CN101487748B - Shearing force measurement bridge circuit in bending-twisting combined test apparatus - Google Patents

Shearing force measurement bridge circuit in bending-twisting combined test apparatus Download PDF

Info

Publication number
CN101487748B
CN101487748B CN2009100082890A CN200910008289A CN101487748B CN 101487748 B CN101487748 B CN 101487748B CN 2009100082890 A CN2009100082890 A CN 2009100082890A CN 200910008289 A CN200910008289 A CN 200910008289A CN 101487748 B CN101487748 B CN 101487748B
Authority
CN
China
Prior art keywords
strain rosette
strain
bridge circuit
rosette
orientation
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.)
Expired - Fee Related
Application number
CN2009100082890A
Other languages
Chinese (zh)
Other versions
CN101487748A (en
Inventor
李�昊
刘一华
詹春晓
王美芹
吴枝根
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hefei University of Technology
Original Assignee
Hefei University of Technology
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hefei University of Technology filed Critical Hefei University of Technology
Priority to CN2009100082890A priority Critical patent/CN101487748B/en
Publication of CN101487748A publication Critical patent/CN101487748A/en
Application granted granted Critical
Publication of CN101487748B publication Critical patent/CN101487748B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)

Abstract

The invention relates to a shearing force measuring bridge circuit in a crankle combined test device. The device consists of an aluminum alloy cylinder cantilever and a crank which is in an angle of 90 degrees with the cylinder cantilever; the outer circumference of the measured cross section of the aluminum alloy cylindrical cantilever is provided with four 45-degree 3-right angle strain rosettes at an interval of a 90-degree interval according to an order of a strain rosette A, a strain rosette B, a strain rosette C and a strain rosette D; and the device is characterized in that the orientations of the strain rosette B, the strain rosette C and the strain rosette D are the same along the axis direction of the cylinder cantilever, the orientation of the strain rosette A is opposite to the orientations of the other strain rosettes, and a circumference position where a measuring point is located is taken as the symmetric center. The shearing force measuring bridge circuit can obtain higher measuring precision on flexural moment and torque, can effectively measure shearing force, so as to add new teaching experiment content, and can provide a model for internal force measurement of similar components in engineering structures.

