A stiffness-non-uniform vibration damping fastener and its design method

Abstract

The present invention provides a stiffness non-uniform vibration damping fastener and its design method; when the compression type vibration damping fastener is subjected to vertical and lateral loads of the wheel, due to the non-uniform load on the elastic vibration damping layer (small load on the inner side of the rail and large load on the outer side of the rail), non-uniform deformation occurs, resulting in the deflection of the rail and the upper tie plate, causing an increase in the lateral displacement of the rail head and a decrease in the lateral stability of the fastener; in view of this problem, through simulation calculation and actual test, the deflection conditions of the rail and the upper tie plate of the vibration damping fastener with conventional stiffness homogenization design are analyzed; the force conditions of different parts of the vibration damping pad are obtained through calculation, and the stiffness of the vibration damping pad is designed to be non-uniform; thus, while ensuring good vibration damping effect of the vibration damping fastener, the safety and stability of the line are greatly improved, and the structure is simple, and installation and maintenance are convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit equipment, and particularly to a non-uniform stiffness vibration damping fastener and a design method thereof. Background Art

[0002] In the field of urban rail transit, double-layer vibration damping fasteners are the most commonly used medium vibration damping measures. With the increasing social attention to vibration and noise reduction, the rail market has higher requirements for the vibration damping performance of vibration damping fasteners. The vibration damping performance of fasteners is directly related to their vertical stiffness. The lower the stiffness, the better the vibration damping performance. The rail is subjected to the dual actions of vertical and lateral loads from the wheels. The reduction of the vertical stiffness of the fastener will indirectly lead to the deterioration of the lateral stability of the rail. Existing double-layer vibration damping fasteners are difficult to meet the dual requirements of vibration damping performance and stability.

[0003] Currently, in the field of urban rail transit, two measures of fastener vibration damping and track bed vibration damping can be adopted to achieve high-level vibration damping of the track. Compared with track bed vibration damping, fastener vibration damping has the advantages of simple construction, convenient maintenance, and low construction cost. Currently, the more commonly used high-level vibration damping fasteners include floating rail fasteners, multi-layer vibration damping fasteners, and ZK fasteners.

[0004] For floating rail fasteners, there are problems such as prominent corrugation, non-universal parts, difficult construction and maintenance, and inability to be used at the rail joints of jointed tracks. Therefore, it is more practical to use compression-type vibration damping fasteners. Generally speaking, the lower the stiffness of the vibration damping fastener, the better the vibration damping effect. However, for compression-type vibration damping fasteners, the lower the stiffness, the greater the offset of the rail head. These two indicators are contradictory. Currently, in the market, to solve the problem of improving the lateral stability of compression-type vibration damping fasteners, the method of adding a lateral limiting device is basically adopted. Shoulder blocks are extended upward at both ends of the lower tie plate, and then filling blocks are placed between the upper and lower tie plates to restrict the lateral displacement and deflection of the upper tie plate through the lower tie plate. With this design scheme, on the one hand, it cannot limit the deflection of the rail caused by non-uniform deformation of the pad under the rail, and the effect of improving the lateral stability of the rail is limited. On the other hand, as the filling blocks wear, a lateral clearance appears between the upper and lower tie plates. At this time, the shoulder blocks of the lower tie plate cannot perform the lateral limiting function on the upper tie plate. Moreover, with this structure, the number of fastener parts is additionally increased, which is not conducive to production cost control and later maintenance. Currently, in the market, no one has achieved improving the lateral stability of fasteners through non-uniform stiffness design of fasteners. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a non-uniform stiffness vibration damping fastener that can effectively solve the damage of components caused by uneven force of rail fasteners.

[0006] The present invention is realized through the following technical solutions: A non-uniform stiffness vibration damping fastener, characterized in that it includes an under-rail pad, an upper iron soleplate, a middle vibration damping pad, a vibration isolation plate, a vibration damping pad under the plate, a lower iron soleplate, and a fixing device; the under-rail pad, the upper iron soleplate, the middle vibration damping pad, the vibration isolation plate, the vibration damping pad under the plate, and the lower iron soleplate are arranged layer by layer from top to bottom; the under-rail pad is a rectangular rubber pad and circular bumps are arranged below the under-rail; the lower iron soleplate is a plate with the same shape as the upper iron soleplate, and the vibration isolation plate is a plate corresponding to the shape of the installation groove on the lower iron soleplate; the vibration damping pad under the plate is a rubber pad with the same shape as the vibration isolation plate and the vibration damping pad under the plate is installed in the installation groove.

