CN107607679A - The accurate identification and localization method that a kind of truss member axial rigidity is degenerated - Google Patents
The accurate identification and localization method that a kind of truss member axial rigidity is degenerated Download PDFInfo
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- CN107607679A CN107607679A CN201710844950.6A CN201710844950A CN107607679A CN 107607679 A CN107607679 A CN 107607679A CN 201710844950 A CN201710844950 A CN 201710844950A CN 107607679 A CN107607679 A CN 107607679A
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Abstract
The accurate identification degenerated the invention discloses a kind of truss member axial rigidity and localization method, comprise the following steps：The temperature and axle power data of long term monitoring and collection each rod member of truss structure；The linear gradient value between each rod member axle power and temperature is calculated using day as chronomere；Calculate the difference value of each rod member linear gradient value；Calculate the local derviation numerical value that the linear gradient value of each rod member is influenceed by each rod member axial direction flexibility；The total differential equation established between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient；Solve the time series that each rod member axial direction flexibility increment coefficient changes with number of days；Enter row degradation identification and positioning to the axial rigidity of truss member using the variation tendency of time series.The present invention utilizes the total differential equation between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient, and the unique solution of each rod member axial direction flexibility increment coefficient can be calculated, so as to realize the accurate identification and positioning degenerated to truss member axial rigidity.
Description
Technical field
The invention belongs to truss structure health monitoring and security performance assessing field, it particularly relates to a kind of truss rod
The accurate identification and localization method that part axial rigidity is degenerated.
Background technology
Rod member in truss structure is two power bars, based on axial push-pull.If the axial rigidity of two power bars is degenerated, meeting
Have a strong impact on the normal use and security function of truss structure.Therefore, two power bars of axial Stiffness Deterioration in truss structure are entered
Row identification in time and positioning, it is significant.Identification that current two power bar axial rigidity is degenerated and localization method are manually to examine
Based on survey, i.e. the technology such as ultrasonic examination, Magnetic Flux Leakage Inspecting, ray detection.Such detection method can not be to the military service of two power rod members
State is assessed in real time, time-lag effect be present on two power bar axial rigidities are degenerated and identify and position.As structural health is supervised
The development of survey technology, can on truss structure install sensor, so as to in truss structure two power bars service state carry out
Monitoring in real time and assessment.However, the Monitoring Data gathered can not reflect truss structure operation state in some cases
Full detail, and load response Monitoring Data are vulnerable to random environment influence so that a large amount of Monitoring Datas can not obtain effectively
Utilize.Therefore, this patent is on the basis of truss structure Monitoring Data is made full use of, by calculate each rod member axle power and temperature it
Between linear slope value difference value, establish complete micro- between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient
Divide equation, the unique solution of each rod member axial direction flexibility increment coefficient can be calculated, truss member axial rigidity is moved back so as to realize
The accurate identification and positioning changed.
The content of the invention
Technical problem：For solve truss structure rod member axial rigidity degenerate be difficult to and orientation problem, the present invention carry
Go out accurate identification and the localization method that a kind of truss member axial rigidity is degenerated.
Technical scheme：The accurate identification and localization method that a kind of truss member axial rigidity of the present invention is degenerated, including such as
Lower step：
Step (1)：The temperature and axle power data of long term monitoring and collection each rod member of truss structure：
Rod member in truss structure is two power bars, based on axial push-pull.Temperature is installed among each rod member of truss structure
Sensor and axial force sensor, long term monitoring and data acquisition are carried out to each rod member temperature and axle power, wherein i-th of rod member is the
The temperature data of collection in j days is designated as Ti,j, the axle power data that i-th of rod member gathers in jth day are designated as Si,j, i=1,2 ..., I, j
=1,2 ..., total number that J, I are all rod members in truss, J is positive integer more than or equal to 2；
Step (2)：The linear gradient value between each rod member axle power and temperature is calculated using day as chronomere：
There are some researches show the correlation properties between axial strain and temperature are linear relationship, and each bar is calculated using following formula
Linear gradient value between part axle power and temperature：
In formula, ki,jRepresent linear gradient value of i-th of rod member between jth day axle power and temperature, Ni,jRepresent i-th of bar
The temperature data or the total number of axle power data that part gathers in jth day, Ti,j,pRepresent Ti,jIn p-th value, Si,j,pRepresent Si,j
In p-th value, p=1,2 ..., Ni,j；
Step (3)：Calculate the difference value of each rod member linear gradient value：
M-th of difference value c of i-th of rod member linear gradient value is calculated using following formulai,m：
ci,m=ki,m+1-ki,1, wherein m=1,2 ..., J-1
In formula, ki,m+1、ki,1Represent i-th of rod member in the m+1 days, the 1st day linear gradient between axle power and temperature respectively
Value；
Step (4)：Calculate the local derviation numerical value that the linear gradient value of each rod member is influenceed by each rod member axial direction flexibility：
The material parameter and geometric parameter of each rod member are obtained using truss structural design drawing, by LSDYNA, ANSYS etc.
