CN107860539A - A kind of Modal Experimental Method for eliminating additional mass and influenceing - Google Patents
A kind of Modal Experimental Method for eliminating additional mass and influenceing Download PDFInfo
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- CN107860539A CN107860539A CN201710952273.XA CN201710952273A CN107860539A CN 107860539 A CN107860539 A CN 107860539A CN 201710952273 A CN201710952273 A CN 201710952273A CN 107860539 A CN107860539 A CN 107860539A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M7/00—Vibration-testing of structures; Shock-testing of structures
- G01M7/02—Vibration-testing by means of a shake table
- G01M7/022—Vibration control arrangements, e.g. for generating random vibrations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M7/00—Vibration-testing of structures; Shock-testing of structures
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- G01M7/025—Measuring arrangements
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Abstract
The invention discloses a kind of Modal Experimental Method for eliminating additional mass and influenceing, comprise the following steps：S1, treat geodesic structure division measuring point；S2, using locomotivity hammer modal test, obtain certain the rank modal frequency for treating geodesic structure；S3, obtain the relative position relation of this rank Mode Shape node and measuring point；S4, update a certain measuring point, the measuring point of neighbor node is moved to overlapped with this rank mode node or the locations of structures of little deviation on；S5, sensor and magnet base are placed on measuring point in the updated, move power hammer modal test, obtain modal frequency, eliminate additional mass influence；S6, judges whether the modal frequency that S5 is obtained reaches precision, if based on step S5 measuring points, repetition S2 S5 reach precision prescribed until the modal frequency of acquisition if not reaching.The present invention can effectively reduce the influence of feeler and magnet base to the original mode of structure in modal test.
Description
Technical field
The invention belongs to modal test technique field, and in particular to a kind of modal test side for eliminating additional mass and influenceing
Method, the problem of being had an impact especially for additional mass such as touch sensor and magnet bases to structural modal frequency, the present invention
Influence of such additional mass to structural modal frequency can effectively be reduced.
Background technology
Structure modal test is widely used in the multiple fields such as Optimal Structure Designing, improvement, fault diagnosis, dynamic analysis.
The modal test of feeler mode is also form (cost is low, technology maturation) extremely common at present, for hammer stimulating
Modal test, have become the dynamics Analysis of Vibration Characteristic methods of the professional standards such as machinery, structure, building.
However, in modal test, concern mostly is obtained by parameters such as the modal frequency of geodesic structure, the vibration shape, dampings, is often neglected
The factor of mode result is slightly influenceed in some modal tests.For example feeler and magnet base are one relative to prototype structure
Kind of additional mass, structural modal will be influenceed, especially influence rigidity it is little by geodesic structure.Once celebrating China swashs for fixing point within 1994
Encourage and the modal test of movable sensor, it is indicated that sensor additional mass has an impact to mode result, especially by geodesic structure matter
When amount is lighter, the quality of sensor has a strong impact on generation to test result；Quality 56g sensors are suspended on into quality is
6.55Kg straight beams, sensor additional mass influence to reach 10 ℅ on mode result.This feeler and magnet base etc. are additional
Influence of the quality to structural modal frequency, the especially influence to modal frequency, can not be ignored in any case.
How to eliminate additional mass influences to have obtained long period concern on modal parameter, and also has certain methods.
Nineteen ninety Zhou Chuanrong etc. carry out lightweight specimen test mode research, consider sensor and vibrator etc. caused by additional mass with
Additional stiffness, analyzed using modal theory and eliminate additional mass to Effect of Mode.However, these theoretical methods are excessively complicated and not
The application being easy in engineering.Therefore, the present invention seeks to break through from test method, by being innovated to test method scheme,
To eliminate influence of the additional mass such as sensor and magnet base to structural modal frequency.The present invention can effectively reduce additional mass pair
The influence of mode, and cost is low, operating process is simple.
