CN111963618A - Inhaul cable multi-order modal vibration control method based on double dampers - Google Patents
Inhaul cable multi-order modal vibration control method based on double dampers Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
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- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
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Abstract
The invention relates to a cable multi-order modal vibration control method based on double dampers, which is based on a cable structure body, wherein the cable structure body comprises a bearing crossing component (beam) which is transversely arranged and a stressed component (tower) which is vertically arranged, anchoring points are respectively arranged on the beam and the tower, a cable is arranged between the anchoring points of the beam and the tower, two cable dampers are arranged on the anchoring points and are divided into a first damper and a second damper, one end of the first damper is fixed on the cable, the other end of the first damper is fixed on the beam through a bracket, the arrangement mode of the second damper comprises a same-end arrangement mode and an opposite-end arrangement mode, the second damper is arranged in a cable sleeve of the beam when the same end is arranged, the second damper is arranged in a cable sleeve of the tower when the opposite end is arranged, and the first damper and the second damper comprehensively control multi-modal vibration of the cable. Compared with the prior art, the invention has the advantages of effectively controlling the low-order vibration and the high-order vortex-induced vibration of the stay cable, improving the stability of the stay cable structure, prolonging the service life of the stay cable structure and the like.
Description
Technical Field
The invention relates to the technical field of vibration control of engineering structures, in particular to a stay cable multi-order modal vibration control method based on double dampers.
Background
The guy bearing structure is a very important civil construction structure, and mainly comprises a cable-stayed bridge, a suspension bridge and a mast structure. Such structures have excellent spanning and shrugging capabilities, with spans or heights still developing and corresponding cables becoming longer and longer. The stay cable in the structure bears axial tension, the cross-sectional dimension, the mass per unit length and the transverse rigidity of the stay cable are small, vibration is easy to occur, and the vibration has the characteristics of multiple modes and multiple mechanisms, so that the development of the stay cable structure is limited.
At present, the most common control methods for inhaul cable vibration mainly comprise: (1) the surface of the inhaul cable sheath adopts aerodynamic measures, including the modes of winding a spiral line, pressing a pit and the like, and the inhaul cable is mainly subjected to vibration reduction by destroying the coupling mechanism of the inhaul cable and wind and rain; (2) the damper is additionally arranged on the position, close to the anchoring point, of the stay cable, the stay cable is connected with a structure connected with the stay cable in the cross-inner transverse direction, the energy dissipation capacity of the stay cable during transverse vibration is improved, and the purpose of vibration reduction and vibration suppression is achieved; (3) and the auxiliary cables are used for connecting the adjacent inhaul cables, so that the overall rigidity and the energy consumption capability of the cables are improved.
In the stay cable vibration reduction scheme, the scheme of comprehensively adopting pneumatic measures and dampers is most widely applied. The damper mainly plays a role in energy consumption and has damping and inhibiting effects on the vibration of the guy cable in different mechanisms and modes. To the low order vibration of cable among the prior art, install the attenuator between cable and roof beam, the low order vibration of cable contains the preceding 5 rank vibrations of cable or the cable vibration frequency is 0 ~ 3.0 Hz's mode, and the cable vibration of wind and rain appears easily in this frequency channel, and the attenuator of adoption mainly is viscous damper, oil damper or stickness shearing damper.
For long cables, this cable-single damper system has the potential for higher order, high frequency vortex-induced vibrations of the cable and has been observed in practical bridges. The reason why the damper installed on the guy cable cannot effectively control the high-order and high-frequency vortex-induced vibration of the guy cable is mainly two: (1) the high-order vortex-induced vibration mode of the stay cable is just a stagnation point at the damper, namely the stay cable does not vibrate at the damper position during vortex-induced vibration, and the damper cannot play a vibration damping role in the vibration of the stay cable; (2) the damper generally adopts viscous damper or other liquid dampers, and the damper has better energy dissipation effect under lower frequency, but the damping performance is not enough under the condition of inhaul cable high-frequency vortex vibration.
