Design method of floor supporting structure integrating bearing and vibration and noise reduction

Abstract

The invention provides a design method of a floor supporting structure integrating bearing and vibration and noise reduction. The design method comprises the following steps that multi-physical-field load coupling analysis is carried out, and a load transmission key path, a vibration response peak value area and a noise transmission weak link are recognized; carrying out bearing-damping function integrated topological optimization, and designing a core structure integrating bearing and damping functions; a layered noise reduction module is embedded in the obtained bearing-damping integrated structure; according to the modular integration and connection design, the floor supporting structure is divided into standardized functional modules; performing multi-objective performance collaborative optimization, and establishing a'weight-bearing strength-damping effect-sound insulation quantity 'multi-objective optimization model by adopting a response surface method; and through iterative optimization, an optimal design parameter combination meeting all performance targets is searched. The three functions of bearing, vibration reduction and noise reduction are subjected to integrated consideration and collaborative optimization in the design stage of the floor supporting structure for the first time, and coupling improvement of multi-physical performance is achieved.

Description

Technical Field

[0001] This invention belongs to the field of rail vehicle structural design, and in particular relates to a design method for a floor support structure that integrates load-bearing and vibration reduction and noise reduction. Background Technology

[0002] In existing technologies, the floor support structure of rail passenger vehicles typically uses a single aluminum profile section, supplemented by simple rubber pads to achieve basic load-bearing functions. This traditional design approach separates load-bearing functions from vibration and noise reduction functions: the support structure is mainly responsible for bearing static and dynamic loads, while vibration and noise reduction rely on additional sound and heat insulation materials (such as sound insulation cotton, damping sheets, etc.) to achieve this separately. This functionally separated design mode has the following drawbacks:

[0003] Structural redundancy and increased weight: The load-bearing structure and the vibration reduction and noise reduction structure are designed and stacked separately, resulting in low material utilization efficiency and an overall large structural weight, which is not conducive to vehicle lightweighting.

[0004] Poor performance synergy: The load-bearing, vibration reduction, and noise reduction performances are not considered and optimized in an integrated manner. There may be conflicts in the performance of each part or the synergistic effect may not be fully utilized, thus limiting the overall vibration reduction and noise reduction effect.

[0005] Complex processes and potential reliability issues: The combination of multiple materials and structures increases the complexity of manufacturing and assembly, and the connection interfaces between different materials / structures (such as adhesives) may have reliability problems such as aging and detachment.

[0006] The design cycle is long: it requires multiple independent designs and verifications for different functions, and the iteration process is cumbersome.

[0007] Therefore, there is an urgent need for a floor support structure design method that can integrate load-bearing, vibration reduction, and noise reduction functions and achieve synergistic optimization to overcome the shortcomings of the existing technologies. Summary of the Invention

[0008] This invention aims to solve the problems of low lightweighting, limited vibration and noise reduction effects, structural redundancy and complex processes caused by functional separation design in the prior art. It provides a floor support structure design method that integrates load-bearing and vibration and noise reduction, which significantly improves the lightweighting level and comprehensive vibration and noise reduction performance of the structure while ensuring the structural load-bearing safety.

[0009] To achieve the above-mentioned objectives, this invention provides a floor support structure design method integrating load-bearing and vibration reduction / noise reduction, comprising the following steps:

[0010] Step 1: Multiphysics Load Coupling Analysis

[0011] A multiphysics load coupling model of the floor support structure was established, with input parameters including mechanical loads, acoustic loads, and environmental parameters; through finite element coupling analysis, the critical load transmission path, the peak region of vibration response, and the weak link of noise transmission were identified.

[0012] Step 2: Integrated topology optimization for load-bearing and vibration damping functions

[0013] A "rigid-flexible coupling" topology optimization strategy was adopted to design a core structure that integrates load-bearing and vibration reduction functions; this included material gradient design and structural form design.