[0007] A design method for a non-uniform stiffness vibration damping fastener includes:

[0008] The design steps of the under-rail pad, the upper iron soleplate, the middle vibration damping pad, the vibration isolation plate, the vibration damping pad under the plate, and the lower iron soleplate include:

[0009] Step 1: Determine the overall device stiffness

[0010] Determine the design range of the static stiffness of the vibration damping fastener according to the dynamic sinking amount of the rail and the vibration damping performance requirements;

[0011] Step 2: Match the stiffness of the vibration damping pads

[0012] Determine the static stiffness of the under-rail pad;

[0013] Determine the static stiffness of the combination of the middle vibration damping pad, the vibration isolation plate, and the vibration damping pad under the plate;

[0014] At the same time, it is required that the static stiffness of the under-rail pad and the combination of the middle vibration damping pad, the vibration isolation plate, and the vibration damping pad under the plate meet the static stiffness of the overall device determined in Step 1;

[0015] Step 3: Deformation analysis

[0016] When the under-rail pad, the upper iron soleplate, the middle vibration damping pad, the vibration isolation plate, the vibration damping pad under the plate, and the lower iron soleplate are in use, they will be subjected to vertical and lateral loads, and the vertical and lateral deflection angles are obtained through measurement and calculation;

[0017] Step 4: Load analysis

[0018] Analyze and calculate the relevant parameters obtained in Step 3;

[0019] Step 5: Non-uniform stiffness design

[0020] When the stiffness of the vibration damping pads of the overall device is uniformly designed, the under-rail pad, the middle vibration damping pad, and the under-slab vibration damping pad undergo non-uniform deformation due to non-uniform loads, resulting in the deflection of the upper tie plate and the rail. To prevent the rail and the upper tie plate from deflecting due to the non-uniform deformation of the vibration damping pads, it is necessary to ensure that the under-rail pad, the middle vibration damping pad, and the under-slab vibration damping pad can still deform uniformly when subjected to non-uniform loads.

[0021] Preferably, Step 1: Determination of the Stiffness of the Overall Device

[0022] When the overall static stiffness of the under-rail pad, the upper tie plate, the middle vibration damping pad, the vibration isolation plate, the under-slab vibration damping pad, the lower tie plate, and the insulation coupling pad is 6 kN / mm, the dynamic settlement of the rail is 3.71 mm (for a 60 kg / m rail and a vehicle speed of 120 km / h), just meeting the requirement that the dynamic settlement of the rail ≤ 4 mm; thus, the lower limit value of the static stiffness of the vibration damping fastener is determined to be 6 kN / mm; according to the requirement that the vibration damping performance of the vibration damping fastener is ≥ 10 dB compared with the general elastic separate fastener, the upper limit value of the fastener static stiffness is obtained as 10 kN / mm.

[0023] Preferably, Step 2: Stiffness Matching of the Vibration Damping Pads

[0024] The under-rail pad plays a direct supporting role for the rail, and the stiffness design of the under-rail pad needs to consider various aspects. If the stiffness of the under-rail pad is too low, it is easy to cause problems such as large amplitudes of the elastic clip, large rotation angles of the rail, increased wear of the gauge block, and low self-strength of the under-rail pad and easy damage, thus leading to problems such as reduced fatigue life of the elastic clip, poor stability of the rail, and serious wear and reduced service life of the gauge block; if the stiffness of the under-rail pad is too high, the constraint damping of the under-rail pad will be reduced, the vibration attenuation of the rail will be slow, and the vibration damping effect will be poor. In addition, an under-rail pad with too high stiffness is prone to inducing resonance of the elastic clip and reducing the life of the elastic clip. For the vibration damping fastener, the designed value of the static stiffness of the under-rail pad is 40 kN / mm;

[0025] Under the condition that the designed values of the static stiffness of the middle vibration damping pad and the under-slab vibration damping pad are 40 kN / mm, to achieve a lower assembly stiffness of the fastener, it is required that the middle elastic layer has a lower static stiffness; when the assembly stiffness of the vibration damping fastener is the same, the middle elastic layer is designed as a composite structure of two elastic vibration damping pads, and the fatigue life of the vibration damping pad has obvious advantages. According to the requirements of the fastener assembly stiffness, the stiffness of the middle elastic layer can be designed to be 7 - 12 kN / mm.

