Method for calculating stress of supporting structure during lightering of module vehicle

Abstract

The invention relates to a method for calculating the stress of a supporting structure during lightering of a module vehicle. The method comprises the following steps: creating a three-dimensional model of a module vehicle group and a lightering block; grid division is carried out; establishing a model of the rotary block; the rotary placing piers are in node coupling connection with the module vehicle lightering block and the module vehicle set through the constraint rigid unit bodies; according to the force balance equation and the moment balance equation, the axial pressure P1 and the axial pressure P2 of each axis of the module vehicle are calculated; calculating the bearing reaction force of the lightering block according to the calculated axial pressure and the axis position of the arrangement of the module vehicle group; the gravity load of the lightering block and the bearing reaction force are calculated and input into Patran software, constraint boundary conditions are set at the two ends of the lightering block, the rotary laying pier and the bottom of the module vehicle set, and the lightering working condition is calculated; and extracting a supporting structure stress cloud picture and a vehicle group overall stress picture of the generation module vehicle group. By means of the method, stress calculation of the module vehicle set during lightering block supporting can be achieved, and data support is provided for actually formulating a lightering scheme.

Description

Technical Field

[0001] The present invention relates to the field of shipbuilding, and particularly to a method for calculating the force on the support structure during the barge transportation of a modular vehicle. Background Art

[0002] The modular vehicle consists of a power module unit and a six-axle or eight-axle vehicle deck. The vehicle width has two types: 2.43 m and 3 m, the axle spacing is 1.4 m and 1.5 m, and the vehicle deck suspension adopts a hydraulic suspension, which consists of two types of suspensions: a driving suspension and a braking suspension. Through ball valve grouping, hydraulic three-point support and four-point support can be achieved, and the vehicle can be lifted and lowered by ±350 mm. The modular vehicle groups communicate through bus signals to achieve coordination and synchronization between the vehicle groups. The vehicle can be lifted and lowered as a whole through height sensors to achieve hard parallel connection and soft parallel connection.

[0003] Modular vehicles are widely used in the shipbuilding industry, which is beneficial to the off-site construction of ship sections. Due to the large weight, large volume, and the use of thin plate structures of large ship sections, a large load will act on the support structure of the modular vehicle during barge transportation. Stress concentration at a certain point of the support structure will cause fatigue cracks and then static load fracture. Once the modular vehicle breaks during use, it will cause safety accidents and is not conducive to the development of production. Summary of the Invention

[0004] In order to avoid safety accidents caused by the fracture of the modular vehicle during use, the present invention provides a method for calculating the force on the support structure during the barge transportation of the modular vehicle, generating a stress cloud map of the modular vehicle structure, and providing a reference for the mechanical properties for formulating the barge transportation plan.

[0005] The technical object of the present invention is achieved through the following technical solutions:

[0006] A method for calculating the force on the support structure during the barge transportation of a modular vehicle, the method comprising:

[0007] Step 1: Obtain the material properties and three-dimensional dimensions of the support structure of the modular vehicle, create a three-dimensional model of the modular vehicle group, and import the three-dimensional model of the barge transportation ship section; simplify the power module unit, tires, and hydraulic suspension structure of the modular vehicle group;

[0008] Step 2: Perform mesh division on the three-dimensional model of the modular vehicle group through finite element analysis software;

[0009] Step 3: Establish a finite element model of the rotating rest pier through Gap units;

[0010] Step 4: Connect the rotating rest pier to the three-dimensional models of the barge transportation ship section and the modular vehicle group through constraint rigid unit bodies Rigid for node coupling;

[0011] Step 5: Assemble the vehicle according to the four-point support, with the axle pressure of the module vehicle at the front support point being P 1 , and the axle pressure of the module vehicle at the rear support point being P 2 . Calculate the axle pressures P 1 and P 2 at each axis of the module vehicle according to the force balance equation and the moment balance equation;

[0012] Step 6: Calculate the reaction forces of the barge section based on the calculated axle pressures and the axis positions of the module vehicle group arrangement;

[0013] Step 7: Calculate the gravity load of the barge section. Input the gravity load of the barge section and the reaction forces calculated in Step 6 into the Patran software. Set the constraint boundary conditions at both ends of the barge section, the rotating supports, and the bottom of the module vehicle group, and calculate the barge operation conditions through the Patran software;

[0014] Step 8: Extract and generate the stress nephogram of the support structure of the module vehicle group and the overall stress diagram of the vehicle group from the Patran software.

