CN109374452A - A kind of prestressed concrete beam fatigue damage state characterization method and test device - Google Patents
A kind of prestressed concrete beam fatigue damage state characterization method and test device Download PDFInfo
- Publication number
- CN109374452A CN109374452A CN201811440739.9A CN201811440739A CN109374452A CN 109374452 A CN109374452 A CN 109374452A CN 201811440739 A CN201811440739 A CN 201811440739A CN 109374452 A CN109374452 A CN 109374452A
- Authority
- CN
- China
- Prior art keywords
- prestressed concrete
- concrete beam
- measured
- fatigue
- test
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011513 prestressed concrete Substances 0.000 title claims abstract description 117
- 238000012360 testing method Methods 0.000 title claims abstract description 78
- 230000006378 damage Effects 0.000 title claims abstract description 67
- 238000012512 characterization method Methods 0.000 title claims abstract description 15
- 238000004458 analytical method Methods 0.000 claims abstract description 32
- 238000009661 fatigue test Methods 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims description 29
- 230000005284 excitation Effects 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 9
- 230000001133 acceleration Effects 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 125000004122 cyclic group Chemical group 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 238000011068 loading method Methods 0.000 abstract description 14
- 230000003068 static effect Effects 0.000 abstract description 13
- 238000005259 measurement Methods 0.000 abstract description 11
- 238000011160 research Methods 0.000 abstract description 7
- 208000027418 Wounds and injury Diseases 0.000 abstract description 3
- 238000013459 approach Methods 0.000 abstract description 3
- 208000014674 injury Diseases 0.000 abstract description 2
- 206010016256 fatigue Diseases 0.000 description 78
- 238000011161 development Methods 0.000 description 15
- 230000018109 developmental process Effects 0.000 description 15
- 239000004567 concrete Substances 0.000 description 11
- 230000035882 stress Effects 0.000 description 6
- 230000035508 accumulation Effects 0.000 description 4
- 238000009825 accumulation Methods 0.000 description 4
- 230000001186 cumulative effect Effects 0.000 description 4
- 230000007850 degeneration Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000003902 lesion Effects 0.000 description 3
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 3
- 230000003014 reinforcing effect Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 240000002853 Nelumbo nucifera Species 0.000 description 2
- 235000006508 Nelumbo nucifera Nutrition 0.000 description 2
- 235000006510 Nelumbo pentapetala Nutrition 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000009429 distress Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 241000555268 Dendroides Species 0.000 description 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000010219 correlation analysis Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000003412 degenerative effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 210000003205 muscle Anatomy 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000000611 regression analysis Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000017260 vegetative to reproductive phase transition of meristem Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0005—Repeated or cyclic
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0073—Fatigue
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Acoustics & Sound (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a kind of prestressed concrete beam fatigue damage state characterization method, include the following steps: the initial driving force parametric measurement and static test for the first time of prestressed concrete beam;Prestressed concrete beam static test and dynamic test in fatigue loading course;The analysis of prestressed concrete beam Vibrating modal parameters;The assessment of prestressed concrete beam Fatigue Damage States.The invention also discloses a kind of measuring devices for realizing above scheme.The present invention is by carrying out dynamic test during prestressed concrete beam fatigue test of structure, position and its degree of injury based on Vibrating modal parameters analysis prestressed concrete beam fatigue damage, prestressed concrete beam Fatigue Damage States are characterized based on modal parameter to realize, provide a kind of new approaches for the research of prestressed concrete beam fatigue behaviour and test.
Description
Technical field
The invention belongs to In Engineering Structural Damage the field of test technology more particularly to a kind of prestressed concrete beam fatigues
Faulted condition characterizing method and test device.
Background technique
Prestressed concrete beam is widely used in the buildings large span engineering structure such as road and rail bridge.This kind is answered in advance
Power beams of concrete is within the designed service life by the long-term repeated action for bearing vehicle fatigue load.Fatigue Load will cause
The occurrence and development of structure fatigue damage, as the accumulation of damage will affect the normal use performance of structure or even jeopardize structure
Safety.Therefore, the fatigue behaviour of prestressed concrete beam causes the universal of many scholars at home and abroad and engineers and technicians
Concern.
In traditional prestressed concrete beam experiment on fatigue properties, it is tired to generally use pulsating fatigue tester application constant amplitude
Labor load, the typical time in fatigue loading course shut down development static(al) and unloading are added to test, thus according to prestressed concrete
The static characteristics such as amount of deflection, the stress and strain of beam speculate the development process of prestressed concrete beam fatigue damage.The incision of these methods
Point is more single, cannot reflect the loading characteristic of tired dynamic load function flowering structure, it is difficult to it is tired to disclose prestressed concrete beam
The development process and fatigue rupture mechanism for wound of straining, need that research and development are new to be mixed based on kinetic test means research prestressing force
The new method of solidifying soil beam fatigue problem.
Summary of the invention
First technical problem to be solved by this invention is to provide a kind of prestressed concrete based on modal parameter
Beam fatigue damage state characterization method.
Second technical problem to be solved by this invention is to provide a kind of above-mentioned fatigue damage state characterization side of realization
The test device of method.