[0026] Preferably, Step 3: Deformation Analysis

[0027] Through simulation calculation and combined with actual tests, the vertical displacements of the two sides of the rail foot of the rail under vertical and lateral loads are obtained, including the inner side d1 and the outer side d2 of the rail, and the vertical displacements of the two sides of the upper iron pad, including the inner side d3 and the outer side d4 of the rail. By combining the spacing of the vertical displacement value-taking points, the deflection angle α2 of the rail and the deflection angle α1 of the upper iron pad can be calculated. Among them, the deflection angle of the rail is equal to the sum of the deflection angle of the upper iron pad and the non-uniform deformation angle of the pad under the rail. Therefore, the non-uniform deformation angle α of the pad under the rail is α = α2 - α1.

[0028] Preferably, in Step Four, Load Analysis

[0029] When the pad under the rail with uniform stiffness design is subjected to non-uniform loads of the rail, it undergoes a certain non-uniform deformation. Without considering the longitudinal length of the pad under the rail, the lateral loads received by the rail are all transmitted to the spring seat of the upper iron pad, and the vertical loads received by the pad under the rail are all transmitted to the middle shock absorber pad, vibration isolation plate, and shock absorber under the plate through the upper iron pad.

[0030] Among them, the overall stiffness of the pad under the rail is K, the effective elastic total length (lateral) is L, and the vertical load received is F.

[0031] The distributed load received by the pad under the rail from the inner side of the rail to the outer side of the rail is calculated as:

[0032]

[0033] Similarly, for the middle shock absorber pad, vibration isolation plate, and shock absorber under the plate, the distributed load received from the inner side of the rail to the outer side of the rail is:

[0034]

[0035] Among them, the middle shock absorber pad, vibration isolation plate, and shock absorber under the plate are regarded as a whole with a stiffness of K1, an effective elastic total length (lateral) of L1, and a vertical load received of F.

[0036] Preferably, in Step Five, Rigid Non-uniform Design

[0037] When the shock absorber pad of the shock-absorbing fastener has a uniform stiffness design, the shock absorber pad undergoes non-uniform deformation due to non-uniform loads, resulting in the deflection of the upper iron pad and the rail. To prevent the rail and the upper iron pad from deflecting due to the non-uniform deformation of the shock absorber pad, the shock absorber pad needs to be able to deform uniformly when subjected to non-uniform loads.

[0038] For the pad under the rail, with an overall stiffness of K and when subjected to a vertical load F, the vertical average deformation amount h0 is:

[0039] H0 = F / K

[0040] The pad under the rail is subjected to a non-uniform distributed load qx When all regions maintain the same deformation amount, that is, the average deformation amount h0, then the rule for the change of its stiffness from the inner side of the rail to the outer side of the rail is as follows:

[0041]

[0042] Similarly, for the middle damping pad, vibration isolation plate, and under-board damping, the rule for the change of their stiffness from the inner side of the rail to the outer side of the rail is as follows:

[0043]

[0044] In actual production and processing, considering the design of the damping pad mold and production process, it is difficult to perform non-uniform stiffness design on the damping pad completely according to the above formula. The deflection of the rail and the upper tie plate mainly occurs along the center line. The damping pad can be divided into two regions, the inner side and the outer side of the rail, along the center line for non-uniform stiffness design.