Finite element analysis software establishes truss structure FEM model, applies temperature load F to all rod members, is obtained by finite element analysis
To the axle power R of i-th of rod memberi, F and RiOne-to-one relationship be present；
F and RiBetween correlation properties be linear relationship, utilize following formula calculate F and RiBetween linear gradient value：
In formula, ρiRepresent F and RiBetween linear gradient value, FqRepresent q-th of value in F, Ri,qRepresent RiIn q-th
Value, M represent F or RiData total number；
The axial flexibility of l-th of rod member in truss structure FEM model is risen into original g times, l=1,2 ..., I,
Temperature load F is applied to all rod members afterwards, the axle power of i-th of rod member is obtained by finite element analysis
F withBetween correlation properties be linear relationship, using following formula calculate F withBetween linear gradient value：
In formula,Represent F withBetween linear gradient value,RepresentIn q-th value；
Calculate the local derviation numerical value d that the linear gradient value of i-th of rod member is influenceed by l-th of rod member axial direction flexibilityi,l：
In formula, LlRepresent the length of l-th of rod member, ElRepresent the modulus of elasticity of l-th of rod member, AlRepresent l-th rod member
Cross-sectional area, L is obtained by truss structure layout design parameterl、ElAnd AlSpecific value；
Step (5)：The total differential equation established between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
The total differential equation established using following formula between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
In formula, δl,mM-th of axial flexibility increment coefficient of l-th of rod member is represented, wherein axial flexibility increment is l-th
For rod member in the axial flexibility of the m+1 days relative to the increment in the axial flexibility of the m days, axial flexibility increment coefficient is axially soft
Spend increment and Ll/(ElAl) between ratio, δl,mIt is value to be solved；
Step (6)：Solve the time series that each rod member axial direction flexibility increment coefficient changes with number of days：
By all c of step (3)i,mAll d of value and step (4)i,lI × (J- is obtained in the formula that value substitutes into step (5)
1) individual equation, variable δ to be solvedl,mI × (J-1) is individual altogether, (i=1,2 ..., I, m=1,2 ..., J-1), therefore simultaneous institute
There is equation to obtain δl,mUnique solution, δl,1,δl,2,...,δl,J-1L-th of rod member axial direction flexibility increment coefficient is formed with number of days to change
Time series；
Step (7)：Enter row degradation identification and positioning to the axial rigidity of truss member using the variation tendency of time series：
If δl,1,δl,2,...,δl,J-1Moderate tone is showed, then the axial rigidity of l-th of truss member is not degenerated
Trend；
If δl,1,δl,2,...,δl,J-1The trend of being gradually increasing is showed, then the axial rigidity of l-th of truss member has occurred
Degradation trend.
Preferably, in the step (1) sample frequency of temperature data and axle power data between [0.0017Hz, 1Hz].
Preferably, in the step (1) the sampling time section of temperature data and axle power data between morning 0 is up to 4 when,
For rod member not by solar radiation and at night after heat transfer, rod member internal temperature tends to be uniform within this period,
So as to which the temperature difference influences to ignore, influence of the complicated temperature difference distribution to rod member strain effectively prevent.
Preferably, temperature load F versus time curves are F=Kt in the step (4), and t unit is the second, wherein
The value of slope K is between [1,10], and load time length is between [6s, 10s].
Preferably, in the step (4) g value between [1.0526,1.1765].