Description

The shearing force measurement bridge circuit that bending-twisting combined test apparatus constitutes
The application is that application number is to divide an application for " bending-twisting combined test apparatus and the application in the plain measurement of internal force thereof " for " on June 30th, 2006 ", denomination of invention " 200610088185.1 ", the applying date.
Technical field
The present invention relates to bending-twisting combined test apparatus, the shearing force measurement bridge circuit in the bending-twisting combined test apparatus of more specifically saying so.
Background technology
The resistance strain measurement technology is one of main means of engineering structure Stress analysis from test result, and is widely used in each field of engineering technology such as machinery, building, Aero-Space.Study resistance strain measurement principle is grasped its measuring method and technology, and can skillfully be applied, and is the students of engineering and polytechnic universities, particularly a basic experiment technical ability must grasping of engineering student.Thereby the electrical measurement stress test is one of requisite important content in the experimental teaching, and wherein " cylinder bending combination experiment " is the basic experiment content of electrical measurement stress test.The experiment content of this experiment is to measure internal force elements such as moment of flexure, moment of torsion, shearing on bending and twisting combined action principle stress and the specified cross-section down.The foil gauge arrangement of existing experimental provision, precision is higher when principle stress, moment of flexure and torque measurement, and the error when still measuring shearing is very big, surpasses 50%, has lost the experiment meaning.
Experiment method:
Fig. 1, Fig. 2 and shown in Figure 3; Experimental provision is to be 90 jiaos 2 of crank throws to constitute by aluminum alloy drum cantilever 1 with it; Can be known that by the bending and twisting combined action loading characteristic A, 2 of C are the pure shear stress state, the 45 ° of line strains with-45 ° of directions in 2 edges are respectively:
τ in the formula TAnd τ QExpression is reversed and crooked shearing stress respectively.During measurement, 45 ° of directions and-45 ° of orientation-sensitive grid in A, 2 strain rosettes of C are connected into full-bridge bridge circuit as shown in Figure 4, then the measured value of crooked shearing stress does
Figure G2009100082890D00013
ε in the formula Q surveys=(ε -45 °) A-(ε 45 °) A+ (ε 45 °) C-(ε -45 °) CBe the bridge circuit real output value.The substitution following formula
Figure G2009100082890D00014
Can obtain the shearing on the I-I cross section, α=d/D wherein, d, D are respectively the inside and outside footpath of cylinder 1.
When acting on the load F=100N of crank throw end, the theoretical value of shearing is F on the I-I cross section Q=100N.During experiment, adopt equivalent Loading Method step by step, table 1 is one group of measured data.According to table 1 measured data, the shearing that records on the I-I cross section is 157.61N, reaches 57.6% with the relative error of theoretical value.
The actual measurement output valve of table 1 electric bridge
Load F/N 50 150 250 350 450
Strain-ga(u)ge reading ε Real/με 34 102 171 239 307
Error analysis
According to the strain gage testing principle, foil gauge records the mean strain that strain is a sensitive grid, is approximately equal to the strain of sensitive grid center position.When adopting 45 °-3 rectangular rosettes to measure, owing to the sensitive grid center does not overlap with measurement point, when adopting full bridge measurement bending shearing stress; Can only offset shearing stress in torsion power; And additional bending normal stresses can't be eliminated, thereby causes measuring error very big, also can be found out by Fig. 5; Except the influence in transversal effect and stickup orientation, the main error of shearing force measurement is because the stress state and inconsistent the causing of measured point pure shear stress state of strain rosette sensitive grid center.
Summary of the invention
The present invention is for avoiding above-mentioned existing in prior technology weak point; Shearing force measurement bridge circuit in a kind of bending-twisting combined test apparatus is provided; As experimental provision, can not only aspect moment of flexure, moment of torsion, obtain higher measuring accuracy on the one hand, can effectively measure shearing simultaneously; Thereby increase new experiment content, transform the experiment of raising type as; Offer reference for the internal force measurement of similar component in the engineering structure on the other hand.
The technical scheme that technical solution problem of the present invention is adopted is:
The shearing force measurement bridge circuit that bending-twisting combined test apparatus of the present invention constitutes; Said bending-twisting combined test apparatus is to adopt aluminum alloy drum cantilever crank throw structure; The crank throw that is 90 jiaos by the aluminum alloy drum cantilever with it constitutes; On the tested xsect excircle of said aluminum alloy drum cantilever,, be 90 angular spacings successively and arrange four 45 °-3 rectangular rosettes according to the order of strain rosette A, strain rosette B, strain rosette C and strain rosette D; Be characterized in that said bending-twisting combined test apparatus is on the axis direction of said cylinder cantilever; Strain rosette B, strain rosette C and strain rosette D towards identical; Strain rosette A and other three strain rosettes are towards on the contrary, and are symcenter with measurement point place circumferential position; Said shearing force measurement bridge circuit is: in the access measurement bridge circuit is 45 ° of directions and-45 ° of orientation-sensitive grid of strain rosette A and strain rosette C;-45 ° of orientation-sensitive grid of said strain rosette A insert input end A and the output terminal B that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette A insert input end C and the output terminal B that measures bridge circuit;-45 ° of orientation-sensitive grid of strain rosette C insert input end A and the output terminal D that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette C insert input end C and the output terminal D that measures bridge circuit, constitute the full bridge measurement bridge circuit.
The present invention with the strain rosette Rotate 180 ° stickup at A point place, then can eliminate shearing stress in torsion power and additional bending normal stresses according to the strain rosette arrangement in the prior art simultaneously, thereby improves the measuring accuracy of shearing.Compared with present technology, beneficial effect of the present invention is embodied in:
1, the shearing and the moment of torsion of 45 ° of directions and-45 ° of orientation-sensitive grid central point place cross-section are all constant in apparatus of the present invention, and moment of flexure changes and is no more than 2%, thereby can be similar to and think that its stress state remains unchanged.
2, apparatus of the present invention can not only obtain higher measuring accuracy aspect moment of flexure, moment of torsion; Can also effectively measure shearing simultaneously; Enriched experimental teaching content on the one hand; Increased the thinking property and the interest of experiment, deepened the understanding of student's counter stress state notion with group bridge principle and method, the internal force measurement for similar component in the engineering structure provides reference on the other hand.
