CN106908128A - The recognition methods of the bridge floor multiaxis traveling load based on Landweber iterative methods - Google Patents

Abstract

The invention discloses a kind of recognition methods of the bridge floor multiaxis traveling load of Landweber iterative methods, comprise the following steps：1), in bridge bottom surface correspondence position x₁,x₂,…x_mM displacement transducer is pasted at place respectively, measures bridge floor multiaxis mobile vehicle load f_kT () displacement of t at x position is v (x, t), k=1,2,3 ..., be the vehicle number of axle；2) oscillatory differential equation, is set up；3), equation (1) is solved；4) bridge, is set up under k axle Vehicle Loads, and multiaxis traveling load system equation is recognized by dynamic respond；5) exact value of multiaxis traveling load, is tried to achieve using Landweber iterative methods.The present invention need to only measure bridge displacement response and can recognize that bridge floor multiaxis traveling load, and recognition methods is simple and precision is higher, with good feasibility, can be widely applied to the moving load identification of all kinds bridge.

Description

The recognition methods of the bridge floor multiaxis traveling load based on Landweber iterative methods

Technical field

Bridge floor multiaxis is recognized by bridge displacement the invention belongs to bridge floor moving load identification technical field, more particularly to one kind The method of traveling load.

Background technology

Bridges in Our Country present situation is " rebuilding light supporting ", and from 1999 to 2013, domestic media disclosed report China because various The bridge that reason collapses up to more than 110 seats, wherein the bridge collapse not caused including Wenchuan earthquake still.Cause bridge damnification and break Bad reason can be summarized as external factor and internal factor, wherein in external factor due to automobile overload cause bridge fatigue damage and Durability reduction occupies leading position, and internal factor is then mainly the reduction of bridge itself bearing capacity and the strength of materials is degenerated.

With the explosive growth of highway in China traffic, the actual vehicle flowrate for bearing of many bridges increases compared with Earlier designs value A lot, the increase of speed and car weight can have a negative impact to bridge, the multiple-axle vehicle and large-scale multiple-axle vehicle especially overloads Appearance substantially exacerbate the risk of bridge collapse.

Highway in China transfinites to stand and make many work in control vehicle overload method, but measuring method is to use ground mostly at present Pound technology, i.e., weigh to realize the measurement of gross combination weight by parking.Under the trend of development rapid transit, how in vehicle row Accurate vehicle load has important practical meaning in engineering during sailing, especially to the accurate measurement of each axle load of multiaxis lorry Security and durability to protecting bridge all have very great help.

It is identified for conventional two-axle car more than existing moving load identification technology, it is impossible to which multiple-axle vehicle load is entered Row identification, therefore it is badly in need of a kind of method that can be identified to bridge floor multiaxis mobile vehicle load.

The content of the invention

Only need to measure the identification bridge floor multiaxis by bridge displacement is responded rapidly and efficiently it is an object of the invention to provide a kind of Mobile vehicle load, accuracy of identification is high and does not influence bridge floor vehicle normal pass.

To reach above-mentioned purpose, the technical solution adopted by the present invention is：It is a kind of based on Landweber iterative methods

The recognition methods of bridge floor multiaxis traveling load, comprises the following steps：

1), in bridge bottom surface correspondence position x₁,x₂,…x_mM displacement transducer is pasted at place respectively, measures the shifting of bridge floor multiaxis Dynamic vehicular load f_kT () displacement of t at x position is v (x, t), k=1,2,3 ..., be the vehicle number of axle；

2) vehicle-bridge system oscillatory differential equation, is set up：Bridge length is taken for L, bending rigidity is EI, bridge unit length matter It is ρ to measure, it is considered to which viscous damping simultaneously takes damped coefficient for C, ignores detrusion and the rotary inertia of bridge, bridge floor multiaxis locomotive Load fk (t) is moved right with speed c from beam left end supporting, then the oscillatory differential equation of vehicle-bridge system is：

Wherein δ (x-ct) is Dirac function；

The boundary condition of equation (1) is：

V (0, t)=0, v (L, t)=0,

3), equation (1) is solved；

4) bridge, is set up under k axle Vehicle Loads, and multiaxis traveling load system equation is recognized by dynamic respond： v_(m×1)=S_(m×k)·f_(k×1) (2)

v_(m×1)It is traveling load f_kT () is in x₁,x₂,…x_mThe actual displacement at place, and m >=k；S_(m×k)It is known system square Battle array；f_(k×1)It is required k axle traveling loads；

The discrete form of formula (2) is expressed as：

Wherein

5) exact value of multiaxis traveling load, is tried to achieve using Landweber iterative methods；