Beneficial effect：Compared with prior art, the present invention has advantages below：
Temperature difference distribution inside truss structure rod member is sufficiently complex, is difficult to ignore shadow of the rod member temperature difference to axle power in analysis
Ring, and the sampling time section of temperature data and axle power data is between morning 0 is up to 4 when in step of the present invention (1), at this
Between for rod member not by solar radiation and at night after heat transfer, rod member internal temperature tends to be uniform in section, so as to the temperature difference
Influence can be ignored, and effectively prevent influence of the complicated temperature difference distribution to rod member axle power.In addition, the Monitoring Data of truss structure is easy
Influenceed by random environment so that the axial rigidity of truss structure rod member is difficult to accurate identification and positioning when degenerating, and this is specially
Profit is on the basis of truss structure Monitoring Data is made full use of, by calculating linear gradient value between each rod member axle power and temperature
Difference value, the total differential equation between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient is established, can be calculated
To the unique solution of each rod member axial direction flexibility increment coefficient, so as to realize the accurate identification degenerated to truss member axial rigidity and determine
Position.Therefore, the accurate identification and localization method that a kind of innovative truss member axial rigidity proposed of the present invention is degenerated, will be
Truss structure health monitoring and security performance assessing field are widely popularized and applied.
Brief description of the drawings
Fig. 1 is the time series changed with number of days of each rod member axial direction flexibility increment coefficient in the embodiment of the present invention；
Fig. 2 is the design drawing of certain Z-type truss structure in the embodiment of the present invention；
Fig. 3 is temperature data T of the 1st rod member of the embodiment of the present invention at the 1st day1,1；
Fig. 4 is axle power data S of the 1st rod member of the embodiment of the present invention at the 1st day1,1；
Fig. 5 is truss structure rod member FEM model in the embodiment of the present invention.
Embodiment
Below with reference to accompanying drawings, technical scheme is described in detail.
Step (1)：The temperature and axle power data of long term monitoring and collection each rod member of truss structure：
Rod member in truss structure is two power bars, based on axial push-pull.Temperature is installed among each rod member of truss structure
Sensor and axial force sensor, long term monitoring and data acquisition are carried out to each rod member temperature and axle power, wherein i-th of rod member is the
The temperature data of collection in j days is designated as Ti,j, the axle power data that i-th of rod member gathers in jth day are designated as Si,j, i=1,2 ..., I, j
=1,2 ..., total number that J, I are all rod members in truss, J is positive integer more than or equal to 2；
Step (2)：The linear gradient value between each rod member axle power and temperature is calculated using day as chronomere：
There are some researches show the correlation properties between axial strain and temperature are linear relationship, and each bar is calculated using following formula
Linear gradient value between part axle power and temperature：
In formula, ki,jRepresent linear gradient value of i-th of rod member between jth day axle power and temperature, Ni,jRepresent i-th of bar
The temperature data or the total number of axle power data that part gathers in jth day, Ti,j,pRepresent Ti,jIn p-th value, Si,j,pRepresent Si,j
In p-th value, p=1,2 ..., Ni,j；
Step (3)：Calculate the difference value of each rod member linear gradient value：
M-th of difference value c of i-th of rod member linear gradient value is calculated using following formulai,m：
ci,m=ki,m+1-ki,1, wherein m=1,2 ..., J-1
In formula, ki,m+1、ki,1Represent i-th of rod member in the m+1 days, the 1st day linear gradient between axle power and temperature respectively
Value；
Step (4)：Calculate the local derviation numerical value that the linear gradient value of each rod member is influenceed by each rod member axial direction flexibility：
The material parameter and geometric parameter of each rod member are obtained using truss structural design drawing, by LSDYNA, ANSYS etc.
