A mechanical analysis method of elevator load-bearing beam based on finite element analysis

Abstract

The present invention relates to a mechanical analysis method of an elevator load-bearing beam based on finite element analysis, comprising the following steps: constructing a three-dimensional model of an elevator load-bearing beam and checking and optimizing interference problems; determining the load coefficient and rated load ratio of the elevator under different working conditions according to relevant standards; calculating the wire rope tension and the main frame tension for the fully loaded car downward braking and fully loaded counterweight downward braking conditions; simplifying the two ends of the load-bearing beam into a simply supported structure, and determining the load borne by each force point of the load-bearing beam; theoretically calculating the strength and stiffness of the load-bearing beam; establishing a finite element model using finite element analysis, and performing simulation analysis on the above two extreme working conditions; comparing theoretical calculations and finite element simulation data, and evaluating whether the strength and stiffness of the load-bearing beam meet the requirements. The present invention can effectively improve the accuracy and reliability of the design of elevator load-bearing beams, reduce design costs, and is suitable for a variety of shaft layouts and wire rope routing methods.

Description

Technical Field

[0001] The present invention relates to the technical field of elevator design and manufacturing technology, and in particular to a mechanical analysis method of an elevator load-bearing beam based on finite element analysis. Background Art

[0002] With the rapid development of the logistics industry, freight elevators, as important equipment for vertical transportation, play an indispensable role in warehouses, factories and logistics centers. As a key component supporting the entire elevator system and its load, the strength and stiffness of the elevator load-bearing beam are directly related to the safety and reliability of the elevator operation. There are two main traditional methods for designing elevator load-bearing beams: one is the calculation method based on the simply supported beam theory. This method handles the load-bearing beam by simplifying assumptions. Although it is simple, the result has limited accuracy and it is difficult to fully reflect the actual working conditions; the other is to make physical samples for experimental testing. Although the results are accurate, it is costly, time-consuming, and consumes a lot of resources.

[0003] With the changes in market demand, it has become a trend to use finite element analysis software to simulate the load-bearing beams of elevators. Finite element analysis can more accurately simulate the stress conditions of load-bearing beams under actual working conditions, helping designers to find potential problems and optimize them at an early stage. However, the existing finite element analysis method still has certain limitations in the design of elevator load-bearing beams, such as insufficient simulation of extreme working conditions, poor adaptability to hoistway layout and wire rope routing, etc. Therefore, a more efficient, accurate and adaptable elevator load-bearing beam mechanical analysis method is urgently needed to meet the needs of modern elevator design. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an efficient, accurate and adaptable elevator load-bearing beam mechanical analysis method based on finite element analysis.

[0005] A mechanical analysis method for an elevator load-bearing beam based on finite element analysis of the present invention comprises the following steps:

[0006] Step 1: Build a 3D model of the elevator load-bearing beam and check the optimization interference problem;

[0007] Step 2: Determine the load factor and rated load ratio of the elevator under different working conditions according to relevant standards;

[0008] Step 3: Calculate the wire rope tension and the mainframe frame tension for the fully loaded car downward braking and fully loaded counterweight downward braking conditions;

[0009] Step 4: Simplify both ends of the load-bearing beam into a simply supported structure and determine the load borne by each stress point of the load-bearing beam;

[0010] Step 5: Theoretically calculate the strength and stiffness of the load-bearing beam;

[0011] Step 6: Use finite element analysis to establish a finite element model, and perform simulation analysis on the two extreme working conditions of fully loaded car downward braking and fully loaded counterweight downward braking;

[0012] Step 7: Compare the theoretical calculation and finite element simulation data to evaluate whether the strength and stiffness of the load-bearing beam meet the requirements;

[0013] Step 8: Adjust the model parameters and calculation methods according to different hoistway layouts and wire rope routing methods;

[0014] Step 9: When conditions permit, conduct experimental tests, compare and analyze the experimental data with theoretical calculations and finite element simulation data, and verify and correct each other;

[0015] Step 10: Based on the analysis results, optimize the structure and material selection of the load-bearing beam.

[0016] Preferably, in the steps of constructing a three-dimensional model of the elevator load-bearing beam and checking and optimizing interference problems, a precise three-dimensional model is constructed using three-dimensional modeling software. During the construction process, the model is comprehensively checked using the interference check function of the software. If interference problems are found between components, the interference is resolved by adjusting the size, shape or position of the components. After each adjustment, the interference check is performed again until there are no interference problems in the model.