The content of the invention
, can the invention provides a kind of Modal Experimental Method for eliminating additional mass and influenceing for the deficiency of foregoing description
High degree reduces influence of the additional mass such as feeler and magnet base to structural modal frequency.
In order to solve the above technical problems, the technical solution adopted in the present invention is as follows：
A kind of Modal Experimental Method for eliminating additional mass and influenceing, comprises the following steps：
S1, treat geodesic structure and carry out measuring point division；It is described to treat that geodesic structure is applied to one-dimensional continuous structure, the two dimensions such as beam, bar
The three-dimensional engineering or test structure of planar structure or complexity.
S2, additional mass being positioned over to any measuring point for treating geodesic structure, the additional mass includes sensor and magnet base,
Modal Experimental Method is hammered using locomotivity hammer, is obtained with LMS data collecting instruments and model analysis software and treats geodesic structure
First-order modal frequency and Mode Shape, feeler and magnet base in such modal test influence modal frequency；
S3, the Mode Shape of certain the rank mode obtained according to step S2, obtain this rank mode Mode Shape node and
The position relationship of node of vibration mode and measuring point, one-dimensional continuous structure are node, and two-dimentional continuous structure is the nodel line or section of node composition
Circle, node is vibration shape fixed point, and high order mode possesses multiple nodes；
S4, some measuring point in measuring point is updated, the measuring point for closing on this rank mode any node is moved to and this node
Overlap or with the locations of structures to be measured of this node little deviation, and updating the finite element that geodesic structure is treated in LMS data collecting instruments
The measuring point of model, do not become by the measuring point number of geodesic structure, but the position of some measuring point is changed, and the position after change and section
Point overlaps or near nodal；
S5, additional mass is placed on measuring point in the updated, power hammer modal test is moved, using LMS data
Acquisition Instrument and model analysis software obtain this rank modal frequency, and resulting modal frequency has been a cancellation additional mass influence
Modal frequency；
Whether the modal frequency that S6, judgment step S5 are obtained meets to require, using step S5 measuring point as base if being unsatisfactory for
Plinth, repeat step S2-S5 reach the modal frequency of required precision until obtaining.
In the present invention, the additional mass includes sensor and magnet base.And the quality of the sensor and magnet base
It is not limited.
In the present invention, in step S2-S6 processes, the arbitrary order for treating geodesic structure or all rank modal frequencies can be obtained, and
The modal frequency of gained has eliminated the influence of additional mass.
Beneficial effect：The present invention according to additional mass and its active position, the action rule of modal frequency and Mode Shape,
The node of Mode Shape is close to by adjusting additional mass and carries out locomotivity hammer modal test at least once, to obtain
Accurate modal frequency corresponding to this vibration shape, the additional mass such as feeler and magnet base can be reduced with high degree to structure
The influence of modal frequency, obtain accurately modal frequency.The present invention carries out modal test based on an Izod test model, its
Middle sensor and magnet base amount to 61g additional mass, using the Modal Experimental Method of the present invention, can make additional mass to mode
The influence of frequency is reduced to less than 0.7% from 12%, it is seen that the present invention eliminates additional mass influence, and the good results are evident.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the required accompanying drawing used in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with
Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is the cantilever beam structure and measuring point distribution map of the present invention.
Fig. 2 is the modal test instrument connection figure of the present invention.
Fig. 3 is additional mass of the present invention to first three rank modal frequency affecting laws figure of cantilever beam.
Fig. 4 is first five rank Mode Shape of cantilever beam of the present invention, wherein (a) first step mode vibration shape；(b) second-order mode
The vibration shape；(c) the 3rd rank Mode Shape；(d) fourth order Mode Shape；(e) the 5th rank Mode Shape.
Fig. 5 is that additional mass of the present invention is located at the 1st measuring point operating mode first five rank mode steady state picture.
