阅读说明：本技术 一种利用扣件间距失谐实现低频减振的系统和方法 (System and method for realizing low-frequency vibration reduction by utilizing fastener spacing detuning ) 是由 史海欧 农兴中 刘文武 罗信伟 贺利工 吴嘉 王仲林 冯青松 孙元广 孙菁 袁江 于 2020-05-15 设计创作，主要内容包括：本发明涉及一种利用扣件间距失谐实现低频减振的系统和方法,所述系统包括：钢轨以及在钢轨设置的多个扣件,扣件之间的间距满足一定的失谐长度。采用本申请的方案,操作简单,扣件间距失谐的设置无需通过在标准扣件间距间焊入一段长钢轨,只需通过控制扣件设置的位置从而达到控制扣件间距的目的；只需要在扣件间距失谐位置的钢轨安装阻尼层等其它能够耗散能量的材料,不需要再轨道结构全段安装,节省了成本的同时,也有效地实现了控制低频振动的效果。(The invention relates to a system and a method for realizing low-frequency vibration reduction by utilizing fastener spacing detuning, wherein the system comprises: the rail and at a plurality of fasteners of rail setting, the interval between the fastener satisfies certain detuning length. By adopting the scheme, the operation is simple, the setting of the gap mismatch of the fasteners does not need to weld a section of long steel rail between the gaps of the standard fasteners, and the purpose of controlling the gap between the fasteners can be achieved only by controlling the positions of the fasteners; other materials capable of dissipating energy such as damping layers are only required to be installed on the steel rail at the position of the gap detuning of the fastener, and the whole section of the rail structure is not required to be installed, so that the cost is saved, and meanwhile, the effect of controlling the low-frequency vibration is effectively achieved.)

1. A system for achieving low frequency vibration damping with fastener pitch detuning, the system comprising: rail and at a plurality of fasteners of rail setting, its characterized in that: the spacing between the fasteners satisfies a certain detuning length.

2. The system for achieving low frequency vibration damping using fastener pitch detuning of claim 1, wherein: the detuning length, the distance between the standard fasteners and the defect state frequency satisfy the following relations

Standard fastener spacing Relation formula 0.59m f＝-17.405×Δl+117.756 0.6m f＝-22.437×Δl+119.685 0.625m f＝-16.705×Δl+127.554 0.65m f＝-25.705×Δl+137.475 0.7m f＝-19.705×Δl+122.756

Wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

3. The system for achieving low frequency vibration damping using fastener pitch detuning of claim 2, wherein: the rail at the pitch detuning position is provided with a vibration energy dissipating structure.

4. A system for achieving low frequency vibration damping using fastener pitch detuning as claimed in claim 3, wherein: the vibration energy dissipation structure is a damping layer.

5. A system for achieving low frequency vibration damping using fastener pitch detuning as claimed in claim 3, wherein: the vibration energy dissipation structure is a dynamic vibration absorber.

6. A method of achieving low frequency vibration damping using fastener pitch detuning, characterised in that it is achieved using the system of any of claims 1-5, the method comprising:

measuring the distance and determining a detuning length relation;

determining the low-frequency vibration frequency of the project so as to determine the detuning length of the fastener distance;

and correspondingly adjusting the fastener spacing according to the fastener spacing detuning length.

7. The method for achieving low frequency vibration damping using fastener pitch detuning as claimed in claim 6, wherein: the rail is also provided with a material for vibration dissipation at the position of the gap detuning.

8. A method of achieving low frequency vibration damping using fastener pitch detuning according to claim 6 or 7, wherein: the detuning length relational expression is the relation between the detuning length and the distance and the defect state frequency of a standard fastener, and specifically comprises the following steps:

wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

Technical Field

The invention belongs to the technical field of rail transit, and particularly relates to a system and a method for realizing low-frequency vibration reduction by utilizing fastener spacing detuning.

Background

With the dramatic increase in speed and operating density of modern railroads, vehicle/track interactions become more intense. Vibrations propagate in the track structure in the form of elastic waves causing severe damage to the track structure components which will seriously affect the safety of the train and the service life of the track structure. In addition, when the high-speed railway passes through residential areas and urban areas, the vibration of the track structure causes serious noise pollution due to the radiation of sound waves, and adverse effects are caused on the working and living health of neighboring residents along the line, the normal use of neighboring buildings and precise instruments, and the like, so that the track structure becomes the most representative environmental problem. The wheel-track noise with slow attenuation, strong penetrating power and long propagation distance has certain harm to the physiological functions of the cardiovascular system, the nervous system, the visual system, the auditory system, the endocrine system and the like of a human body, and low-frequency noise in certain frequency bands can even generate resonance with the thoracic cavity and the brain cavity of the human body, so that the symptoms of heart disease, hypertension and the like are caused. Therefore, it is important to control the environmental vibration caused by the train running.

At present, the vibration reduction type track structure mainly aiming at controlling environmental vibration mainly comprises various vibration reduction type elastic fasteners such as pioneer fasteners, and vibration reduction of an under-rail foundation such as elastic sleepers and floating slab tracks. In high-speed railway engineering, factors such as safety are considered, and optimization of elastic fasteners, vibration-damping plate-type rails, damping steel rails, steel rail vibration absorbers and the like is considered as a main vibration control measure of a high-speed railway track structure. However, the existing vibration damping measures are not ideal in the control effect of low-frequency vibration of the track structure.

Disclosure of Invention

The invention aims to provide a steel rail vibration absorption system and a steel rail vibration absorption method for solving the problems. Specifically, the present application provides a system for achieving low frequency damping with fastener pitch detuning, the system comprising: rail and at a plurality of fasteners of rail setting, its characterized in that: the spacing between the fasteners satisfies a certain detuning length.

The system for achieving low frequency vibration damping using fastener pitch detuning of claim 1, wherein: the detuning length, the distance between the standard fasteners and the defect state frequency satisfy the following relations

Wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

Further, it is characterized in that: the rail at the pitch detuning position is provided with a vibration energy dissipating structure.

Further, it is characterized in that: the vibration energy dissipation structure is a damping layer.

Further, it is characterized in that: the vibration energy dissipation structure is a dynamic vibration absorber.

The application also provides a method for realizing low-frequency vibration reduction by utilizing fastener spacing detuning, which is characterized by being realized by adopting any one of the systems, and the method comprises the following steps:

measuring the distance and determining a detuning length relation;

determining the low-frequency vibration frequency of the project so as to determine the detuning length of the fastener distance;

and correspondingly adjusting the fastener spacing according to the fastener spacing detuning length.

Further, it is characterized in that: the rail is also provided with a material for vibration dissipation at the position of the gap detuning.

Further, it is characterized in that: the detuning length relational expression is the relation between the detuning length and the distance and the defect state frequency of a standard fastener, and specifically comprises the following steps:

standard fastener spacing	Relation formula
		0.59m	f＝-17.405×Δl+117.756
0.6m	f＝-22.437×Δl+119.685
		0.625m	f＝-16.705×Δl+127.554
0.65m	f＝-25.705×Δl+137.475
		0.7m	f＝-19.705×Δl+122.756

Wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

The method is simple to operate, and the purpose of controlling the distance between the fasteners can be achieved by controlling the positions of the fasteners without welding a section of long steel rail between the distances between the standard fasteners in the detuned arrangement of the fastener distances; other materials capable of dissipating energy such as damping layers are only required to be installed on the steel rail at the position of the gap detuning of the fastener, and the whole section of the rail structure is not required to be installed, so that the cost is saved, and meanwhile, the effect of controlling the low-frequency vibration is effectively achieved.

Drawings

FIG. 1 is a graph of the effect of fastener pitch detuning on dispersion characteristics, where A is the fastener pitch detuned case; b is the fastener pitch detuning condition;

FIG. 2 is a graph of the effect of fastener pitch detuning on transmission characteristics, where A is the fastener pitch detuned case; b is the fastener pitch detuning condition;

FIG. 3 is a graph showing the response of the track structure to displacement for a fastener pitch, where A is the non-detuned condition of the fastener pitch; b is the fastener pitch detuning condition;

FIG. 4 is a power flow distribution diagram of a track structure under a fastener pitch detune condition;

FIG. 5 is an analysis diagram of a defect state versus mode shape; wherein A is a defect state frequency corresponding mode diagram; b is a partial enlarged view;

FIG. 6 is a graph of pitch detuning length versus defect state frequency for fasteners of the present application;

fig. 7 is a schematic diagram of the system of the present application.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The basic principle of the invention is as follows:

in actual engineering, the integral track bed has the advantages of simple structure, convenience in construction and the like, for the integral track bed track, the track bed is formed by integrally pouring concrete, the rigidity of a lower structure is high, the influence of the lower structures such as track plates and the like is not considered, the periodic ballastless track structure is simplified into an infinite-length single-layer elastic point supporting beam model, a steel rail is simplified into an Eular beam model, and fasteners are simplified into supporting springs. According to elementary beam theory, a plane wave expansion method is utilized to expand a free vibration balance equation of the steel rail beam into:

in the formula, M₁(G₃-G₁)、M₂(G₃-G₁)、K(G₃-G₁) Respectively representing a Fourier coefficient of the product of the elastic modulus and the moment of inertia of the steel rail, a Fourier coefficient of the product of the density and the cross section area of the steel rail and a Fourier coefficient of the vertical rigidity of the fastener; u shape_k(G₁) Fourier coefficient representing vertical displacement of the steel rail beam; g₁、G₃Representing the reciprocal lattice vector space.

If the infinite series is approximated by summing N reciprocal lattice vectors, the formula (1) is converted into a characteristic value problem of an NxN matrix, and the band gap of the periodic ballastless track structure in vertical vibration is obtained by solving. In an actual engineering structure, whether the track structure is produced or installed, the track structure does not exhibit perfect periodicity, and the problems of inconsistent fastener pitches and the like occur, which further cause the periodic track structure to generate detuning, that is, a defect state in a phononic crystal theory may be generated. The presence or absence of such a characteristic is further analyzed below.

Firstly, the influence of inconsistent fastener spacing on the frequency dispersion characteristic of the periodic ballastless track structure is analyzed, as shown in fig. 1.

In the analysis of frequency dispersion characteristics, the distance between the standard fasteners is 0.7m, and a section of long steel rail with the length of 0.9m is inserted in the middle of the distance between the standard fasteners to introduce detuning. As can be seen from fig. 1A, within a frequency range of 0 to 200Hz, a first-order bandgap (0 to 122.17Hz) is generated by vertical vibration of a periodic ballastless track structure, and it can be found by comparing 1A and 1B that after detuning is introduced, the original bandgap position does not change greatly, and at the same time, a flat and straight band (corresponding to a in fig. 1B) is generated within the bandgap range, and a frequency of not 118.38Hz is a defect state described in the phononic crystal theory. The effect of fastener pitch detuning on vibration transmission characteristics is further analyzed below.

FIG. 2 shows the vibration transmission characteristic curve for fastener pitch detuning/no-detuning, in which the fastener pitch detuning length was consistent with that in the dispersion analysis, and was still 0.9 m.

It can be seen from figure 2 that the rail vibration transmission characteristic curve produces a distinct vibration attenuation region (left part of figure 2) in the frequency range of 0-200Hz, corresponding to the resulting band gap in figure 1. Meanwhile, as can be seen by comparing fig. 2A and 2B, when the fastener pitch mismatch occurs in the track structure, a vibration peak (point B in fig. 2B) occurs in the vibration attenuation region in the vibration transmission characteristic curve, and the corresponding frequency is 118.38Hz, which is also consistent with the frequency corresponding to the flat band a in fig. 1B.

Through the analysis of the influence of the fastener spacing detuning on the frequency dispersion characteristic and the transmission characteristic of the periodic ballastless track structure, the defect state can be generated in the track structure when the fastener spacing is inconsistent in the track structure. According to the phonon crystal defect state theory, when the one-dimensional phonon crystal generates a defect state, the elastic wave is limited at the defect position, so that the vibration localization characteristic appears at the defect position, and the vibration energy is also limited at the defect position. The periodic track structure as a new one-dimensional phonon crystal structure should also have such characteristics when defect states are generated, as further demonstrated by vibration response and energy flow below.

Fig. 3 shows a displacement response distribution diagram in a finite-length ballastless track structure corresponding to a defect state frequency of 118.38Hz under the action of unit harmonic load.

As is apparent from fig. 3A, when the distance between the fasteners is not detuned, the defect frequency of 118.38Hz originally falls within the band gap range, and the vibration waves cannot be transmitted along the longitudinal direction of the rail; in contrast, in fig. 3B, due to the introduction of the gap mismatch of the fasteners, the rail structure generates a defect state, the vibration wave can be transmitted along the longitudinal direction of the rail, and a significant vibration amplification phenomenon is generated at the gap mismatch of the fasteners, so that the vibration localization characteristic under the effect of the defect state characteristic is proved. The flow of energy is further analyzed below.

As can be seen from fig. 4, when the track structure is detuned in the fastener pitch, the generated defect frequency is a pass band, the vibration source can greatly input power flow into the track structure, and the main elastic wave energy is concentrated at the detuned position in the fastener pitch, thereby causing vibration localization at the detuned position. Analysis of the dynamic response and energy transfer characteristics proves that when the track structure causes a defect state due to fastener pitch detuning, the elastic wave at the frequency of the defect state is limited at the detuning position, so that energy concentration is caused, and a new idea is provided for environmental vibration control: the fastener spacing detuning can be artificially set, the vibration wave energy of a certain frequency band is concentrated at the detuning position, and then the concentrated energy is dissipated by adding a damping layer or a steel rail vibration absorber, so that the vibration reduction function is realized. However, it can be known from the foregoing analysis that when the fastener pitch mismatch occurs at a certain position of the track structure, the vibration of the track structure will generate a defect state, but the defect state corresponds to only one frequency, and the application value of the vibration reduction is not high, and meanwhile, an idea is provided: through introducing fastener interval detuning in a plurality of positions of periodic track structure to adjust detuning length, thereby make track structure produce a plurality of defect state frequencies, and then cover certain frequency channel, realize the damping of certain frequency channel.

Fig. 5 shows a defect state frequency corresponding mode caused by the gap mismatch of the fasteners, which shows that the defect state is essentially a local vibration mode of the track structure, and fig. 5B shows that the defect state mainly involves the vibration deformation, namely, three steel rail cells (each cross steel rail is a cell, namely, a section of steel rail between adjacent fasteners) at the detuning position and adjacent left and right sides, and the deformation of the steel rail cells is gradually reduced to 0 as continuing to extend to the two sides. Table 1 shows the number of selected steel rail cells and a corresponding defect state frequency table. It can be seen that the defect state is a local vibration mode of the track structure, in this mode, only three steel rail unit cells at the detuning position, adjacent to the left and right sides, are mainly involved in the deformation, and the degree of the other steel rail unit cells involved in the deformation decreases with the distance from the detuning unit cells, that is, the defect state frequency is a convergence value. The defect state can be generated at a plurality of frequency positions only by introducing the fastener intervals with different detuning degrees at different positions of the track structure and only by meeting the requirement that the interval between two adjacent detuning positions is at least beyond 3 steel rail cell lengths (namely 3 times of the normal fastener interval), the defect state frequencies generated at the detuning positions are not influenced with each other, a small-range frequency band defect state frequency set is formed, then concentrated energy is dissipated only by adopting additional damping or a vibration absorber at the detuning positions of the fastener intervals, and the vibration reduction effect is further realized.

TABLE 1 analysis of the frequency of the defect state corresponding to the number of steel rail cells

Fig. 6 shows a relationship curve between the off-tuned length of the fastener pitch and the frequency of the defect state, and research shows that when the off-tuned length of the fastener pitch is smaller than the fastener pitch set in the standard, the defect state characteristic generated in the track structure is not obvious, and only when the off-tuned length of the fastener pitch is larger than the fastener pitch set in the standard, the defect state characteristic generated in the track structure is obvious. It can be seen from fig. 6 that the defect state frequency and the fastener pitch detuning length exhibit negative correlation and are linearly fitted, and it can be seen that the defect state frequency and the fastener pitch detuning length can be approximately fitted into a straight line, that is, the defect state frequency and the fastener pitch detuning length can be approximately in a linear relationship and can be expressed as:

f＝-19.705×Δl+122.756 (2)

wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

Therefore, the required fastener pitch detuning length can be calculated by using the formula (2) according to the requirement of the actual engineering vibration attenuation frequency band, and then the corresponding arrangement is carried out. Table 2 shows the detuning length versus defect state frequency for a typical standard fastener pitch.

TABLE 2 relationship between detuning length and defect state frequency corresponding to common standard fastener pitch

Standard fastener spacing	Relation formula
		0.59m	f＝-17.405×Δl+117.756
0.6m	f＝-22.437×Δl+119.685
		0.625m	f＝-16.705×Δl+127.554
0.65m	f＝-25.705×Δl+137.475
		0.7m	f＝-19.705×Δl+122.756

The following description will be made in conjunction with the accompanying drawings, and in accordance with the principles set forth above, a system for implementing low frequency damping using fastener pitch detuning, the system including: rail and at a plurality of fasteners of rail setting, its characterized in that: the spacing between the fasteners satisfies a certain detuning length.

Further, the detuning length and the standard fastener spacing and defect state frequency satisfy the following relations:

wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.

In one aspect, the rails at the pitch detuned locations are provided with vibration energy dissipating structures. Preferably, the vibration energy dissipation structure is a damping layer, preferably made of rubber material, attached to two sides of the steel rail. In another aspect, the vibration energy dissipating structure is a dynamic vibration absorber that can be installed at a mid-span location of the rail between two adjacent fasteners. Preferably, the dynamic vibration absorber is in the form of a rubber-metal block (having a certain mass).

The application also provides a method for realizing low-frequency vibration reduction by utilizing fastener spacing detuning, which comprises the following steps:

(1) measuring spacing and determining detuning length relations

Manually measuring to determine the standard fastener spacing of an actual track structure, accurately measuring to millimeter units, and determining a corresponding relation between defect state frequency and fastener spacing detuning length according to table 2;

(2) table for determining engineering low-frequency vibration frequency band and further determining fastener spacing detuning length range

The vibration frequency ranges required to be controlled in different engineering environments are not consistent, so that the low-frequency vibration frequency band required to be controlled is determined in advance according to the actual engineering condition, and a fastener pitch detuning length range table is determined by combining the defect state frequency and the fastener pitch detuning length relational expression;

(3) adjusting the fastener pitch correspondingly according to the fastener pitch detuning length range table

For the adjustment of the distance between the fasteners, loosening two adjacent fasteners on a section of steel rail at any position of a track structure by using a torque wrench, then determining the length of the detuned steel rail to be introduced according to the determined fastener distance detuning length table, and making an obvious mark at the corresponding position of the steel rail so as to be convenient for accurate installation; then, the fasteners are installed again at the marks, after the installation is finished, the fastener spacing detuning is successfully introduced, the adjustment and control of the fastener spacing are realized by changing the positions of the fasteners, the time required for directly welding a section of new detuned long steel rail is also reduced, and the working efficiency is improved.

Preferably, two adjacent fastener pitch detuned locations should be at least a distance of three standard fastener pitches. As can be seen from fig. 5B, the main vibration deformation is the detuning part, the adjacent left and right steel rail cells, and the deformation of the steel rail cells gradually decreases to 0 as the steel rail cells continue to extend to both sides. Table 1 shows the number of selected steel rail cells and a corresponding defect state frequency table. It can be seen that the defect state is a local vibration mode of the track structure, in this mode, only three steel rail unit cells at the detuning position, adjacent to the left and right sides, are mainly involved in the deformation, and the degree of the other steel rail unit cells involved in the deformation decreases with the distance from the detuning unit cells, that is, the defect state frequency is a convergence value. This shows that by introducing the fastener spacing with different detuning degrees at different positions of the track structure, defect states can be generated at multiple frequencies only by satisfying that the interval between two adjacent detuning positions is at least 3 rail unit cell lengths (namely 3 times of the normal fastener spacing), and the defect state frequencies generated at the detuning positions are not influenced by each other, thereby forming a small-range frequency band defect state frequency set

(4) Rail mounted vibration energy dissipating material at spaced detuned locations

After correctly setting up the fastener interval detune, only need the rail installation damping layer or other materials that can dissipate energy such as bump leveller of fastener interval detune position can: if the damping layer is installed, the damping layer is attached to two sides of the steel rail by adopting a simple rubber material; if the dynamic vibration absorber is installed, the dynamic vibration absorber can be installed at the midspan position of the steel rail between two adjacent fasteners, and a rubber-metal block (with certain mass) form can also be used for replacing a complex dynamic vibration absorber. In the previous step, the distance between the fasteners is changed to introduce detuning, so that the energy of the vibration waves is limited at the defect, and the energy at the defect can be dissipated by installing the energy dissipation material in the step, so that the very good vibration damping effect is achieved

Wherein, for a steel rail with a standard fastener spacing of 0.59m, the relation between the detuning length and the defect state frequency is as follows: -17.405 × Δ l + 117.756;

for a rail with a standard fastener spacing of 0.6m, the relationship between the detuning length and the frequency of the defect state is: -22.437 × Δ l + 119.685;

for a rail with a standard fastener spacing of 0.625m, the detuning length is related to the defect state frequency by the formula: -16.705 × Δ l + 127.554;

for a rail with a standard fastener spacing of 0.65m, the relationship between the detuning length and the frequency of the defect state is as follows: -25.705 × Δ l + 137.475;

for a rail with a standard fastener spacing of 0.7m, the relationship between the detuning length and the frequency of the defect state is: -25.705 × Δ l + 137.475;

0.7m	f＝-19.705×Δl+122.756

wherein f represents a defect state frequency; Δ l represents the fastener pitch detuning length.