[0045] For the under-rail pad, with the center line as the boundary, the stiffness on both the inner and outer sides of the rail can be designed respectively as:

[0046] The stiffness of the described under-rail pad in the inner part of the rail

[0047]

[0048] The stiffness of the described under-rail pad in the outer part of the rail

[0049]

[0050] The beneficial effects of the present invention are as follows: While maintaining the low stiffness (6 kN / mm - 10 kN / mm) of the compression-type damping fastener and the damping effect ≥ 10 dB, the lateral stability of the damping fastener is effectively ensured, and the dynamic lateral displacement of the rail head is controlled within 2 mm; at the same time, the present device also has the following beneficial effects

[0051] (1) High stability and high damping effect

[0052] This device adopts a three-layer elastic cushion plate - the "non-linear high-torsion resistant rubber cushion plate". This kind of rubber elastic cushion plate has the non-linear characteristic of "low load and low stiffness, high load and high stiffness". Moreover, the rubber cushion plate starts to work from no load and is not affected by the bolt tightening force, making full use of the elasticity of the rubber, and can obtain the lowest dynamic stiffness to the greatest extent, with good vibration reduction and noise reduction effects. The upper and lower iron cushion plates of this fastener are in direct contact without a connecting sleeve structure, reducing the number of lateral fits between the upper and lower iron cushion plates. And the fitting area of the upper and lower iron cushion plates adopts a precision machining method, with an extremely low clearance between the two, effectively enhancing the constraint of the lower iron cushion plate of the fastener on the upper iron cushion plate, thus improving the lateral stability of the fastener. In addition, the lower iron cushion plate of this fastener is an integral non-through-hole structure, which has better safety and stability compared with some high-vibration reduction fasteners on the market that adopt a support column structure or a through-hole structure.

[0053] (2) Design of low-shear bottom plate connection structure

[0054] Only one layer of low-density polyethylene cushion plate, that is, the insulation coupling cushion plate, is designed under the lower iron cushion plate of this device. This cushion plate only plays a coupling role in the rigid contact between the lower iron cushion plate and the top surface of the sleeper. Its stiffness is relatively large and it is not an elastic providing component. When loaded, its deformation is extremely small, and most of the lateral shear forces are offset by the frictional forces between the coupling cushion plate, the iron cushion plate and the top surface of the sleeper, effectively reducing the shear force borne by the spike and increasing the service life and safety of the spike.

[0055] (3) Design of height adjustment ability and gauge adjustment ability

[0056] To overcome the track unevenness caused by reasons such as construction errors of foundation engineering, creep camber of bridges, uneven settlement of bridge piers and uneven settlement of subgrades, it is required that the fastener system must have a large ability to adjust the height and left-right position of the rail. Especially for ballastless tracks, the adjustment ability of the track is almost completely realized by the fasteners, and the height adjustment and gauge adjustment abilities of the fasteners are very crucial. This device adjusts the gauge through gauge blocks and covers, and the maximum gauge adjustment amount can reach not less than -12 to +8 mm; the height adjustment is realized by adding height adjustment cushion plates under the rail or under the fastener, and the height adjustment amount can reach 0 to 30 mm, or (-4 to +26) mm, and these settings can fully meet the laying requirements of the line. Description of the drawings

[0057] Figure 1 It is a schematic flow chart of a design method for a non-uniform stiffness vibration reduction fastener.

[0058] Figure 2 It is a schematic diagram of the split structure of the overall device of a non-uniform stiffness vibration reduction fastener.

[0059] Figure 3 It is a schematic diagram of the general assembly structure of the overall device of a non-uniform stiffness vibration reduction fastener.

[0060] Figure 4 Schematic diagram of track force analysis for a design method of a non-uniform stiffness vibration damping fastener.

[0061] Figure 5 Schematic diagram of the force analysis of the pad under the rail for a design method of a non-uniform stiffness vibration damping fastener.

[0062] Figure 6 Diagram of the force analysis of the deformation of the overall device for a design method of a non-uniform stiffness vibration damping fastener.

[0063] Wherein: 1. Pad under the rail; 2. Upper iron plate; 3. Middle vibration damping pad; 4. Vibration isolation plate; 5. Vibration damping pad under the plate; 6. Lower iron plate; 7. Fixing device. Specific implementation manners