Description of drawings
Fig. 1 is the experimental provision structural representation.
Fig. 2 is the point position synoptic diagram on the I-I xsect.
Strain rosette arrangement synoptic diagram in Fig. 3 prior art.
Fig. 4 is the shearing force measurement bridge circuit synoptic diagram in the prior art.
Fig. 5 is the strain rosette structural representation.
Fig. 6 is a strain rosette arrangement synoptic diagram of the present invention.
Fig. 7 is used for the bridge arrangement synoptic diagram of shearing force measurement for apparatus of the present invention.
Fig. 8 is used for the bridge arrangement synoptic diagram of torque measurement for apparatus of the present invention.
Fig. 9 is used for the bridge arrangement synoptic diagram of addition bend normal stress measurement for apparatus of the present invention.
Label among the figure: 1 aluminum alloy drum cantilever, 2 crank throws.
Below through embodiment the present invention is further described:
Embodiment
Referring to Fig. 1, Fig. 2 and Fig. 6, present embodiment is according to the strain rosette arrangement in the prior art, with the strain rosette Rotate 180 ° stickup at A point place.Shown in the figure; Identical with prior art is; Adopt aluminum alloy drum cantilever crank throw structure, the crank throw 2 that is 90 jiaos by aluminum alloy drum cantilever 1 with it constitutes, on the tested xsect excircle of aluminum alloy drum cantilever 1; According to the order of strain rosette A, strain rosette B, strain rosette C and strain rosette D, be 90 angular spacings successively and arrange four 45 °-3 rectangular rosettes.Different is along on the axis direction of cylinder cantilever 1 with prior art, strain rosette B, strain rosette C and strain rosette D towards identical, strain rosette A and other three strain rosettes are towards on the contrary, and are symcenter with measurement point place circumferential position.
The application of present embodiment bending-twisting combined test apparatus in the plain measurement of internal force:
One of use: the measurement of shearing
The stress state that A, 2 of C locate 45 ° of directions and-45 ° of orientation-sensitive grid central points in the strain rosette can be regarded the stack of uniaxial stressed state and pure shear stress state as.According to generalized Hooke law, when adopting present embodiment cloth sheet scheme, its line strain along the grid length direction is respectively
Figure G2009100082890D00041
Figure G2009100082890D00042
Figure G2009100082890D00043
Figure G2009100082890D00044
τ in the formula TAnd τ QExpression is reversed and crooked shearing stress, σ respectively MBe addition bend normal stress.
45 ° of directions and-45 ° of orientation-sensitive grid that A, 2 of C are located in the strain rosette insert bridge circuit respectively by Fig. 7; That is :-45 of strain rosette A ° of orientation-sensitive grid insert input end A and the output terminal B that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette A insert input end C and the output terminal B that measures bridge circuit;-45 ° of orientation-sensitive grid of strain rosette C insert input end A and the output terminal D that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette C insert input end C and the output terminal D that measures bridge circuit, constitute the full bridge measurement bridge circuit.
The measurement strain stress of then exporting Q surveysFor
The shearing that records does
Figure G2009100082890D00046
Can find out, adopt new paster mode, eliminate shearing stress in torsion power and addition bend normal stress simultaneously, can obtain shearing force measurement value comparatively accurately.
Two of application: torque measurement
Adopt present embodiment paster mode,, can't eliminate the addition bend normal stress of sensitive grid central point if still select the strain rosette of 2 of A, C to measure shearing stress in torsion power.Like this, can increase the measuring error of moment of torsion, measuring accuracy is had a negative impact.In the present embodiment, 45 ° of directions and-45 ° of orientation-sensitive grid of selecting B, 2 of D to locate strain rosette are measured.The crooked shearing stress of these sensitive grid central points is very little, is approximately zero, and shearing stress in torsion power and A, C point are identical.Its line strain along the grid length direction is respectively:
Figure G2009100082890D00051
Figure G2009100082890D00052
Figure G2009100082890D00053
Figure G2009100082890D00054
σ is a B point bending normal stresses in the formula.
45 ° of directions and-45 ° of orientation-sensitive grid in B, 2 strain rosettes of D are inserted bridge circuit by Fig. 8, that is:
-45 ° of orientation-sensitive grid of strain rosette B are inserted input end A and the output terminal B that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette B insert input end C and the output terminal B that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette D insert input end A and the output terminal D that measures bridge circuit;-45 ° of orientation-sensitive grid of strain rosette D insert input end C and the output terminal D that measures bridge circuit, constitute the full bridge measurement bridge circuit
The measurement strain stress of then exporting T surveysFor:
Figure G2009100082890D00055
The moment of torsion that records is:
Figure G2009100082890D00056
Measurement result is consistent with the original measurement effect of A, 2 strain rosettes of C of selecting.
Three of application: addition bend normal stress measurement
Adopt present embodiment paster mode, can increase the new experiment content of measuring A, 2 strain rosette addition bends of C normal stress.45 ° of directions and-45 ° of orientation-sensitive grid in A, B, C, the D four measuring point strain rosette are inserted the measurement bridge circuit respectively according to Fig. 9, that is:
In the access measurement bridge circuit is 45 ° of directions and-45 ° of orientation-sensitive grid of strain rosette A, strain rosette B, strain rosette C and strain rosette D; 45 ° of orientation-sensitive grid series connection of-45 ° of orientation-sensitive grid of strain rosette B and strain rosette A insert input end A and the output terminal B that measures bridge circuit again;-45 ° of orientation-sensitive grid series connection of the 45 ° of orientation-sensitive grid of strain rosette B and strain rosette A insert input end C and the output terminal B that measures bridge circuit again; 45 ° of orientation-sensitive grid series connection of-45 ° of orientation-sensitive grid of strain rosette C and strain rosette D insert input end A and the output terminal D that measures bridge circuit again;-45 ° of orientation-sensitive grid series connection of the 45 ° of orientation-sensitive grid of strain rosette C and strain rosette D insert input end C and the output terminal D that measures bridge circuit again, formation full bridge measurement bridge circuit
According to the characteristics of Wheatstone bridge series connection bridge circuit, and combine (4) and (5) formula, can export the measurement strain stress M surveysFor
Figure G2009100082890D00061
Figure G2009100082890D00062
= 1 - v E σ M
The addition bend normal stress that records does
Figure G2009100082890D00064
This experiment content not only can be measured the source of error (addition bend normal stress) that produces shearing dexterously, and the Wheatstone bridge bridge circuit of connecting is applied in the experimental teaching, thereby deepens the understanding of student to bridge circuit, widens the vision.