[0014] Step 3: Noise Cancellation Function Integration Design

[0015] Based on acoustic transmission path analysis, a layered noise reduction module is embedded in the load-bearing-damping integrated structure obtained in step 2; including the setting of a low-frequency vibration isolation layer and a mid-to-high frequency sound absorption layer, and acoustic-solid coupling optimization is performed;

[0016] Step 4: Modular Integration and Connection Design

[0017] The floor support structure, which integrates load-bearing, vibration reduction, and noise reduction functions, is divided into standardized functional modules; module interfaces and connection methods are designed.

[0018] Step 5: Multi-objective performance collaborative optimization

[0019] A multi-objective optimization model of "weight-load strength-vibration reduction effect-sound insulation" was established using the response surface methodology; through iterative optimization, the optimal combination of design parameters that satisfies all performance objectives was found.

[0020] Furthermore, in step 1:

[0021] The mechanical loads include static loads of 5-8 kPa, dynamic loads including impact loads with a peak value of 15-20 kPa, and vehicle body vibration excitation frequencies of 5-80 Hz with accelerations of 0.5-2g; the acoustic loads include the main frequency band of wheel-rail noise of 50-2000 Hz and the main frequency band of equipment noise of 100-1000 Hz; the environmental parameters include a temperature range of -40℃ to 45℃ and a humidity range of 5% to 95%.

[0022] Furthermore, in step 2: the material gradient design includes: embedding rubber or shape memory alloy damping elements in low-stress deformation areas; using high-strength aluminum alloy in high-stress areas; the structural design includes constructing a "truss-honeycomb" composite topology.

[0023] Furthermore, the rubber body is neoprene rubber with a Poisson's ratio of 0.49; the high-strength aluminum alloy is 6061-T6 with a yield strength ≥240MPa; the honeycomb unit has a side length of 10-20mm and a wall thickness of 0.5-1mm, and the honeycomb unit is filled with a porous damping medium.

[0024] Furthermore, the porous damping medium is open-cell aluminum foam; the perforation rate of the "truss-honeycomb" composite topology is 50%-60%, and the damping ratio is increased by more than 30% in the 50-200Hz frequency band.

[0025] Furthermore, in step 3: the low-frequency vibration isolation layer is set at the connection between the load-bearing frame and the vehicle body chassis, and is a "sandwich" type vibration isolator with an outer aluminum alloy plate, a middle viscoelastic damping layer, and an inner stainless steel plate; the mid-to-high frequency sound absorption layer is filled in the cavity of the floor support structure, including gradient density sound absorption material, and micro-perforated plates are laid on the cavity wall.

[0026] Furthermore, the viscoelastic damping layer is butyl rubber with a loss factor ≥0.3; the gradient density sound-absorbing material includes an upper layer of low-density glass wool and a lower layer of high-density polyester fiber cotton; the micro-perforated plate has a pore size of 0.5-1mm, a perforation rate of 1%-3%, and a target sound absorption coefficient ≥0.8.

[0027] Furthermore, in step 4: the module interface adopts a combination connection method of "boss-slot + elastic buckle"; the main body of the load-bearing frame is rigidly connected to the vehicle body chassis through high-strength bolts; adjacent modules are quickly spliced ​​together through elastic buckles, and a 2mm thermal expansion gap is reserved between modules.

[0028] Furthermore, in step 5: the optimization variables in the iterative optimization include the topological parameters of the load-bearing frame, the performance parameters of the damping material, and the structural parameters of the sound-absorbing layer; the optimization objective is: structural weight ≤ 42.3 kg / m². 2 The static strength safety factor is ≥1.5, the vibration transmissibility in the 50-200Hz frequency band is ≤25%, and the noise level inside the vehicle is ≤65dB under the operating condition of 60km / h.

[0029] Compared with the prior art, the present invention has the following significant advantages and advancements:

[0030] Functional integration and synergistic optimization: For the first time, the three major functions of load-bearing, vibration reduction and noise reduction are considered and optimized in an integrated manner during the design stage of floor support structure. This breaks the traditional design mode of functional separation and realizes the coupling and improvement of multiple physical properties.

