JP2019139585A - Contact determination model for cae analysis and contact determination method - Google Patents

Abstract

To provide a contact determination model for CAE analysis and a contact determination method using the model which can omit burdensome works by an engineering operator and which can improve accuracy in calculation with preventing an element quality from being lowered.SOLUTION: A gap element G is set between a joint A of a part model 10 and a joint P0 newly obtained by projecting the joint A as reference joint to a part model 20 in a normal direction. The joint P0 and existing joints P1 through P4 are linked with restriction elements K1 through K4. Weight values W1 through W4 are given to the joint P1 through P4. Displacement of the joints P1 through P4 and displacement of the joint P0 from the weight values W1 through W4 are calculated. There is employed a contact determination model M which, if a relative displacement amount obtained from the displacement of the joint A and the displacement of the joint P0 becomes less than a certain value, determines that there is a contact.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a contact determination model and a contact determination method for CAE analysis that are used when performing contact analysis of an object model using a computer.

  2. Description of the Related Art Conventionally, CAE (Computer Aided Engineering) analysis that analyzes and evaluates design problems in advance using a computer at the product design stage has been widely performed (see Patent Document 1). For example, in the design of automobiles, in order to achieve both weight reduction and cost reduction, there are many examples in which an outer panel and an inner panel are made of a composite material (for example, aluminum and steel plate, steel plate and FRP resin). Resin adhesives are mainly used to join such composite materials, but contact behavior (deformation) may occur between the panels due to differences in the thermal expansion of the materials during baking coating. Need to be evaluated. In addition, depending on the external force input conditions, contact deformation may occur between the panels.

  A contact determination model shown in FIG. 7 is known as a model used for CAE analysis of such contact behavior on a computer.

The contact determination model M ₀ shown in FIG. 7 uses a gap element as a contact determination element. The contact determination model M ₀ is set so that a gap element (contact determination element) G is connected between the nodes of the opposed part models 10 and 20. If the relative displacement amount between the nodes set with the gap element G becomes less than a certain value due to the displacement of both the component models 10 and 20 due to the conditions and additional conditions, both nodes are determined to be in contact with each other. It is possible to reproduce the contact behavior (deformation, stress distribution, etc.) under such a restrained state.

Japanese Patent Laying-Open No. 2015-109021

Incidentally, the conventional contact determination model M ₀ shown in FIG. 7 has sufficient contact determination accuracy because the gap closing direction (contact determination direction) is determined by the positional relationship between the nodes located at both ends of the gap element G. In order to secure the gap, it is necessary to set the direction of the gap element G as perpendicular to the two component models 10 and 20 as possible (normal direction).

  However, in order to realize the setting as described above on the model, when the node A of one component model 10 is used as a reference, the closest node P1 of the other component model 20 is set to the node as shown in FIG. A correction operation is required to move to a position perpendicular to the plane (normal direction) with respect to A, and as the position of the node P1 is corrected, the shapes of the elements (S1 to S4) around the node P1 The problem that quality deteriorates arises. The correction work is a very complicated work for the designer, and the deterioration of the shape quality of the elements has a problem that the calculation accuracy (stress and rigidity) is lowered.

  The present invention has been made in view of the above-mentioned problems, and it is possible to omit complicated work by a design worker, and it is possible to improve calculation accuracy by preventing deterioration of element quality, for CAE analysis. It is an object of the present invention to provide a contact determination model and a contact determination method using the model.

In order to solve the above problem, the present invention is a contact determination model for CAE analysis used when performing contact analysis of an object model using a computer,
Both nodes are connected between the node of one object model facing each other and the node newly obtained by projecting the node in the normal direction with respect to the other object model as the reference node. A gap element that is determined to be in contact when the relative displacement between the nodes is equal to or less than a certain value is set,
In the other object model, the newly obtained node is set as a dependent node, the existing nodes arranged around the node are set as independent nodes, and the newly obtained node and the plurality of surrounding nodes are Are connected via restraint elements,
When calculating the relative displacement between the nodes of both object models with gap elements set, the displacement of the nodes that are the dependent nodes in the other object model is the displacement of the nodes that are independent nodes and the independent nodes. The main feature is that it is configured to be calculated from weight values assigned to a plurality of nodes.

