closest in distance through the center point of the unit, and calculates through the dot product of the tangent vector of the projection point and the x-direction vector of the unit ply coordinate system to obtain an accurate and real ply angle. Through cyclic iteration, the actual change in the tow track angle is quickly introduced into the finite element model of the simulation analysis, making the subsequent evaluation results of structural integrity such as strength, stiffness, and stability more reasonable, and accurately simulating the performance of the actual automatic fiber placement structure. Detailed implementation manners

[0020] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Provide a method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material, the method comprising the following steps:

[0022] Step 1: First, establish a three-dimensional shell element finite element model for the composite material structure using the automatic fiber placement process. The size of the shell element is an integer multiple of the tow width, and the theoretical ply angle of each single ply of each shell element is generated.

[0023] Step 2: Import all the center lines of all the tows of all the single plies from the automatic fiber placement trajectory database according to the composite material ply sequence; select the first ply.

[0024] Step 3: Select the shell element as the calculation unit in sequence according to the shell element number.

[0025] For each selected calculation unit, the center point coordinates are obtained by averaging the coordinates of all the nodes of the calculation unit; perpendicular projection points are made from the center point coordinates to all the center lines of the tows of the currently selected ply. After obtaining the projection point coordinates, the distance formula is used to calculate the shortest distance from the center point to all the center lines of the tows of the selected ply. By comparing all the above shortest distances, the center line of the tow track closest to the center of the calculation unit is determined, and its tow track is selected; a tangent line of the selected tow track is made, and the tangent line passes through the projection point. The tangent vector of the track line at the projection point is calculated with this tangent line; the dot product calculation of the tangent vector and the ply coordinate system of the calculation unit is performed to obtain the true ply angle of the single ply of the selected calculation unit, and the theoretical ply angle of the single ply of the selected calculation unit is replaced with the true ply angle.

[0026] Step 4: Determine whether there is an unselected ply. If so, select an unselected ply and return to Step 3. If not, end.

[0027] In Step 1, the three-dimensional shell elements are automatically generated as quadrilateral elements by HyperMesh, which contain the coordinate information of each node and the element coordinate information for mesh generation.

[0028] In Step 1, the size of the shell element is 1 to 32 times the width of the tow to improve efficiency.

[0029] In Step 3, they are selected in ascending or descending order of the shell element numbers.

[0030] In Step 3, it is obtained by comparing the shortest distances of all the above-mentioned centerlines of the tow trajectories and using a sorting method.

[0031] As mentioned above, the above are only specific embodiments of the present invention, which are described in detail. The parts not elaborated are conventional technologies. However, the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material, characterized in that: The method includes the following steps: Step 1: First, establish a three-dimensional shell element finite element model for the composite material structure using the automated fiber placement process. The size of the shell element is an integer multiple of the tow width, and the theoretical ply angles of each layer of each shell element are generated. Step 2: Import the centerlines of all tows of all layers from the automated fiber placement trajectory database according to the composite material ply sequence; select the first ply. Step 3: Select the shell elements as calculation units in sequence according to the shell element numbers. For each selected calculation unit, obtain the center point coordinates by averaging the coordinates of all nodes of the calculation unit; make perpendicular projection points from the center point coordinates to the centerlines of all tows of the currently selected ply. After obtaining the projection point coordinates, calculate the shortest distance from the center point to the centerlines of all tows of the selected ply using the distance formula. By comparing all the above shortest distances, determine the tow centerline closest to the center of the calculation unit, and select its tow trajectory; make a tangent to the selected tow trajectory such that the tangent passes through the projection point, and calculate the tangent vector of the trajectory line at the projection point using this tangent; perform a vector dot product calculation between the tangent vector and the ply coordinate system of the calculation unit to obtain the true ply angle of the single layer of the selected calculation unit, and replace the theoretical ply angle of the single layer of the selected calculation unit with the true ply angle. Step 4: Determine whether there are still unselected plies. If so, select an unselected ply and return to Step 3. If not, end.

2. The method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material according to claim 1, characterized in that: In Step 1, the three-dimensional shell elements are automatically generated as quadrilateral elements by HyperMesh, which contain the coordinate information of each node and the element coordinate information of the mesh generation.

3. The method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material according to claim 1, characterized in that: In Step 1, the three-dimensional shell elements are automatically generated as triangular elements by HyperMesh, which contain the coordinate information of each node and the element coordinate information of the mesh generation.

4. The method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material according to claim 1, characterized in that: In Step 1, the size of the shell element is 1 to 32 times the tow width.

5. The method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material according to claim 1, characterized in that: In Step 3, select in ascending or descending order of the shell element numbers.

6. The method for simulating and modeling the projection of the automatic fiber placement trajectory of a composite material according to claim 1, characterized in that: In Step 3, the above-mentioned shortest distances of all tow centerlines are obtained by sorting.