In order to solve the first technical problem mentioned above, the present invention adopts the following technical scheme:
A kind of prestressed concrete beam fatigue damage state characterization method, which comprises the steps of:
Step 1: prestressed concrete beam to be measured being placed on two freely-supported supports, intact to be measured pre- is answered to initial first
Power beams of concrete carries out dynamic test, obtains the initial modal frequency w of prestressed concrete beam to be measured0;
Step 2: opening fatigue tester and fatigue test, the certain number of fatigue and cyclic are carried out to prestressed concrete beam to be measured
It shuts down afterwards and carries out dynamic test, obtain the modal frequency w of prestressed concrete beam to be measured when fatigue life cycle is n ten thousand timesn;
Step 3: the damage variable of prestressed concrete beam to be measured under different cycle-indexes is obtained according to the following formula:
Wherein: w0For initial modal frequency, wNModal frequency when for prestressed concrete beam fatigue rupture to be measured, N be to
Survey cycle-index when prestressed concrete beam fatigue rupture;
Step 4: the damage variable of prestressed concrete beam to be measured is intended under the different cycle-indexes obtained to step 3
It closes, obtains the tired Complete Damage Process variable Evolution based on modal frequency, it is tired thus to characterize prestressed concrete beam to be measured
Labor faulted condition.
Further, damage variable is fitted with cycle-index using following formula:
Wherein: α, β are to fitting parameter, and n is cycle-index, following when N is prestressed concrete beam fatigue rupture to be measured
Ring number.
Further, dynamic test uses excitation method, is managed by mobile vibration excitor to each rank of prestressed concrete beam to be measured
Scanning frequency excitation nearby is carried out by vibration shape amplitude maximum amplitude point, is transferred to mould measurement after acquiring acceleration signal by vibration pickup
Analysis system carries out model analysis.
Further, the damage variable defined with modal frequency chooses first step mode frequency.
Further, when dynamic test, vibration excitor is arranged in a staggered manner with vibration pickup.
To solve above-mentioned second technical problem, the present invention adopts the following technical scheme:
It is a kind of to realize the test device for weighing above-mentioned characterizing method, including be oppositely arranged two freely-supported supports on the ground,
Prestressed concrete beam to be measured, excitation system and Modal testing and analysis system on two freely-supported supports are set;
The excitation system includes sequentially connected vibration excitor, power amplifier and signal amplifier, and vibration excitor can be free
The mobile lower section that prestressed concrete beam to be measured is arranged in is located between two freely-supported supports;
The Modal testing and analysis system includes sequentially connected vibration pickup, signal acquiring system and model analysis system
System, vibration pickup are arranged in the top surface of prestressed concrete beam to be measured.
Further, vibration pickup is along the isometric arrangement of prestressed concrete beam length direction to be measured.
Further, vibration excitor is arranged on walking dolly.
Further, fatigue tester is set above prestressed concrete beam to be measured, and fatigue tester is solid by reaction frame
Dingan County fills on the ground, and the lower section that the top of prestressed concrete beam to be measured is located at fatigue tester actuation head is distributed equipped with load
Beam, the actuation head central point of fatigue tester face the center of prestressed concrete beam central point and load distribution beam to be measured
Point.
Further, the both ends top of prestressed concrete beam to be measured be located at freely-supported support, position and load in girder span
Load(ing) point bottom is equipped with displacement meter.
Further, the both ends of load distribution beam are connect by freely-supported support with prestressed concrete beam to be measured.
Compared with prior art, the invention has the following beneficial effects:
1, the present invention utilizes the Fatigue Damage States and mould of structure in prestressed concrete beam fatigue loading and destructive process
There are good mapping relations for state parameter, prestressed concrete beam fatigue test of structure are combined with dynamic test test, base
Position and its degree of injury in Vibrating modal parameters analysis prestressed concrete beam fatigue damage, to realize based on mode
Parameter characterization prestressed concrete beam Fatigue Damage States provide one for the research of prestressed concrete beam fatigue behaviour and test
Kind new approaches.
2, conventional fixed-type excitational equipment is improved to mobile excitational equipment by test device of the present invention, can be according to exciting
Point position fast transportation, make test progress it is more convenient, have the advantages that structure simply, convenient test.