Fig. 6 is that additional mass of the present invention is located at the 1st measuring point first five rank Mode Shape：(a) the first step mode vibration shape；(b)
The second-order modal vibration shape；(c) the 3rd rank Mode Shape；(d) fourth order Mode Shape；(e) the 5th rank Mode Shape.
Fig. 7 is that additional mass of the present invention is located at the 8th measuring point operating mode first five rank mode steady state picture.
Fig. 8 is that additional mass of the present invention is located at the 8th measuring point operating mode second-order mode steady state picture.
Fig. 9 is that additional mass of the present invention is located at the 8th measuring point first five rank Mode Shape：(a) the first step mode vibration shape；(b)
The second-order modal vibration shape；(c) the 3rd rank Mode Shape；(d) fourth order Mode Shape；(e) the 5th rank Mode Shape.
Figure 10 is that additional mass of the present invention is located at the 9th measuring point operating mode first five rank mode steady state picture.
Figure 11 is that additional mass of the present invention is located at the 9th measuring point first five rank Mode Shape：(a) the first step mode vibration shape；(b)
The second-order modal vibration shape；(c) the 3rd rank Mode Shape；(d) fourth order Mode Shape；(e) the 5th rank Mode Shape.
Figure 12 is that additional mass of the present invention is located at the 6th measuring point operating mode first five rank mode steady state picture.
Figure 13 is that additional mass of the present invention is located at the 6th measuring point first five rank Mode Shape：(a) the first step mode vibration shape；(b)
The second-order modal vibration shape；(c) the 3rd rank Mode Shape；(d) fourth order Mode Shape；(e) the 5th rank Mode Shape.
Figure 14 is that the present invention eliminates the Modal Experimental Method flow chart that additional mass influences.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art are obtained every other under the premise of creative work is not paid
Embodiment, belong to the scope of protection of the invention.
A kind of Modal Experimental Method for eliminating additional mass and influenceing, comprises the following steps：
S1, treat geodesic structure and carry out measuring point division；It is described to treat that geodesic structure is applied to one-dimensional continuous structure, the two dimensions such as beam, bar
The three-dimensional engineering or test structure of planar structure or complexity.
S2, additional mass is positioned over to any measuring point for treating geodesic structure, Modal Experimental Method is hammered using locomotivity hammer,
Obtained with LMS data collecting instruments and model analysis software and treat a certain rank modal frequency of geodesic structure and Mode Shape, such mode
Feeler and magnet base in experiment influence modal frequency.The additional mass includes sensor and magnet base, and described
The quality of sensor and magnet base is not limited.
S3, the Mode Shape of certain the rank mode obtained according to step S2, obtain this rank mode Mode Shape node and
The position relationship of node of vibration mode and measuring point, one-dimensional continuous structure are node, and two-dimentional continuous structure is the nodel line or section of node composition
Circle, node is vibration shape fixed point, and high order mode possesses multiple nodes.
S4, some measuring point in measuring point is updated, the measuring point for closing on this rank mode any node is moved to and this node
Overlap or with the locations of structures to be measured of this node little deviation, and updating the finite element that geodesic structure is treated in LMS data collecting instruments
The measuring point of model, do not become by the measuring point number of geodesic structure, but the position of some measuring point is changed, and the position after change and section
Point overlaps or near nodal.
S5, additional mass is placed on measuring point in the updated, power hammer modal test is moved, using LMS data
Acquisition Instrument and model analysis software obtain this rank modal frequency, and resulting modal frequency has been a cancellation additional mass influence
Modal frequency.
Whether the modal frequency that S6, judgment step S5 are obtained meets to require, using step S5 measuring point as base if being unsatisfactory for
Plinth, repeat step S2-S5 reach the modal frequency of required precision until obtaining.
In the present invention, the head of the power hammer uses vulcanie.
The theory of the present invention is specifically described below.