In the prior art, rubber filler is arranged at a sleeve opening of a stay cable and is used for dust prevention, moisture prevention and vibration reduction; or a mode of combining a beam damper with a tower sleeve opening rubber filler is adopted, but the method has the following defects: (1) the design of the rubber shock absorber is not aimed at high-order vortex vibration, and the mutual influence between the rubber shock absorber and a beam damper is not considered quantitatively; (2) the synergistic effect of the beam and the sleeve opening damper on multi-mode vibration control of the cable when the beam is simultaneously provided with the damper and the sleeve opening damper is not considered. In the prior art, a double-damper system is installed at different positions of a guy cable, the comprehensive vibration reduction effect of two dampers on a certain specific order of a low order of the guy cable is concerned, and the vibration reduction effect of the two dampers on the vibration of the guy cable in different modes/mechanisms is not considered.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for controlling the multi-order modal vibration of a guy cable based on double dampers, so that the low-order vibration and the high-order vortex-induced vibration of the guy cable can be effectively controlled.
The purpose of the invention can be realized by the following technical scheme:
the utility model provides a multistage modal vibration control method of cable based on two dampers, is based on cable structure body, cable structure body includes horizontal roof beam and the tower of erectting to put, all be equipped with the anchor point on roof beam and the tower, be equipped with the cable between the anchor point of roof beam and tower, the anchor point side of roof beam and tower is equipped with two dampers, divide into first damper and second damper, the one end of first damper is fixed on the cable, and the other end passes through the support to be fixed at the roof beam, the mode of setting of second damper includes that the same end sets up and different end sets up, wherein when the same end sets up the second damper is located on the sleeve pipe of roof beam, when different end sets up the second damper is located on the sleeve pipe of tower, the multistage modal of vibration frequency of cable is controlled to first damper and second damper, control method's step specifically is as follows:
step S1: determining the installation position and damping parameters of a first damper according to the damping requirements of the low-order mode, and determining the high-order mode of the vortex-induced vibration of the inhaul cable according to the installation position and the damping parameters of the first damper;
step S2: determining the installation position and damping parameters of a second damper according to the high-order mode of the vortex-induced vibration of the stay cable;
step S3: and judging whether the low-order damping of the affected first damper meets a set threshold value or not according to the influence of the second damper on the first damper, if so, keeping the current installation positions and damping parameters of the first damper and the second damper unchanged, if not, adjusting the installation positions and the damping parameters of the first damper, and turning to the step S1.
The distance from the first damper to the adjacent anchoring point is larger than the distance from the second damper to the adjacent anchoring point, the distance from the first damper to the adjacent anchoring point is 1% -3% of the length of the inhaul cable, and the distance from the second damper to the adjacent anchoring point is 0.5% -1.5% of the length of the inhaul cable.
Further, the distance from the first damper to the adjacent anchoring point is 1-3 times that from the second damper to the adjacent anchoring point.
The first damper controls a low-order vibration mode of the stay cable.
Further, the vibration frequency of the low-order vibration is 0-3.0 Hz, and specifically comprises the following steps:
fn≤3.0Hz
wherein f isnThe vibration frequency of the cable is represented, and n is 1,2,3 and … which are integers to represent the modal order of cable vibration;
when the stay cable is long, the vibration frequency of the stay cable is calculated through a tension string model, and the method specifically comprises the following steps:
wherein T is the stay force, m is the mass of the stay per unit length, and is the total length of the L stay chord.
According to the sag of the stay cable, the odd-order vibration mode dimensionless frequency of the stay cable passes through
Using a fixed point or Newton's method as an initial valuePerforming iterative solution, specifically:
wherein,
the dimensionless circular frequency of the stay cable vibrating without the damper;
the dimensionless frequency of the even order vibration mode is:
in the calculation of dimensionless frequencies of odd-order vibration modes, λ2For dimensionless parameters related to the sag of the inhaul cable, the specific calculation formula is as follows:
wherein theta is the inclination angle of the cable, E is the elastic modulus of the cable, A is the effective cross-sectional area of the cable, and g is the gravitational acceleration (9.81 m/s)2)，LeThe length of the stay cable after being stressed and extended is as follows:
sag parameter lambda of stay cable used in current cable-stayed bridge2The value of (2) is between 0 and 2.5, the sag mainly affects the first order vibration of the cable, and the first order vibration frequency in the cable surface affected by the sag is as follows:
and the second damper controls a high-order high-frequency vortex-induced vibration mode of the inhaul cable.
