CN101487791A - Damage diagnosis method for light grid sandwich materials - Google Patents
Damage diagnosis method for light grid sandwich materials Download PDFInfo
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- CN101487791A CN101487791A CNA2008100809769A CN200810080976A CN101487791A CN 101487791 A CN101487791 A CN 101487791A CN A2008100809769 A CNA2008100809769 A CN A2008100809769A CN 200810080976 A CN200810080976 A CN 200810080976A CN 101487791 A CN101487791 A CN 101487791A
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Abstract
The invention relates to improvement of a method for diagnosing the damage of a light-weight grid sandwich material, in particular to a method for diagnosing the damage degree of a light-weight grid sandwich material. The invention mainly relates to a method for implementing non-destructive detection on the material by dynamic test under the excitation of the environmental loads. The invention raises a damage degree diagnosis method that is suitable to the real-time monitoring of the light-weight grid sandwich material and is used for establishing a material health monitoring system and increasing the endurance life of the material so as to increase the safety and the economical efficiency of the structure. The damage detection of the grid sandwich material by the modal analysis technology is a marginal application technology after the modal analysis technology develops to a relatively complete stage. The fundamental principle of the damage detection is as follows: various damages, such as result in the quality or rigidity change of the system caused by structural crack, partially component peeling-off and unit disjoint and the like, further result in the change of the modal parameters, therefore, the damages can be judged and evaluated by the change of the modal parameters.
Description
Affiliated technical field
The present invention relates to the improvement of the damage diagnosis method of light grid sandwich materials, specifically is a kind of diagnostic method to the light grid sandwich materials degree of injury.It is primarily aimed under the excitation of environmental load, utilizes dynamic test material to be carried out the method for Non-Destructive Testing.The present invention proposes to be applicable to the light grid sandwich materials degree of injury diagnostic method of monitoring in real time, is used to set up the material health monitoring systems, improves the fatigue lifetime of material, to reach security, the economy that improves structure.
Background technology
The light grid sandwich materials long service is in various natures and industrial environment, and be subjected to the reciprocation of various load (as thermal force, shock load etc.), its complex structure, involve great expense, in case damage, not only can cause very big damage, also might cause immeasurable economic loss and casualties commercial unit.Usually damage is inevitably in structure during one's term of military service, and in order to ensure people's life security, minimizing property loss, unique method is to diagnose out the damage of structure, and can in time repair.Compare with technology such as the X-ray radiography technology that is widely used in Non-Destructive Testing, acoustic emission, current vortex, UT (Ultrasonic Testing), acoustic soundings, utilizing the material structure vibration characteristics to carry out damage has signal and is easy to extract, detector can be installed in people should not carry out advantages such as long-term on-line measurement by approaching structure position, so numerous experts and scholars are just attempting the damage technology that the bar structure vibration-mode analysis develops into a kind of new grid sandwich materials.
Summary of the invention
The damage that utilizes modal analysis technique to carry out grid sandwich materials is the edge application technology that develops into the more complete stage in modal analysis technique.Its ultimate principle is: various forms of damages, such as structure crackle appears, partial component is peeled off and the unit disconnects or the like can cause that all mass of system or rigidity change, and then cause the variation of modal parameter, thereby judge, estimate damage by the variation of modal parameter.
From the document of the material lossless detection method that changes based on structural dynamic characteristic, can see that there is the limitation of some practical applications in most methods, need complete modal information, modal parameter of high-order or the like.The present invention is directed to above-mentioned limitation, proposing new goal of the invention is: use substructure mode strain energy method, under the known situation of damage position, degree to damage is diagnosed, and the present invention only needs the structural modal information of the part of low order just can provide diagnosis accurately to the light grid sandwich materials degree of injury.
The present invention is based on a typical light grid sandwich beam or other lattice structure, its main member is by the post member, and horizontal brace member and diagonal supporting member are formed.When damage took place the member in the grid sandwich beam, the rigidity value of member can reduce, and was corresponding, and near the Mode Shape this member has significant variation, thereby judges, estimates damage by the relation of mode and structure.。
The technical solution adopted for the present invention to solve the technical problems is: the measured data of utilizing engineering framework structural vibration, judge the variation of structural dynamic parameter by the systematic parameter recognition technology, with the significant difference between the analog value before and after modal parameter that structure the is discerned damage as the sign that damage is arranged, and after utilizing prior art to judge damage position, the substructure mode strain energy method is set up the degree that concerns the deagnostic structure damage of damage and structural parameters in the employing the technical program, and it comprises the steps:
(1) data acquisition step: capturing material is the environmental load excitation dynamic response data down of faulted condition, and deposit in the private memory, secondly, with the environmental load excitation of the faulted condition of above-mentioned material down the dynamic response data deposit storer in;
(2) damage identification positioning step: utilize the Modal Parameter Identification technology to obtain modal parameter before and after the structural damage, and the position that occurs of definite material members damage;
(3) degree of injury diagnosis algorithm: determine after the material members damage position, use substructure mode strain energy method diagnosis above-mentioned material component damage degree.