The contact determination model according to the present invention is:
The weight value assigned to a plurality of nodes that become independent nodes is given as a ratio to the area surrounded by the plurality of nodes that become independent nodes, based on the coordinate position before displacement of the node that becomes a dependent node. Two features.

The contact determination model according to the present invention is:
When both object models consist of shell elements or solid elements, and each element is composed of quadrilateral elements, the weight value assigned to multiple nodes that are independent nodes is the coordinate position before displacement of the nodes that are dependent nodes. A third feature is that, as a reference, it is given as a ratio with respect to the area of the parent element obtained by coordinate-transforming a quadrilateral real element surrounded by the four nodes as independent nodes.

The contact determination model according to the present invention is:
When both object models are composed of shell elements or solid elements, and each element is composed of triangular elements, the weight values assigned to multiple nodes that are independent nodes are based on the coordinate position before displacement of the nodes that are dependent nodes. As a fourth feature, it is given as a ratio to the area of the triangular real element surrounded by the three nodes that are independent nodes.

A contact determination method according to the present invention is a method of performing contact determination of an object model using a computer,
The computer is
Reading a plurality of object models composed of three-dimensional shape elements;
A step of providing a new node by projecting in a normal direction from the node to the other object model, using a node of one of the object models as a reference node among the plurality of read object models;
If both nodes are connected between the node of one object model and the newly obtained node of the other object model, and the relative displacement between the nodes of both object models is below a certain value, Setting a gap element to be determined;
With respect to the other object model, the newly obtained node and the plurality of nodes obtained by using the newly obtained node as a dependent node and the existing nodes arranged around the node as independent nodes. Setting a plurality of constraining elements to be coupled;
With respect to a plurality of nodes that are independent nodes of the other object model, a plurality of weight values that are ratios relative to the area surrounded by the plurality of nodes that are independent nodes are determined based on the coordinate positions before displacement of the nodes that are dependent nodes. A step of giving to the nodes of
Calculating a displacement of a node serving as a dependent contact from a displacement of a plurality of nodes serving as independent nodes of the other object model and a weight value assigned to the plurality of nodes;
Calculating a relative displacement amount between nodes of both object models in which a gap element is set from the calculated displacement;
The step of performing contact determination between both object models based on the calculated relative displacement amount,
The main feature is to execute each.

The contact determination method according to the present invention includes:
If both object models are composed of shell elements or solid elements, and each element is composed of quadrilateral elements,
The step of assigning a weight value is based on the coordinate position before displacement of the node that becomes the subordinate node, and the parent element obtained by converting the real element of the quadrilateral surrounded by the four nodes that become the independent nodes into a square. A second feature is that a weight value composed of a ratio to the area is given to the four nodes.

The contact determination method according to the present invention includes:
If both object models are composed of shell elements or solid elements, and each element is composed of triangular elements,
The step of assigning a weight value is based on the coordinate position before displacement of the node that becomes the dependent node, and the weight value that is a ratio to the area of the real element of the triangle surrounded by the three nodes that become independent nodes is the three nodes It is the third feature that is given to the above.

  As described above, according to the present invention, in setting the gap element in the contact determination model for CAE analysis, the position of the node where the gap element is set and the shape of the three-dimensional shape element accompanying the movement of the node Thus, there is an effect that it is possible to reduce the man-hours and the burden on the designer.

  In addition, according to the present invention, in the contact analysis, it is possible to improve the calculation accuracy by preventing the deterioration of the element quality, thereby improving the efficiency of the design work.