When bridge displacement response is measured, made an uproar comprising less in the dynamic respond generally measured due to measurement noise interference Sound, actually measured dynamic respond is v^δ, i.e., equation Sf=v right-hand vectors be typically with disturbance data v^δ, and meet

||v-v^δ||≤δ (4)

Wherein δ is noise threshold limit value, and this noise threshold limit value is determined by environmental factor, and span is 0 to 1 Between；

Landweber Iterations are：

Wherein S^*It is the adjoint matrix of vehicle bridge moving load identification sytem matrix S,

Stopping criterion for iteration is：

Wherein C is the influence coefficient of noise threshold limit value, is a constant, and this value is manually set, according to identification essence Degree requires different freely to set；

Taking multiaxis traveling load initial value isIteration can be written as：

Wherein l is unit matrix, if initial value is taken asIteration can be written as：

WhereinThe multiaxis traveling load for as being recognized based on Landweber alternative manners.

Described step 3) in equation (1) is solved comprise the following steps that it is described：

Based on modal superposition principle, it is assumed that the n-th order Mode Shape function of bridge isThen equation (1) Solution be expressed as：

Matrix form is：

Here n is mode number, q_nT () (n=1,2 ... ∞) are n-th order modal displacements, equation (12) is substituted into equation (1), And x is integrated in [0, L], using boundary condition and Dirac function characteristic, vehicle-bridge system oscillatory differential equation q_n T () is expressed as：

HereIt is q_nThe second dervative of (t),It is q_nThe first derivative of (t), Respectively circular frequency, damping rate and bridge floor mobile vehicle load mod table Up to formula；

As vehicle has a k axletree, and k-th axletree to first distance of axletree be x_k(x₁=0), then equation (14) It is written as：

Then corresponding to the modal displacement at m measuring point can be expressed as by equation (13)：

X on bridge₁,x₂,…x_mThe speed at place is tried to achieve by the once differentiation of displacement：

Further, x on bridge₁,x₂,…x_mThe acceleration at place is tried to achieve by the second differential of displacement：

Similarly, x on beam₁,x₂,…x_mThe moment of flexure at place can utilize relational expressionTry to achieve：

If f₁,f₂,…,f_kIt is each axle correspondence load of known k axles vehicle, ignores the influence of damping, then the solution of equation (1) can It is expressed as：

Wherein

The present invention can respond identification multiaxis traveling load, the method letter of measurement bridge displacement response by measuring bridge displacement List and precision is higher, therefore identification bridge floor traveling load is responded by bridge displacement there is good feasibility and accuracy of identification energy Guarantee is accessed, dynamic respond need to be only obtained using method proposed by the present invention and be can recognize that bridge floor multiaxis traveling load, therefore Recognition methods proposed by the present invention has good feasibility, can be widely applied to the moving load identification of all kinds bridge. But in actual application, the dynamic respond of measurement is the influence of noise, Landweber iteration with small distracter Method can accurately recognize multiaxis traveling load by limiting stopping criterion for iteration by the dynamic respond comprising noise, in the complicated ring of measurement There is larger advantage when border or more noise jamming.

Brief description of the drawings

Fig. 1 is flow chart of the method for the present invention.

Specific embodiment

As shown in figure 1, the invention discloses a kind of identification of the bridge floor multiaxis traveling load based on Landweber iterative methods Method, comprises the following steps：

1), in bridge bottom surface correspondence position x₁,x₂,…x_mM displacement transducer is pasted at place respectively, measures the shifting of bridge floor multiaxis Dynamic vehicular load f_k(t) at x position t displacement for v (x, t), k=1,2,3 ... be the vehicle number of axle；

2) vehicle-bridge system oscillatory differential equation, is set up：Bridge length is taken for L, bending rigidity is EI, bridge unit length matter It is ρ to measure, it is considered to which viscous damping simultaneously takes damped coefficient for C, ignores detrusion and the rotary inertia of bridge, bridge floor multiaxis locomotive Load fk (t) is moved right with speed c from beam left end supporting, then the oscillatory differential equation of vehicle-bridge system is：

Wherein δ (x-ct) is Dirac function；

The boundary condition of equation (1) is：

V (0, t)=0, v (L, t)=0,

3), equation (1) is solved；

31), based on modal superposition principle, it is assumed that the n-th order Mode Shape function of beam isThen equation (1) solution is represented by：

Matrix form is：

Here n is mode number, q_nT () (n=1,2 ... ∞) are n-th order modal displacements, equation (12) is substituted into equation (1), And x is integrated in [0, L], using boundary condition and Dirac function characteristic, vehicle-bridge system oscillatory differential equation q_n T () is expressed as：

HereIt is q_nThe second dervative of (t),It is q_nThe first derivative of (t), Respectively circular frequency, damping rate and bridge floor mobile vehicle load mod table Up to formula.