[0017] Preferably, in the step of determining the load factor and rated load ratio under different operating conditions of the elevator according to relevant standards, the relevant standards include but are not limited to GB / T7588.2-2020; the operating conditions include car loading conditions, emergency braking conditions, and car or counterweight retention conditions; for emergency braking conditions, the load factor value range of the car fully loaded acceleration stage is set to 1.2-1.5, and the load factor is determined according to the actual operating speed and braking performance of the elevator. The load factor of the car no-load deceleration stage is determined within the range of 0.8-0.5 according to the actual operating speed and braking performance of the elevator. The specific load factor and rated load ratio values ​​under each operating condition are accurately obtained by consulting the standard documents and combining the actual operating parameters of the elevator.

[0018] Preferably, in the step of calculating the wire rope tension and the tension borne by the main frame for the fully loaded car downward braking and the fully loaded counterweight downward braking conditions, the calculation formula is as follows:

[0019] When the fully loaded car is braking downward: the tension of the wire rope on the car side ;

[0020] Counterweight side wire rope tension ;

[0021] The mainframe frame bears the tensile force ;

[0022] When braking downward with full counterweight:

[0023] Car side wire rope tension ;

[0024] Counterweight side wire rope tension ;

[0025] The mainframe frame bears the tensile force ;

[0026] Among them, P is the weight of the car (kg), Q is the rated load (kg), r is the traction ratio, is the balance coefficient, is the acceleration (m / s2), is the weight of the wire rope (kg), is the weight of the compensation chain (kg), is the weight of the host (kg), is the acceleration of gravity; at the same time, considering the influence of the elastic deformation of the wire rope on the tension under different working conditions, the calculation result is corrected by introducing the elastic coefficient of the wire rope. The elastic coefficient is determined by referring to the wire rope material manual or conducting experimental tests based on the material, specifications and actual stress conditions of the wire rope.

[0027] Preferably, in the step of simplifying the two ends of the load-bearing beam into a simply supported structure and determining the load borne by each stress point of the load-bearing beam, the stress points include the car rope end, the car guide wheel, the main engine vibration damping pad, the counterweight guide wheel, and the counterweight rope end; according to the principle of mechanical equilibrium and the force transfer relationship, a static or dynamic model is used for analysis, and the actual installation position and connection method of the car, counterweight, main engine and other components in the elevator system are combined to reasonably distribute the forces of these components to the various stress points of the load-bearing beam; for the load at the main engine vibration damping pad, the actual load acting on the load-bearing beam is calculated based on the material properties of the vibration damping pad (such as elastic modulus, damping coefficient, etc.) and the actual compression deformation, through the stress-strain relationship in material mechanics or the performance curve provided by the vibration damping pad manufacturer, combined with the relationship between force and deformation.

[0028] Preferably, in the step of theoretically calculating the strength and stiffness of the load-bearing beam, the calculation steps are as follows: Calculate the load borne by the support end: According to the load size and position of each force point, use the static equilibrium equation:

[0029] ,in is the load on the support ends A and B, For the The load at each stress point, L is the length of the load-bearing beam, For the The distance from the force-bearing point to the support end A, n is the total number of force-bearing points, calculate the load borne by the support end;

[0030] List the bending moment equation and calculate the maximum bending moment and maximum stress: List the bending moment equation segment by segment according to the load distribution on each section of the load-bearing beam

[0031] ;

[0032] in , find the maximum bending moment by taking the derivative of the bending moment equation or analyzing its function characteristics , and then according to the formula ,in is the maximum stress, W is the bending section coefficient, calculate the maximum stress;

[0033] Calculate the maximum deflection: Use the superposition method to calculate the maximum deflection of the load-bearing beam. For the deflection generated at each stress point, use the beam deflection calculation formula in material mechanics.

[0034] ,in , Calculate, where , and then add the deflections generated by each stress point to get the maximum deflection , where E is the elastic modulus of the material and I is the moment of inertia. According to the specific cross-sectional shape of the load-bearing beam, the bending section coefficient W and the moment of inertia I are calculated by the corresponding set formula.