[0015] Furthermore, in Step 2, mesh the three-dimensional model of the module vehicle group using plate-beam composite elements.

[0016] Furthermore, after meshing, it also includes adjusting the density of each structure of the three-dimensional model of the module vehicle group, so that the weight and the center of gravity position of the finite element model of the module vehicle group are close to the actual situation, with the deviation controlled within 5%.

[0017] Furthermore, the method also includes performing a mass diagnosis on the finite element model of the module vehicle group after the density adjustment is completed, and modifying the points with abnormal diagnosis.

[0018] Furthermore, in Step 3, the stiffness coefficient of the Gap element where E is the elastic modulus of the rotating support, A is the projected stress area of the rotating support, and H is the height of the rotating support.

[0019] Furthermore, in Step 5, establish a coordinate system with the head of the module vehicle group as the origin, with the barge movement direction as the X-axis, the height direction of the barge section as the Y-axis, and the direction perpendicular to the X-axis and Y-axis as the Z-axis;

[0020] The force balance equation is:

[0021]

[0022] The moment balance equation is:

[0023]

[0024] In the formula, m 1The number of axles of the modular vehicle serving as the front support point, n 1 The number of axles of the modular vehicle serving as the rear support point. The number of axles on each modular vehicle is Ni, and the number of rotating supports on each modular vehicle is Ni″, G 0 The total weight of the barge section, G i The weight of the axle, G i ″ is the weight of the rotating support. L is the horizontal distance from the centroid of the barge section to the origin, L ′ i The horizontal distance from the centroid of each axle in the X-axis direction to the origin, L ′ i ′ The horizontal distance from the centroid of each rotating support to the origin.

[0025] Furthermore, in step 2, it also includes optimizing the mesh division at the perforated part of the support structure and reducing the mesh specification at the perforated part.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows. Through the method of the present invention, the stress calculation of the modular vehicle group during the barge section support can be realized, providing data support for the actual formulation of the barge plan. In addition, by taking the reaction force received above the modular vehicle as the input condition for finite element analysis, the present invention improves the calculation accuracy of the support structure when the modular vehicle barges the barge section. By simplifying the model, the present invention eliminates the structures irrelevant to finite element calculation, effectively improving the calculation efficiency of finite element. By adjusting the density, the finite element model is made close to the real situation, ensuring the accuracy of the finite element calculation results. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the coordinate system establishment when the modular vehicle group supports the barge section in the present invention.

[0028] Figure 2 It is the stress nephogram of the support structure of the modular vehicle group extracted in the present invention.

[0029] Figure 3 It is the overall stress diagram of the modular vehicle group extracted in the present invention. Detailed Embodiments

[0030] The technical solution of the present invention will be further described below in conjunction with the detailed embodiments:

[0031] A method for calculating the force on the support structure during the barge of a modular vehicle, the method comprising:

[0032] Step 1: Obtain the material properties and three-dimensional dimensions of the support structure of the modular vehicle. Create a three-dimensional model of the modular vehicle group using CATIA software (Computer Aided Three-dimensional Interactive Application, CATIA), and import the three-dimensional model of the barge section. Simplify the power module unit, tires, and hydraulic suspension structure of the modular vehicle group. By simplifying the model, eliminate the structures that are irrelevant to the finite element calculation to improve the efficiency of the finite element calculation.