Illustrated by taking cantilever beam as an example, described to treat that geodesic structure is cantilever beam structure, the root of cantilever beam is consolidated by bench vice
It is fixed, and it is evenly equipped with 10 measuring points along beam length direction in cantilever beam；Sensor is installed to a measuring point every time by magnet base
Place, and the quality of the sensor and magnet base and for 61 grams, the mode hammered into shape with locomotivity beats cantilever beam, and sensor surveys this
Into LMS data collecting instruments, LMS data collecting instruments obtain 10 measuring points and export cantilever after being analyzed the data transfer pointed out
First five rank Mode Shape of girder construction；By the Analysis Mode vibration shape, the position relationship of every rank Mode Shape node and measuring point is obtained；
Then certain rank modal frequency is corrected according to the actual requirements, the modal frequency that the additional mass that is eliminated influences.
1st, experimental rig and basic condition
Test structure is cantilever beam, and root is fixed such as Fig. 1, cantilever beam geometric ＆ physical property such as table 1 by bench vice.
The Flexural cantilever model geometric ＆ physical property of table 1
Based on this structure, carry out the Test Research for eliminating additional mass influence mode.Sensor passes through magnetic force
Seat is connected with cantilever beam, and relative to cantilever beam, sensor and magnet base are a kind of additional mass, will influence the mould of prototype structure
State.In structure modal test, such additional mass is generally more than ten grams or tens of grams.Influenceed for prominent additional mass, experiment is ground
Middle additional mass is studied carefully from 61g (sensor and magnet base quality), and test apparatus is LMS analysis softwares and signal sampler.It is outstanding
Measuring point of the arm beam in LMS is that 10 measuring points, such as Fig. 1 are distributed along beam length.
Apparatus in modal test in experiment as shown in Fig. 2 use hammering method modal test, and be locomotivity
The mode of hammer.Some parameters in experiment, analysis bandwidth 640Hz (the 5th rank modal frequency is less than 640Hz), spectral line number 8192,
Power tup uses vulcanie.
Additional mass, additional mass active position, the action rule of modal frequency and Mode Shape are as shown in Figure 3.It is additional
Influence of the quality to modal frequency is depending on the Mode Shape value of additional mass position and the distance of the constant shaped position of structure
Size, distance is bigger, and influence of the additional mass to modal frequency is bigger.This rule can use modal frequency to the sensitive of quality
Topology degree explains.
2nd, the two modal testing results of additional mass effect
The Modal Test result of structure is obtained roughly first, to obtain the position of each rank Mode Shape of interest and measuring point
Put relation.Additional mass (61g) is placed in the measuring points of Fig. 1 the 10th (cantilever beam end), carries out a modal test, is closed with obtaining
First five rank modal frequency of note, as shown in table 2 and five rank Mode Shapes, as shown in Figure 4.
First five rank modal frequency of the cantilever beam of table 2 (61g additional mass is placed in the 10th measuring point)
Because additional mass and its active position depend on Mode Shape to the influence degree of modal frequency.Work as additional mass
Positioned at Mode Shape node or it is neighbouring when, additional mass does not influence or influenceed on this rank modal frequency smaller.First five rank obtained
In Mode Shape, the first first order mode node is located at the 1st measuring point, second-order node of vibration mode positioned at the 1st, 8 measuring points or near, the 3rd rank
Node of vibration mode is positioned at the 1st, 6,9 measuring points or nearby, fourth order node of vibration mode is located at the 1st, 4,7,9 measuring points or near, the 5th rank mould
State node of vibration mode is positioned at the 1st, 4,8 measuring points or near.To find more accurate mode node and point position relation, then need
Divide more multi-measuring point.
It is cantilever beam by geodesic structure, there is fixed constraint (the 1st measuring point), therefore fixed constraint position is that all rank mode are shaken
The node of type.Additional mass (sensor etc.) is positioned over the 1st measuring point, the whole mode not influenceed by additional mass can be obtained
Frequency.However, being also widely present the structure for being free of fixed constraint in engineering, it is all mode that some point, which is now also not present,
Node.Therefore, except fixing end constraint node, additional mass be located at remaining node or it is neighbouring when, the modal frequency of acquisition also has
There is degree of precision.
3rd, the Modal Experimental Method that additional mass influences is eliminated
Collective effect rule according to additional mass and active position with Mode Shape to modal frequency.Additional mass is located at
During certain rank mode node, this rank modal frequency is unaffected；When additional mass is located at certain rank Mode Shape value extreme value place, this rank
What modal frequency was subject to has a great influence；For multinode mode, when additional mass is located at certain rank Mode Shape value maximum value position,
This rank modal frequency is by being influenceed maximum.
And then using the rule of measuring point and mode node, by additional mass be positioned over this rank mode node or near, can
Obtain that this rank mode is unaffected or the modal frequency of weak influence.For every first-order modal, carry out once similar modal test,
Obtain and eliminate every single order modal frequency that additional mass influences.
3.1 first step mode frequencies
Based on preliminary modal test, mode of interest (first five rank) frequency and the vibration shape have been obtained.For the rank of cantilever beam first
Mode, there is a node (measuring points of Fig. 1 the 1st) for being located at fixing end.The additional mass that sensor is formed with magnet base is positioned over
Near 1st measuring point, carry out modal test.Due to magnet base contact area and fixed constraint factor, additional mass is located at the first rank
Mode near nodal, but do not overlapped with node.
The Modal Experimental Method hammered into shape using locomotivity, the cantilever beam structure of the 1st measuring point operating mode is located to additional mass, carried out
Modal test, the steady state picture of acquisition is as shown in figure 5, obvious formant occurs in first five rank mode.First five the rank mode frequency obtained
Rate such as table 3.
The additional mass of table 3 (61g) is located at the cantilever beam of the 1st measuring point operating mode first five rank modal frequency
Because measuring point 1 (fixed constraint) is the node of all rank mode, the modal frequency obtained under this operating mode is closer to very
Real value.On the basis of this operating mode mode result, judge under other operating modes (additional mass is located at other rank Mode Shape nodes)
Modal frequency precision.The 1st measuring point operating mode is such as located at based on additional mass, modal frequency change such as table 4 under the 10th measuring point operating mode.
The additional mass of table 4 is located at the 10th measuring point operating mode first five rank modal frequency change (being based on the 1st measuring point operating mode)
Additional mass is located at the Mode Shape obtained under the operating mode of measuring point 1, as shown in fig. 6, measuring point 1 (fixed constraint) is institute
There is a node of rank mode, first five rank modal frequency of acquisition is closest to actual value.But and not all structure exist it is fixed about
Beam, during active position of the node as additional mass of on-fixed constraint, the structural modal frequency of acquisition also can reach higher
Precision.
3.2 second-order modal frequencies
The relation of second-order Mode Shape node and measuring point based on acquisition is adapted to place according to Fig. 4 and Fig. 6, the 8th measuring point
The additional mass of sensor and magnet base composition, to obtain accurate second-order modal frequency.Additional mass (61g) is located at the 8th
Measuring point, first five rank mode steady state picture is obtained as shown in fig. 7, the formant unobvious of second-order mode, remaining quadravalence mode are total to
The peak that shakes is obvious.Reduce and analyze bandwidth, second-order mode steady state picture, as shown in Figure 8, it is possible to find formant be present in second-order mode,
Because additional mass (sensor etc.) is located at second-order mode node.
Additional mass (sensor etc.) is located under the 8th measuring point operating mode, and first five rank modal frequency of acquisition is shown in Table 5.
The additional mass of table 5 (61g) is located at the cantilever beam of the 8th measuring point operating mode first five rank modal frequency
It is located at the 1st measuring point operating mode compared to additional mass (sensor etc.), second-order modal frequency reduces 0.2Hz, the range of decrease
0.29%, remaining rank modal frequency range of decrease is still larger, such as table 6.
The additional mass of table 6 is located at the 8th measuring point operating mode first five rank modal frequency change (being based on the 1st measuring point operating mode)
The bending vibation mode picture of first five rank mode, such as Fig. 9, Fig. 9 b are second-order Mode Shape, and measuring point 8 is second-order mode section
Point, i.e. measuring point 8 are located in constant shaped position；But measuring point 8 is not remaining rank mode node, in remaining rank Mode Shape, measuring point 8
There is certain distance with constant shaped position.
3.3 third and fourth rank modal frequency
The relation (Fig. 4, Fig. 6) of the 3rd rank Mode Shape node and measuring point based on acquisition, the 9th measuring point is selected to place sensing
The additional mass that device is formed with magnet base.First five the rank mode steady state picture obtained, such as Figure 10, the resonance of first five rank mode steady state picture
Peak is obvious, and the 9th measuring point has a certain distance not at the node of the 3rd rank Mode Shape, such as Figure 11 with constant shaped position.
First five the rank modal frequency obtained is shown in Table 7.
The additional mass of table 7 (61g) is located at the cantilever beam of the 9th measuring point operating mode first five rank modal frequency
It is located at the 1st measuring point (fixing end) compared to additional mass (sensor etc.), the 3rd rank modal frequency reduces 1.26Hz, drop
0.64%, as shown in table 8.
The additional mass of table 8 is located at the 9th measuring point operating mode first five rank modal frequency change (being based on the 1st measuring point operating mode)
It is worth noting that fourth order modal frequency precision is also higher, 2.1Hz, the range of decrease 0.55% are reduced.Remaining rank mode
The deviation of frequency is larger.The reason for this is that：9th measuring point be located at the 3rd rank, fourth order Mode Shape node or near, its excess-three rank
The distance of the node of Mode Shape and the 9th measuring point is big, such as Figure 11.
For fourth order modal frequency, from table 8 and Figure 11, the 9th measuring point is close from the node of fourth order mode, obtains
Modal frequency deviation it is smaller, so the 9th measuring point can be as the placement location of additional mass (sensor and magnet base), with identification
The fourth order modal frequency of cantilever beam.For high order mode, the nodal distance of the different modalities vibration shape is close (common node), can lead to
Cross a measuring point and obtain accurate multi-modes frequency.
3.4 the 5th rank modal frequencies
The 5th rank Mode Shape node and the relation (Fig. 4) of measuring point obtained based on preliminary test, can not obtain the 5th rank
The nearer measuring point of mode nodal distance, but Figure 11 can provide preliminary suitable measuring point (measuring point 1,4,6,7,9).Through trying for several times
Test, the 6th measuring point is moved down into 36mm establishes the 6th new measuring point, to place additional mass (sensor and magnet base).Before obtaining
Five rank mode steady state pictures, such as Figure 12, the formant of the 5th rank mode is not apparent.Show that the 6th measuring point shakes with the 5th rank mode
The distance of the node of type is near.First five the rank modal frequency obtained is shown in Table 9.
The additional mass of table 9 (61g) is located at the cantilever beam of the 6th measuring point operating mode first five rank modal frequency
It is located at the 1st measuring point (fixing end) compared to additional mass (sensor), the 5th rank modal frequency reduces 4.07Hz, the range of decrease
0.65%, such as table 10.
The additional mass of table 10 is located at the 6th measuring point operating mode first five rank modal frequency change (being based on the 1st measuring point operating mode)
3rd rank and the 5th rank modal frequency deviation are smaller, and remaining rank modal frequency deviation is big.The reason for this is that：6th measuring point
Positioned at the 5th rank, the 3rd rank Mode Shape node or near, the distance of the node and the 6th measuring point of its excess-three rank Mode Shape is remote,
Such as Figure 13.
Using the Modal Experimental Method of this elimination additional mass, with the outstanding of additional mass 61g (sensor and magnet base)
Exemplified by arm beam, the modal frequency of acquisition and with base operation condition experiment obtain modal frequency deviation such as table 11 such as show.
Table 11 proposes that test method obtains first five rank modal frequency and deviation containing additional mass (61g) cantilever beam
By this test method and scheme, the modal frequency of acquisition can be made more accurate, obtain first five rank modal frequency
Deviation is within 0.7%, and compared to 12% deviation occurred in table 4, additional mass can be greatly reduced in experiment to structural modal
The influence of frequency.
4th, conclusion
The modal test of feeler formula is commonplace, but the relatively primitive structure of sensor is a kind of additional mass, attached
Quality is added to influence structure modal test result.Conducted a research with this problem, the Main Conclusions that the present invention obtains is as follows：
Influence of 1 additional mass to modal frequency, the size of additional mass is depended not only on, additional mass is additionally depended on and puts
The position (related to Mode Shape) put；
2 propose a kind of Modal Experimental Method for eliminating additional mass and influenceing, and are obtained first through preliminary test of interest each
The position relationship of rank Mode Shape node and measuring point, then by additional mass be positioned over every rank mode node or near, it is and right
Carried out a test per first-order modal, after carrying out campaign, you can obtain every single order modal frequency of the weak influence of additional mass；
3 using the Modal Experimental Method proposed, by taking the cantilever beam structure of 61g additional mass as an example, first five rank mould of acquisition
State frequency, influence of the additional mass to modal frequency can be made to be reduced to less than 0.7% from 12%.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
God any modification, equivalent substitution and improvements made etc., should be included in the scope of the protection with principle.
Claims (5)
1. a kind of Modal Experimental Method for eliminating additional mass and influenceing, it is characterised in that comprise the following steps：S1, to knot to be measured
Structure carries out measuring point division；
S2, additional mass is positioned over to any measuring point for treating geodesic structure, Modal Experimental Method is hammered using locomotivity hammer, used
LMS data collecting instruments and model analysis software, which obtain, treats a certain rank modal frequency of geodesic structure and Mode Shape；
S3, the Mode Shape of certain the rank mode obtained according to step S2, obtain the Mode Shape node and the vibration shape of this rank mode
The position relationship of node and measuring point；
S4, some measuring point in measuring point is updated, the measuring point for closing on this rank mode any node is moved to and overlapped with this node
Or with the locations of structures to be measured of this node little deviation, and updating the FEM model that geodesic structure is treated in LMS data collecting instruments
Measuring point；
S5, additional mass is placed on measuring point in the updated, power hammer modal test is moved, using LMS data acquisitions
Instrument and model analysis software obtain this rank modal frequency, the modal frequency that the additional mass that is eliminated influences；
S6, judgment step S5 obtain modal frequency whether meet to require, if if being unsatisfactory for based on step S5 measuring point, weight
Multiple step S2-S5 reaches the modal frequency of required precision until obtaining.
A kind of 2. Modal Experimental Method for eliminating additional mass and influenceing according to claim 1, it is characterised in that：It is described attached
Quality is added to include sensor and magnet base.
A kind of 3. Modal Experimental Method for eliminating additional mass and influenceing according to claim 2, it is characterised in that：The biography
The quality of sensor and magnet base is not limited.
A kind of 4. Modal Experimental Method for eliminating additional mass and influenceing according to claim 1, it is characterised in that：In step
S2-S6 process, the arbitrary order for treating geodesic structure or all rank modal frequencies can be obtained, and resulting modal frequency has eliminated
The influence of additional mass.