[0031] Significant weight reduction effect: Through topology optimization and "truss-cell" composite structure design, a high void ratio is achieved while ensuring load-bearing capacity. Combined with the application of material gradient, the structural weight is significantly reduced.

[0032] Excellent vibration and noise reduction performance: By utilizing material gradient design, built-in damping medium, layered noise reduction modules (low-frequency vibration isolation, mid-to-high frequency sound absorption) and sound-solid coupling optimization, it specifically covers a wide frequency band of vibration and noise, effectively reducing vibration transmission rate and in-vehicle noise level.

[0033] High reliability and ease of maintenance: Modular design facilitates manufacturing, transportation and installation; the combination of elastic locking and rigid bolts ensures connection strength and adapts to thermal expansion and contraction; the integral molding process of shock-absorbing elements and frame (such as vulcanization) improves product durability and reliability and reduces maintenance requirements.

[0034] The design methodology is scientific and efficient: based on multi-physics coupling analysis, topology optimization and response surface methodology and other multi-objective optimization techniques, the design process is more scientific and systematic, which helps to quickly obtain a final design solution with balanced and superior performance and shorten the development cycle. Attached Figure Description

[0035] Figure 1 : Flowchart of multiphysics load coupling analysis in this embodiment of the invention.

[0036] Figure 2 : Schematic diagram comparing the stress of different sections in the vibration reduction functional area in this embodiment of the invention.

[0037] Figure 3 : A schematic diagram of the topology optimization of the main carrying area in this embodiment of the invention. Detailed Implementation

[0038] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a method for designing an integrated load-bearing and vibration-damping noise reduction floor support structure.

[0039] Reference Figures 1 to 3 This invention provides a design method for a floor support structure integrating load-bearing and vibration / noise reduction. Its core lies in achieving a synergistic improvement in multiple performance aspects of the floor support structure through multi-physics coupling analysis, integrated topology optimization of "load-bearing-vibration-noise reduction," functionally graded material design, and modular integration technology. The design method includes the following steps:

[0040] Step 1: Multiphysics Load Coupling Analysis

[0041] Establish a multiphysics load coupling model of the floor support structure, with input parameters including:

[0042] Mechanical loads: static loads (5-8 kPa), dynamic loads (including impact loads, peak value 15-20 kPa), vehicle body vibration excitation (frequency 5-80 Hz, acceleration 0.5-2 g);

[0043] Acoustic loads: wheel-rail noise (main frequency band 50-2000Hz), equipment noise (main frequency band 100-1000Hz);

[0044] Environmental parameters: Temperature range -40℃ to 45℃, humidity 5% to 95%.

[0045] Finite element coupled analysis is used to identify critical load transfer paths, peak vibration response regions, and weak points in noise transmission, serving as the core basis for subsequent structural design. For detailed procedures, please refer to [link to relevant documentation]. Figure 1 .

[0046] Step 2: Integrated topology optimization for load-bearing and vibration damping functions

[0047] A core structure integrating load-bearing and vibration reduction functions is designed using a "rigid-flexible coupling" topology optimization strategy.

[0048] Material gradient design:

[0049] In the low-stress deformation region identified in step 1 (defined as the vibration damping functional region), a rubber body (such as neoprene rubber, Poisson's ratio 0.49) or shape memory alloy damping element is embedded. The nonlinear deformation of the material is used to dissipate vibration energy. See the schematic diagram for details. Figure 2 .

[0050] In the high-stress areas (defined as the main load-bearing areas) such as the support connection points and the main load transmission path identified in step 1, high-strength aluminum alloys (such as 6061-T6, yield strength ≥240MPa) are used.

[0051] Structural design:

[0052] A truss-cell composite topology is constructed. The main truss structure bears the primary load; the cellular units (side length 10-20mm, wall thickness 0.5-1mm) are filled with a porous damping medium (such as open-cell aluminum foam). This structure achieves a high permeability (50%-60%) for weight reduction while simultaneously increasing the damping ratio (target increase of over 30%) in the 50-200Hz frequency band using the damping medium, effectively attenuating vibrations. See the example below. Figure 3 .

[0053] Step 3: Noise Cancellation Function Integration Design

[0054] Based on acoustic transmission path analysis, a layered noise reduction module is embedded in the load-bearing-damping integrated structure obtained in step 2:

[0055] Low-frequency vibration isolation layer: A "sandwich" type vibration isolator is installed at the connection between the load-bearing frame and the vehicle body chassis. Its structure consists of an outer aluminum alloy plate, a middle viscoelastic damping layer (such as butyl rubber, loss factor ≥0.3), and an inner stainless steel plate, which is used to block the transmission of 50-100Hz low-frequency vibrations to the inside of the vehicle body.

[0056] Mid-to-high frequency sound-absorbing layer: The cavity of the floor support structure is filled with gradient density sound-absorbing material, for example, the upper layer uses low density (e.g., 20 kg / m³). 3 Glass wool is used to absorb high-frequency noise above 800Hz, and the lower layer uses a higher density (e.g., 50kg / m²). 3 Polyester fiber cotton is used to absorb mid-frequency noise in the range of 200-800Hz. At the same time, micro-perforated plates (pore diameter 0.5-1mm, perforation rate 1%-3%) are laid on the cavity wall to form a Helmholtz resonance sound absorption structure with the cavity behind it. This is optimized for the main peak frequency of wheel-rail noise (such as 630Hz), with a target sound absorption coefficient ≥0.8.

[0057] Sound-structure coupling optimization: Using finite element acoustic simulation software (such as LMS Virtual.Lab), the thickness distribution of the sound-absorbing layer and the parameters (pore size, perforation rate) of the micro-perforated plate are analyzed and adjusted to ensure that the resonant frequency of the floor support structure itself avoids the main noise frequency band and prevents resonance amplification of noise.

[0058] Step 4: Modular Integration and Connection Design

[0059] The floor support structure, which integrates load-bearing, vibration damping, and noise reduction functions, is divided into standardized functional modules (example dimensions of a single module: 1000mm × 800mm × 100mm):

[0060] Module interface: A combination connection method of "boss-slot + elastic buckle" is adopted. The main body of the load-bearing frame is rigidly connected to the vehicle body chassis through high-strength bolts (pre-tightening force 50-80kN); adjacent modules are quickly spliced ​​through elastic buckles (requiring tensile strength ≥5kN), and a thermal expansion gap of about 2mm is reserved between modules.

[0061] Maintenance-free design: For the combination of shock-absorbing elements (such as rubber bodies) and metal load-bearing frames, an integral molding process (such as the vulcanization composite of rubber and aluminum alloy frames) is adopted to replace the traditional adhesive method, so as to improve the reliability and durability of the connection and avoid the problem of adhesive aging.

[0062] Step 5: Multi-objective performance collaborative optimization

[0063] A multi-objective optimization model for "weight-load-bearing capacity-vibration damping effect-sound insulation" was established using response surface methodology. The optimization variables include:

[0064] Topological parameters of the load-bearing frame (such as truss angle and cell element side length);

[0065] Performance parameters of damping materials (such as damping ratio and elastic modulus);

[0066] Structural parameters of the sound-absorbing layer (such as thickness and density gradient).

[0067] The optimization target is set as follows: structural weight ≤ 42.3 kg / m². 2 The static strength safety factor is ≥1.5, the vibration transmissibility in the 50-200Hz frequency band is ≤25%, and the in-vehicle noise level is ≤65dB (A-weighted) under operating conditions of 60km / h. Through iterative optimization, the optimal combination of design parameters that meets all performance objectives is sought.

Claims

1. A design method for a floor support structure integrating load-bearing capacity and vibration reduction / noise reduction, characterized in that, Includes the following steps: Step 1: Multiphysics Load Coupling Analysis A multiphysics load coupling model of the floor support structure was established, with input parameters including mechanical loads, acoustic loads, and environmental parameters; through finite element coupling analysis, the critical load transmission path, the peak region of vibration response, and the weak link of noise transmission were identified. Step 2: Integrated topology optimization for load-bearing and vibration damping functions A core structure integrating load-bearing and vibration reduction functions is designed by adopting a "rigid-flexible coupling" topology optimization strategy. This includes material gradient design and structural form design; Step 3: Noise Cancellation Function Integration Design Based on acoustic transmission path analysis, a layered noise reduction module is embedded in the load-bearing-damping integrated structure obtained in step 2. This includes the installation of low-frequency vibration isolation layers and mid-to-high-frequency sound absorption layers, and the optimization of acoustic-solid coupling. Step 4: Modular Integration and Connection Design The floor support structure, which integrates load-bearing, vibration reduction, and noise reduction functions, is divided into standardized functional modules; Design module interfaces and connection methods; Step 5: Multi-objective performance collaborative optimization A multi-objective optimization model for "weight-load strength-vibration reduction effect-sound insulation" was established using the response surface methodology. Through iterative optimization, the optimal combination of design parameters that satisfies all performance objectives was found.

2. The design method according to claim 1, characterized in that, In step 1: The mechanical loads include static loads of 5-8 kPa, dynamic loads including impact loads with a peak value of 15-20 kPa, and vehicle body vibration excitation frequencies of 5-80 Hz with accelerations of 0.5-2g; the acoustic loads include the main frequency band of wheel-rail noise of 50-2000 Hz and the main frequency band of equipment noise of 100-1000 Hz; the environmental parameters include a temperature range of -40℃ to 45℃ and a humidity range of 5% to 95%.

3. The design method according to claim 1, characterized in that, In step 2: the material gradient design includes: embedding rubber or shape memory alloy damping elements in low-stress deformation areas; using high-strength aluminum alloy in high-stress areas; the structural design includes constructing a "truss-honeycomb" composite topology.

4. The design method according to claim 3, characterized in that: The rubber body is neoprene rubber with a Poisson's ratio of 0.49; the high-strength aluminum alloy is 6061-T6 with a yield strength ≥240MPa; the honeycomb unit has a side length of 10-20mm and a wall thickness of 0.5-1mm, and is filled with a porous damping medium.

5. The design method according to claim 4, characterized in that: The porous damping medium is open-cell aluminum foam; the "truss-honeycomb" composite topology has a perforation rate of 50%-60%, and the damping ratio is increased by more than 30% in the 50-200Hz frequency band.

6. The design method according to claim 1, characterized in that, In step 3: the low-frequency vibration isolation layer is set at the connection between the load-bearing frame and the vehicle body chassis, and is a "sandwich" type vibration isolator with an outer aluminum alloy plate, a middle viscoelastic damping layer, and an inner stainless steel plate; the mid-to-high frequency sound absorption layer is filled in the cavity of the floor support structure, including gradient density sound absorption material, and micro-perforated plates are laid on the cavity wall.

7. The design method according to claim 6, characterized in that: The viscoelastic damping layer is butyl rubber with a loss factor ≥0.3; the gradient density sound-absorbing material includes an upper layer of low-density glass wool and a lower layer of high-density polyester fiber cotton; the micro-perforated plate has a pore size of 0.5-1mm, a perforation rate of 1%-3%, and a target sound absorption coefficient ≥0.

8.

8. The design method according to claim 1, characterized in that, In step 4: the module interface adopts a combination connection method of "boss-slot + elastic buckle"; the main body of the load-bearing frame is rigidly connected to the vehicle body frame through high-strength bolts; adjacent modules are quickly spliced ​​together through elastic buckles, and a 2mm thermal expansion gap is reserved between modules.

9. The design method according to claim 1, characterized in that, In step 5: the optimization variables in the iterative optimization include the topological parameters of the load-bearing frame, the performance parameters of the damping material, and the structural parameters of the sound-absorbing layer; the optimization objective is: structural weight ≤ 42.3 kg / m². 2 The static strength safety factor is ≥1.5, the vibration transmissibility in the 50-200Hz frequency band is ≤25%, and the noise level inside the vehicle is ≤65dB under the operating condition of 60km / h.

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