Using substructure mode strain energy method diagnostic materials component damage degree in described (3) degree of injury diagnosis algorithm, is the relation of having utilized component damage and material structure vibration parameters, that is:
The structural vibration control equation of substructure mode strain energy method:
Wherein { δ }
VsBe the v rank Mode Shape of s minor structure in the grid material, [β] is transfer function matrix, [Δ K
g] be the boundary element stiffness matrix, [Δ M
g] be the boundary element mass matrix, [K
p] be the resiliency supported stiffness matrix, [k
Jz] be damage stiffness of structural member matrix.Under the condition that above parameter has obtained, solving an equation to obtain the degree of injury α of j member in z minor structure of material
Jz
The above intact material parameter and dynamic response data thereof, itself or elastic modulus, and/or be modulus of shearing, and/or be density of material, and/or be acceleration, and/or be speed, and/or be displacement.
The above damage material parameter and actual measurement dynamic response data thereof, itself or elastic modulus, and/or be modulus of shearing, and/or be density of material, and/or be acceleration, and/or be speed, and/or be displacement.
The invention has the beneficial effects as follows, one, utilize environmental excitation to carry out vibration-testing, whole damage process can not influence the operate as normal of structure, and the vibration-testing under the environmental excitation makes long-term and online material structure health monitoring become possibility, two, utilize the substructure mode strain energy, only need the structural modal information of the low order of part just can provide diagnosis accurately the frame structure damage degree.
Description of drawings
The present invention is further described below in conjunction with drawings and Examples.
Fig. 1 is a techniqueflow chart of the present invention.
Fig. 2 is an enforcement light grid sandwich beam illustraton of model of the present invention.
Fig. 3 is an enforcement light grid sandwich beam finite element synoptic diagram of the present invention.
Embodiment, protection scope of the present invention not only is confined in following examples.
One, set up finite element numerical model:
Embodiments of the invention have been modeling effories light grid sandwich beam under the resiliency supported, structure is made up of vertical post, horizontal brace and diagonal supporting member, totally 10 minor structures, 40 member units are seen shown in Figure 1.Utilize software for calculation MATLAB to produce the dynamic response data of simulation.
Two, material members degree of injury diagnosis:
The finite element model that the front is introduced is as a benchmark model.For the ease of the explanation of diagnostic result, each minor structure of grid sandwich beam and each member indicate with different numbers.Present embodiment has been simulated three kinds of typical damage operating modes, comprises the post component damage, horizontal brace component damage, diagonal supporting member damage.Concrete damage operating mode is shown in Table 1.
Table 1 Simulation Damage operating mode
| The damage operating mode | The damage member | Unit number | The stiffness of structural member loss |
| A | Post | 21 | 5％ |
| B | Horizontal brace | 22 | 5％ |
| C | Diagonal brace | 23 | 5％ |
Damage operating mode A---post component damage: simulation be unit 21 losss of rigidity 5%; The substructure mode Strain Method that utilization the present invention proposes has calculated correct component damage degree.Damage operating mode B---horizontal brace component damage: simulation be unit 22 losss of rigidity 5%; The substructure mode Strain Method that utilization the present invention proposes has calculated correct component damage degree.Damage operating mode C---diagonal supporting member damage: simulation be unit 23 losss of rigidity 5%; The substructure mode Strain Method that utilization the present invention proposes has calculated correct component damage degree.The position of the rank number of mode that calculating is utilized and the minor structure of test sees Table 2.
Table 2 Simulation Damage condition calculating result
| The damage operating mode | Rank number of mode | Test position (minor structure) | The degree of injury diagnostic result |
| A | Single order | 1st, 6,10 |
5％ |
| B | Single order | 1st, 6,10 |
5％ |
| C | Single order | 1st, 6,10 |
5％ |
Those of ordinary skill in the art can understand, and in protection scope of the present invention, makes amendment for the foregoing description, and it all is possible adding and replacing, and it does not all exceed protection scope of the present invention.
Claims (4)
1. diagnostic method to light grid sandwich materials damage, its characteristic is: described diagnostic method is based on light grid sandwich materials existing structure kinematic behavior and the method implemented, and it comprises the steps:
(1) data acquisition step: capturing material is the environmental load excitation dynamic response data down of faulted condition, and deposit in the private memory, secondly, with the environmental load excitation of the faulted condition of above-mentioned material down the dynamic response data deposit storer in;
(2) damage identification positioning step: utilize the Modal Parameter Identification technology to obtain modal parameter before and after the structural damage, and the position that occurs of definite material members damage;
(3) degree of injury diagnosis algorithm: determine after the material members damage position, use substructure mode strain energy method diagnosis above-mentioned material component damage degree.