[0035] Preferably, the finite element model is established by using a finite element analysis tool, and the finite element analysis tool is set to Femap with NX Nastran software. In the step of simulating and analyzing the above two extreme working conditions, in Femap with NX Nastran software, the constraints at both ends of the load-bearing beam are set to be completely fixed; the properties of the load-bearing beam material are accurately set, including but not limited to elastic modulus, Poisson's ratio, density, etc., and these property values ​​are obtained by consulting a material manual or performing a material performance test; according to the structural characteristics of the load-bearing beam, such as the length, cross-sectional shape, and stress conditions of the beam, a suitable meshing method (such as tetrahedral mesh, hexahedral mesh, etc.) is used to mesh the load-bearing beam, and the size and density of the mesh are adjusted according to the calculation accuracy requirements and computer performance to improve the accuracy of the simulation results; corresponding loads and boundary conditions are applied to the two extreme working conditions of fully loaded car downward braking and fully loaded counterweight downward braking, respectively, and simulation calculations are performed to obtain the deformation cloud map, stress cloud map, and the values ​​of maximum stress and maximum deflection of the load-bearing beam.

[0036] Preferably, in the step of comparing the theoretical calculation and finite element simulation data to evaluate whether the strength and stiffness of the load-bearing beam meet the requirements, the maximum stress and maximum deflection values ​​obtained by the theoretical calculation are compared and analyzed with the corresponding values ​​obtained by the finite element simulation, and the error between the two is calculated; the evaluation standard refers to the allowable stress and allowable deformation range specified in relevant standards (such as BS5655-6:2011); if the finite element simulation results show that the maximum stress or maximum deflection of the load-bearing beam exceeds the allowable range, the finite element simulation analysis is re-performed by adjusting the structural parameters of the load-bearing beam (such as increasing the thickness of the beam, changing the cross-sectional shape, adjusting the span of the beam, etc.) until the strength and stiffness of the load-bearing beam meet the design requirements.

[0037] Preferably, in the step of adjusting the model parameters and the calculation method according to different shaft layouts and wire rope routing methods, for different shaft layouts (such as single shaft, double shaft, parallel shaft, etc.) and wire rope routing methods (such as 1:1 winding method, 2:1 winding method, etc.), the influence of them on the stress condition of the load-bearing beam is analyzed; when the shaft layout changes and the relative positions of the car, counterweight and load-bearing beam change, the position and load size of each stress point are re-determined; when the wire rope routing method changes, the wire rope tension is recalculated according to the new winding method, and the calculation of the tension borne by the main frame is adjusted accordingly; at the same time, in the finite element model, the model parameters such as the boundary conditions and load application method of the load-bearing beam are adjusted according to the actual situation to accurately simulate the mechanical properties of the load-bearing beam under different conditions.

[0038] Preferably, when conditions permit, in the step of conducting experimental tests, comparing and analyzing the experimental data with the theoretical calculation and finite element simulation data, and verifying and correcting each other, the experimental tests include but are not limited to stress testing and deflection testing of the load-bearing beam at the actual elevator installation site; using strain gauges and displacement sensors, such testing equipment to collect experimental data; comparing the stress and deflection data obtained from the experiment with the theoretical calculation and finite element simulation data, and analyzing the differences between the three; when the relative error between the stress and deflection data obtained from the experiment and the theoretical calculation and finite element simulation data exceeds a preset 10% When performing the analysis, check whether the assumptions of the theoretical calculation are reasonable, whether the parameters of the finite element model are accurately set, and whether there are errors in the experimental test methods and equipment. Then, correct the theoretical calculation method and the finite element model parameters, or improve the experimental test method to improve the accuracy of the analysis results. In the step of optimizing the structure and material selection of the load-bearing beam according to the analysis results, if the analysis results show that the strength safety factor of the load-bearing beam exceeds the preset 1.5, consider reducing the cross-sectional size of the beam and replacing it with a lightweight material to optimize the structure and material to reduce costs. If the strength or stiffness of the load-bearing beam is insufficient, increase the thickness of the beam, change the cross-sectional shape, and select high-strength materials for improvement. At the same time, comprehensively consider the cost and processing technology factors to determine the optimal optimization plan. In the entire mechanical analysis process, record the calculation data, simulation results, experimental data and analysis process of each step in detail to form a complete analysis report, which is convenient for subsequent reference, tracing and further optimization and improvement of the mechanical analysis method.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. Improve design accuracy:

[0041] By using finite element analysis software (such as Femap with NX Nastran) to simulate the elevator load-bearing beam, it is possible to more accurately simulate the stress conditions of the load-bearing beam under actual working conditions, avoid the errors caused by the simplified assumptions of the traditional simply supported beam theory calculation method, and significantly improve the accuracy of the design.