Finite element analysis software establishes truss structure FEM model, applies temperature load F to all rod members, is obtained by finite element analysis
To the axle power R of i-th of rod memberi, F and RiOne-to-one relationship be present；
F and RiBetween correlation properties be linear relationship, utilize following formula calculate F and RiBetween linear gradient value：
In formula, ρiRepresent F and RiBetween linear gradient value, FqRepresent q-th of value in F, Ri,qRepresent RiIn q-th
Value, M represent F or RiData total number；
The axial flexibility of l-th of rod member in truss structure FEM model is risen into original g times, l=1,2 ..., I,
Temperature load F is applied to all rod members afterwards, the axle power of i-th of rod member is obtained by finite element analysis
F withBetween correlation properties be linear relationship, using following formula calculate F withBetween linear gradient value：
In formula,Represent F withBetween linear gradient value,RepresentIn q-th value；
Calculate the local derviation numerical value d that the linear gradient value of i-th of rod member is influenceed by l-th of rod member axial direction flexibilityi,l：
In formula, LlRepresent the length of l-th of rod member, ElRepresent the modulus of elasticity of l-th of rod member, AlRepresent l-th rod member
Cross-sectional area, L is obtained by truss structure layout design parameterl、ElAnd AlSpecific value；
Step (5)：The total differential equation established between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
The total differential equation established using following formula between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
In formula, δl,mM-th of axial flexibility increment coefficient of l-th of rod member is represented, wherein axial flexibility increment is l-th
For rod member in the axial flexibility of the m+1 days relative to the increment in the axial flexibility of the m days, axial flexibility increment coefficient is axially soft
Spend increment and Ll/(ElAl) between ratio, δl,mIt is value to be solved；
Step (6)：Solve the time series that each rod member axial direction flexibility increment coefficient changes with number of days：
By all c of step (3)i,mAll d of value and step (4)i,lI × (J- is obtained in the formula that value substitutes into step (5)
1) individual equation, variable δ to be solvedl,mI × (J-1) is individual altogether, (i=1,2 ..., I, m=1,2 ..., J-1), therefore simultaneous institute
There is equation to obtain δl,mUnique solution, δl,1,δl,2,...,δl,J-1L-th of rod member axial direction flexibility increment coefficient is formed with number of days to change
Time series；
Step (7)：Enter row degradation identification and positioning to the axial rigidity of truss member using the variation tendency of time series：
If δl,1,δl,2,...,δl,J-1Moderate tone is showed, then the axial rigidity of l-th of truss member is not degenerated
Trend；
If δl,1,δl,2,...,δl,J-1The trend of being gradually increasing is showed, then the axial rigidity of l-th of truss member has occurred
Degradation trend.
The sample frequency of temperature data and axle power data is between [0.0017Hz, 1Hz] in the step (1).The sampling
Frequency is the empirical value obtained by multiple tentative calculation.
The sampling time section of temperature data and axle power data is between morning 0 is up to 4 when in the step (1), at this
For rod member not by solar radiation and at night after heat transfer, rod member internal temperature tends to be uniform in period, so as to temperature
Difference influences to ignore, and effectively prevent influence of the complicated temperature difference distribution to rod member strain.
Temperature load F versus time curves are F=Kt in the step (4), t unit is the second, wherein slope K
Value is between [1,10], and load time length is between [6s, 10s].
G value is between [1.0526,1.1765] in the step (4).The span is obtained by multiple tentative calculation
The empirical value arrived.
Embodiment：
Below by taking the identification and positioning that certain Z-type truss structure rod member axial rigidity is degenerated as an example, illustrate that the present invention's is specific
Implementation process.
(1) design drawing of certain Z-type truss structure is as shown in Fig. 2 upper boom and the angle β of X-axis are 1.856 °, slash and X
The angle theta of axle is 44.057 °, and the angle γ of lower beam and X-axis is 2.314 degree, the cross-sectional area A of upper boom, brace and lower beam1、A2
And A3Respectively 0.2370m2、0.0807m2And 0.1127m2, the length L of upper boom, brace and lower beam1、L2And L3Respectively 12m,
16.778m and 12m, the elastic modulus E of upper boom, brace and lower beam1、E2And E3It is 205.9GPa, upper boom, brace and lower beam
Thermalexpansioncoefficientα is 0.000013/ DEG C.