Detailed description of the invention
Fig. 1 is the flow chart of characterizing method of the present invention;
Fig. 2 is dynamic test schematic diagram one of the present invention;
Fig. 3 is fatigue test process apparatus schematic diagram one of the present invention;
Fig. 4 is sectional view of the invention;
Fig. 5 is that Position of Vibrating chooses schematic diagram;
Fig. 6 is that curve is compared in practical frequency degeneration in tired course;
Fig. 7 is the prestressed concrete beam fatigue damage evolutionary rule figure characterized with first-order modal frequency.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
Referring to Fig. 1, a kind of prestressed concrete beam fatigue damage state characterization method includes the following steps:
Step 1: prestressed concrete beam to be measured being placed on two freely-supported supports, intact to be measured pre- is answered to initial first
Power beams of concrete carries out dynamic test, obtains the initial modal frequency w of prestressed concrete beam to be measured0;
Step 2: opening fatigue tester and fatigue test, the certain number of fatigue and cyclic are carried out to prestressed concrete beam to be measured
It shuts down afterwards and carries out dynamic test, obtain the modal frequency w of prestressed concrete beam to be measured when fatigue life cycle is n ten thousand timesn;
Step 3: the damage variable of prestressed concrete beam to be measured under different cycle-indexes is obtained according to the following formula:
Wherein: w0For initial modal frequency, wNModal frequency when for prestressed concrete beam fatigue rupture to be measured, N be to
Survey cycle-index when prestressed concrete beam fatigue rupture;
Step 4: the damage variable of prestressed concrete beam to be measured is intended under the different cycle-indexes obtained to step 3
It closes, obtains the tired Complete Damage Process variable Evolution based on modal frequency, it is tired thus to characterize prestressed concrete beam to be measured
Labor faulted condition.
Further, damage variable is fitted with cycle-index using following formula:
Wherein: α, β are to fitting parameter, and n is cycle-index, following when N is prestressed concrete beam fatigue rupture to be measured
Ring number.
Further, dynamic test uses excitation method, is managed by mobile vibration excitor to each rank of prestressed concrete beam to be measured
Scanning frequency excitation nearby is carried out by vibration shape amplitude maximum amplitude point, is transferred to mould measurement after acquiring acceleration signal by vibration pickup
Analysis system carries out model analysis.
Further, the damage variable defined with modal frequency chooses first step mode frequency.
Further, when dynamic test, vibration excitor is arranged in a staggered manner with vibration pickup.
When mould measurement, the selection of Position of Vibrating follows following principle: 1) it is theoretical vibration excitor to be moved to each rank of beam to be measured
Vibration shape amplitude maximum amplitude point nearby carries out scanning frequency excitation;2) the vibration excitor placement location should avoid vibration pickup placement location just
Lower section, the vibration signal measured to avoid the point are distorted because of overload.
The modal analysis method that Modal testing and analysis system is selected is stochastic subspace SSI method, and it is outer that this method does not have to input
Portion's excitation or external drive can not survey, and effectively can extract modal parameters from the structural response of environmental excitation.
- Fig. 5 referring to fig. 2, a kind of test device for realizing above-mentioned characterizing method, including be oppositely arranged on ground 10 two
A freely-supported support 1, the prestressed concrete beam to be measured 2 being arranged on two freely-supported supports 1, excitation system 3 and mould measurement
Analysis system 4.
Specifically, excitation system 3 is put including vibration excitor 301, the power amplifier 302 connecting with vibration excitor 301, with power
The signal amplifier 303 that big device 302 connects, what vibration excitor 301 can move freely is arranged under prestressed concrete beam 2 to be measured
Orientation is between two freely-supported supports 1.The signal that Modal testing and analysis system 4 includes vibration pickup 401, connect with vibration pickup 401
Acquisition system 402 and the modal analysis system 403 being connect with signal acquiring system 402, the mould that signal acquiring system 402 connects
The components such as state analysis system 403 are existing structure, do not chase after repeat herein.
Vibration pickup 401 is arranged in the top surface of prestressed concrete beam 2 to be measured, and vibration pickup 401 is adsorbed on magnetic stand, magnetic
Property support is fixed at prestressed concrete beam 2 to be measured.Actuation head is additionally provided with above prestressed concrete beam 2 to be measured just to treat
The fatigue tester 5 of prestressed concrete beam 2 is surveyed, fatigue tester 5 is fixedly mounted on the ground by reaction frame 6.
Preferably, vibration pickup 401 is along the isometric arrangement of 2 length direction of prestressed concrete beam to be measured, the output of vibration pickup 401
End is connected with the input terminal of signal acquiring system 402, and the output end of signal acquiring system 402 is defeated with modal analysis system 403
Enter end to be connected, the vibration signal that signal acquiring system 402 is measured by acquiring vibration pickup 401, and sends it to model analysis system
System 403, modal analysis system 403 handles obtain beam modal parameter to be measured by analysis.
It is envisioned that vibration excitor 301 is arranged on walking dolly 11 in actual design, walking dolly 11 is arranged
On the ground, vibration excitor will rapidly be transported specified impacting point by walking dolly, makes mould measurement by each mould measurement
It is more convenient effective.
It should be noted that in practical applications, freely-supported support 1 includes the pedestal 101 being fixedly mounted on the ground and sets
The hinged-support 102 on pedestal 101 is set, two hinged-supports 102 are used to support beam to be measured (prestressed concrete beam), pedestal 101
It is fixedly mounted on experiment room floor 10 by fastening bolt.It is additionally provided at the top of prestressed concrete beam 2 to be measured for inciting somebody to action
The load that fatigue tester 5 applies passes to the load distribution beam 7 of beam to be measured, the both ends of load distribution beam 7 by hinged-support 8 with
Prestressed concrete beam 2 to be measured connects, position in the corresponding beam upper end of both ends freely-supported support of prestressed concrete beam to be measured, girder span
It sets and load load(ing) point bottom is equipped with displacement meter 9.When test, according to the loading procedure of static(al) monotonic loading test, divided
Grade is loaded onto tired upper limit load, measures strain, crack, amount of deflection under loads at different levels etc. and its development.