Claims (1)

1. the shearing force measurement bridge circuit that constitutes of a bending-twisting combined test apparatus; Said bending-twisting combined test apparatus is to adopt aluminum alloy drum cantilever crank throw structure; The crank throw (2) that is 90 jiaos by aluminum alloy drum cantilever (1) with it constitutes; On the tested xsect excircle of said aluminum alloy drum cantilever (1),, be 90 angular spacings successively and arrange four 45 °-3 rectangular rosettes according to the order of strain rosette A, strain rosette B, strain rosette C and strain rosette D; It is characterized in that:
Said bending-twisting combined test apparatus is along on the axis direction of said cylinder cantilever (1), strain rosette B, strain rosette C and strain rosette D towards identical, strain rosette A and other three strain rosettes are towards on the contrary, and to belong to circumferential position with measurement point be symcenter;
Said shearing force measurement bridge circuit in the bridge circuit is 45 ° of directions and-45 ° of orientation-sensitive grid of strain rosette A and strain rosette C for insert measuring;-45 ° of orientation-sensitive grid of said strain rosette A insert input end A and the output terminal B that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette A insert input end C and the output terminal B that measures bridge circuit;-45 ° of orientation-sensitive grid of strain rosette C insert input end A and the output terminal D that measures bridge circuit; 45 ° of orientation-sensitive grid of strain rosette C insert input end C and the output terminal D that measures bridge circuit, constitute the full bridge measurement bridge circuit.
CN2009100082890A 2006-06-30 2006-06-30 Shearing force measurement bridge circuit in bending-twisting combined test apparatus Expired - Fee Related CN101487748B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2009100082890A CN101487748B (en) 2006-06-30 2006-06-30 Shearing force measurement bridge circuit in bending-twisting combined test apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2009100082890A CN101487748B (en) 2006-06-30 2006-06-30 Shearing force measurement bridge circuit in bending-twisting combined test apparatus