[0042] 2. Reduce design costs:

[0043] The present invention replaces part of the physical test by finite element simulation, thus reducing the cost and time consumption of making physical samples, avoiding the waste of resources, and significantly reducing the design cost.

[0044] 3. Shorten the design cycle:

[0045] The use of 3D modeling and finite element simulation technology can discover and solve potential interference problems and structural defects in the early stages of design, reducing the time for later modifications and optimizations and significantly shortening the design cycle.

[0046] 4. Adapt to various working conditions and layouts:

[0047] The present invention can flexibly adjust model parameters and calculation methods according to different hoistway layouts and wire rope routing modes, is applicable to a variety of elevator design scenarios, and improves the versatility and adaptability of the method.

[0048] 5. Optimize structural design:

[0049] By combining theoretical calculation with finite element simulation, the strength and stiffness of the load-bearing beam can be accurately evaluated, and the structure and material selection of the load-bearing beam can be optimized based on the analysis results to avoid over-design or under-design, thereby improving the safety and economy of the structure.

[0050] 6. Experimental verification and correction:

[0051] When conditions permit, the present invention also supports verification and correction of theoretical calculations and simulation results through experimental testing, further improving the reliability and accuracy of the analysis results.

[0052] 7. Form a complete analysis report:

[0053] The present invention records the calculation data, simulation results and experimental data of each step in detail during the mechanical analysis process to form a complete analysis report, which is convenient for subsequent review, tracing and further optimization, and improves the traceability and repeatability of the design process.

[0054] Summary: Through the application of finite element analysis technology, the present invention significantly improves the accuracy, reliability and economy of elevator load-bearing beam design, while reducing design costs and cycles. It is suitable for a variety of elevator design scenarios and has broad application prospects and significant technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a flow chart of the method of the present invention;

[0056] Figure 2 It is a force diagram of the load-bearing beam 1 of the present invention;

[0057] Figure 3 It is a force diagram of the load-bearing beam 2 of the present invention; DETAILED DESCRIPTION

[0058] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0059] like Figures 1 to 3 As shown,

[0060] 1. Build a 3D model of the elevator load-bearing beam and check the optimization interference problem

[0061] The 3D model of the elevator load-bearing beam was constructed using Solid Edge software. During the model construction process, the interference check function of Solid Edge was used to conduct a comprehensive check on the model. If interference problems were found between components, the interference was resolved by adjusting the size, shape or position of the components. After each adjustment, the interference check was repeated until there was no interference problem in the model.

[0062] 2. Determine the load factor and rated load ratio of the elevator under different working conditions according to relevant standards

[0063] According to GB / T 7588.2-2020 standard, determine the load factor and rated load ratio of the elevator under different working conditions. Specific working conditions include car loading conditions, emergency braking conditions, and car or counterweight retention conditions. For emergency braking conditions, the load factor value range of the car fully loaded acceleration stage is set to 1.2-1.5, and the load factor of the car unloaded deceleration stage is determined in the range of 0.8-0.5 according to the actual operating speed and braking performance of the elevator. By consulting the standard documents and combining the actual operating parameters of the elevator, the specific load factor and rated load ratio values ​​under each working condition can be accurately obtained;

[0064] Combined with the load factors corresponding to the extreme load conditions at different positions of the car in the hoistway, as shown in Table 1 below:

[0065] Table 1

[0066]

[0067] 3. Calculate the wire rope tension and the mainframe frame tension for fully loaded car downward braking and fully loaded counterweight downward braking conditions.

[0068] According to the load conditions and load factors in Table 1, calculate the wire rope tension and mainframe tension under the conditions of fully loaded car downward braking and fully loaded counterweight downward braking. The calculation formula is as follows:

[0069] When the fully loaded car is braking downward: the tension of the wire rope on the car side ;

[0070] Counterweight side wire rope tension ;

[0071] The mainframe frame bears the tensile force ;

[0072] When braking downward with full counterweight:

[0073] Car side wire rope tension ;

[0074] Counterweight side wire rope tension ;

[0075] The mainframe frame bears the tensile force ;

[0076] Among them, P is the weight of the car (kg), Q is the rated load (kg), r is the traction ratio, is the balance coefficient, is the acceleration (m / s2), is the weight of the wire rope (kg), is the weight of the compensation chain (kg), is the weight of the host (kg), is the acceleration due to gravity.

[0077] 4. Define load-bearing beam 1 and load-bearing beam 2 and determine the load borne by each load point

[0078] Load-bearing beam 1: Load-bearing beam 1 is mainly used to support the load on the car side, including the car rope head, car guide wheel and part of the main engine vibration damping pad. According to the structural layout of the elevator system, load-bearing beam 1 has a total of 5 stress points.