Below in conjunction with specific embodiment, the present invention is further illustrated.
Embodiment
Selection 32m common height standard railroad bridge prestress concrete Simple T-Girders are prototype beam, according to the theory of similarity,
The 1:6 scaled model of prototype beam is made as prestressed concrete beam 3 to be measured, design parameter see the table below 1.The present embodiment is prepared altogether
3 Model Beams a, wherein beam (number No.1) is used for static test, with static(al) ultimate load needed for determining fatigue test
Pu, survey Pu=265kN;(number No.2, No.3) two other is used for fatigue test.
1 model of tableBeam designParameter
Concrete mix is cement: water: stone: sand: water-reducing agent=460:118:1092:735:4.2, each test beam pour
When reserved concrete test block, Mechanics Performance Testing carries out simultaneously with model beam test, and measuring mechanical property see the table below 2:
Table 2 surveys mechanical performance of concrete parameter
Vertical muscle uses HRB335 grades of reinforcing bars, diameter 10mm;According to the requirement of railroad bridge design structure, the cloth in beam simple bending section
It sets diameter 8mm (HPB300), the stirrup that spacing is 100mm, is 50mm in other sections.The actual measurement mechanical property parameters of reinforcing bar are shown in
The following table 3:
Table 3 surveys steel bar mechanics performance parameter
Deformed bar uses 2 beam, 7 φ, 5 steel strand wires, nominal diameter d=15.2mm, ultimate strength standard value fptk=
1860MPa is arranged using parabolic type.Presstressed reinforcing steel using both ends tensioning (single hole jack single steel strand to drawing, in two times
Complete), control stress for prestressing σcon=1116MPa, ultra stretching 5%, the age of concrete is more than 28 days when tensioning.
A kind of prestressed concrete beam fatigue damage state characterization method, mainly comprises the steps that
1) the initial driving force parametric measurement of prestressed concrete beam and for the first time static test: by prestressed concrete beam to be measured
2 are placed on freely-supported support 1, carry out dynamic test to initial intact prestressed concrete beam 2 to be measured first, dynamic test uses
Excitation method nearby carries out scanning frequency excitation by mobile vibration excitor 301 to each rank theory vibration shape amplitude maximum amplitude point, passes through pick-up
Device 401 is transferred to the progress model analysis of Modal testing and analysis system after acquiring acceleration signal, obtains each rank modal parameter;Then
Arrange that load distribution beam 7, load distribution beam 7 are placed in prestressing force to be measured by hinged-support 8 and mix according to four-point bending loading method
On solidifying soil beam 2, and guarantee that the actuation head central point of fatigue tester 5 faces 2 central point of prestressed concrete beam to be measured and lotus
Carry the central point of distribution beam 7;According to the loading procedure of static(al) monotonic loading test, hierarchical loading is carried out to tired upper limit load,
Measure strain, crack, amount of deflection under loads at different levels etc. and its development;
2) it prestressed concrete beam static test and dynamic test in fatigue loading course: after completing step 1), opens tired
Labor testing machine 5 carries out fatigue loading, reaches 10,000 times, 50,000 times, 100,000 times, 250,000 inferior rear shutdown in fatigue load cycle-index
(and so on, until prestressed concrete beam 2 to be measured is close to when fatigue rupture), respectively such as power of the step 1) progress
Test and be loaded onto the static test of tired upper limit load;After 2 fatigue rupture of prestressed concrete beam to be measured, then once moved
Power test and static test.
Fatigue test is loaded using constant amplitude sinusoid, loading frequency 3.5Hz, and test major parameter see the table below 4, tired lotus
It carries lower limit value and takes Pmin=0.2Pu, fatigue load upper limit value Pmax0.45P is taken respectivelyuAnd 0.5Pu。
4 Model Beam test parameters of table and fatigue life
3) prestressed concrete beam Vibrating modal parameters are analyzed: as shown in step 1) and step 2), respectively at first static load
Dynamic test is carried out to initial intact prestressed concrete beam 2 to be measured in preceding and tired course, passes through Modal testing and analysis system
Vibrating modal parameters analysis is carried out, each rank modal parameter in tired course is obtained.
In initial driving force parametric measurement, supports 8 devices to remove load distribution beam 7 and freely-supported, will match with vibration pickup 401
The magnetic stand of set is pasted on prestressed concrete beam 2 to be measured, and vibration pickup 401 is by being adsorbed on magnetic stand, thus solid
It is scheduled on prestressed concrete beam 2 to be measured;In fatigue test CYCLIC LOADING, the keeping of vibration pickup 401 is removed, in the certain number of fatigue
When shutting down progress dynamic test, taking-up vibration pickup 401 is adsorbed on magnetic stand to be measured again.