[0064] In the description of the present invention, it should also be noted that, unless otherwise clearly defined and limited, the terms "arranged", "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0066] Such as Figure 2-3As shown in the figure, a non-uniform stiffness vibration damping fastener includes an under-rail pad 1, an upper tie plate 2, a middle vibration damping pad 3, a vibration isolation plate 4, an under-plate vibration damping pad 5, a lower tie plate 6 and a fixing device 7; the under-rail pad 1, the upper tie plate 2, the middle vibration damping pad 3, the vibration isolation plate 4, the under-plate vibration damping pad 5 and the lower tie plate 6 are arranged layer by layer from top to bottom. Among them, the under-rail pad 1 is in direct contact with the rail to support the rail and play a vibration damping role. The upper tie plate 2 is used to fix the rail and cooperate with other structures to realize the fixing function of the overall track fastener. The combination of the middle vibration damping pad 3, the vibration isolation plate 4 and the under-plate vibration damping pad 5 realizes the improvement of the vibration damping effect of the device, and improves the vibration damping effect of the device on the premise of ensuring the support rigidity of the device. The lower tie plate 6 cooperates with the upper tie plate 2 to realize the fixing of the overall device; the under-rail pad 1 is a rectangular rubber pad and circular convex points are arranged below the under-rail; the lower tie plate 6 is a plate with the same shape as the upper tie plate 2, and the vibration isolation plate 4 is a plate corresponding to the shape of the installation groove on the lower tie plate 6; the under-plate vibration damping pad 5 is a rubber pad with the same shape as the vibration isolation plate 4 and the under-plate vibration damping pad 5 is installed in the installation groove.

[0067] As Figure 1 shown, a design method of a non-uniform stiffness vibration damping fastener includes:

[0068] The design steps of the under-rail pad 1, the upper tie plate 2, the middle vibration damping pad 3, the vibration isolation plate 4, the under-plate vibration damping pad 5 and the lower tie plate 6 include:

[0069] Step 1: Determine the overall device stiffness

[0070] Determine the design range of the static stiffness of the vibration damping fastener according to the dynamic settlement of the rail and the vibration damping performance requirements;

[0071] Step 2: Match the stiffness of the vibration damping pads

[0072] Determine the static stiffness of the under-rail pad 1;

[0073] Determine the static stiffness of the combination of the middle vibration damping pad 3, the vibration isolation plate 4 and the under-plate vibration damping pad 5;

[0074] At the same time, it is required that the static stiffness of the under-rail pad 1 and the combination of the middle vibration damping pad 3, the vibration isolation plate 4 and the under-plate vibration damping pad 5 meet the static stiffness of the overall device determined in Step 1;

[0075] Step 3: Deformation analysis

[0076] When the under-rail pad 1, the upper tie plate 2, the middle vibration damping pad 3, the vibration isolation plate 4, the under-plate vibration damping pad 5 and the lower tie plate 6 are in use, they will be subjected to vertical and lateral loads, and the vertical and lateral deflection angles are obtained through measurement and calculation;

[0077] Step 4: Load analysis

[0078] Analyze and calculate the relevant parameters obtained in Step 3;

[0079] Step 5. Stiffness non-uniform design

[0080] When the stiffness of the vibration damping pads of the overall device is uniformly designed, the under-rail pad 1, the middle vibration damping pad 3, and the under-board vibration damping pad 5 undergo non-uniform deformation due to non-uniform loads, resulting in the deflection of the upper tie plate 2 and the rail. To prevent the rail and the upper tie plate 2 from deflecting due to the non-uniform deformation of the vibration damping pads, it is necessary to ensure that the under-rail pad 1, the middle vibration damping pad 3, and the under-board vibration damping pad 5 can still undergo uniform deformation when subjected to non-uniform loads.

[0081] In Step 1. Determination of the overall device stiffness, when the overall static stiffness of the under-rail pad 1, the upper tie plate 2, the middle vibration damping pad 3, the vibration isolation plate 4, the under-board vibration damping pad 5, the lower tie plate 6, and the insulating coupling pad is 6 kN / mm, the dynamic sinking amount of the rail is 3.71 mm (60 kg / m rail, vehicle speed 120 km / h), just meeting the requirement that the dynamic sinking amount of the rail ≤ 4 mm; thus, the lower limit value of the static stiffness of the vibration damping fastener is determined to be 6 kN / mm; according to the requirement that the vibration damping performance of the vibration damping fastener is ≥ 10 dB compared with the general elastic separated fastener, the upper limit value of the fastener static stiffness is obtained as 10 kN / mm.

[0082] In Step 2. Stiffness matching of the vibration damping pads, the under-rail pad 1 plays a direct supporting role for the rail, and the stiffness design of the under-rail pad 1 needs to consider various issues. If the stiffness of the under-rail pad 1 is too low, it is easy to cause problems such as large amplitudes of the elastic clip, large rotation angles of the rail, increased wear of the gauge block, and low self-strength of the under-rail pad 1, which are prone to damage, resulting in problems such as reduced fatigue life of the elastic clip, poor stability of the rail, and serious wear and reduced service life of the gauge block; if the stiffness of the under-rail pad 1 is too high, the constraint damping of the under-rail pad 1 will be reduced, the vibration attenuation of the rail will be slow, and the vibration damping effect will become poor. In addition, the under-rail pad 1 with too high stiffness is prone to induce resonance of the elastic clip and reduce the life of the elastic clip. For the vibration damping fastener, the static stiffness design value of the under-rail pad 1 is 40 kN / mm;

[0083] Under the condition that the static stiffness design values of the middle vibration damping pad and the under-board vibration damping pad 5 are 40 kN / mm, to achieve a lower fastener assembly stiffness, it is required that the middle elastic layer has a lower static stiffness; when the fastener assembly stiffness is the same, the middle elastic layer is designed as a composite structure of two elastic vibration damping pads, and the fatigue life of the vibration damping pads has obvious advantages. According to the fastener assembly stiffness requirements, the stiffness of the middle elastic layer can be designed to be 7 - 12 kN / mm.

[0084] Step 3. In the deformation analysis, through simulation calculation and combined with actual tests, the vertical displacements of the inner side d1 and the outer side d2 of the rail feet on both sides of the rail and the vertical displacements of the inner side d3 and the outer side d4 of the upper tie plate on both sides are obtained when the rail is subjected to vertical and lateral loads. Combining the spacing of the vertical displacement value-taking points, the deflection angle α2 of the rail and the deflection angle α1 of the upper tie plate 2 can be calculated; among them, the deflection angle of the rail is equal to the sum of the deflection angle of the upper tie plate 2 and the non-uniform deformation angle of the rail pad 1. Then, the non-uniform deformation angle α of the rail pad 1 is α = α2 - α1.

[0085] Step 4. In the load analysis, when the rail pad 1 with a uniform stiffness design is subjected to non-uniform loads of the rail, it undergoes a certain non-uniform deformation; without considering the longitudinal length of the rail pad 1, the lateral load received by the rail is all transmitted to the spring clip seat of the upper tie plate 2, and the vertical load received by the rail pad 1 is all transmitted to the middle shock absorber 3, the vibration isolation plate 4, and the under-slab shock absorption through the upper tie plate 2;

[0086] Among them, the overall stiffness of the rail pad 1 is K, the effective elastic total length (transverse) is L, and the vertical load received is F;

[0087] The distributed load received by the rail pad 1 from the inner side of the rail to the outer side of the rail is calculated as:

[0088]

[0089] Similarly, for the middle shock absorber 3, the vibration isolation plate 4, and the under-slab shock absorption, the distributed load received from the inner side of the rail to the outer side of the rail is:

[0090]

[0091] Among them, the middle shock absorber 3, the vibration isolation plate 4, and the under-slab shock pad 5 are regarded as a whole with a stiffness of K1, an effective elastic total length (transverse) of L1, and a vertical load received of F.

[0092] Step 5. In the rigid non-uniform design, when the shock absorption pad of the shock absorption fastener has a uniform stiffness design, the shock absorption pad undergoes non-uniform deformation due to non-uniform loads, resulting in the deflection of the upper tie plate 2 and the rail. To prevent the rail and the upper tie plate 2 from deflecting due to the non-uniform deformation of the shock absorption pad, it is necessary to make the shock absorption pad still able to deform uniformly when subjected to non-uniform loads;

[0093] For the rail pad 1, its overall stiffness is K, and when it is subjected to a vertical load F, the vertical average deformation amount h0 is:

[0094] H0 = F / K

[0095] The rail pad 1 is subjected to a non-uniform distributed load q xWhen all regions maintain the same amount of deformation, that is, the average deformation amount h0, then the rule for the change in its stiffness from the inner side of the rail to the outer side of the rail is as follows:

[0096]

