An automobile trunk cover production line auxiliary tool operation process strength simulation analysis method

Abstract

The present application relates to a kind of automobile trunk lid production line auxiliary operation process strength simulation analysis method, including automobile trunk lid auxiliary assembly state modeling;Lid operation condition;Lid impact misoperation condition;Knock lid impact misoperation condition;Press lid misoperation, when the auxiliary handle lap in the rear wall edge position under the closed state of trunk lid, simulate the misoperation condition of operating personnel in the rear surface of trunk lid;Evaluation.The present application automobile trunk lid production line auxiliary operation process strength simulation analysis method, mainly for the trunk lid assembly operation process, due to the randomness of operating environment, the uncertainty of operating personnel's job status, and the necessary multiple opening and closing requirements;Investigate the plastic deformation state and strength of the flat feature surface of the trunk lid structure around the auxiliary under the action of the simulated typical working condition;The method can simulate and verify the above process operating environment, provide basis for product design.

Description

Technical Field

[0001] This invention belongs to the field of vehicle painting technology, specifically relating to a simulation analysis method for the operational process strength of auxiliary fixtures in an automobile trunk lid production line. Background Technology

[0002] Traditional simulation methods for automotive trunk lids only consider operational conditions, such as overall structural rigidity, local structural rigidity, and impact and fatigue strength related to opening and closing performance. However, there are no mature simulation analysis methods for operational conditions involving manufacturing fixtures during production. This leads to plastic deformation of samples after necessary processing at these stations, rendering them unusable and resulting in significant economic losses. Exploring simulation analysis methods for the operational strength of automotive trunk lids is essential. Exposing structural defects during operational conditions at the product design stage can prevent unnecessary economic losses, cost losses, and cycle risks. Summary of the Invention

[0003] The purpose of this invention is to provide a simulation analysis method for the operational process intensity of auxiliary tools in an automotive trunk lid production line, in order to solve the problem of the lack of mature simulation analysis for operational conditions involving production process auxiliary tools.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A simulation analysis method for the operational process strength of auxiliary fixtures in an automobile trunk lid production line includes the following steps:

[0006] A. Modeling the assembly state of automotive trunk lid fixtures for simulation of typical working conditions of subsequent automotive trunk lid production line fixture operations;

[0007] B. Lid Lifting Operation Condition: This simulates the operation of an operator using a tool to open and lift the sheet metal welded assembly of the luggage compartment lid.

[0008] C. Impact of falling cover misoperation: This is used to simulate the situation where an operator is holding an assistive device and, due to a mistake, the device is in a high position and the force is suddenly unloaded, causing it to fall freely. When the device reaches the limit of the operator's arm operation, the device is tightened to stop the fall, resulting in the impact of the fall.

[0009] D. Impact and misoperation scenario: This scenario simulates the impact between the handle and the rear panel caused by the operator releasing the auxiliary handle at the lower limit of the human arm's operating range, resulting in the weight of the object falling from that distance.

[0010] E. Misoperation of the lid: When the trunk lid is closed, i.e. the handle of the auxiliary tool is attached to the edge of the rear panel, the operation simulates the situation where the operator presses on the rear surface of the trunk lid.

[0011] F. Evaluation: This is used to determine the key indicator standards of the results to replace the visual perception of the users on site. By selecting the flat surface features around the assistive device, we observe its deformation trend and strength results, i.e., plastic strain, to provide a basis for the design scheme.

[0012] Further, step A specifically includes:

[0013] A1. Modeling features of the auxiliary assembly: The auxiliary assembly is divided into two parts: a connecting plate and an operating handle. Both are meshed using solid elements. They are connected using conn3D2 type elements with the element property type being hinge. The local coordinate X-axis direction of the element is the same as the X-axis direction of the same type of element as the hinge connecting the trunk lid and the body. The mesh model of the connecting plate and the operating handle has a contact setting with a contact friction coefficient of 0.12.

[0014] A2. Modeling features of the trunk lid assembly: Assign plastic property parameters to the structural materials around the auxiliary parts, edit the *plastic property parameter data under the *material keyword, and assign plastic stress-strain curve property parameter data to the material so that subsequent simulation outputs plastic strain results; Define contact interactions between all sheet metal parts of the assembly and set the relevant parameters of the *contact keyword;

[0015] A3. Overall Assembly Modeling Features: Connect the auxiliary assembly model and the luggage compartment lid assembly model with rigid coupling elements to obtain the overall assembly model; rbe3 characteristic elements are not allowed in the overall assembly model; all rigid coupling elements are of type coupkin.

[0016] Furthermore, in the model, the load step results are output as field variables, node outputs are displacement variables, and element outputs are plastic strain variables.

[0017] Further, step B specifically includes:

[0018] B1. Modeling characteristics: The luggage compartment lid accessory assembly is in a closed position under this working condition;

[0019] B2. Algorithm characteristics: The algorithm uses a solver and employs a static analysis method. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed.

[0020] B3 constraint features: All trunk lid hinges and body connection holes surrounding unit nodes are constrained to 1-6 degrees of freedom. Under the Abaqus load step *step keyword, set the parameters under the *boundary keyword, and the above nodes are geometrically constrained to 1-6 degrees of freedom.

[0021] B4. Loading Feature: The engagement point of the luggage compartment lid latch is coupled with the surrounding latch nodes, moving vertically upwards by a distance h1+h2. Set the parameters under the *boundary keyword, setting only the 3-DOF displacement parameter to the distance h1+h2; leave the other DDOs unset. Apply a downward vertical gravitational load to the overall model, with a load magnitude of 1.5 times the gravitational acceleration.

[0022] Further, step C specifically includes:

[0023] C1. Modeling Features: A conn3D2 type element is created at the end of the handle model. One node of the element is rigidly coupled to a node in the handle end model, and the other node is used for subsequent constraints. The element property type is hinge, and certain stiffness and damping parameters are assigned to 1-3 degrees of freedom.

[0024] C2. Algorithm characteristics: The algorithm uses a solver and employs an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed.

[0025] C3. Constraint Features: All trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom at their surrounding unit nodes. Under the *step keyword in the Abaqus load step, the parameters under the *boundary keyword are set, and the geometric constraints of the above nodes are 1-6 degrees of freedom. The trunk lid latch engagement point is coupled with the surrounding latch nodes, and the numerical translational degrees of freedom of the trunk lid latch engagement point are constrained. The parameters under the *boundary keyword are set, and the constraints are 3 degrees of freedom.

[0026] C4. Loading Characteristics: When the trunk lid is in the open, high position, and reaches the limit of human arm operation due to gravity, the parameters are as follows: M represents the mass of the trunk lid, F represents the reaction force of the arm pushing the handle during descent, g represents the acceleration due to gravity, v represents the velocity of the center of mass of the trunk lid when it falls from position 3 to position 2, and h represents the velocity of the trunk lid. ′ 2 represents the distance the center of mass moves downwards, and ω2 represents the angular velocity of the suitcase lid when it falls from position 3 to position 2;

[0027] According to the law of conservation of energy:

[0028]

[0029]

[0030]

[0031] Before the *step keyword, set the parameters under the *initial keyword, give the initial angular velocity value as the calculated value of equation (3), set the *cload keyword in the *step load step, and apply the F force value vertically upward at the end of the handle.

[0032] Further, step D specifically includes:

[0033] D1. Modeling features: Establish a local structural mesh model of the contact area between the handle and the rear enclosure, extract all nodes of the section to create a set for constraints, establish the contact relationship between the nodes in the contact area between the rear enclosure and the handle, and take the friction coefficient as 0.15; In the model, a small gap is artificially made between the handle and the rear enclosure to ensure the effect of the impact simulation under working conditions.

[0034] D2. Algorithm characteristics: The algorithm uses a solver and employs an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed.

[0035] D3. Constraint Features: All unit nodes around the trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. In step D1, the local structural mesh model of the handle and rear enclosure contact area is used to extract the set of all nodes of the extracted portion, which are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom.

[0036] D4. Loading Characteristics: The parameters of the luggage compartment lid from its open position (limit of human arm operation) to its closed position are as follows: M represents the mass of the luggage compartment lid, g represents the acceleration due to gravity, v represents the velocity of the center of mass of the luggage compartment lid when it falls from position 3 to position 2, φ represents the angular velocity of the luggage compartment lid when it falls from position 3 to position 2, and h represents the angular velocity of the luggage compartment lid when it falls from position 3 to position 2. ′ 1 represents the distance the center of mass moves downwards. The angular velocity under the influence of gravity is derived as follows;

[0037] According to the law of conservation of energy:

[0038]

[0039]

[0040]

[0041] Before the *step keyword, set the parameters under the *initial keyword, and give the initial angular velocity value as the calculated value of equation (6).

[0042] Further, step E specifically includes:

[0043] E1. Modeling Features: Establish a local structural mesh model of the contact area between the handle and the rear panel. Select all nodes of the selected portion to create a set for constraints. Establish contact relationships between the nodes in the contact area between the rear panel and the handle, with a friction coefficient of 0.15. In the model, a small gap is artificially created between the handle and the rear panel to ensure the effect of the working condition contact simulation. Select several different rectangular areas on the rear surface of the trunk lid, with the area size similar to a human palm. Use the geometric center of the area as the master line and all nodes of the outer plate mesh of the rear surface of the trunk lid within the area as slave points. Create rbe3 elements to apply loads to the master points of the nodes.

[0044] E2. Algorithm characteristics: The algorithm uses a solver and employs a static analysis method. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed.

[0045] E3. Constraint Features: All unit nodes around the trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. In step E1, the local structural mesh model of the handle and rear enclosure contact area is used to extract the set of all nodes of the extracted portion, which are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom.

[0046] E4. Loading Features: Apply concentrated force loads to the principal points of the rbe3 element described in step E1. Establish the number of load steps based on the number of regions, ensuring that each load step applies one concentrated load. Set the parameters under the *cload keyword, establish a local coordinate system, and apply the concentrated load along the normal coordinate axis to the inside of the surface. Except for the first load step, set op=new after the *cload keyword for the remaining load steps.

[0047] Furthermore, in step E1, the rear surface of the trunk lid extends from the end of the rear surface to the middle of the rear surface.

[0048] Further, step F: Select the flat surface features around the assistive device, such as smooth curved surfaces or straight planes; areas with complex features do not need to be considered; observe its deformation trend and strength results.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] This invention relates to a simulation analysis method for the strength of auxiliary components in an automotive trunk lid production line. This method primarily addresses the challenges of trunk lid assembly processes, including the randomness of the operating environment, the uncertainty of operator status, and the necessary multiple opening and closing requirements. It examines the plastic deformation and strength of the flat surfaces surrounding the trunk lid structure under simulated typical operating conditions. This method can simulate and verify the aforementioned process operating environment, providing a basis for product design. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A diagram illustrating the process of an operator using an auxiliary tool to open and close the suitcase lid;

[0053] Figure 2 The flowchart of the simulation analysis method for the operational process strength of auxiliary fixtures in the automotive trunk lid production line of the present invention;

[0054] Figure 3 A diagram illustrating the limit of human arm movement when the suitcase lid is opened to a high position and reaches the limit of human arm operation due to gravity.

[0055] Figure 4 A diagram showing the luggage lid from its open position (limit of human arm movement) to its closed position.

[0056] Figure 5 This diagram illustrates a scenario where an operator accidentally presses on the rear surface of the luggage compartment lid when the lid is closed and the accessory handle is positioned at the edge of the rear panel. Detailed Implementation

[0057] The present invention will be further described below with reference to embodiments:

[0058] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0059] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0060] The trunk lid sheet metal welding assembly is installed onto the vehicle body. After the electrophoresis process, the tailgate's auxiliary tooling is replaced so that workers can use it to open and close the trunk lid during subsequent assembly processes. In these subsequent processes, due to the randomness of the operating environment, the uncertainty of the operator's working state, and the necessary multiple opening and closing requirements, this invention proposes a simulation analysis method for the operational process strength of auxiliary tooling in an automotive trunk lid production line. The simulation verifies the aforementioned operational environment, providing a basis for product design.

[0061] During the process of the operator using the assistive device to open and close the suitcase lid, the relevant parameter diagrams are shown below. Figure 1 There are three positions: Position 1, with the luggage compartment lid closed and the auxiliary handle resting on the edge of the rear panel; Position 2, the limit of arm movement for a standing person (lower); Position 3, with the luggage compartment in a high position, where the on-site auxiliary tool is used to support the middle of the inner panel of the luggage compartment lid to facilitate the operator's work. The vertical height from Position 1 to Position 2 is h1; the vertical height from Position 2 to Position 3 is h2. The radius of rotation of the luggage compartment lid's center of gravity from the hinge axis is r, and the radius of rotation of the auxiliary handle's hand position from the hinge axis is R.

[0062] This invention relates to a simulation analysis method for the strength of auxiliary components in an automotive trunk lid production line. It primarily addresses the challenges of trunk lid assembly processes, including the randomness of the operating environment, the uncertainty of operator states, and the necessary multiple opening and closing operations. The method examines the plastic deformation and strength of the flat surfaces surrounding the auxiliary components of the trunk lid structure under simulated typical operating conditions.

[0063] like Figure 2 As shown, the present invention provides a simulation analysis method for the operational process strength of auxiliary fixtures in an automotive trunk lid production line, comprising the following steps:

[0064] 1. Modeling the assembly state of automotive trunk lid fixtures for simulation of typical working conditions of subsequent automotive trunk lid production line fixture operations;

[0065] 2. Lid Lifting Operation Condition: This simulates the operation of an operator using a hand tool to open and lift the sheet metal welded assembly of the luggage compartment lid.

[0066] 3. Impact simulation of misoperation during cover lowering: This simulation is used to simulate the situation where an operator holding an assistive device makes a mistake and the device is in a high position when the force is suddenly unloaded, causing it to fall freely. The device is then pulled up to stop the fall when it reaches the limit of the operator's arm's operating range, resulting in a falling impact.

[0067] 4. Impact and misoperation scenario: This scenario simulates the situation where an operator is at the lower limit of their arm's operational range (there is still a certain distance between the handle and the rear panel of the assistive device), and releases the handle, causing the weight of the object to fall and impact the handle with the rear panel.

[0068] 5. Misoperation of the lid: When the trunk lid is in the "closed" state (i.e., when the auxiliary handle is attached to the edge of the rear panel), simulate the situation where the operator presses on the rear surface of the trunk lid.

[0069] 6. Evaluation: This is used to determine key performance indicators to replace the visual perception of users on site. By selecting the flat surface features around the assistive device, its deformation trend and strength results (plastic strain) are observed to provide a basis for the design scheme.

[0070] Specifically, it includes the following steps:

[0071] 1. Modeling the assembly state of automotive trunk lid fixtures for simulation of typical operating conditions in subsequent automotive trunk lid production line fixture operations. Specifically:

[0072] ① Modeling features of the auxiliary assembly: The auxiliary assembly is divided into two parts: a connecting plate and an operating handle. Both are meshed using solid elements. They are connected by conn3D2 type elements with hinge type. The local coordinate X-axis of the element is the same as the X-axis of the hinge connecting the trunk lid and the body. The mesh model of the connecting plate and the operating handle has a contact setting with a contact friction coefficient of 0.12.

[0073] ② Modeling features of the trunk lid assembly: Assign plastic property parameters to the structural materials around the auxiliary parts, edit the *plastic property parameter data under the *material keyword, and assign plastic stress-strain curve property parameter data to the material so that the plastic strain results can be output in subsequent simulations; define the contact interaction between all sheet metal parts of the assembly and set the relevant parameters of the *contact keyword.

[0074] ③ Overall Assembly Modeling Features: The connecting holes between the auxiliary assembly model and the trunk lid assembly model are connected using rigid coupling elements to obtain the overall assembly model. The overall assembly model does not allow RBE3 characteristic elements to avoid errors in the subsequent explicit solver; all rigid coupling elements are of type Coupkin for compatibility with both standard and explicit solvers.

[0075] ④ In the model, the load step results are output as field variables, node outputs are output as displacement variables, and element outputs are output as plastic strain variables, so as to view the results of plastic deformation and plastic strain later.

[0076] ⑤ The above are the general modeling features for subsequent typical working conditions. Some typical working conditions also have independent and special modeling features, which will be mentioned in the working condition introduction.

[0077] 2. Lid Lifting Operation: This simulates the operation of a person using a tool to open and lift the sheet metal welded assembly of the trunk lid. The specific steps are as follows:

[0078] ① Modeling features: The luggage compartment lid accessory assembly is in a "closed" position under this working condition (i.e., the accessory handle is attached to the edge of the rear panel). Figure 1 (As shown in position 1)

[0079] ② Algorithm characteristics: The solution is obtained using the Abaqus / Standard solver, and the static analysis method is adopted. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed;

[0080] ③ Constraint features: All trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom in the surrounding unit nodes. Under the Abaqus load step *step keyword, set the parameters under the *boundary keyword. The above nodes are geometrically constrained to 1-6 degrees of freedom.

[0081] ④ Loading Features: The engagement point of the luggage compartment lid latch is coupled with the surrounding latch nodes, moving vertically upwards by a distance h1+h2. Set the parameters under the *boundary keyword, setting only the 3-DOF displacement parameter to the distance h1+h2; leave the other DDOs unset. Apply a downward vertical gravitational load to the overall model, with a load magnitude of 1.5 times the gravitational acceleration.

[0082] 3. Impact-induced misoperation scenario when the cover is lowered: This simulates an operator holding an auxiliary tool, where an error occurs and the tool is in a high position ( Figure 1 Position 3) Sudden unloading causes free fall, reaching the limit of human standing arm operation ( Figure 1 Location 2) The impact of a sudden taut restraint stopping the fall. Specifically:

[0083] ① Modeling features: The posture of the luggage compartment lid accessory assembly under this working condition is that it rotates around the hinge to the limit of human arm operation. Figure 1Position 2); To simulate the buffering effect of the human body (acting on the arm) on the overall model (acting on the handle) at the moment when the human arm reaches its operational limit, a conn3D2 type element is created at the end of the handle model (non-hinge side). One node of the element is rigidly coupled to a node of the handle end model, and the other node is used for subsequent constraints. The element property type is hinge, and certain stiffness and damping parameters are assigned to 1-3 degrees of freedom.

[0084] ② Algorithm characteristics: The algorithm uses the Abaqus / explicit solver and adopts an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed.

[0085] ③ Constraint Features: All trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom at the surrounding unit nodes. Under the Abaqus load step *step keyword, the parameters under the *boundary keyword are set, and the geometric constraints of the above nodes are 1-6 degrees of freedom. The trunk lid lock hook engagement point is coupled with the surrounding lock hook nodes, and the numerical translational degree of freedom of the trunk lid lock hook engagement point is constrained. The parameters under the *boundary keyword are set, and the constraint is 3 degrees of freedom.

[0086] ④ Loading characteristics: The trunk lid is in the high open position ( Figure 1 Position 3) Due to the influence of gravity, the arm reaches its limit of operational range. Figure 1 Position 2) Parameters are as follows Figure 3 Where M represents the mass of the suitcase lid, F represents the reaction force of the arm pushing the handle during the descent, g represents the acceleration due to gravity, v represents the velocity of the center of mass of the suitcase lid when it falls from position 3 to position 2, and h represents the velocity of the center of mass. ′ 2 represents the distance the center of mass moves downwards, and ω2 represents the angular velocity of the suitcase lid when it falls from position 3 to position 2.

[0087] According to the law of conservation of energy:

[0088]

[0089]

[0090]

[0091] Before the *step keyword, set the parameters under the *initial keyword, giving the initial angular velocity value as the calculated value of equation (3). Set the *cload keyword in the *step load step, and apply the force F vertically upward at the end of the handle (handheld part).

[0092] 4. Impact and misoperation scenario, used to simulate the operator's arm movement limits. Figure 1 Position 2) At the lower end, releasing the accessory handle causes the weight of the object to fall, resulting in a collision between the handle and the rear panel. Specifically:

[0093] ① Modeling features: The luggage compartment lid accessory assembly is in a "closed" position under this working condition (i.e., when the accessory handle is attached to the edge of the rear panel); a local structural mesh model of the handle contacting the rear panel is established, and all nodes of the cut-off part are used to create a set for constraints. The nodes in the contact area between the rear panel and the handle are used to establish contact relationships, and the friction coefficient is set to 0.15; a small gap (e.g., 0.5mm) is artificially made between the handle and the rear panel in the model to ensure the effect of the impact simulation under the working condition;

[0094] ② Algorithm characteristics: The algorithm uses the Abaqus / explicit solver and adopts an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed.

[0095] ③ Constraint Features: All trunk lid hinges and body connection holes surrounding unit nodes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The above node geometry is constrained to 1-6 degrees of freedom. The local structural mesh model of the handle and rear enclosure contact area mentioned in "①" is used to constrain all node sets of the extracted portion to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The above node geometry is constrained to 1-6 degrees of freedom.

[0096] ④ Loading characteristics: The trunk lid is opened to the limit of human arm operation ( Figure 1 Position 2) When the attitude changes to the "closed" attitude ( Figure 1 Parameters at position 1) are as follows Figure 4 Where M represents the mass of the trunk lid, g represents the acceleration due to gravity, v represents the velocity of the center of mass of the trunk lid when it falls from position 3 to position 2, φ represents the angular velocity of the trunk lid when it falls from position 3 to position 2, and h represents the angular velocity of the trunk lid when it falls from position 3 to position 2. ′ 1 represents the distance the center of mass moves downwards. The angular velocity under the influence of gravity is derived as follows.

[0097] According to the law of conservation of energy:

[0098]

[0099]

[0100]

[0101] Before the *step keyword, set the parameters under the *initial keyword, and give the initial angular velocity value as the calculated value of equation (6).

[0102] 5. Accidental operation of the lid: Simulates the scenario where an operator presses down on the rear surface of the trunk lid while it is in the "closed" state (i.e., with the auxiliary handle resting on the edge of the rear panel). Figure 5 As shown.

[0103] Specifically:

[0104] ① Modeling Features: The luggage compartment lid accessory assembly is in a "closed" position (i.e., when the accessory handle is attached to the edge of the rear panel). A local structural mesh model of the handle and the rear panel is established. All nodes of the cut-off portion are used to create a set for constraints. The nodes in the contact area between the rear panel and the handle are used to establish contact relationships, and the friction coefficient is set to 0.15. A small gap (e.g., 0.5mm) is artificially created between the handle and the rear panel in the model to ensure the effect of the contact simulation under working conditions. Several different rectangular regions are selected on the rear surface of the luggage compartment lid (from the end of the rear surface to the middle of the rear surface). The size of the region is similar to that of a human hand. The geometric center of the region is the main line. All nodes of the outer plate mesh of the rear surface of the luggage compartment lid within the region are slave points. RBE3 elements are established to apply loads to the master points of the nodes.

[0105] ② Algorithm characteristics: The solution is obtained using the Abaqus / Standard solver, and the static analysis method is adopted. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed;

[0106] ③ Constraint Features: All trunk lid hinges and body connection holes surrounding unit nodes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword, and the above node geometry is constrained to 1-6 degrees of freedom. The local structural mesh model of the handle and rear enclosure contact area mentioned in "Step ①" is used to extract the set of all nodes of the extracted portion, which are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword, and the above node geometry is constrained to 1-6 degrees of freedom.

[0107] ④ Loading Features: Apply concentrated force loads (e.g., F = 200N) to the principal points of the rbe3 element mentioned in "Step ①". Establish the number of load steps according to the number of regions, ensuring that each load step applies one concentrated load. Set the parameters under the *cload keyword, establish a local coordinate system, and apply the concentrated load along the normal coordinate axis to the inside of the surface. Except for the first load step, set op = new after the *cload keyword for the remaining load steps.

[0108] 6. Simulation analysis and evaluation of the strength of auxiliary equipment operation process in the automotive trunk lid production line. This is used to determine the key indicator standards to replace the visual perception of users on site. Its characteristics are: after the structure is painted, the local deformation state of the smooth and flat area structure will be sensitively displayed under external light. The flat surface features around the auxiliary equipment, smooth curved surface or flat plane, are selected. Areas with complex features do not need to be considered. The deformation trend and strength results (plastic strain) are observed to provide a basis for the design scheme.

[0109] Example 1

[0110] The luggage lid has a rotation radius of 1.5m for the handle and a rotation radius of 0.8m for the center of gravity. h1 = 0.67m and h2 = 0.04m. The luggage lid weighs 20kg, and the load on a person's hand is assumed to be around 10kg.

[0111] 1. During the lifting operation, the maximum strain is 7.5%, and there is obvious plastic deformation in the flat area around the auxiliary tool;

[0112] 2. Under the impact condition of the cover being lowered, the angular velocity is 0.84 rad / s, the maximum strain is 8.3%, and there is obvious plastic deformation in the flat area around the auxiliary tool;

[0113] 3. Impact failure during operation: angular velocity 0.81 rad / s, maximum strain 4.7%, obvious plastic deformation in the flat area around the auxiliary tool;

[0114] 4. Under the condition of misoperation of the pressure cap, the pressing load is set at 200N, the maximum strain is 0.1%, and there is no obvious plastic deformation in the flat area around the auxiliary tool.

[0115] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A simulation analysis method for the operational process strength of auxiliary fixtures in an automobile trunk lid production line, characterized in that, Includes the following steps: A. Modeling the assembly state of automotive trunk lid fixtures for simulation of typical working conditions of subsequent automotive trunk lid production line fixture operations; B. Lid Lifting Operation Condition: This simulates the operation of an operator using a tool to open and lift the sheet metal welded assembly of the luggage compartment lid. C. Impact of falling cover misoperation: This is used to simulate the situation where an operator is holding an assistive device and, due to a mistake, the device is in a high position and the force is suddenly unloaded, causing it to fall freely. When the device reaches the limit of the operator's arm operation, the device is tightened to stop the fall, resulting in the impact of the fall. D. Impact and misoperation scenario: This scenario simulates the impact between the handle and the rear panel caused by the operator releasing the auxiliary handle at the lower limit of the human arm's operating range, resulting in the weight of the object falling from that distance. E. Misoperation of the lid: When the trunk lid is closed, i.e. the handle of the auxiliary tool is attached to the edge of the rear panel, the operation simulates the situation where the operator presses on the rear surface of the trunk lid. F. Evaluation: This is used to determine the key indicator standards of the results to replace the visual perception of the users on site. By selecting the flat surface features around the assistive device, we observe its deformation trend and strength results, i.e., plastic strain, to provide a basis for the design scheme. Step D, specifically: D1. Modeling features: Establish a local structural mesh model of the contact area between the handle and the rear enclosure, extract all nodes of the section to create a set for constraints, establish the contact relationship between the nodes in the contact area between the rear enclosure and the handle, and take the friction coefficient as 0.15; In the model, a small gap is artificially made between the handle and the rear enclosure to ensure the effect of the impact simulation under working conditions. D2. Algorithm characteristics: The algorithm uses a solver and employs an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed. D3. Constraint Features: All unit nodes around the trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. In step D1, the local structural mesh model of the handle and rear enclosure contact area is used to extract the set of all nodes of the extracted portion, which are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. D4. Loading Characteristics: The parameters of the luggage compartment lid from its open position (reaching the limit of human arm operation) to its closed position are as follows, where M represents the mass of the luggage compartment lid, g represents the acceleration due to gravity, v represents the velocity of the center of mass of the luggage compartment lid when it falls from position 3 to position 2, and φ represents the angular velocity of the luggage compartment lid when it falls from position 3 to position 2. The angular velocity, representing the downward movement of the center of mass, is derived as follows due to gravity. According to the law of conservation of energy: ； Before the *step keyword, set the parameters under the *initial keyword, and give the initial angular velocity value as the calculated value of equation (6).

2. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 1, characterized in that, Step A, specifically: A1. Modeling features of the auxiliary assembly: The auxiliary assembly is divided into two parts: a connecting plate and an operating handle. Both are meshed using solid elements. They are connected using conn3D2 type elements with the element property type being hinge. The local coordinate X-axis direction of the element is the same as the X-axis direction of the same type of element as the hinge connecting the trunk lid and the body. The mesh model of the connecting plate and the operating handle has a contact setting with a contact friction coefficient of 0.

12. A2. Modeling features of the luggage compartment lid assembly: Assign plastic property parameters to the structural materials around the auxiliary parts, edit the *plastic property parameter data under the *material keyword, and assign plastic stress-strain curve property parameter data to the material so that subsequent simulation outputs plastic strain results; Define the contact relationships between all sheet metal parts in the assembly and set the relevant parameters for the *contact keyword; A3. Modeling features of the overall assembly model: The connecting holes between the auxiliary assembly model and the trunk lid assembly model are connected by rigid coupling units to obtain the overall assembly model; In the overall assembly model, rbe3 characteristic elements are not allowed; all rigidly coupled elements are of type coupkin.

3. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 2, characterized in that: In the model, the load step results are output as field variables, node outputs are output as displacement variables, and element outputs are output as plastic strain variables.

4. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 1, characterized in that, Step B, specifically: B1. Modeling characteristics: The luggage compartment lid accessory assembly is in a closed position under this working condition; B2. Algorithm characteristics: The algorithm uses a solver and employs a static analysis method. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed. B3 constraint features: All trunk lid hinges and body connection holes surrounding unit nodes are constrained to 1-6 degrees of freedom. Under the Abaqus load step *step keyword, set the parameters under the *boundary keyword, and the above nodes are geometrically constrained to 1-6 degrees of freedom. B4. Loading Features: The engagement point of the luggage compartment lid latch hook is coupled with the surrounding latch nodes. Along the vertical upward direction + distance, set the parameters under the *boundary keyword, only set the displacement parameter of 3 degrees of freedom to + distance; do not set the other degrees of freedom; apply a vertical downward gravity field load to the overall model, the load size is 1.5 times the gravitational acceleration.

5. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 1, characterized in that, Step C, specifically: C1. Modeling features: Conn3D2 type elements are created at the end of the handle model. One node of the element is rigidly coupled to the node of the handle end model, and the other node is used for subsequent constraints. The element property type is hinge type, and certain stiffness and damping parameters are assigned to the 1-3 degrees of freedom. C2. Algorithm characteristics: The algorithm uses a solver and employs an explicit dynamic analysis method. Under the Abaqus load step *step keyword, the *explicit analysis type is set, and the analysis type parameters are set as needed. C3. Constraint Features: All trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom at their surrounding unit nodes. Under the *step keyword in the Abaqus load step, the parameters under the *boundary keyword are set, and the geometric constraints of the above nodes are 1-6 degrees of freedom. The trunk lid latch engagement point is coupled with the surrounding latch nodes, and the numerical translational degrees of freedom of the trunk lid latch engagement point are constrained. The parameters under the *boundary keyword are set, and the constraints are 3 degrees of freedom. C4. Loading Features: When the trunk lid is in its highest open position and reaches the limit of human arm operation due to gravity, the parameters are as follows: M represents the mass of the trunk lid, F represents the reaction force of the arm pushing the handle during descent, g represents the acceleration due to gravity, and v represents the velocity of the center of mass of the trunk lid when it falls from position 3 to position 2. This represents the distance the center of mass moves downwards. This represents the angular velocity of the suitcase lid as it falls from position 3 to position 2; According to the law of conservation of energy: ； Before the *step keyword, set the parameters under the *initial keyword, give the initial angular velocity value as the calculated value of equation (3), set the *cload keyword in the *step load step, and apply the F force value vertically upward at the end of the handle.

6. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 1, characterized in that, Step E, specifically: E1. Modeling Features: Establish a local structural mesh model of the contact area between the handle and the rear panel. Select all nodes of the selected portion to create a set for constraints. Establish contact relationships between the nodes in the contact area between the rear panel and the handle, with a friction coefficient of 0.

15. In the model, a small gap is artificially created between the handle and the rear panel to ensure the effect of the working condition contact simulation. Select several different rectangular areas on the rear surface of the trunk lid, with the area size similar to a human palm. Use the geometric center of the area as the master line and all nodes of the outer plate mesh of the rear surface of the trunk lid within the area as slave points. Create rbe3 elements to apply loads to the master points of the nodes. E2. Algorithm characteristics: The algorithm uses a solver and employs a static analysis method. Under the Abaqus load step *step keyword, the *static analysis type is set, and the analysis type parameters are set as needed. E3. Constraint Features: All unit nodes around the trunk lid hinges and body connection holes are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. In step E1, the local structural mesh model of the handle and rear enclosure contact area is used to extract the set of all nodes of the extracted portion, which are constrained to 1-6 degrees of freedom. Under the *step keyword in the Abaqus load step, set the parameters under the *boundary keyword. The geometric constraints of the above nodes are 1-6 degrees of freedom. E4. Loading Features: Apply concentrated force loads to the main points of the rbe3 element mentioned in step E1. Establish the number of load steps according to the number of regions to ensure that each load step loads one concentrated load. Set the parameters under the *cload keyword, establish a local coordinate system, and apply concentrated loads to the inside of the surface along the normal coordinate axis. Except for the first load step, set op=new after the *cload keyword for the remaining load steps.

7. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 6, characterized in that: Step E1, the rear surface of the trunk lid, from the end of the rear surface to the middle of the rear surface.

8. The method for simulation analysis of the operational process strength of auxiliary fixtures in an automobile trunk lid production line according to claim 1, characterized in that, Step F: Select flat surface features around the assistive device, such as smooth curved surfaces or flat planes. Areas with complex features do not need to be considered. Observe its deformation trend and strength results.

Images