The modal analysis method that Modal testing and analysis system is selected is stochastic subspace SSI method, and it is outer that this method does not have to input
Portion's excitation or external drive can not survey, and effectively can extract modal parameters from the structural response of environmental excitation.
4) prestressed concrete beam Fatigue Damage States are assessed: each rank mould in the tired course obtained by step 3) analysis
State parameter is assessed by the Fatigue Damage States that correlation analysis carries out prestressed concrete beam 2 to be measured.
The instrument model and manufacturer used in the present embodiment see the table below 5:
5 test apparatus of table
Based on a kind of prestressed concrete beam fatigue damage state characterization method based on modal parameter of the present invention
And test device, obtain the frequency such as the following table 6 of two fatigue test beams in tired course.
Summary sheet is compared in the tired course actual measurement of table 6 and degeneration
Define fatigue effect lower frequency degeneration ratio:
γ (n)=wn/w0
In formula, ω0For the original frequency of intact beam;ωnFor the frequency of tired ten thousand back rest of n.Before then obtaining in tired course
The frequency of three rank practical frequencies is degenerated than upper table 6, and is drawn frequency and degenerated than curve as shown in attached drawing 6.
By upper table 6 and attached drawing 6 as it can be seen that with times of fatigue increase, first three order frequency of prestressed concrete beam has
Declined.Load starts, and the more significant range of decrease occurs in modal frequency;Into after tired mid-term, frequency fall off rate slows down, with
One lesser numerical value is gradually decreasing, and has fluctuation but kept stable;When reaching fatigue life, it is lesser to there is an amplitude
It reduces, it is respectively 19.5%, 15.8%, 9.0% that final first three order frequency of beam No.2, which reduces amplitude, first three order frequency of beam No.3 drop
Low amplitude value is respectively 19.4%, 13.6%, 7.4%.It can be seen that the frequency of fundamental frequency reduces amplitude under fatigue effect
It is maximum;Second order frequency is taken second place;And the frequency of three order frequencies reduces amplitude minimum.
Can also be seen that from attached drawing 6: there is also similar fatigues for the degenerative process of prestressed concrete beam modal frequency just
Spend the three-stage evolution rule degenerated.The tired initial stage modal frequency range of decrease is larger, this is because when load just starts, distress in concrete
Development and effective prestress loss it is larger, reduce significantly test beam rigidity, to make the beam modal frequency be in
Reveal the characteristics of being reduced rapidly.Into after tired mid-term, in slow extension, extension, effective prestress loses rate and reduces in crack
And tend towards stability, occur local bonding sliding rupture between reinforcing bar and concrete, making beam rigidity is in the state of development of approximately linear, mould
Also approximate linear reduction, opposite development are relatively stable for state frequency.Tired latter stage, distress in concrete sharply extend and occur again
Dendroid crack, beam body rigidity reduces again at this time, therefore frequency has a decline stage again.
Define the damage variable based on modal frequency:
Wherein: w0For initial modal frequency, wNModal frequency when for prestressed concrete beam fatigue rupture to be measured, N be to
Survey cycle-index when prestressed concrete beam fatigue rupture.The variation range for the damaging parameter D that this formula defines is between 0~1;
D=0 corresponds to the nondestructive state of test beam;D=1 corresponds to the complete fatigue rupture of beam.Damaging parameter D is the function of monotonic increase,
I.e. the fatigue damage degree of test beam increases with the increase of load cycle-index, and it is irreversible for damaging.
In view of in the bridge dynamic test of Practical Project, since the energy etc. of first step mode frequency occupies larger ratio
Example, accuracy with higher, and meanwhile it is maximum by the frequency degeneration amplitude that discovery first step mode frequency is studied in front, so this
In damage variable defined using first step mode frequency.Research of the comprehensive numerous scholars to damage accumulation matched curve, passes through
After choosing, following formula is selected to be fitted:
Wherein: α, β are to fitting parameter, and n is cycle-index, following when N is prestressed concrete beam fatigue rupture to be measured
Ring number.Nonlinear regression analysis is carried out using least square method by test result, obtaining parameter see the table below 7.Two panels beam is intended
Right R2Close to 100%, illustrate that the models fitting degree is preferable.
7 fatigue damage Fitting of Nonlinear Models parameter of table
The damage of two beam fatigue accumulations based on first-order modal frequency can be obtained according to above-mentioned matched curve and fitting parameter
Hurt Evolution, sees attached drawing 7.
From attached drawing 7 as can be seen that each test beam fatigue damage evolutionary rule is with apparent non-linear.Entire fatigue damage
Evolution can be divided into 3 stages.In the 1st stage of damage initial development, Cumulative Fatigue Damage, which sharply increases, reaches maintenance level;The
2 stages, Cumulative Fatigue Damage steadily slowly increase;As cycle-index increases, Cumulative Fatigue Damage entered for the 3rd stage, the 3rd
Stage Cumulative Fatigue Damage starts to sharply increase again on the basis of the 2nd stage accumulated damage, until test beam destroys mistake completely
Remove bearing capacity.
Comparing two beam fatigue damage evolution curves can also be seen that Fatigue Stress Amplitude is bigger, and lesion development is more violent.