(2) because truss member is difficult to obvious axial rigidity degeneration occurs in a short time, therefore the present embodiment uses mould
Plan method obtains temperature and axle power data to substitute Monitoring Data, assumes the upper boom axial rigidity hair in truss member in simulations
Raw to degenerate, brace and lower beam axial rigidity are not degenerated.I-th of rod member is designated as T in the temperature data that jth day is simulatedi,j, i-th
The axle power data that individual rod member is simulated in jth day are designated as Si,j, digital simulation number of days totally 5 days, i=1,2,3, j=1,2,3,4,5, its
In temperature data T of the 1st rod member at the 1st day1,1As shown in figure 3, axle power data S of the 1st rod member at the 1st day1,1Such as Fig. 4 institutes
Show, further choose the temperature and axle power data between morning 0 is up to 4 when daily；
(3) formula of step (2) is utilized, the linear gradient between each rod member axle power and temperature is calculated using day as chronomere
Value, upper boom k1,1、k1,2、k1,3、k1,4And k1,5Result of calculation be -5.076 × 105、-4.822×105、-4.568×105、-
4.416×105With -4.314 × 105, brace k2,1、k2,2、k2,3、k2,4And k2,5Result of calculation be -1.728 × 105、-1.694
×105、-1.727×105、-1.792×105With -1.699 × 105, lower beam k3,1、k3,2、k3,3、k3,4And k3,5Result of calculation
For -2.417 × 105、-2.440×105、-2.412×105、-2.380×105With -2.416 × 105；
(4) formula of step (3) is utilized, calculates the difference value of each rod member linear gradient value, upper boom c1,1、c1,2、c1,3With
c1,4Result of calculation be 25400,50800,66000 and 76200, brace c2,1、c2,2、c2,3And c2,4Result of calculation for 3400,
100th, -6400 and 2900, lower beam c3,1、c3,2、c3,3And c3,4Result of calculation be -2300,500,3700 and 100；
(5) truss structure rod member FEM model, is established based on LSDYNA finite element analysis softwares as shown in figure 5, utilizing
The formula of step (4), calculate the local derviation numerical value d that the linear gradient value of i-th of rod member is influenceed by l-th of rod member axial direction flexibilityi,l,
Wherein g=1.0526, because upper boom, brace and lower beam both ends are be hinged, therefore the linear gradient value of each rod member is only by certainly
The influence of body axial direction flexibility, therefore d1,2=0, d1,3=0, d2,1=0, d2,3=0, d3,1=0 and d3,2=0, furthermore with step
(4) d is calculated in formula1,1=4.8260E1A1/L1×105, d2,2=1.6340E2A2/L2×105And d3,3=
1.0800E3A3/L3×105；
(6) total differential established using step (5) between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient
Equation is as follows：
(7) time series changed with number of days of each rod member axial direction flexibility increment coefficient is solved using step (6),
δ1,1、δ1,2、δ1,3And δ1,4Value be respectively 0.0526,0.1053,0.1368 and 0.1579, δ2,1、δ2,2、δ2,3And δ2,4Value point
Wei 0.0208,0.0006, -0.0392 and 0.0177, δ3,1、δ3,2、δ3,3And δ3,4Value be respectively -0.0213,0.0046,
0.0343 and 0.0009, as a result as shown in Figure 1；
As shown in Figure 1, the time series of upper boom axial direction flexibility increment coefficient shows ascendant trend, illustrates the axial direction of upper boom
There is degradation trend in rigidity；The time series of brace and lower beam axial direction flexibility increment coefficient shows moderate tone, illustrates brace
Do not occur degradation trend with the axial rigidity of lower beam, be consistent with hypothesis, demonstrate the validity of this patent method.
Above example be only the present invention program is further elaborated with, read the embodiment of the present invention it
Afterwards, those of ordinary skill in the art to the present invention various equivalents modification and replacement belong to the present patent application right will
Seek the scope of limited protection.