2. according to the damage diagnosis method of the described light grid sandwich materials of claim 1, it is characterized in that: use substructure mode strain energy method diagnostic materials component damage degree in described (3) degree of injury diagnosis algorithm, be the relation of having utilized component damage and material structure vibration parameters, that is:
Following formula is a substructure mode strain energy structural vibration control equation, wherein { δ }
VsBe the v rank Mode Shape of s minor structure in the grid material, [β] is transfer function matrix, [Δ K
g] be the boundary element stiffness matrix, [Δ M
g] be the boundary element mass matrix, [K
p] be the resiliency supported stiffness matrix, [k
Jz] be damage stiffness of structural member matrix.Under the condition that above parameter has obtained, solving an equation to obtain the degree of injury α of j member in z minor structure of material
Jz
3. according to the damage diagnosis method of the described light grid sandwich materials of claim 1, it is characterized in that: described intact material parameter and dynamic response data thereof, itself or elastic modulus, and/or be modulus of shearing, and/or be density of material, and/or be acceleration, and/or be speed, and/or be displacement.
4. according to the damage diagnosis method of the described light grid sandwich materials of claim 1, it is characterized in that: described damage material parameter and actual measurement dynamic response data thereof, itself or elastic modulus, and/or be modulus of shearing, and/or be density of material, and/or be acceleration, and/or be speed, and/or be displacement.
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| CNA2008100809769A CN101487791A (en) | 2008-01-15 | 2008-02-28 | Damage diagnosis method for light grid sandwich materials |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102901611A (en) * | 2012-09-29 | 2013-01-30 | 西安空间无线电技术研究所 | Rapid checking method for damage of modal test-based spaceborne antenna structure |
| CN103913722A (en) * | 2014-04-02 | 2014-07-09 | 南京航空航天大学 | Low-speed impact locating method for composite material cell structure |
| CN104777054A (en) * | 2015-05-18 | 2015-07-15 | 浙江工业大学 | Method for identifying parameters of resonant fatigue crack propagation test vibration system based on soft sensing technology |
| CN107976329A (en) * | 2018-01-17 | 2018-05-01 | 上海核工程研究设计院有限公司 | A kind of nuclear power station structure damage monitoring system based on vibration |
| CN108802176A (en) * | 2018-04-08 | 2018-11-13 | 大连理工大学 | A kind of Damage Assessment Method experimental method based on PVDF sensors and strain mode |
| CN112444563A (en) * | 2020-11-25 | 2021-03-05 | 大连理工大学 | Transverse isotropic material damage evaluation method based on ultrasonic back reflection |
-
2008
- 2008-02-28 CN CNA2008100809769A patent/CN101487791A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102901611A (en) * | 2012-09-29 | 2013-01-30 | 西安空间无线电技术研究所 | Rapid checking method for damage of modal test-based spaceborne antenna structure |
| CN102901611B (en) * | 2012-09-29 | 2015-10-21 | 西安空间无线电技术研究所 | A kind of quick arrange distinguish method of satellite antenna structural damage based on modal test |
| CN103913722A (en) * | 2014-04-02 | 2014-07-09 | 南京航空航天大学 | Low-speed impact locating method for composite material cell structure |
| CN103913722B (en) * | 2014-04-02 | 2016-05-18 | 南京航空航天大学 | Grid-stiffened composite structure low velocity impact localization method |
| CN104777054A (en) * | 2015-05-18 | 2015-07-15 | 浙江工业大学 | Method for identifying parameters of resonant fatigue crack propagation test vibration system based on soft sensing technology |
| CN107976329A (en) * | 2018-01-17 | 2018-05-01 | 上海核工程研究设计院有限公司 | A kind of nuclear power station structure damage monitoring system based on vibration |
| CN108802176A (en) * | 2018-04-08 | 2018-11-13 | 大连理工大学 | A kind of Damage Assessment Method experimental method based on PVDF sensors and strain mode |
| CN112444563A (en) * | 2020-11-25 | 2021-03-05 | 大连理工大学 | Transverse isotropic material damage evaluation method based on ultrasonic back reflection |
| CN112444563B (en) * | 2020-11-25 | 2022-05-10 | 大连理工大学 | Transverse isotropic material damage evaluation method based on ultrasonic back reflection |
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Owner name: XI AN COMMUNICATION UNIV. Free format text: FORMER OWNER: YIN ZHENGNAN Effective date: 20090918 |
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Application publication date: 20090722 |