Further, the first damper is located on a mode stagnation point under a high-order high-frequency vortex-induced vibration mode.
The first damper is a viscous damper or a viscoelastic damper, and the force between two end parts of the first damper and the relative displacement and speed of the two end parts meet the following formula:
wherein k isIIs the stiffness coefficient of the first damper, cIIs the damping coefficient of the first damper, uIAnd
respectively, displacement and velocity of relative deformation of the two ends of the first damper, FIIs the force across the first damper; the frequency and deformation amplitude dependency of the stiffness coefficient and the damping coefficient are determined according to the test result; the stiffness coefficient and the damping coefficient of the first damper at the nth order vibration of the inhaul cable are recorded as kI,nAnd cI,nThe damping values of the first damper for the even-order vibration of the stay are obtained as follows:
wherein the dimensionless stiffness coefficient
Damping coefficient
Relative mounting position of the first damper
The following were used:
wherein lIIs the distance of the first damper from the adjacent anchor point.
The mode damping of the first damper affected by the sag to odd orders of the stay is as follows:
wherein the process variable
The method specifically comprises the following steps:
the second damper is a viscoelastic damper or a high-damping rubber damper, the mode of the inhaul cable vortex-induced vibration aimed at by the second damper is determined according to the installation position of the first damper, and the specific mode order is as follows:
n＝int(L/lI)
wherein the function int () represents taking the nearest integer;
the force at the two ends of the second damper and the displacement and the speed of the deformation of the second damper satisfy the following formula:
wherein,
is the unit of an imaginary number,
loss factor, k, for high damping rubber dampersIIIs the stiffness coefficient of the second damper, uIIIs a relative deformation displacement of both ends of the second damper, FIIIs the force across the second damper; the additional damping values of the high-damping rubber damper to each even-order vibration of the inhaul cable are as follows:
wherein the dimensionless stiffness coefficient
And the mounting position of the second damper
The method comprises the following specific steps:
wherein lIIIs the distance of the second damper from the adjacent anchor point.
High damping rubber damper mainly is to the high-order vibration of cable, and the cable sag mainly influences its first-order additional damping to the cable, specifically is:
wherein the process variable
The method specifically comprises the following steps:
when the different end is set, the damping values of the second damper and the first damper are calculated in a superposition mode, and the method specifically comprises the following steps:
ξn＝ξI,n+ξII,n
wherein ξnIs a comprehensive damping value;
when the same end is arranged, the comprehensive damping value of the two dampers to the even-order vibration of the stay rope is as follows:
wherein the dimensionless parameters are defined as follows:
the additional damping values of the two dampers affected by the sag effect on odd-order vibration of the stay rope are specifically as follows:
the double dampers perform comprehensive damping vibration attenuation on low-order multimode and high-order mode, and a more accurate damping value can be solved by adopting a numerical method according to the following equation, wherein the specific equation is as follows:
Θ+2ΞIXI+2ΞIIXII+4ΛXIXII＝0
wherein the parameters are defined as follows:
wherein,
dimensionless circular frequency of nth order vibration after installing dampers on the guy cable, and the distance between the two dampers is recorded as
When the different end is set:
when the same end is set:
solutions when mounting undamped dampers
Performing iterative solution as an initial value to obtain a complex frequency
The comprehensive damping value obtained by calculation is as follows:
here, "imag () represents the imaginary part of the complex number, and" | "represents the modulus of the complex number.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention combines the first damper and the second damper to control the multi-mode vibration of the stay cable, effectively controls the low-order vibration and the high-order vortex-induced vibration of the stay cable, eliminates the hidden danger that the fatigue life of the stay cable is damaged by the high-order high-frequency vortex-induced vibration of a cable-single damper system, and improves the stability of the stay cable structure.
2. The second damper for controlling vortex-induced vibration is arranged close to the anchoring point, so that the maintenance and replacement are convenient.
3. The second damper is arranged in the stay cable sleeve, compared with the method that the surface of the stay cable is wound or the auxiliary cable is additionally arranged to control the vortex vibration of the stay cable, the appearance of the bridge is not influenced, the wind load borne by the stay cable and the whole bridge is not increased, and meanwhile, the method is suitable for the multi-mode vibration reduction of a newly-built stay cable structure and the treatment of the vortex vibration of an in-service stay cable-damper system.
Drawings
FIG. 1 is a schematic structural diagram of the present invention, wherein (a) is a schematic diagram of an opposite end arrangement, and (b) is a schematic diagram of an identical end arrangement;
FIG. 2 is a graph showing the results of real cable vibration monitoring and comparison between a single damper and a double damper according to the present invention;
FIG. 3 is a schematic view of the design and installation process of the dual damper system of the present invention;
FIG. 4 is a diagram showing the effect of the vortex-induced vibration damper of the present invention on the damping effect of the low-order vibration damping damper.
Reference numerals:
1-a first damper; 2-a second damper; 3-a guy cable; 4-a sleeve; 5-a bracket; 6-a column; 7-beam.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
As shown in figure 1, the inhaul cable multi-order modal vibration control method based on double dampers is based on an inhaul cable structure body, the inhaul cable structure body comprises a beam 7 and a tower 6 which are transversely arranged, anchoring points are arranged on the beam 7 and the tower 6, an inhaul cable 3 is arranged between the anchoring points of the beam 7 and the tower 6, two dampers are arranged on the anchoring points of the beam 7 and the tower 6 and are divided into a first damper 1 and a second damper 2, one end of the first damper 1 is fixed on the inhaul cable 3, the other end of the first damper is fixed on the beam 7 through a bracket 5, the arrangement mode of the second damper 2 comprises the same-end arrangement and the different-end arrangement, wherein the second damper 2 is arranged on the sleeve 4 of the beam 7 when the same end is arranged, the second damper 2 is arranged on the sleeve 4 of the tower 6 when the different end is arranged, the first damper 1 and the second damper 2 comprehensively control the multi-order modal vibration of the guy cable, as shown in fig. 3, the control method specifically comprises the following steps:
step S1: determining the installation position and damping parameters of the first damper 1 according to the damping requirements of the low-order mode, and determining the high-order mode of the cable in which vortex-induced vibration occurs according to the installation position and the damping parameters of the first damper 1;
step S2: determining the installation position and damping parameters of the second damper 2 according to the high-order mode of the vortex-induced vibration of the stay cable;
step S3: and judging whether the low-order damping of the affected first damper 1 meets a set threshold value or not according to the effect of the second damper 2 on the first damper 1, if so, keeping the current installation positions and damping parameters of the first damper 1 and the second damper 2 unchanged, if not, adjusting the installation positions and damping parameters of the first damper 1, and turning to the step S1.
The distance from the first damper 1 to the adjacent anchoring point is larger than the distance from the second damper 2 to the adjacent anchoring point, the distance from the first damper 1 to the adjacent anchoring point is 1% -3% of the length of the inhaul cable, and the distance from the second damper 2 to the adjacent anchoring point is 0.5% -1.5% of the length of the inhaul cable.
The distance from the first damper 1 to the adjacent anchoring point is 1-3 times the distance from the second damper 2 to the adjacent anchoring point.
The first damper 1 controls the low-order vibration mode of the cable.
The vibration frequency of the low-order vibration is 0-3.0 Hz, and specifically comprises the following steps:
fn≤3.0Hz
wherein f isnThe vibration frequency of the stay cable is shown, and n is an integer and represents the modal order of cable vibration;
the vibration frequency of the inhaul cable 3 is calculated through the tension string model when the inhaul cable is long, and the method specifically comprises the following steps:
wherein T is the stay force, m is the mass of the stay per unit length, and is the total length of the L stay.