Claims (5)
1. accurate identification and localization method that a kind of truss member axial rigidity is degenerated, it is characterised in that this method includes as follows
Step：
Step (1)：The temperature and axle power data of long term monitoring and collection each rod member of truss structure：
Mounting temperature sensor and force snesor among each rod member of truss structure, each rod member temperature and axial force are carried out long-term
Monitoring and data acquisition, wherein i-th of rod member is designated as T in the temperature data that jth day gathersi,j, i-th of rod member is in the collection of jth day
Axial force data be designated as Si,j, i=1,2 ..., total number that I, j=1,2 ..., J, I are all rod members in truss, J is big
In the positive integer equal to 2；
Step (2)：The linear gradient value between each rod member axial force and temperature is calculated using day as chronomere：
The linear gradient value between each rod member axial force and temperature is calculated using following formula：
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In formula, ki,jRepresent linear gradient value of i-th of rod member between jth day axial force and temperature, Ni,jRepresent i-th of rod member
The total number of the temperature data of collection or axle power data in jth day, Ti,j,pRepresent Ti,jIn p-th value, Si,j,pRepresent Si,jIn
P-th value, p=1,2 ..., Ni,j；
Step (3)：Calculate the difference value of each rod member linear gradient value：
M-th of difference value c of i-th of rod member linear gradient value is calculated using following formulai,m：
ci,m=ki,m+1-ki,1, wherein m=1,2 ..., J-1
In formula, ki,m+1、ki,1Represent i-th of rod member in the m+1 days, the 1st day linear gradient value between axle power and temperature respectively；
Step (4)：Calculate the local derviation numerical value that the linear gradient value of each rod member is influenceed by each rod member axial direction flexibility：
According to the material parameter and geometric parameter of each rod member, truss structure FEM model is established by finite element analysis software,
Temperature load F is applied to all rod members, the axle power R of i-th of rod member is obtained by finite element analysisi；
F and R is calculated using following formulaiBetween linear gradient value：
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<mo>&Sigma;</mo>
<mrow>
<mi>q</mi>
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</mrow>
<mi>M</mi>
</munderover>
<msub>
<mi>F</mi>
<mi>q</mi>
</msub>
<msub>
<mi>R</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>q</mi>
</mrow>
</msub>
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<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>q</mi>
</mrow>
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</mrow>
<mrow>
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<mrow>
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<mo>&Sigma;</mo>
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<msup>
<mrow>
<mo>(</mo>
<msub>
<mi>F</mi>
<mi>q</mi>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<mo>-</mo>
<msup>
<mrow>
<mo>(</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>q</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
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<mi>F</mi>
<mi>q</mi>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
</mrow>
</mfrac>
</mrow>
In formula, ρiRepresent F and RiBetween linear gradient value, FqRepresent q-th of value in F, Ri,qRepresent RiIn q-th value, M
Represent F or RiData total number；
The axial flexibility of l-th of rod member in truss structure FEM model is risen into original g times, l=1,2 ..., I are rear right
All rod members apply temperature load F, and the axle power of i-th of rod member is obtained by finite element analysis
Using following formula calculate F withBetween linear gradient value：
<mrow>
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<mi>&rho;</mi>
<mo>~</mo>
</mover>
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<mi>M</mi>
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</munderover>
<msub>
<mi>F</mi>
<mi>q</mi>
</msub>
<msub>
<mover>
<mi>R</mi>
<mo>~</mo>
</mover>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>q</mi>
</mrow>
</msub>
<mo>)</mo>
</mrow>
<mo>-</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>q</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>M</mi>
</munderover>
<msub>
<mi>F</mi>
<mi>q</mi>
</msub>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>q</mi>
<mo>=</mo>
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<mo>~</mo>
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<msub>
<mi>F</mi>
<mi>q</mi>
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</mrow>
<mn>2</mn>
</msup>
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</mrow>
<mo>-</mo>
<msup>
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</mfrac>
</mrow>
In formula,Represent F withBetween linear gradient value,RepresentIn q-th value；
Calculate the local derviation numerical value d that the linear gradient value of i-th of rod member is influenceed by l-th of rod member axial direction flexibilityi,l：