[0097] Similarly, for the middle vibration damping pad 3, the vibration isolation plate 4, and the under-board vibration damping, the rule for the change in their stiffness from the inner side of the rail to the outer side of the rail is as follows:

[0098]

[0099] For the under-rail pad 1, taking the center line as the boundary, the stiffness on both the inner and outer sides of the rail can be designed respectively as:

[0100] The stiffness of the inner part of the under-rail pad 1 on the inner side of the rail

[0101]

[0102] The stiffness of the outer part of the under-rail pad 1 on the outer side of the rail

[0103]

[0104] Example: Substitute the example parameters of the previous under-rail pad 1 into the formula, and it can be obtained that the stiffness on both the inner and outer sides of the under-rail pad 1 under this working condition can be designed as 13.89 kN / mm and 26.11 kN / mm respectively to achieve the purpose of uniform deformation of the under-rail pad 1 when it is subjected to non-uniform loads and suppressing the deflection of the rail.

[0105] Similarly, the stiffness distributions on the inner and outer sides of the middle vibration damping pad 3, the vibration isolation plate 4, and the under-board vibration damping pad 5 can be calculated.

[0106] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for a vibration damping fastener with non-uniform stiffness, characterized in that: It includes an under-rail pad, an upper tie plate, a middle damping pad, a vibration isolation plate, a damping pad under the plate, a lower tie plate, and a fixing device; the under-rail pad, the upper tie plate, the middle damping pad, the vibration isolation plate, the damping pad under the plate, and the lower tie plate are arranged layer by layer from top to bottom; the under-rail pad is a cuboid rubber pad and circular bumps are arranged below the under-rail; the lower tie plate is a plate with the same shape as the upper tie plate, and the vibration isolation plate is a plate corresponding to the shape of the installation groove on the lower tie plate; the damping pad under the plate is a rubber pad with the same shape as the vibration isolation plate and the damping pad under the plate is installed in the installation groove; an insulating coupling pad is arranged under the lower tie plate, and the design steps of the under-rail pad, the upper tie plate, the middle damping pad, the vibration isolation plate, the damping pad under the plate, and the lower tie plate include: Step 1: Determine the overall device stiffness Determine the design range of the static stiffness of the vibration damping fastener according to the dynamic settlement of the rail and the requirements of the vibration damping performance; Step 2: Match the stiffness of the damping pads Determine the static stiffness of the under-rail pad; Determine the static stiffness of the combination of the middle damping pad, the vibration isolation plate, and the damping pad under the plate; At the same time, it is required that the static stiffness of the under-rail pad and the combination of the middle damping pad, the vibration isolation plate, and the damping pad under the plate meet the static stiffness of the overall device determined in Step 1; Step 3: Deformation analysis When the under-rail pad, the upper tie plate, the middle damping pad, the vibration isolation plate, the damping pad under the plate, and the lower tie plate are in use, they will be subjected to vertical and lateral loads, and the vertical and lateral deflection angles are obtained through measurement and calculation; Step 4: Load analysis Analyze and calculate the relevant parameters obtained in Step 3; Step 5: Non-uniform stiffness design When the stiffness of the damping pads of the overall device is uniformly designed, the under-rail pad, the middle damping pad, and the damping pad under the plate will undergo non-uniform deformation due to non-uniform loads, resulting in the deflection of the upper tie plate and the rail; to prevent the rail and the upper tie plate from deflecting due to the non-uniform deformation of the damping pads, it is necessary to make the under-rail pad, the middle damping pad, and the damping pad under the plate still be able to deform uniformly when subjected to non-uniform loads; Among them, Step 2: Match the stiffness of the damping pads The under-rail pad plays a direct supporting role for the rail. The stiffness design of the under-rail pad needs to consider many aspects. If the stiffness of the under-rail pad is too low, problems such as the rotation angle of the rail being too large, the wear of the gauge block being aggravated, and the low strength of the under-rail pad being easily damaged will occur, and problems such as the poor stability of the rail and the serious wear of the gauge block reducing the service life will occur; if the stiffness of the under-rail pad is too high, the constraint damping of the under-rail pad will be reduced, the vibration attenuation of the rail will be slow, and the vibration damping effect will be poor. In addition, the under-rail pad with too high stiffness is prone to induce resonance of the elastic strip and reduce the