[0079] Load-bearing beam 2: Load-bearing beam 2 is mainly used to support the load on the counterweight side, including the counterweight rope head, counterweight guide wheel and another part of the main engine vibration damping pad. According to the structural layout of the elevator system, load-bearing beam 2 has a total of 6 stress points.

[0080] Simplify the two ends of the load-bearing beam into a simply supported structure, and determine the load borne by each stress point of the load-bearing beam. The stress points include the car rope end, the car guide wheel, the main engine vibration damping pad, the counterweight guide wheel, and the counterweight rope end. According to the principle of mechanical balance and the force transmission relationship, combined with the actual installation position and connection method of the car, counterweight, main engine and other components in the elevator system, the forces of these components are reasonably distributed to the stress points of the load-bearing beam. For the load on the main engine vibration damping pad, according to the material properties of the vibration damping pad and the actual compression deformation, the actual load acting on the load-bearing beam is calculated through the stress-strain relationship in material mechanics or the performance curve provided by the vibration damping pad manufacturer, combined with the relationship between force and deformation.

[0081] When the car with 100% rated load is braked downward, the loads borne by the load-bearing beams 1 and 2 are shown in Table 2 below:

[0082] Table 2

[0083]

[0084] When the counterweight with 100% rated load is braked downward, the loads borne by the load-bearing beams 1 and 2 are shown in Table 3 below:

[0085] Table 3

[0086]

[0087] 5. Theoretical calculation of the strength and stiffness of the load-bearing beam

[0088] According to the basic technical parameters of the elevator in Table 4, the strength and stiffness of the load-bearing beam are theoretically calculated. The specific steps are as follows:

[0089] Calculate the load on the support end: According to the load size and position of each force point, use the static equilibrium equation: ,in is the load on the support ends A and B, For the The load at each stress point, L is the length of the load-bearing beam, For the The distance from the force-bearing point to the support end A, n is the total number of force-bearing points.

[0090] List the bending moment equation and calculate the maximum bending moment and maximum stress: List the bending moment equation segment by segment according to the load distribution on each section of the load-bearing beam

[0091] ;

[0092] in , find the maximum bending moment by taking the derivative of the bending moment equation or analyzing its function characteristics , and then according to the formula ,in is the maximum stress, W is the bending section coefficient, and the maximum stress is calculated.

[0093] Calculate the maximum deflection: Use the superposition method to calculate the maximum deflection of the load-bearing beam. For the deflection generated at each stress point, use the beam deflection calculation formula in material mechanics.

[0094] ,in , and then add up the deflections generated by each force point to get the maximum deflection: , where E is the elastic modulus of the material and I is the moment of inertia. According to the specific cross-sectional shape of the load-bearing beam, the bending section coefficient W and the moment of inertia I are calculated by the corresponding set formula; the basic technical parameters of the elevator are shown in Table 4 below:

[0095] Table 4

[0096]

[0097] 6. Use finite element analysis to establish a finite element model and perform simulation analysis on the above two extreme working conditions

[0098] In Femap with NX Nastran software, the constraints at both ends of the load-bearing beam are set to be completely fixed. The properties of the load-bearing beam material, including elastic modulus, Poisson's ratio, density, etc., are accurately set. These property values ​​are obtained by consulting the material manual or conducting material performance tests. According to the structural characteristics of the load-bearing beam, the meshing method of tetrahedral mesh or hexahedral mesh is used to mesh the load-bearing beam. The size and density of the mesh are adjusted according to the calculation accuracy requirements and computer performance to improve the accuracy of the simulation results. The corresponding loads and boundary conditions are applied to the two extreme working conditions of fully loaded car downward braking and fully loaded counterweight downward braking, and simulation calculations are performed to obtain the deformation cloud map, stress cloud map, and the values ​​of the maximum stress and maximum deflection of the load-bearing beam.

[0099] 7. Compare theoretical calculations and finite element simulation data to assess whether the strength and stiffness of the load-bearing beams meet the requirements

[0100] Compare and analyze the maximum stress and maximum deflection values ​​obtained by theoretical calculation with the corresponding values ​​obtained by finite element simulation, and calculate the error between the two. The evaluation standard refers to the allowable stress and allowable deformation range specified in relevant standards (such as BS 5655-6:2011). If the finite element simulation results show that the maximum stress or maximum deflection of the load-bearing beam exceeds the allowable range, the structural parameters of the load-bearing beam are adjusted (such as increasing the thickness of the beam, changing the cross-sectional shape, adjusting the span of the beam, etc.), and the finite element simulation analysis is repeated until the strength and stiffness of the load-bearing beam meet the design requirements.