<mrow>
<msub>
<mi>d</mi>
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<mrow>
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<mi>&rho;</mi>
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</mover>
<mi>i</mi>
</msub>
<mo>-</mo>
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<mi>&rho;</mi>
<mi>i</mi>
</msub>
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<msub>
<mi>E</mi>
<mi>l</mi>
</msub>
<msub>
<mi>A</mi>
<mi>l</mi>
</msub>
</mrow>
<mrow>
<mo>(</mo>
<mi>g</mi>
<mo>-</mo>
<mn>1</mn>
<mo>)</mo>
<msub>
<mi>L</mi>
<mi>l</mi>
</msub>
</mrow>
</mfrac>
</mrow>
In formula, LlRepresent the length of l-th of rod member, ElRepresent the modulus of elasticity of l-th of rod member, AlRepresent the transversal of l-th rod member
Face area；
Step (5)：The total differential equation established between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
The total differential equation established using following formula between each rod member difference value and local derviation numerical value, axial flexibility increment coefficient：
<mrow>
<msub>
<mi>c</mi>
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<mfrac>
<mrow>
<msub>
<mi>d</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>l</mi>
</mrow>
</msub>
<msub>
<mi>&delta;</mi>
<mrow>
<mi>l</mi>
<mo>,</mo>
<mi>m</mi>
</mrow>
</msub>
<msub>
<mi>L</mi>
<mi>l</mi>
</msub>
</mrow>
<mrow>
<msub>
<mi>E</mi>
<mi>l</mi>
</msub>
<msub>
<mi>A</mi>
<mi>l</mi>
</msub>
</mrow>
</mfrac>
</mrow>
In formula, δl,mM-th of axial flexibility increment coefficient of l-th of rod member is represented, is variable to be solved；
Step (6)：Solve the time series that each rod member axial direction flexibility increment coefficient changes with number of days：
By all c of step (3)i,mAll d of value and step (4)i,lIt is individual that I × (J-1) is obtained in the formula of value substitution step (5)
Equation, variable δ to be solvedl,mI × (J-1) is individual altogether, therefore all equations of simultaneous obtain δl,mUnique solution, δl,1,δl,2,...,
δl,J-1Form the time series that l-th of rod member axial direction flexibility increment coefficient changes with number of days；
Step (7)：Enter row degradation identification and positioning to the axial rigidity of truss member using the variation tendency of time series：
If δl,1,δl,2,...,δl,J-1Moderate tone is showed, then the axial rigidity of l-th of truss member does not occur degradation trend；
If δl,1,δl,2,...,δl,J-1The trend of being gradually increasing is showed, then the axial rigidity of l-th of truss member has been degenerated
Trend.
2. accurate identification and localization method, its feature that a kind of truss member axial rigidity as claimed in claim 1 is degenerated exist
In the sample frequency of temperature data and axle power data is between [0.0017Hz, 1Hz] in the step (1).
3. accurate identification and localization method, its feature that a kind of truss member axial rigidity as claimed in claim 1 is degenerated exist
In the sampling time section of temperature data and axle power data is between morning 0 is up to 4 when in the step (1).
4. accurate identification and localization method, its feature that a kind of truss member axial rigidity as claimed in claim 1 is degenerated exist
In temperature load F versus time curves are F=Kt in the step (4), and t unit is the value of second, wherein slope K
Between [1,10], load time length is between [6s, 10s].
5. accurate identification and localization method, its feature that a kind of truss member axial rigidity as claimed in claim 1 is degenerated exist
In g value is between [1.0526,1.1765] in the step (4).
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604656A (en) * | 2013-12-09 | 2014-02-26 | 东南大学 | Damaged cable/concentrated load/linear displacement progressive recognition method on basis of cable power monitoring |
| CN105698975A (en) * | 2016-01-26 | 2016-06-22 | 华北水利水电大学 | Suspension rod tension force measurement method in variable temperature environment based on frequency method |
| CN105930571A (en) * | 2016-04-15 | 2016-09-07 | 东南大学 | Unit temperature response monitoring value based correction method for finite element model of large-span steel bridge |
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2017
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604656A (en) * | 2013-12-09 | 2014-02-26 | 东南大学 | Damaged cable/concentrated load/linear displacement progressive recognition method on basis of cable power monitoring |
| CN105698975A (en) * | 2016-01-26 | 2016-06-22 | 华北水利水电大学 | Suspension rod tension force measurement method in variable temperature environment based on frequency method |
| CN105930571A (en) * | 2016-04-15 | 2016-09-07 | 东南大学 | Unit temperature response monitoring value based correction method for finite element model of large-span steel bridge |
Non-Patent Citations (1)
| Title |
|---|
| GAO-XINWANG: "Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains", 《MATHEMATICAL PROBLEMS IN ENGINEERING》 * |
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