life of the elastic strip. For the vibration damping fastener, the static stiffness of the under-rail pad is designed to be 40 kN / mm; Under the condition that the static stiffness design values of the middle damping pad and the under-board damping pad are 40 kN / mm, to achieve a lower fastener assembly stiffness, it is required that the middle elastic layer has a lower static stiffness; when the fastener assembly stiffness is the same, designing the middle elastic layer as a composite structure of two elastic damping pads has obvious advantages in the fatigue life of the damping pads. According to the requirements of the fastener assembly stiffness, the stiffness of the middle elastic layer can be designed to be 7 - 12 kN / mm; Step Four, Load Analysis as described above When the under-rail pad with uniform stiffness design is subjected to non-uniform loads from the rail, certain non-uniform deformations occur; without considering the longitudinal length of the under-rail pad, the lateral loads on the rail are all transmitted to the elastic clip seat of the upper tie plate, and the vertical loads on the under-rail pad are all transmitted to the middle damping pad, vibration isolation plate, and under-board damping pad through the upper tie plate; Among them, the overall stiffness of the under-rail pad is K, the effective elastic total length in the transverse direction is L, and the vertical load received is F; The distributed load received by the under-rail pad from the inner side of the rail to the outer side of the rail is calculated as: Similarly, for the composite elastic layer composed of the middle damping pad, vibration isolation plate, and under-board damping pad, the distributed load received from the inner side of the rail to the outer side of the rail is: Among them, the overall stiffness of the middle damping pad, vibration isolation plate, and under-board damping pad as a whole is K1, the effective elastic total length in the transverse direction is L1, and the vertical load received is F, Step Five, Rigid Non-uniform Design as described above When the damping pad stiffness of the vibration isolation fastener is uniformly designed, the damping pad undergoes non-uniform deformation due to non-uniform loads, resulting in deflection of the upper tie plate and the rail. To prevent the rail and the upper tie plate from deflecting due to the non-uniform deformation of the damping pad, it is necessary to make the damping pad still able to deform uniformly when subjected to non-uniform loads; For the under-rail pad, with an overall stiffness of K, when subjected to a vertical load F, the vertical average deformation amount h0 is: H0 = F / K When the described under-rail pad is subjected to a non-uniformly distributed load q x all regions maintain the same deformation, i.e., the average deformation h0. Then, the requirement for the change rule of its stiffness from the inner side of the rail to the outer side of the rail is as follows: Similarly, for the composite elastic layer composed of the middle damping pad, vibration isolation plate, and under-board damping pad, the variation rule of its stiffness from the inner side of the rail to the outer side of the rail is: For the under-rail pad, taking the center line as the boundary, the stiffness on both the inner and outer sides of the rail can be designed respectively as: The stiffness of the under-rail pad on the inner side of the rail The stiffness of the under-rail pad on the outer side of the rail 。 2. The design method of a non-uniform stiffness vibration damping fastener according to claim 1, characterized in that: Step One, Determination of the Overall Device Stiffness as described above The overall static stiffness of the under-rail pad, upper tie plate, middle damping pad, vibration isolation plate, under-board damping pad, lower tie plate, and insulating coupling pad is 6 kN / mm, and the dynamic settlement of the rail is 3.71 mm; the lower limit value of the static stiffness of the vibration isolation fastener is 6 kN / mm; the vibration isolation performance of the elastic separate fastener is ≥ 10 dB, and the upper limit value of the static stiffness of the fastener is 10 kN / mm.

3. The design method of a non-uniform stiffness vibration damping fastener according to claim 1, characterized in that: Step Three, Deformation Analysis as described above Through simulation calculation and combined with actual tests, the vertical displacements of the inner side d1 and the outer side d2 of the rail feet on both sides of the rail under vertical and lateral loads, and the vertical displacements of the inner side d3 and the outer side d4 of the upper tie plate on both sides are obtained. By combining the spacing of the vertical displacement value-taking points, the deflection angle α2 of the rail and the deflection angle α1 of the upper tie plate can be calculated; among them, the deflection angle of the rail is equal to the sum of the deflection angle of the upper tie plate and the non-uniform deformation angle that occurs under the rail pad. Then, the non-uniform deformation angle α that occurs under the rail pad is α = α2 - α1.

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