A kind of 5. Modal Experimental Method for eliminating additional mass and influenceing according to claim 1, it is characterised in that：It is described to treat
Geodesic structure is applied to the three-dimensional engineering or test structure of the one-dimensional continuous structures, two-dimension plane structure or complexity such as beam, bar.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539537A (en) * | 2011-12-30 | 2012-07-04 | 大连理工大学 | Frame structure damage method based on additional virtual quality |
| CN103093026A (en) * | 2012-12-07 | 2013-05-08 | 中国海洋大学 | Added mass vibration inverse algorithm for fluid |
| CN203360714U (en) * | 2013-07-22 | 2013-12-25 | 江苏万工科技集团有限公司 | Heald frame bending modal control device |
| CN103528667A (en) * | 2013-10-23 | 2014-01-22 | 东北大学 | Laser scanning based cylindrical shell modal shape testing device and method |
| CN104776963A (en) * | 2015-04-14 | 2015-07-15 | 北京强度环境研究所 | Acoustic excitation non-contact modal testing system and method |
| CN104931218A (en) * | 2015-06-30 | 2015-09-23 | 宁波大学 | System of modal vibration mode of non-contact measuring flexible structure |
| CN204903118U (en) * | 2015-06-30 | 2015-12-23 | 宁波大学 | System for non -contact measures flexible construction's mode mode of vibration |
| CN106017834A (en) * | 2016-05-26 | 2016-10-12 | 工业和信息化部电子第五研究所 | Non-contact modality testing method, device, and system |
| CN106289947A (en) * | 2016-08-31 | 2017-01-04 | 中国人民解放军军械工程学院 | A kind of high-strength light girder construction damnification recognition method |
| CN205981439U (en) * | 2016-09-07 | 2017-02-22 | 湖南科技大学 | Thin wall task work makes mode testing arrangement based on machine vision |
| CN106596011A (en) * | 2016-11-21 | 2017-04-26 | 中国船舶重工集团公司第七0五研究所 | Small impeller mode testing method based on exciting point optimization and vibration measurement with laser |
-
2017
- 2017-10-13 CN CN201710952273.XA patent/CN107860539B/en not_active Expired - Fee Related
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539537A (en) * | 2011-12-30 | 2012-07-04 | 大连理工大学 | Frame structure damage method based on additional virtual quality |
| CN103093026A (en) * | 2012-12-07 | 2013-05-08 | 中国海洋大学 | Added mass vibration inverse algorithm for fluid |
| CN203360714U (en) * | 2013-07-22 | 2013-12-25 | 江苏万工科技集团有限公司 | Heald frame bending modal control device |
| CN103528667A (en) * | 2013-10-23 | 2014-01-22 | 东北大学 | Laser scanning based cylindrical shell modal shape testing device and method |
| CN104776963A (en) * | 2015-04-14 | 2015-07-15 | 北京强度环境研究所 | Acoustic excitation non-contact modal testing system and method |
| CN104931218A (en) * | 2015-06-30 | 2015-09-23 | 宁波大学 | System of modal vibration mode of non-contact measuring flexible structure |
| CN204903118U (en) * | 2015-06-30 | 2015-12-23 | 宁波大学 | System for non -contact measures flexible construction's mode mode of vibration |
| CN106017834A (en) * | 2016-05-26 | 2016-10-12 | 工业和信息化部电子第五研究所 | Non-contact modality testing method, device, and system |
| CN106289947A (en) * | 2016-08-31 | 2017-01-04 | 中国人民解放军军械工程学院 | A kind of high-strength light girder construction damnification recognition method |
| CN205981439U (en) * | 2016-09-07 | 2017-02-22 | 湖南科技大学 | Thin wall task work makes mode testing arrangement based on machine vision |
| CN106596011A (en) * | 2016-11-21 | 2017-04-26 | 中国船舶重工集团公司第七0五研究所 | Small impeller mode testing method based on exciting point optimization and vibration measurement with laser |
Non-Patent Citations (1)
| Title |
|---|
| 李智劳 等: ""基于锤击法的复材结构模态试验研究"", 《机电信息》 * |
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