According to the sag of the stay cable 3, the odd-order vibration mode dimensionless frequency of the stay cable 3 passes through
Iterative solution using stationary point or Newton's method as initial valueThe solution specifically comprises the following steps:
wherein,
the dimensionless circular frequency of the stay cable 3 vibrating without the damper;
the dimensionless frequency of the even order vibration mode is:
in the calculation of dimensionless frequencies of odd-order vibration modes, λ2For dimensionless parameters related to the sag of the inhaul cable, the specific calculation formula is as follows:
where θ is the inclination angle of the cable 3, E is the modulus of elasticity of the cable 3, A is the effective cross-sectional area of the cable 3, and g is the gravitational acceleration (9.81 m/s)2)，LeThe length of the stay cable 3 after being stressed and stretched is as follows:
parameter λ of sag of the cable 32Between 0 and 2.5, the first order vibration of the cable 3 is affected, and the first order vibration frequency in the plane of the cable 3 affected by sag is:
the second damper 2 controls a high-order high-frequency vortex-induced vibration mode of the cable 3.
The first damper 1 is located at a mode stagnation point under a high-order high-frequency vortex-induced vibration mode.
The first damper 1 is a viscous damper or a viscoelastic damper, and the force between the two ends of the first damper 1 and the relative displacement and velocity of the two ends satisfy the following formula:
wherein k isIIs the stiffness coefficient of the first damper 1, cIIs the damping coefficient, u, of the first damper 1IAnd
respectively, displacement and velocity of relative deformation of the two ends of the first damper 1, FIIs the force across the first damper 1; the frequency and deformation amplitude dependency of the stiffness coefficient and the damping coefficient is determined according to a test method; the stiffness coefficient and the damping coefficient of the first damper 1 at the nth order vibration of the cable 3 are denoted by kI,nAnd cI,nThe obtained damping value of the first damper 1 to the even-order vibration of the cable 3 is as follows:
wherein the dimensionless stiffness coefficient
Damping coefficient
Relative mounting position with the first damper 1
The following were used:
wherein lIIs the distance of the first damper from the adjacent anchor point.
The mode damping of the first damper 1 affected by the sag to the odd-order inhaul cable 3 is as follows:
wherein the process variable
The method specifically comprises the following steps:
the second damper 2 is a viscoelastic damper or a high-damping rubber damper, the mode of the cable vortex-induced vibration of the second damper 2 is determined according to the installation position of the first damper 1, and the specific mode order is as follows:
n＝int(L/lI)
wherein the function int () represents taking the nearest integer;
the following equation is satisfied between the force at both ends of the second damper 2 and the displacement and speed at which the second damper 2 deforms:
wherein,
is the unit of an imaginary number,
loss factor, k, for high damping rubber dampersIIIs the stiffness coefficient, u, of the second damper 2IIIs a relative deformation displacement of both ends of the second damper 2, FIIIs the force across the second damper 2; the additional damping values of the high-damping rubber damper to the even-order vibration of the stay rope 3 are as follows:
wherein the dimensionless stiffness coefficient
And the mounting position of the second damper 2
The method comprises the following specific steps:
wherein lIIIs the distance of the second damper from the adjacent anchor point.
The high damping rubber damper mainly influences the high-order vibration of the stay cable 3, and the stay cable sag mainly influences the first-order additional damping of the stay cable 3, and specifically comprises the following steps:
wherein the process variable
The method specifically comprises the following steps:
when the different end is set, the damping values of the second damper 2 and the first damper 1 are calculated in a superposition mode, specifically:
ξn＝ξI,n+ξII,n
wherein ξnIs a comprehensive damping value;
when the same end is arranged, the comprehensive damping value of the two dampers to the vibration of the guy cable 3 with even orders is as follows:
wherein the dimensionless parameters are defined as follows:
the additional damping value of the two dampers affected by the sag effect on the odd-order vibration of the inhaul cable 3 is specifically as follows:
the double dampers perform comprehensive damping vibration attenuation on low-order multimode and high-order mode, and a more accurate damping value is obtained by adopting a numerical method based on the following equation, and the specific process is as follows:
Θ+2ΞIXI+2ΞIIXII+4ΛXIXII＝0
wherein, each parameter satisfies:
wherein,
dimensionless circular frequency of nth order vibration after installing dampers on the guy cable 3, and the distance between the two dampers is recorded as
When the different end is set:
when the same end is set:
solutions when dampers are not present
Performing iterative solution as an initial value to obtain a complex frequency
The comprehensive damping value obtained by calculation is as follows:
here, "imag () represents the imaginary part of the complex number, and" | "represents the modulus of the complex number.