[0101] 8. Adjust model parameters and calculation methods according to different hoistway layouts and wire rope routing methods

[0102] For different shaft layouts (such as single shaft, double shaft, parallel shaft, etc.) and wire rope routing methods (such as 1:1 winding method, 2:1 winding method, etc.), analyze their impact on the stress condition of the load-bearing beam. When the change in shaft layout causes the relative position of the car, counterweight and load-bearing beam to change, redetermine the position and load size of each stress point. When the wire rope routing method changes, recalculate the wire rope tension according to the new winding method, and adjust the calculation of the tension borne by the main frame accordingly. At the same time, in the finite element model, adjust the model parameters such as the boundary conditions and load application method of the load-bearing beam according to the actual situation to accurately simulate the mechanical properties of the load-bearing beam under different conditions.

[0103] 9. When conditions permit, conduct experimental tests, compare and analyze the experimental data with theoretical calculations and finite element simulation data, and verify and correct each other.

[0104] When conditions permit, conduct experimental tests, including stress tests and deflection tests on load-bearing beams at the actual elevator installation site. Use strain gauges, displacement sensors and other testing equipment to collect experimental data. Compare the stress, deflection and other data obtained from the experiment with the theoretical calculation and finite element simulation data, and analyze the differences between the three. If there are large differences, check whether the assumptions of the theoretical calculation are reasonable, whether the parameter settings of the finite element model are accurate, whether there are errors in the experimental test methods and equipment, etc., and then correct the theoretical calculation method and finite element model parameters, or improve the experimental test method to improve the accuracy of the analysis results.

[0105] 10. Based on the analysis results, optimize the structure and material selection of the load-bearing beam

[0106] According to the analysis results, the structure and material selection of the load-bearing beam are optimized. If the analysis results show that the strength of the load-bearing beam is relatively surplus, consider reducing the cross-sectional size of the beam, replacing it with lightweight materials, etc. to optimize the structure and materials to reduce costs. If the strength or stiffness of the load-bearing beam is insufficient, increase the thickness of the beam, change the cross-sectional shape, select high-strength materials, etc. for improvement. At the same time, comprehensively consider factors such as cost and processing technology to determine the best optimization plan. During the entire mechanical analysis process, the calculation data, simulation results, experimental data and analysis process of each step are recorded in detail to form a complete analysis report, which is convenient for subsequent reference, tracing, and further optimization and improvement of the mechanical analysis method.

[0107] Example 1, according to the basic technical parameters of the elevator in Table 4, the load-bearing beam uses 27at I-beam, the bending section coefficient W=485cm³, and the moment of inertia , the material elastic modulus E = 210GPa. According to the above formula, the maximum bending moment, maximum stress and maximum deflection of the load-bearing beams 1 and 2 under each working condition are calculated, as shown in Table 5 below, which meets the requirements of allowable stress and allowable deformation:

[0108] Table 5

[0109]

[0110] The strength and stiffness of the load-bearing beam are verified by finite element simulation. The simulation results are shown in Table 6 below, which meet the requirements of allowable stress and allowable deformation:

[0111] Table 6

[0112]

[0113] By comparing theoretical calculations and finite element simulation data, it is evaluated whether the strength and stiffness of the load-bearing beam meet the requirements, and the structure and material selection of the load-bearing beam are optimized based on the analysis results.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A mechanical analysis method for elevator load-bearing beams based on finite element analysis, characterized in that: The following steps are involved: Step 1: Build a 3D model of the elevator load-bearing beam and check the optimization interference problem; Step 2: Determine the load factor and rated load ratio of the elevator under different working conditions according to relevant standards; Step 3: Calculate the wire rope tension and the mainframe frame tension for the fully loaded car downward braking and fully loaded counterweight downward braking conditions; Step 4: Simplify both ends of the load-bearing beam into a simply supported structure and determine the load borne by each stress point of the load-bearing beam; Step 5: Theoretically calculate the strength and stiffness of the load-bearing beam; Step 6: Use finite element analysis to establish a finite element model and perform simulation analysis on the above two extreme working conditions; Step 7: Compare theoretical calculation and finite element simulation data to evaluate whether the strength and stiffness of the load-bearing beam meet the requirements; Step 8: Adjust the model parameters and calculation methods according to different hoistway layouts and wire rope routing methods; Step 9: When conditions permit, conduct experimental tests, compare and analyze the experimental data with theoretical calculations and finite element simulation data, and verify and correct each other; Step 10: Based on the analysis results, optimize the structure and material selection of the load-bearing beam.

2. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: In the steps of constructing a three-dimensional model of the elevator load-bearing beam and checking and optimizing interference problems, a precise three-dimensional model is constructed using three-dimensional modeling software. During the construction process, the model is comprehensively checked using the interference check function of the software. If interference problems are found between components, the interference is resolved by adjusting the size, shape or position of the components. After each adjustment, the interference check is performed again until there is no interference problem in the model.

3. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: In the step of determining the load factor and rated load ratio under different working conditions of the elevator according to relevant standards, the relevant standards include but are not limited to GB / T7588.2-2020; the working conditions include car loading conditions, emergency braking conditions, and car or counterweight retention conditions; for emergency braking conditions, the load factor value range of the car full-load acceleration stage is set to 1.2-1.5, which is determined according to the actual situation of the elevator running speed and braking performance, and the load factor of the car no-load deceleration stage is determined in the range of 0.8-0.5 according to the actual running speed and braking performance of the elevator. The specific load factor and rated load ratio values ​​under each working condition are accurately obtained by referring to the standard documents and combining the actual operating parameters of the elevator.

4. The method for mechanical analysis of elevator load-bearing beams based on finite element analysis according to claim 1, characterized in that: In the step of calculating the wire rope tension and the tension borne by the main frame for the fully loaded car downward braking and fully loaded counterweight downward braking conditions, the calculation formula is as follows: When the fully loaded car brakes downward: Car side wire rope tension ; Counterweight side wire rope tension ; The mainframe frame bears the tensile force ; When braking downward with full counterweight: Car side wire rope tension ; Counterweight side wire rope tension ; The mainframe frame bears the tensile force ; Among them, P is the weight of the car (kg), Q is the rated load (kg), r is the traction ratio, is the balance coefficient, is the acceleration (m / s2), is the weight of the wire rope (kg), is the weight of the compensation chain (kg), is the weight of the host (kg), is the acceleration of gravity; at the same time, considering the influence of the elastic deformation of the wire rope on the tension under different working conditions, the calculation result is corrected by introducing the elastic coefficient of the wire rope. The elastic coefficient is determined by referring to the wire rope material manual or conducting experimental tests based on the material, specifications and actual stress conditions of the wire rope.

5. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: In the step of simplifying the two ends of the load-bearing beam into a simply supported structure and determining the load borne by each stress point of the load-bearing beam, the stress points include the car rope end, the car guide wheel, the main engine vibration damping pad, the counterweight guide wheel and the counterweight rope end; according to the principle of mechanical balance and the force transfer relationship, a static or dynamic model is used for analysis, and the forces of the car, counterweight and main engine in the elevator system are reasonably distributed to the stress points of the load-bearing beam in combination with the actual installation position and connection method of the car, counterweight and main engine in the elevator system; for the load at the main engine vibration damping pad, the actual load acting on the load-bearing beam is calculated based on the material properties of the vibration damping pad and the actual compression deformation, through the stress-strain relationship in material mechanics or the performance curve provided by the vibration damping pad manufacturer, combined with the relationship between force and deformation.

6. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: In the step of theoretically calculating the strength and stiffness of the load-bearing beam, the calculation steps are as follows: Calculate the load on the support end: According to the load size and position of each force point, use the static equilibrium equation: ,in is the load on the support ends A and B, For the The load at each stress point, L is the length of the load-bearing beam, For the The distance from the force-bearing point to the support end A, n is the total number of force-bearing points, calculate the load borne by the support end; List the bending moment equation and calculate the maximum bending moment and maximum stress: List the bending moment equation segment by segment according to the load distribution on each section of the load-bearing beam ; in , find the maximum bending moment by taking the derivative of the bending moment equation or analyzing its function characteristics , and then according to the formula ,in is the maximum stress, W is the bending section coefficient, calculate the maximum stress; Calculate the maximum deflection: Use the superposition method to calculate the maximum deflection of the load-bearing beam. For the deflection generated at each stress point, use the beam deflection calculation formula in material mechanics. ,in , Calculate, where , and then add the deflections generated by each stress point to get the maximum deflection , where E is the elastic modulus of the material and I is the moment of inertia. According to the specific cross-sectional shape of the load-bearing beam, the bending section coefficient W and the moment of inertia I are calculated by the corresponding set formula.

7. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: The finite element model is established by using a finite element analysis tool, and the finite element analysis tool is set to Femap with NXNastran software. In the step of simulating and analyzing the above two extreme working conditions, in Femap with NX Nastran software, the constraint conditions at both ends of the load-bearing beam are set to be completely fixed; the properties of the load-bearing beam material are accurately set, and the property values ​​are obtained by consulting the material manual or performing material performance tests; according to the structural characteristics of the load-bearing beam, the load-bearing beam is meshed by using a tetrahedral mesh or a hexahedral mesh method, and the size and density of the mesh are adjusted according to the calculation accuracy requirements and computer performance to improve the accuracy of the simulation results; corresponding loads and boundary conditions are applied to the two extreme working conditions of fully loaded car downward braking and fully loaded counterweight downward braking, respectively, and simulation calculations are performed to obtain the deformation cloud map, stress cloud map, and the values ​​of maximum stress and maximum deflection of the load-bearing beam.

8. The method for mechanical analysis of elevator load-bearing beams based on finite element analysis according to claim 1, characterized in that: In the step of comparing the theoretical calculation and finite element simulation data to evaluate whether the strength and stiffness of the load-bearing beam meet the requirements, the maximum stress and maximum deflection values ​​obtained by the theoretical calculation are compared and analyzed with the corresponding values ​​obtained by the finite element simulation to calculate the error between the two; The evaluation criteria refer to the allowable stress and allowable deformation range specified in the relevant standards; if the finite element simulation results show that the maximum stress or maximum deflection of the load-bearing beam exceeds the allowable range, the finite element simulation analysis is re-performed by adjusting the structural parameters of the load-bearing beam until the strength and stiffness of the load-bearing beam meet the design requirements.

9. The method for mechanical analysis of elevator load-bearing beams based on finite element analysis according to claim 1, characterized in that: In the step of adjusting the model parameters and the calculation method according to different hoistway layouts and wire rope routing methods, the influence of different hoistway layouts and wire rope routing methods on the stress condition of the load-bearing beam is analyzed; when the change of the hoistway layout causes the relative position of the car, counterweight and load-bearing beam to change, the position and load size of each stress point are re-determined; when the wire rope routing method changes, the wire rope tension is recalculated according to the new winding method, and the calculation of the tension borne by the main frame is adjusted accordingly; at the same time, in the finite element model, the boundary conditions of the load-bearing beam and the model parameters of the load application method are adjusted according to the actual situation to accurately simulate the mechanical properties of the load-bearing beam under different conditions.

10. The elevator load-bearing beam mechanical analysis method based on finite element analysis according to claim 1, characterized in that: The step of conducting experimental tests when conditions permit, comparing and analyzing the experimental data with the theoretical calculation and finite element simulation data, and mutually verifying and correcting the experimental data includes, but is not limited to, conducting stress tests and deflection tests on the load-bearing beams at the actual elevator installation site; using strain gauges and displacement sensors, such testing equipment to collect experimental data; comparing the stress and deflection data obtained from the experiment with the theoretical calculation and finite element simulation data, and analyzing the differences between the three; when the relative error between the stress and deflection data obtained from the experiment and the theoretical calculation and finite element simulation data exceeds a preset 10%, checking whether the assumptions of the theoretical calculation are reasonable, whether the parameter settings of the finite element model are accurate, and whether there are errors in the experimental test methods and equipment, and then correcting the theoretical calculation method and finite element model parameters, or improving the experimental test method, so as to improve the accuracy of the analysis results; In the step of optimizing the structure and material selection of the load-bearing beam according to the analysis results, if the analysis results show that the strength safety factor of the load-bearing beam exceeds the preset 1.5, consider reducing the cross-sectional size of the beam and replacing it with lightweight materials to optimize the structure and materials to reduce costs; if the strength or rigidity of the load-bearing beam is insufficient, increase the thickness of the beam, change the cross-sectional shape, and select high-strength materials for improvement. At the same time, comprehensively consider cost and processing technology factors to determine the best optimization plan. In the entire mechanical analysis process, record the calculation data, simulation results, experimental data and analysis process of each step in detail to form a complete analysis report, which is convenient for subsequent reference, tracing and further optimization and improvement of the mechanical analysis method.

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