Explanatory drawing which shows the contact determination model for the CAE analysis which concerns on this invention, FIG. 3 is a perspective view showing two component models to which the contact determination model of FIG. 1 is applied; The figure used for explanation for calculating the weight value when the part model consists of shell elements of quadrilateral elements, The figure used for explanation for calculating the weight value when the part model is composed of triangular shell elements, The figure which shows the structure of the contact determination apparatus which concerns on this invention, The flowchart which shows the execution procedure of the contact determination method which concerns on this invention, It is explanatory drawing which shows the conventional contact determination model.

  An embodiment for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows an example of a contact determination model for CAE analysis according to the present invention.

  First, an article model to which the contact determination model of the present invention is applied will be described. FIG. 2 shows component models 10 and 20 for vehicle body configuration. As shown in the figure, each of the component models 10 and 20 is a thin panel-shaped hexahedron composed of vertices and ridge lines, and each surface is divided into meshes as indicated by a circle B. Shell element E. The shell element consists of a quadrilateral element or a triangular element (the quadrilateral element in the example of FIG. 2), nodes are provided at the top and middle points of each element, and the coordinates (X, Y, Z) of each node are displaced. A vector (dx, dy, dz) is assigned. The part models 10 and 20 may be composed of a large number of solid elements composed of quadrilateral elements or triangular elements.

  The contact determination model M shown in FIG. 1 includes an arbitrarily selected node A on the lower surface of the upper component model 10 and a node P0 newly provided on the upper surface of the lower component model 20 with the node A as a reference node. A gap element G for contact determination is set between them. The node P0 is newly set immediately above the upper surface by projecting in the normal direction from the node A to the component model 20 with the node A on the lower surface of the component model 10 as a reference node.

  The gap element G is determined to come into contact when the relative displacement between the node A on the part model 10 side and the node P0 on the part model 20 side becomes equal to or less than a certain value as the part models 10 and 20 approach. However, if it is determined that they are in contact with each other, the displacements of both nodes A and P0 are restrained.

  The node P0 of the lower part model 20 in which the gap element G is set and the four nodes P1 to P4 around the node P0 on the same plane have the node P0 as a subordinate node, and each node P1 to P4 The independent nodes are connected via constraint elements K1 to K4 with weight values. Note that the relative displacement between the node (subordinate node) node P0 and the nodes (independent nodes) P1 to P4 is constrained, and the relative displacement between the nodes P1 to P4 is not constrained.

  The constraint elements K1 to K4 add weight values (W1 to W4) to the nodes P1 to P4, and are dependent on the displacements of the nodes P1 to P4 and the weight values (W1 to W4) of the nodes P1 to P4. This is for calculating the displacement of the node P0 as the node, and the displacement of the subordinate node P0 is obtained by the following calculation formula (1).

  Further, in the constraint elements K1 to K4, the weight values W1 to W4 of the nodes P1 to P4 are the nodes P0 that are subordinate nodes with respect to the total area of the shell elements (S1 to S4) surrounded by the nodes P1 to P4. It is given as a reference ratio (area ratio).

  When the shell element is composed of quadrilateral elements, in the quadrilateral real element shown in FIG. 3, first, the ratio of dividing each side from the node P0 toward two opposite sides of the four sides is two sides. The dividing line L1 intersecting at the node P0 so as to be the same as each other (so that the upper and lower sides are divided at a ratio of a: b and the left and right sides are respectively divided at a ratio of c: d in the real elements in FIG. 3) , L2 and division points C1 to C4 are set on each side.

  Next, in the square parent element obtained by converting the coordinates as shown by arrows, the division ratio of the two opposite sides is the same as the division ratio of the two corresponding sides of the real element (see FIG. 3 so that the upper and lower sides are divided at a ratio of a: b and the left and right sides are divided at a ratio of c: d), and the dividing lines L1 ′ and L2 intersect at the node P0 ′ after the coordinate conversion. 'And division points C1' to C4 'are set on each side. And weight value W1-W4 of each node P1-P4 is calculated | required by the following calculation formulas (2).