Example one
The target cable length L is 546.9m, the unit length mass m is 91.3kg/m, the cable force T is 6240.5kN, the diameter of the cable 3 is D152 mm, and the cable sag parameter is lambda21.97. Solving a frequency equation according to the sag
The calculated vibration frequency of the inhaul cable 3 is as follows:
the first damper 1 is a viscoelastic damper and is mounted at a position of lI12.08m, e.g.As shown in table 1, under the periodic forced displacement with the amplitude of 10mm and the frequencies of 0.24Hz, 0.48Hz, 1.20Hz, 1.92Hz and 3.12Hz, the stiffness coefficient and the damping coefficient of the damper and the corresponding dimensionless coefficients are measured, and the measured frequencies respectively correspond to 1,2, 5, 8 and 13-order modes of the stay cable vibration, and table 1 is as follows:
TABLE 1 actual measurement of stiffness and damping coefficients of dampers
The dimensionless installation positions of the first damper 1 are:
the second damper 2 is a high damping rubber damper and is arranged in the sleeve 4 at the same end of the first damper 1 at the mounting position lII4.592m, loss factor
Rigidity kII1439.62kN/m, the corresponding dimensionless mounting position and stiffness coefficient are:
as shown in table 2, the damping effect of only installing the damper I and installing the dual dampers is shown, and table 2 is as follows:
TABLE 2 damping Effect of the first damper and the double damper on the Low order mode of the stay
After the second damper is installed, the low-order vibration reduction effect of the first damper 1 is reduced, the damping of the vibration mode of the second damper 2 with the front cable frequency and the rear cable frequency of 0-3Hz meets the requirement that the Scruton number is larger than 10, wherein the Scruton number is calculated according to the following formula:
wherein S iscThe Scruton number is the logarithmic damping rate of the cable vibration, and ρ is 1.225kg/m3If the air density is required to satisfy the requirement that the Scruton number is more than 10, the logarithmic decrement of the cable is 0.019.
For high-order vortex vibration, solving is carried out according to the mode of the first damper 1 near the vibration stagnation point, and the specific vibration mode is as follows:
analyzing the damping effect of the 43 th-47 th-order modal vibration of the inhaul cable, wherein the corresponding frequency is 10-12 Hz, and the following table 3 shows that:
TABLE 3 damping Effect of higher order vortex induced vibration modes
If the action of the first damper 1 is not considered, the damping value of the stay cable is smaller due to the fact that the damping provided by the high-damping rubber damper is calculated according to the logarithmic attenuation rate of 0.0045 in the mode of the stay cable; as shown in table 1, as the vibration frequency increases, the stiffness of the viscous shear damper increases and the damping coefficient decreases, and when the vibration frequency is 10Hz, the damping effect of the first damper 1 is ignored, and the damping function is regarded as a spring, specifically:
wherein the stiffness coefficient is the stiffness estimate at a frequency of 3.12Hz in Table 1; according to the spring action of the first damper 1, the second damper 2 greatly improves the high-order damping effect, the logarithmic decrement reaches more than 0.011, and the requirement that the Scruton number is more than 5 is met.
As shown in fig. 2, the vibration of the cable with two dampers is monitored, and compared with the cable without the second damper 2, the double-damper scheme suppresses the vortex-induced vibration of the cable; as shown in fig. 4, after the guy cable is provided with the first damper 1 or the double dampers, the damping of the low-order vibration of the guy cable is tested, wherein the multi-order modal damping ratio of the double dampers is more stable, although the second damper 2 causes a certain reduction of the damping effect of the 4-order damper before the guy cable, the requirement is still met after the reduction, which indicates that the guy cable provided with the double dampers has better stability.