Tired early period, the biggish beam No.2 lesion development degree of stress amplitude is rapider compared with beam No.3, respectively reaches numerical value about in two beams
For 0.68 and 0.56 damage threshold when, into damage stable development tired mid-term;Damage latter stage beam No.2 threshold value be about
0.85, the threshold value 0.82 greater than beam No.3.Entire development process is made a general survey of, the biggish beam lesion development of stress amplitude, which is always ahead of, answers
The lesser beam of power, and the low life characteristic of big stress amplitude beam in comparison also shows the reasonability of this Evolution.
It is non-thread effectively to simulate three stage of prestressed concrete beam using first natural frequency as damage variable for the present embodiment
Fatigue damage evolution law.It can be seen that by the research to fatigue damage accumulation curve, in conjunction with three stage of fatigue damage threshold
The identification of value can provide Research foundation for Deterioration of Structural Performance deciding degree and predicting residual useful life, have certain application prospect,
New approaches are provided for the research of prestressed concrete beam fatigue behaviour.
Above-described embodiment is only to clearly demonstrate examples made by the present invention, rather than the restriction to embodiment.For
For those of ordinary skill in the art, other various forms of variations or change can also be made on the basis of the above description
It is dynamic.Here without can not be also exhaustive to all embodiments.And the obvious variation or change thus amplified out
It is dynamic to be still in the protection scope of this invention.
Claims (10)
1. a kind of prestressed concrete beam fatigue damage state characterization method, which comprises the steps of:
Step 1: prestressed concrete beam to be measured is placed on two freely-supported supports, it is mixed to initial intact prestressing force to be measured first
Solidifying Tu Liang carries out dynamic test, obtains the initial modal frequency w of prestressed concrete beam to be measured0;
Step 2: opening fatigue tester and fatigue test is carried out to prestressed concrete beam to be measured, stop after the certain number of fatigue and cyclic
Machine carries out dynamic test, obtains the modal frequency w of prestressed concrete beam to be measured when fatigue life cycle is n ten thousand timesn;
Step 3: the damage variable of prestressed concrete beam to be measured under different cycle-indexes is obtained according to the following formula:
Wherein: w0For initial modal frequency, wNModal frequency when for prestressed concrete beam fatigue rupture to be measured, N are to be measured pre-
Cycle-index when prestressed concrete beam fatigue rupture;
Step 4: the damage variable of prestressed concrete beam to be measured is fitted under the different cycle-indexes obtained to step 3, is obtained
To the tired Complete Damage Process variable Evolution based on modal frequency, prestressed concrete beam fatigue damage to be measured is thus characterized
State.
2. prestressed concrete beam fatigue damage state characterization method according to claim 1, it is characterised in that: damage becomes
Amount is fitted with cycle-index using following formula:
Wherein: α, β are to fitting parameter, and n is cycle-index, the circulation time when N is prestressed concrete beam fatigue rupture to be measured
Number.
3. prestressed concrete beam fatigue damage state characterization method according to claim 1, it is characterised in that: power is surveyed
Excitation method is used, near mobile vibration excitor to each rank theory vibration shape amplitude maximum amplitude point of prestressed concrete beam to be measured
Scanning frequency excitation is carried out, is transferred to the progress model analysis of Modal testing and analysis system after acquiring acceleration signal by vibration pickup.
4. prestressed concrete beam fatigue damage state characterization method according to claim 1, it is characterised in that: it is described with
The damage variable that modal frequency defines chooses first step mode frequency.
5. prestressed concrete beam fatigue damage state characterization method according to claim 1, it is characterised in that: power is surveyed
When examination, vibration excitor is arranged in a staggered manner with vibration pickup.
6. a kind of test device for realizing any one of claim 1-5 characterizing method, it is characterised in that: including being oppositely arranged
Two freely-supported supports on the ground, the prestressed concrete beam to be measured being arranged on two freely-supported supports, excitation system and
Modal testing and analysis system;
The excitation system includes sequentially connected vibration excitor, power amplifier and signal amplifier, and vibration excitor can move freely
The lower section that prestressed concrete beam to be measured is set be located between two freely-supported supports;
The Modal testing and analysis system includes sequentially connected vibration pickup, signal acquiring system and modal analysis system, is picked up
Vibration device is arranged in the top surface of prestressed concrete beam to be measured.
7. test device according to claim 6, it is characterised in that: vibration pickup is along prestressed concrete beam length side to be measured
To isometric arrangement, vibration excitor is arranged on walking dolly.
8. test device according to claim 6, it is characterised in that: setting fatigue examination above prestressed concrete beam to be measured
Machine is tested, fatigue tester is fixedly mounted on the ground by reaction frame, and the top of prestressed concrete beam to be measured is located at fatigue examination
The lower section for testing machine actuation head is equipped with load distribution beam, and the actuation head central point of fatigue tester faces prestressed concrete to be measured
The central point of beam central point and load distribution beam.
9. test device according to claim 6, it is characterised in that: the both ends top of prestressed concrete beam to be measured is located at
Position and load load(ing) point bottom are equipped with displacement meter at freely-supported support, in girder span.