  When the shell element is composed of triangular elements, the dividing values L1 to L3 are set from the node P0 to the nodes P1 to P3 as the weight values of the nodes P1 to P3 in the triangular real element shown in FIG. It is given as a ratio (area ratio) to the area of the real elements obtained by the lines L1 to L3. That is, the weight values W1 to W3 of the nodes P1 to P3 are obtained by the following calculation formula (3).

  FIG. 5 shows a contact determination device S for realizing the contact determination model M. The contact determination device S includes a device main body (computer) 100, an input device 200, and an output device 300, and the device main body 100 is connected to a database 400 through a communication line 101. The apparatus main body 100 includes a condition setting unit 110, a model reading unit 120, a gap element setting unit 130, a constraint element setting unit 140, a displacement calculation unit 150, a contact determination processing unit 160, a storage unit 170, and an output. Unit 180 and a control unit 190.

  The condition setting unit 110 includes contact conditions of the part model (selection of a reference node for setting a gap element, setting of a relative displacement amount between nodes regarded as contact) and additional conditions (initial temperature, maximum temperature, heating time, thermal expansion). Set heating conditions such as coefficients, pressure conditions such as load and stress distribution, etc.). The set value can be input by an operation from the input device 200. The model reading unit 120 reads the part model from the database 400 into the storage unit 170.

  The gap element setting unit 130 sets one or a plurality of gap elements G between the two component models 10 and 20 read into the storage unit 170. Specifically, the node A on the part model 10 side is used as a reference node, and the node A is projected in a normal direction from the node A to the part model 20, and a new node P0 is set immediately above the upper surface of the part model 20. A gap element G is set between the nodes A and P0.

  The constraint element setting unit 140 includes, in the part model 20, the constraint elements K1 to K4 having the node P0 as a dependent node and the four nodes P1 to P4 around the node P0 on the same plane as the node P0. The nodes P1 to P4 are connected and set, and the weight values W1 to W4 obtained by the calculation formula (2) are given to the nodes P1 to P4.

  The displacement calculation unit 150 calculates the displacements (P1 (dx1, dy1, dz1) to P4 (dx4, dy4, dz4)) of the nodes P1 to P4 where the constraint elements K1 to K4 are set in the component model 20 and the above calculation. The displacement (dx0, dy0, dz0) of the node P0 is calculated from the weight values W1 to W4 obtained by the expression (2) according to the calculation expression (1). Further, the relative displacement amount between the nodes A and P0 is calculated from the displacement of the node A of the component model 10 and the displacement of the node P0 of the component model 20.

  The contact determination processing unit 160 determines whether or not the component models 10 and 20 are in contact with each other based on the result of the relative displacement amount between the nodes A and P0 of the calculated component models 10 and 20. Further, when the relative displacement amount between the nodes A and P0 is equal to or less than a set value (a constant value), it is determined that the contact is made, and the displacements of the nodes A and P0 are subjected to constraint processing.

  The output unit 180 outputs an analysis result based on the calculation result of the displacement calculation unit 150 and the determination process of the contact determination processing unit 160. The output result is output to the output device 300 as, for example, reproducing the displacement distribution immediately after contact of the component models 10 and 20 and reproducing the contact behavior due to thermal expansion of the component models 10 and 20. The output can be displayed. The control unit 190 controls execution processing of the condition setting unit 110 to the output unit 180.

  Next, a procedure for performing contact determination processing on the component models 10 and 20 using the contact determination device S will be described with reference to a flowchart of FIG. Note that the conditions and set values specifically described below are examples for explaining the embodiment of the present invention, and the present invention is not limited to this.

  First, a computer operator opens a program by an operation from the input device 200, selects a part model to be analyzed, and sets conditions (such as contact conditions and heating conditions) by the condition setting unit 110 (step S1). Next, the program is executed by an operation from the input device 200. When the program is executed, the model reading unit 120 reads the part models 10 and 20 from the database 400 into the storage unit 170 (step S2).