In addition, it should be noted that the specific embodiments described in the present specification may have different names, and the above descriptions in the present specification are only illustrations of the structures of the present invention. All equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the invention. Various modifications or additions may be made to the described embodiments or methods may be similarly employed by those skilled in the art without departing from the scope of the invention as defined in the appending claims.
Claims (10)
1. A cable multi-order modal vibration control method based on double dampers is based on a cable structure body, the cable structure comprises a beam (7) which is transversely arranged and a tower (6) which is vertically arranged, anchoring points are arranged on the beam (7) and the tower (6), and a cable (3) is arranged between the anchoring points of the beam (7) and the tower (6), and the cable control method is characterized in that two dampers are arranged on the side edges of the anchoring points of the beam (7) and the tower (6) and are divided into a first damper (1) and a second damper (2), one end of the first damper (1) is fixed on the cable (3), the other end of the first damper is fixed on the beam (7) through a bracket (5), the setting mode of the second damper (2) comprises a same-end setting mode and a different-end setting mode, when the same-end setting mode is carried out, the second damper (2) is arranged on a sleeve (4) of the beam (7), and when the different-end setting mode is carried out, the second damper (2) is arranged on a sleeve (4) of the tower (6), the first damper (1) and the second damper (2) control the mode of the multi-step vibration frequency of the stay cable, and the control method specifically comprises the following steps:
step S1: determining the installation position and damping parameters of the first damper (1) according to the damping requirements of the low-order mode, and determining the high-order mode of the cable in vortex-induced vibration according to the installation position and the damping parameters of the first damper (1);
step S2: determining the installation position and damping parameters of a second damper (2) according to the high-order mode of the vortex-induced vibration of the stay cable;
step S3: and judging whether the low-order damping of the affected first damper (1) meets a set threshold value or not according to the influence of the second damper (2) on the first damper (1), if so, keeping the current installation positions and damping parameters of the first damper (1) and the second damper (2) unchanged, if not, adjusting the installation positions and damping parameters of the first damper (1), and turning to the step S1.
2. A guy cable multi-order modal vibration control method based on double dampers according to claim 1, wherein the distance from the first damper (1) to the adjacent anchoring point is larger than the distance from the second damper (2) to the adjacent anchoring point.
3. The method for controlling the multi-order modal vibration of the guy cable based on the double dampers as claimed in claim 2, wherein the distance from the first damper (1) to the adjacent anchoring point is 1% -3% of the length of the guy cable, and the distance from the second damper (2) to the adjacent anchoring point is 0.5% -1.5% of the length of the guy cable.
4. A guy cable multi-order modal vibration control method based on double dampers according to claim 3, wherein the distance from the first damper (1) to the adjacent anchoring point is 1-3 times the distance from the second damper (2) to the adjacent anchoring point.
5. A cable multi-order mode vibration control method based on double dampers as claimed in claim 1, characterized in that the first damper (1) controls the low-order vibration mode of the cable (3).
6. The method for controlling the multi-order modal vibration of the guy cable based on the dual dampers as claimed in claim 5, wherein the vibration frequency of the low-order vibration is 0-3.0 Hz.
7. A cable multi-order modal vibration control method based on double dampers as claimed in claim 1, wherein the second damper (2) controls a high-order high-frequency vortex-induced vibration mode of the cable (3).
8. The inhaul cable multi-order modal vibration control method based on the double dampers as claimed in claim 7, wherein the first damper (1) is located at a mode stagnation point under a high-order high-frequency vortex-induced vibration mode.
9. A cable multi-order modal vibration control method based on double dampers as claimed in claim 1, wherein the first damper (1) is a viscous damper or a viscoelastic damper.
10. A cable multi-order modal vibration control method based on dual dampers as claimed in claim 1, wherein the second damper (2) is a viscoelastic damper or a high damping rubber damper.
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