As vehicle has a k axletree, and k-th axletree to first distance of axletree be x_k(x₁=0), then equation (14) It is written as：

Then corresponding to the modal displacement at m measuring point can be expressed as by equation (13)：

X on bridge₁,x₂,…x_mThe speed at place is tried to achieve by the once differentiation of displacement：

Further, x on bridge₁,x₂,…x_mThe acceleration at place is tried to achieve by the second differential of displacement：

Similarly, x on beam₁,x₂,…x_mThe moment of flexure at place can utilize relational expressionTry to achieve：

If f₁,f₂,…,f_kIt is each axle correspondence load of known k axles vehicle, ignores the influence of damping, then the solution of equation (1) can It is expressed as：

Wherein

4) bridge, is set up under k axle Vehicle Loads, and multiaxis traveling load system equation is recognized by dynamic respond：

v_(m×1)=S_(m×k)·f_(k×1) (2)

v_(m×1)It is traveling load f_kT () is in x₁,x₂,…x_mThe actual displacement at place (is exactly measured position in step (1) Move), and m >=k；S_(m×k)It is known sytem matrix；f_(k×1)It is required k axle traveling loads；

The discrete form of formula (2) is expressed as

Wherein

5) exact value of multiaxis traveling load, is tried to achieve using Landweber iterative methods；

When bridge displacement response is measured, made an uproar comprising less in the dynamic respond generally measured due to measurement noise interference Sound, actually measured dynamic respond is v^δ, i.e., equation Sf=v right-hand vectors be typically with disturbance data v^δ, and meet

||v-v^δ||≤δ (4)

Wherein δ is noise threshold limit value, and this noise threshold limit value is determined by environmental factor, and span is 0 to 1 Between；

Landweber Iterations are：

Wherein S^*It is the adjoint matrix of vehicle bridge moving load identification sytem matrix S,

Stopping criterion for iteration is：

Wherein C is the influence coefficient of noise threshold limit value, is a constant, and this value is manually set, according to identification essence Degree requires different freely to set；

Taking multiaxis traveling load initial value isIteration can be written as：

Wherein l is unit matrix, if initial value is taken asIteration can be written as：

WhereinThe multiaxis traveling load for as being recognized based on Landweber alternative manners.

Claims (2)

1. a kind of recognition methods of the bridge floor multiaxis traveling load based on Landweber iterative methods, it is characterised in that：Including following Step：

1), in bridge bottom surface correspondence position x₁,x₂,…x_mM displacement transducer is pasted at place respectively, measures bridge floor multiaxis locomotive Load f_kT () displacement of t at x position is v (x, t), k=1,2,3 ..., be the vehicle number of axle；

2) vehicle-bridge system oscillatory differential equation, is set up：Bridge length is taken for L, bending rigidity is EI, and bridge linear mass is ρ, it is considered to which viscous damping simultaneously takes damped coefficient for C, ignores detrusion and the rotary inertia of bridge, bridge floor multiaxis mobile vehicle lotus Carry f_kT () is moved right with speed c from beam left end supporting, then the oscillatory differential equation of vehicle-bridge system is：

$\mathrm{\ρ}\·\frac{{\∂}^{2}v(x,t)}{\∂t^2}+C\·\frac{\∂v(x,t)}{\∂t}+EI\·\frac{{\∂}^{4}v(x,t)}{\∂x^4}=\mathrm{\δ}(x-ct)\·f\left(t\right)---\left(1\right)$

Wherein δ (x-ct) is Dirac function；

The boundary condition of equation (1) is：

V (0, t)=0, v (L, t)=0,V (x, 0)=0,

3), equation (1) is solved；

4) bridge, is set up under k axle Vehicle Loads, and multiaxis traveling load system equation is recognized by dynamic respond：

v_(m×1)=S_(m×k)·f_(k×1) (2)

v_(m×1)It is traveling load f_kT () is in x₁,x₂,…x_mThe actual displacement at place, and m >=k；S_(m×k)It is known sytem matrix； f_(k×1)It is required k axle traveling loads；

The discrete form of formula (2) is expressed as：

Wherein

5) exact value of multiaxis traveling load, is tried to achieve using Landweber iterative methods；

When bridge displacement response is measured, comprising less noise in the dynamic respond generally measured due to measurement noise interference, Actually measured dynamic respond is v⁶, i.e., equation Sf=v right-hand vectors be typically with disturbance data v⁶, and meet

||v-vδ||≤δ (4)

Wherein δ be noise threshold limit value, this noise threshold limit value is determined by environmental factor, span for 0 to 1 it Between；

Landweber Iterations are：

$f_{b+1}^{\mathrm{\δ}}=f_b^{\mathrm{\δ}}+{\mathrm{aS}}^{*}(v^{\mathrm{\δ}}-{\mathrm{Sf}}_b^{\mathrm{\δ}})---\left(5\right)$

Wherein S^*It is the adjoint matrix of vehicle bridge moving load identification sytem matrix S,

Stopping criterion for iteration is：

$\left|\right|S\·f_b^{\mathrm{\δ}}-v^{\mathrm{\δ}}\left|\right|\≤C\mathrm{\δ}---\left(6\right)$

Wherein C is the influence coefficient of noise threshold limit value, is a constant, and this value is manually set, will according to accuracy of identification Ask different freely to set；

Taking multiaxis traveling load initial value isIteration can be written as：

$\begin{array}{c}{f}_b^{\mathrm{\δ}}=f_{b=1}^{\mathrm{\δ}}+{\mathrm{aS}}^{*}(v^{\mathrm{\δ}}-{\mathrm{Sf}}_{b=1}^{\mathrm{\δ}})=(l-{\mathrm{aS}}^{*}S)f_{b=1}^{\mathrm{\δ}}+{\mathrm{aS}}^{*}{v}^{\mathrm{\δ}}\\ =a{\Σ}_{n=0}^{b-1}{(l-{\mathrm{aS}}^{*}S)}^n{S}^{*}{v}^{\mathrm{\δ}}+{(l-{\mathrm{aS}}^{*}S)}^b{f}_0^{\mathrm{\δ}}\end{array}---\left(7\right)$

Wherein l is unit matrix, if initial value is taken asIteration can be written as：

$f_b^{\mathrm{\δ}}=a{\Σ}_{n=0}^b{(l-{\mathrm{aS}}^{*}S)}^n{S}^{*}{v}^{\mathrm{\δ}}---\left(8\right)$

WhereinThe multiaxis traveling load for as being recognized based on Landweber alternative manners.

2. the recognition methods of the bridge floor multiaxis traveling load based on Landweber iterative methods as claimed in claim 1, its feature It is：Described step 3) in equation (1) is solved comprise the following steps that it is described：

Based on modal superposition principle, it is assumed that the n-th order Mode Shape function of bridge isThe then solution of equation (1) It is expressed as：

$v(x,t)=\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}{\mathrm{\φ}}_n\left(x\right)\·q_n\left(t\right)---\left(12\right)$

Matrix form is：

$v=\left\{\begin{array}{cccc}sin\frac{\mathrm{\π}x}{L}& sin\frac{2\mathrm{\π}x}{L}& ...& sin\frac{n\mathrm{\π}x}{L}\end{array}\right\}{\left\{\begin{array}{cccc}{q}_1& q_2& ...& q_n\end{array}\right\}}^T---\left(13\right)$

Here n is mode number, q_nT () (n=1,2 ... ∞) are n-th order modal displacements, by equation (12) substitution equation (1), and X is integrated in [0, L], using boundary condition and Dirac function characteristic, vehicle-bridge system oscillatory differential equation q_n(t) table It is shown as：

${\stackrel{\·\·}{q}}_n\left(t\right)+2{\mathrm{\ξ}}_n{\mathrm{\ω}}_n{\stackrel{\·}{q}}_n\left(t\right)+{\mathrm{\ω}}_n^2{q}_n\left(t\right)=\frac{2}{\mathrm{\ρ}L}{p}_n\left(t\right),(n=1,2,...,\mathrm{\∞})---\left(14\right)$

HereIt is q_nThe second dervative of (t),It is q_nThe first derivative of (t), Respectively circular frequency, damping rate and bridge floor mobile vehicle load mod table Up to formula；

As vehicle has a k axletree, and k-th axletree to first distance of axletree be x_k(x₁=0), then equation (14) is written as：

Then corresponding to the modal displacement at m measuring point can be expressed as by equation (13)：

X on bridge₁,x₂,…x_mThe speed at place is tried to achieve by the once differentiation of displacement：

Further, x on bridge₁,x₂,…x_mThe acceleration at place is tried to achieve by the second differential of displacement：

Similarly, x on beam₁,x₂,…x_mThe moment of flexure at place can utilize relational expressionTry to achieve：

If f₁,f₂,…,f_kIt is each axle correspondence load of known k axles vehicle, ignores the influence of damping, then the solution of equation (1) can be represented For：

$v(x,t)=\frac{L^3}{48EI}\underset{i=1}{\overset{k}{\Σ}}{f}_i\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}\frac{1}{n^2(n^2-{\mathrm{\α}}^2)}sin\frac{n\mathrm{\π}x}{L}\left(sin\frac{n\mathrm{\π}(ct-{\stackrel{\‾}{x}}_i)}{L}-\frac{\mathrm{\α}}{n}{\mathrm{sin\ω}}_n\left(t-\frac{{\stackrel{\‾}{x}}_i}{c}\right)\right)---\left(10\right)$

Wherein