10. test device according to claim 6, it is characterised in that: the both ends of load distribution beam by freely-supported support with
Prestressed concrete beam connection to be measured.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201811440739.9A CN109374452B (en) | 2018-11-29 | 2018-11-29 | Fatigue damage state characterization method and test device for prestressed concrete beam |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201811440739.9A CN109374452B (en) | 2018-11-29 | 2018-11-29 | Fatigue damage state characterization method and test device for prestressed concrete beam |
Publications (2)
Publication Number | Publication Date |
---|---|
CN109374452A true CN109374452A (en) | 2019-02-22 |
CN109374452B CN109374452B (en) | 2023-11-10 |
Family
ID=65374613
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201811440739.9A Active CN109374452B (en) | 2018-11-29 | 2018-11-29 | Fatigue damage state characterization method and test device for prestressed concrete beam |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN109374452B (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110082080A (en) * | 2019-04-11 | 2019-08-02 | 中铁大桥局集团第二工程有限公司 | A kind of PC track girder static test pedestal suitable for different beam lengths and curvature |
CN110132511A (en) * | 2019-05-30 | 2019-08-16 | 山东省建筑科学研究院 | A kind of bridge structure monitoring and assessing method based on dynamic deflection attenuation law |
CN110455650A (en) * | 2019-07-10 | 2019-11-15 | 河海大学 | A method of quickly determining prefabricated cracked concrete beam fatigue life |
CN110987661A (en) * | 2019-11-25 | 2020-04-10 | 中南大学 | Method for improving Harris distributed structural surface shear damage constitutive model |
CN113092290A (en) * | 2021-03-26 | 2021-07-09 | 太原理工大学 | External prestress reinforced concrete beam fatigue test device and method |
CN113218789A (en) * | 2021-04-13 | 2021-08-06 | 同济大学 | Reinforced concrete beam post-crack fatigue performance testing system and method |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5327358A (en) * | 1991-08-07 | 1994-07-05 | The Texas A&M University System | Apparatus and method for damage detection |
GB0227382D0 (en) * | 2001-12-18 | 2002-12-31 | Visteon Global Tech Inc | Fatigue sensitivity determination procedure |
US20040107772A1 (en) * | 2002-12-04 | 2004-06-10 | Ford Global Technologies Llc | Method for determining automotive brake structure vibration damping and friction material bonding |
US20070272018A1 (en) * | 2006-05-24 | 2007-11-29 | Honeywell International Inc. | Determination of remaining useful life of gas turbine blade |
US20100262390A1 (en) * | 2009-04-10 | 2010-10-14 | University Of South Carolina | System and method for modal identification using smart mobile sensors |
GB201104864D0 (en) * | 2011-03-23 | 2011-05-04 | Rolls Royce Plc | Device for fatigue testing a specimen |
NL2010556C2 (en) * | 2013-04-03 | 2014-10-06 | Onderzoekscentrum Voor Aanwending Van Staal N V | Fatigue testing of a test specimen. |
CN104297456A (en) * | 2014-10-11 | 2015-01-21 | 陈振富 | Method for recognizing meso-structure parameter of dynamic performance of radiation shield concrete |
CN104931364A (en) * | 2015-06-04 | 2015-09-23 | 浙江大学 | Reinforced concrete structure fatigue test method and device based on piezomagnetic effect |
JP2016102323A (en) * | 2014-11-28 | 2016-06-02 | 大成建設株式会社 | Design method of prestress concrete girder |
CN106404914A (en) * | 2016-08-26 | 2017-02-15 | 四川省建筑科学研究院 | Method used for measuring structure damages and safety conditions of Ying county buddha tower |
CN209167040U (en) * | 2018-11-29 | 2019-07-26 | 中南大学 | A kind of prestressed concrete beam fatigue damage test device |
-
2018
- 2018-11-29 CN CN201811440739.9A patent/CN109374452B/en active Active
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5327358A (en) * | 1991-08-07 | 1994-07-05 | The Texas A&M University System | Apparatus and method for damage detection |
GB0227382D0 (en) * | 2001-12-18 | 2002-12-31 | Visteon Global Tech Inc | Fatigue sensitivity determination procedure |
US20040107772A1 (en) * | 2002-12-04 | 2004-06-10 | Ford Global Technologies Llc | Method for determining automotive brake structure vibration damping and friction material bonding |
US20070272018A1 (en) * | 2006-05-24 | 2007-11-29 | Honeywell International Inc. | Determination of remaining useful life of gas turbine blade |
US20100262390A1 (en) * | 2009-04-10 | 2010-10-14 | University Of South Carolina | System and method for modal identification using smart mobile sensors |
GB201104864D0 (en) * | 2011-03-23 | 2011-05-04 | Rolls Royce Plc | Device for fatigue testing a specimen |
NL2010556C2 (en) * | 2013-04-03 | 2014-10-06 | Onderzoekscentrum Voor Aanwending Van Staal N V | Fatigue testing of a test specimen. |