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CNB2006100881851A Division CN100494934C (en) 2006-06-30 2006-06-30 Bending and twisting combined test device and its use in measuring internal force

Publications (2)

Publication Number Publication Date
CN101487748A CN101487748A (en) 2009-07-22
CN101487748B true CN101487748B (en) 2012-05-09

Family

ID=40890724

Family Applications (1)

Application Number Title Priority Date Filing Date
CN2009100082890A Expired - Fee Related CN101487748B (en) 2006-06-30 2006-06-30 Shearing force measurement bridge circuit in bending-twisting combined test apparatus

Country Status (1)

Country Link
CN (1) CN101487748B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102519648B (en) * 2011-12-22 2013-11-20 北京航空航天大学 Simple shear connection structure pin load vector measuring method and measuring instrument thereof
CN112649130B (en) * 2020-12-29 2022-03-08 上海海事大学 Integrated testing method for interaction mechanical property of medical puncture biopsy needle interface
CN113108686B (en) * 2021-04-13 2023-05-05 上海卫星工程研究所 Strain measuring device for spacecraft and measuring method thereof

Also Published As

Publication number Publication date
CN101487748A (en) 2009-07-22

Similar Documents

Publication Publication Date Title
CN101482436B (en) Additional bending normal stress measurement bridge circuit in bending combination test apparatus
GS Holister Experimental stress analysis: principles and methods
US7188535B1 (en) Load cell having strain gauges of arbitrary location
CN103551922B (en) Strain gauge integrated three-dimensional turning force sensor
CN103837275A (en) Dynamic bending moment test system for ship shafting
CN204924542U (en) A wave force testing arrangement for wave wall
CN101487748B (en) Shearing force measurement bridge circuit in bending-twisting combined test apparatus
CN100494934C (en) Bending and twisting combined test device and its use in measuring internal force
CN202582833U (en) Standard torsion wrench
CN106768523A (en) A kind of press tonnage measuring method and its device
CN110108575A (en) Bolt pure bending fatigue test tool and system
CN105092121A (en) Method of measuring radial force of rigid pipe
CN103278399A (en) Experimental device for testing elasticity modulus G of material
CN1667387A (en) Measuring method in normal stress and shear stress test of compression spring
CN2938051Y (en) Twist combined test device and its composed of measuring bridge
US3899922A (en) Double lever strain multiplier apparatus and method
CN112857632B (en) Axial force measuring equipment
CN207396254U (en) A kind of auxiliary device based on the calibrating of bolt torsion tester torque
CN110095269A (en) Duplex dynamic search hydraulic steel gate hoisting capacity condition monitoring device
RU2323079C2 (en) Dynamometric wrench
CN218121225U (en) Torque measuring device
CN211085530U (en) Bending-resistant static torque sensor and bending-resistant static torque sensor system
Wirström Development and validation of threaded fastener test rig
CN115326263B (en) Strain inversion method for cable grip screw shaft force
Bynum et al. Birefringent-coating analysis of laterally loaded perforated plates: The distribution of principal stresses and the deflections across the ligaments of thick perforated circular plates subjected to uniform lateral loading while simply supported were experimentally determined

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20120509

Termination date: 20150630

EXPY Termination of patent right or utility model