  Next, the gap element setting unit 130 sets the node A on the part model 10 side as a reference node, projects in a normal direction from the node A to the part model 20, and newly adds a node P0 directly above the upper surface of the part model 20. And a gap element G is set between the nodes A and P0 (step S3). Next, the constraining element setting unit 140 converts the constraining elements K1 to K4 having the node P0 as the subordinate node and the four nodes P1 to P4 around the node P0 on the same plane as the independent nodes in the part model 20. In addition to setting connection between P0 and each of the nodes P1 to P4 (step S4), the weight values W1 to W4 are calculated by the calculation formula (2) (step S5), and the obtained weight values W1 to W4 are used as the nodes P1 to P4. (Step S6).

  Next, the displacement calculation unit 150 obtains the displacements of the nodes P1 to P4 (P1 (dx1, dy1, dz1) to P4 (dx4, dy4, dz4)) in the component model 20 and the calculation formula (2). The displacement (dx0, dy0, dz0) of the node P0 is calculated from the weight values W1 to W4 according to the calculation formula (1) (step S7), and the displacement of the node A of the component model 10 and the node P0 of the component model 20 are calculated. The relative displacement amount between both nodes A and P0 is calculated from the displacement (step S8).

  Next, the contact determination processing unit 160 determines whether or not the component models 10 and 20 are in contact with each other based on the result of the relative displacement amount between the nodes A and P0 of the component models 10 and 20 (step S9). ). When the relative displacement amount between the nodes A and P0 is not less than or equal to the set value, it is determined that no contact is made, and the process returns to step S7. When the relative displacement amount between the nodes A and P0 is equal to or less than the set value, it is determined that the contact is made (step S10), and the displacements of the nodes A and P0 are restrained (step S11).

  Next, the output unit 180 outputs the result based on the calculation result of the displacement calculation unit 150 and the determination process of the contact determination processing unit 160 to the output device 300 (step S12), whereby the computer operator outputs With reference to the result of the contact analysis displayed on the apparatus 300, it is possible to grasp the displacement distribution after contact of the component models 10 and 20, the contact behavior due to thermal expansion, and the like.

  By using the contact determination model M of this embodiment, the computer operator sets the gap element G between the nodes of the part models 10 and 20 according to the position of the node of one of the part models 10 as in the past. Thus, there is no correction work for moving the existing node of the other component model 20 to the perpendicular position, and the man-hours for creating the contact determination model can be greatly reduced.

  Further, in the contact determination model M of the present embodiment, a new node is provided on the other component model 20 side in order to set the gap element G, and an existing node in the other component model 20 is moved. Therefore, the existing nodes are held as independent nodes at the original positions, and thereby the quality of the elements can be improved without deteriorating the element quality as in the prior art.

  In the above embodiment, the square real element shown in FIG. 3 is coordinate-transformed to obtain a square parent element. However, the parent element obtained is not limited to a square. It can be rectangular.

  As described above, according to the present invention, in setting the gap element, there is no need to modify the shape of the three-dimensional shape element, which contributes to the reduction of man-hours, and the calculation accuracy is prevented by preventing deterioration of the element quality. Therefore, the efficiency of design work can be improved.

  The present invention can be used as a contact determination model used for contact analysis of an object model using a computer, and as a contact determination method using the model.

10, 20 Component model 100 Main unit (computer)
DESCRIPTION OF SYMBOLS 101 Communication line 110 Condition setting part 120 Model reading part 130 Gap element setting part 140 Constraining element setting part 150 Displacement calculation part 160 Contact determination process part 170 Storage part 180 Output part 190 Control part 200 Input apparatus 300 Output apparatus A Gap element sets One node (reference node)
P0 The other node where the gap element is set (dependent node)
P1-P4 Dependent nodes and nodes constrained (independent nodes)
G Gap element K1 to K4 Constraint element S Contact determination device W1 to W4 Weight value

Claims (7)

A contact determination model for CAE analysis used when performing contact analysis of an object model using a computer,
Both nodes are connected between the node of one object model facing each other and the node newly obtained by projecting the node in the normal direction with respect to the other object model as the reference node. A gap element that is determined to be in contact when the relative displacement between the nodes is equal to or less than a certain value is set,
In the other object model, the newly obtained node is set as a dependent node, the existing nodes arranged around the node are set as independent nodes, and the newly obtained node and the plurality of surrounding nodes are Are connected via restraint elements,
When calculating the relative displacement between the nodes of both object models with gap elements set, the displacement of the nodes that are subordinate nodes in the other object model is the displacement of the nodes that are independent nodes and the plurality of nodes that are independent nodes. A contact determination model for CAE analysis, wherein the contact determination model is configured to be calculated from assigned weight values.   The weight value assigned to a plurality of nodes that are independent nodes is given as a ratio to the area surrounded by the plurality of nodes that are independent nodes, based on the coordinate position before displacement of the node that is a dependent node. The contact determination model for CAE analysis according to claim 1.   When both object models consist of shell elements or solid elements, and each element is composed of quadrilateral elements, the weight value assigned to multiple nodes that are independent nodes is the coordinate position before displacement of the nodes that are dependent nodes. The reference is given as a ratio with respect to the area of the parent element obtained by converting a quadrilateral real element surrounded by the four nodes that are independent nodes into a square as a reference. The contact determination model for the CAE analysis described.   When both object models are composed of shell elements or solid elements, and each element is composed of triangular elements, the weight values assigned to multiple nodes that are independent nodes are based on the coordinate position before displacement of the nodes that are dependent nodes. The contact for CAE analysis according to any one of claims 1 to 3, wherein the contact is given as a ratio to the area of a triangular real element surrounded by the three nodes that are independent nodes. Judgment model. A contact determination method for CAE analysis for determining contact of an object model using a computer,
The computer is
Reading a plurality of object models composed of three-dimensional shape elements;
A step of providing a new node by projecting in a normal direction from the node to the other object model, using a node of one of the object models as a reference node among the plurality of read object models;
If both nodes are connected between the node of one object model and the newly obtained node of the other object model, and the relative displacement between the nodes of both object models is below a certain value, Setting a gap element to be determined;
With respect to the other object model, the newly obtained node and the plurality of nodes obtained by using the newly obtained node as a dependent node and the existing nodes arranged around the node as independent nodes. Setting a plurality of constraining elements to be coupled;
With respect to a plurality of nodes that are independent nodes of the other object model, a plurality of weight values that are ratios relative to the area surrounded by the plurality of nodes that are independent nodes are determined based on the coordinate positions before displacement of the nodes that are dependent nodes. A step of giving to the nodes of
Calculating displacements of a plurality of nodes serving as independent nodes of the other object model and a displacement of a node serving as a dependent contact from a weight value assigned to the plurality of nodes;
Calculating a relative displacement amount between nodes of both object models in which a gap element is set from the calculated displacement;
The step of performing contact determination between both object models based on the calculated relative displacement amount,
A contact determination method for CAE analysis, which is performed respectively. If both object models are composed of shell elements or solid elements, and each element is composed of quadrilateral elements,
The step of assigning a weight value is based on the coordinate position before displacement of the node that becomes the subordinate node, and the parent element obtained by converting the real element of the quadrilateral surrounded by the four nodes that become the independent nodes into a square. 6. The contact determination method for CAE analysis according to claim 5, wherein a weight value including a ratio to an area is assigned to the four nodes. If both object models are composed of shell elements or solid elements, and each element is composed of triangular elements,
The step of assigning a weight value is based on the coordinate position before displacement of the node that becomes the dependent node, and the weight value that is a ratio to the area of the real element of the triangle surrounded by the three nodes that become independent nodes is the three nodes 6. The contact determination method for CAE analysis according to claim 5, wherein

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