[0033] Step 2: Perform mesh division on the three-dimensional model of the modular vehicle group. Specifically, perform mesh division on the three-dimensional model of the modular vehicle group using plate-beam composite elements, and set the material properties of each structure of the modular vehicle according to the actual material properties. It is also possible to optimize the mesh division at the perforated parts of the support structure, reduce the mesh size at the perforated parts. The smaller the mesh size, the higher the accuracy of the finite element calculation, and the accuracy of the finite element calculation results can be increased.

[0034] After mesh division, it also includes adjusting the density of each structure of the three-dimensional model of the modular vehicle group, so that the weight and center of gravity position of the finite element model of the modular vehicle group are close to the actual situation, and the deviation is controlled within 5%. Avoid excessive deviation between the weight and center of gravity position of the modular vehicle and the actual situation, which may affect the calculation results.

[0035] After the density adjustment is completed, perform a quality diagnosis on the finite element model of the modular vehicle group through DIAG (Model Diagnosis, DIAG), and modify the points with abnormal diagnosis results until all diagnosis results meet the requirements.

[0036] Step 3: Establish a finite element model of the rotating support pier through Gap elements; the rotating support pier is only under compression above the frame support structure, and the Gap element is only under compression in the vertical direction. Therefore, it is more in line with the actual situation to use Gap elements to establish the rotating support pier.

[0037] The stiffness coefficient of the Gap element where E is the elastic modulus of the rotating support pier, A is the projected stress area of the rotating support pier, and H is the height of the rotating support pier.

[0038] Step 4: Couple the nodes of the rotating support pier to the three-dimensional models of the modular vehicle barge section and the modular vehicle group respectively through constraint rigid element bodies;

[0039] Step 5: Configure the vehicles according to four-point support. The axle pressure of the modular vehicle at the front support point is P 1 , and the axle pressure of the modular vehicle at the rear support point is P 2 . Calculate the axle pressures P 1 and P 2 at each axis of the modular vehicle according to the force balance equation and the moment balance equation.; Establish a coordinate system with the head of the modular vehicle group as the origin, the barge moving direction as the X-axis, the total height direction of the barge section as the Y-axis, and the direction perpendicular to the X-axis and Y-axis as the Z-axis, as shown in Figure 1 shown;

[0040] The force balance equation is:

[0041]

[0042] The moment balance equation is:

[0043]

[0044] In the formula, m 1 is the number of axles of the modular vehicle at the front support point, n 1 is the number of axles of the modular vehicle at the rear support point. The number of axles on each modular vehicle is Ni, and the number of rotating supports on each modular vehicle is Ni″. G 0 is the weight of the barge section, G i is the axle weight, G i ″ is the weight of the rotating support. L is the horizontal distance from the centroid of the barge section to the origin. L ′ i is the horizontal distance from the centroid of each axle in the X-axis direction to the origin. L ′ i ′ is the horizontal distance from the centroid of each rotating support to the origin.

[0045] Step 6: Calculate the reaction force of the barge section according to the calculated axial compression and the axial position of the modular vehicle group arrangement. The reaction force of the modular vehicle on the barge section is equal to the sum of the reaction forces at all supports. The reaction force at each support is equal to the number of axles occupied by the support multiplied by the axial compression. For example, a rotating support occupies 2 axles and the axial compression is P1, then the reaction force of the support here is 2P1. The total reaction force of the supports is the reaction force of the modular vehicle on the barge section.

[0046] Step 7: Calculate the gravity load of the barge section. Input the gravity load of the barge section and the reaction force calculated in Step 6 into the Patran software, set the constraint boundary conditions for both ends of the barge section, the rotating supports, and the bottom of the modular vehicle group, and calculate the barge working condition through the Patran software; when setting the constraint boundary conditions, perform translational constraints in the X-axis direction at both ends of the barge section, perform translational and rotational constraints in the X-axis and Y-axis directions on the rotating supports, and perform translational and rotational constraints in the X-axis, Y-axis, and Z-axis directions on the bottom of the modular vehicle group.

[0047] Step 8: Extract and generate the stress nephogram of the support structure of the modular vehicle group and the overall stress diagram of the vehicle group from the Patran software, as shown in Figure 2 and Figure 3 shown.

[0048] This embodiment is only a further explanation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for calculating the force of a supporting structure during module vehicle barge transport, characterized in that: The method includes: Step 1: Obtain the material properties and 3D dimensions of the supporting structure of the modular vehicle, create a 3D model of the modular vehicle group, and import the 3D model of the transfer section; simplify the power module unit, tires, and hydraulic suspension structure of the modular vehicle group; Step 2, meshing the three-dimensional model of the module vehicle group; Step 3, establishing a finite element model of the rotating pier through the Gap unit; Step 4: Connect the rotating pier to the three-dimensional models of the module vehicle barge section and the module vehicle group through node coupling through the constrained rigid unit body; Step 5: Assemble the vehicle according to the four-point support. The axle pressure of the module vehicle at the front support point is P1, and the axle pressure of the module vehicle at the rear support point is P2. The axle pressures P1 and P2 at each axis of the module vehicle are calculated according to the force balance equation and the moment balance equation; Step 6: Calculate the support reaction force of the transfer section according to the calculated axle pressure and the axis position of the module train arrangement; Step 7: Calculate the gravity load of the barge section, input the gravity load of the barge section and the support reaction force calculated in step 6 into the Patran software, set constraint boundary conditions for both ends of the barge section, the rotating pier and the bottom of the module train, and calculate the barge working condition through the Patran software; Step 8: Extract and generate the stress cloud diagram of the supporting structure of the module train set and the overall stress diagram of the train set from the Patran software.

2. The method for calculating the force of the supporting structure of a modular vehicle during barge transport according to claim 1 is characterized in that: In the step 2, the three-dimensional model of the modular train set is meshed by using plate-beam composite units.

3. The method for calculating the force of the supporting structure during the transportation of a module vehicle according to claim 2 is characterized in that: After meshing, the density of each structure of the three-dimensional model of the modular vehicle set is also adjusted, so that the weight and center of gravity position of the finite element model of the modular vehicle set are close to the actual situation, and the deviation is controlled within 5%.

4. The method for calculating the force of the supporting structure of a modular vehicle during barge transport according to claim 3 is characterized in that: The method also includes performing quality diagnosis on the finite element model of the module vehicle group after the density adjustment is completed, and modifying the points with abnormal diagnosis.

5. The method for calculating the force of the supporting structure of a modular vehicle during barge transport according to claim 1 is characterized in that: In step 3, the stiffness coefficient of the Gap element is Wherein E is the elastic modulus of the rotating pier, A is the projected force area of ​​the rotating pier, and H is the height of the rotating pier.

6. The method for calculating the force of the supporting structure of a modular vehicle during barge transport according to claim 1 is characterized in that: In step 5, a coordinate system is established with the front of the module train set as the origin, the moving direction of the barge is the X-axis, the height direction of the barge section is the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is the Z-axis; The force balance equation is: The moment balance equation is: Where m1 is the number of axes of the module car at the front support point, n1 is the number of axes of the module car at the rear support point, the number of axes on each module car is Ni, the number of rotating piers on each module car is Ni″, G0 is the total weight of the lightering section, G i is the axis weight, G i ″ is the weight of the rotating pier, L is the horizontal distance from the center of gravity of the lightering section to the origin, L ′ i L is the horizontal distance from the center of gravity of each axis in the X-axis direction to the origin, ′ i ′ It is the horizontal distance between the center of gravity of each rotating pier and the origin.

7. The method for calculating the force of the supporting structure of a modular vehicle during transportation according to claim 1, wherein The characteristic is that, in the step 2, it also includes optimizing and dividing the grid of the holes of the support structure, Reduce the size of the mesh with holes.

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