CN104297456A (en) * | 2014-10-11 | 2015-01-21 | 陈振富 | Method for recognizing meso-structure parameter of dynamic performance of radiation shield concrete |
JP2016102323A (en) * | 2014-11-28 | 2016-06-02 | 大成建設株式会社 | Design method of prestress concrete girder |
CN104931364A (en) * | 2015-06-04 | 2015-09-23 | 浙江大学 | Reinforced concrete structure fatigue test method and device based on piezomagnetic effect |
CN106404914A (en) * | 2016-08-26 | 2017-02-15 | 四川省建筑科学研究院 | Method used for measuring structure damages and safety conditions of Ying county buddha tower |
CN209167040U (en) * | 2018-11-29 | 2019-07-26 | 中南大学 | A kind of prestressed concrete beam fatigue damage test device |
Non-Patent Citations (3)
Title |
---|
刘红兵;陈国明;刘康;孟文波;韩彬彬;刘秀全;: "深水测试管柱-隔水管耦合涡激疲劳分析", 中国石油大学学报(自然科学版), no. 01 * |
周迅;俞小莉;: "曲轴疲劳裂纹扩展速率测量的扫频法", 浙江大学学报(工学版), no. 11 * |
杜金龙;郭少华;: "损伤梁动力特性的空间有限元分析", 铁道科学与工程学报, no. 02 * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110082080A (en) * | 2019-04-11 | 2019-08-02 | 中铁大桥局集团第二工程有限公司 | A kind of PC track girder static test pedestal suitable for different beam lengths and curvature |
CN110132511A (en) * | 2019-05-30 | 2019-08-16 | 山东省建筑科学研究院 | A kind of bridge structure monitoring and assessing method based on dynamic deflection attenuation law |
CN110132511B (en) * | 2019-05-30 | 2020-10-27 | 山东省建筑科学研究院有限公司 | Bridge structure monitoring and evaluating method based on dynamic deflection attenuation law |
CN110455650A (en) * | 2019-07-10 | 2019-11-15 | 河海大学 | A method of quickly determining prefabricated cracked concrete beam fatigue life |
CN110987661A (en) * | 2019-11-25 | 2020-04-10 | 中南大学 | Method for improving Harris distributed structural surface shear damage constitutive model |
CN110987661B (en) * | 2019-11-25 | 2021-08-27 | 中南大学 | Method for improving Harris distributed structural surface shear damage constitutive model |
CN113092290A (en) * | 2021-03-26 | 2021-07-09 | 太原理工大学 | External prestress reinforced concrete beam fatigue test device and method |
CN113218789A (en) * | 2021-04-13 | 2021-08-06 | 同济大学 | Reinforced concrete beam post-crack fatigue performance testing system and method |
Also Published As
Publication number | Publication date |
---|---|
CN109374452B (en) | 2023-11-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN109374452A (en) | A kind of prestressed concrete beam fatigue damage state characterization method and test device | |
CN209167040U (en) | A kind of prestressed concrete beam fatigue damage test device | |
CN106485029B (en) | Bearing capacity evaluation method after Concrete beam bridge damage based on overstrain | |
Daniel et al. | Laboratory evaluation of fatigue damage and healing of asphalt mixtures | |
Anastasopoulos et al. | Influence of damage versus temperature on modal strains and neutral axis positions of beam-like structures | |
CN110031312A (en) | A kind of corrosion presstressed reinforcing steel mechanical property in-situ testing device and method | |
CN110470542B (en) | Durable loading device for load-holding reinforced concrete beam | |
Jamadin et al. | Effect of high-cyclic loads on dynamic response of reinforced concrete slabs | |
Vázquez-Herrero et al. | Evaluation of strand bond properties along the transfer length of prestressed lightweight concrete members | |
CN113075051B (en) | Simulation test device and test method for soft rock compressive creep similar environment | |
JP2005315611A (en) | Horizontal load testing method of pile | |
Azenha et al. | Continuous stiffness monitoring of cemented sand through resonant frequency | |
CN114397199B (en) | Pile torsion resistance testing method | |
Thayalan et al. | Behaviour of concrete-filled steel tubes under static and variable repeated loading | |
CN108151939B (en) | The method for detecting prestress value in unbonded prestressed concrete structure | |
KR19990073388A (en) | an process of loading teste for loading structure use of transferable loading-apparatus | |
Wang et al. | Research on destructive test of pretensioning prestressed concrete hollow slab in service | |
Daneshjoo et al. | Experimental and theoretical dynamic system identification of damaged RC beams | |
Tissera | Realistic Wind Loads on Reinforced Masonry Walls | |
RU2797787C1 (en) | Method for non-destructive assessment and control of the bearing capacity and reliability of steel trusses | |
Dai et al. | Vibration of spun-cast prestressed concrete poles | |
Sener et al. | On the influence of load width on web compression buckling strength | |
CN114062151B (en) | Method for measuring secondary bending moment of prestressed concrete frame beam in plastic stage | |
RU2331858C1 (en) | Method of test of building frame unit | |
CN212612672U (en) | Be applied to experimental device of high-strength concrete precast tubular pile resistance to plucking |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |