CN1529140A - Photoelctric combined force-measuring method - Google Patents

Abstract

The invention refers to a kind of photoelectron compound measuring method for force, the steps are: takes the key parts on the mechanism device needed to be measured, and process the part into photo elastic mould, and adds effect and the similar force on the mechanism device to the mould, gets the shape parameter: phi= [E/2 (1+mu)] X[KLKTPM/NBO]; produces a small piece with the same material to the key parts, attaches the resistance strain piece on it, and forms the measuring bridge; the marked small piece is attached onto the measured point of the key mechanism part; gets the epsi through the resistance strain piece; gets P= phiX epsi, accomplishes the measurement of mechanism force.

Description

The compound force measuring method of a kind of photoelectricity

Technical field

The present invention relates to the compound force measuring method of a kind of photoelectricity, belong to the dynamometry technical field.

Background technology

For some main equipments or some high precision equipment, in default load display instrument or instrument while on these equipment and when these equipment do not allow to install ready-made sensor or device, it is very difficult reaching measurement target when wanting to understand the used load on these equipment.Some traditional heavy (merchant) mills for example, the roll-force tonnage all about kiloton, is rolled the power test to this milling train and will processes a large-scale pressure head, because size is very big, except processing and fabricating takes costliness, be problematic in that the demarcation to this pressure head is difficult to find the large-tonnage testing machine.Another typical problem is as the steel plate shearing machine on the 2030 cold continuous rolling lines, for the motor of selecting to be complementary, when design, need understand shearing force, and this shearer structure is not only compact, and is slider-crank mechanism, can not lay on equipment and put any type of sensor.

Summary of the invention

The objective of the invention is on equipment the dynamometry problem of placing any type of sensor can not be installed in order to solve in the engineering survey, the present invention proposes compound force measuring method of a kind of photoelectricity and system.

Technical scheme of the present invention is achieved like this, and its method step is:

1, getting vital part on the plant equipment that need are surveyed is object, is processed into photoelastic model, and model is applied the similar power that acts on the plant equipment, obtains the shape coefficient of the part at similar measuring point place: $\mathrm{\Φ}=\frac{E}{2(1+\mathrm{\μ})}\frac{K_L{K}_T{P}^M}{{\mathrm{N\σ}}_O}$

The elastic feel quantity of E-part; The Poisson ratio of μ-part

K _LThe shape ratio of-part and photoelastic model; K _TThe thickness ratio of-part and photoelastic model; P ^M-similar power; The fringe order of N-photoelastic model;

σ _o-stress fringe value;

2, make a flakelet, its material is pasted selected resistance strain gage with the crucial material of part in addition of plant equipment on flakelet, form measuring bridge, connects the input/output signal line;

3, flakelet is demarcated, obtained calibration coefficient

Use glue (or epoxy resin) flakelet to be pasted the measuring point place of crucial mechanical component then;

4, by the resistance strain gage on the flakelet on the crucial mechanical component, the strain value ε when recording equipment work;

5, being multiplied each other in multiplier by shape coefficient Φ and strain value ε is P=Φ * ε, finishes the test of mechanical force.

Its principle of work is: form measuring bridge by the resistance strain gage on flakelet, as shown in Figure 1, establish each brachium pontis and satisfy R ₁=R ₂=R ₃=R ₄, then the reading strain has: ε=2 (ε ₁+ ε ₂); Be in some stress states as measuring point, introducing generalized Hooke's law has: $\mathrm{\ϵ}=\frac{2(1+\mathrm{\μ})}{E}({\mathrm{\σ}}_1+{\mathrm{\σ}}_2);$ Application photoelasticity theory, the mathematic(al) representation of its deviator stress line is: ${\mathrm{\σ}}_1^M-{\mathrm{\σ}}_2^M={\mathrm{N\σ}}_o;$ Have according to similarity theory: $K_{\mathrm{\σ}}=\frac{K_p}{K_L{K}_T},$ So have: ${\mathrm{\σ}}_1-{\mathrm{\σ}}_2=\frac{K_p}{K_L{K}_T}{\mathrm{N\σ}}_O$ With $\mathrm{\ϵ}=\frac{2(1+\mathrm{\μ})}{E}\frac{K_p}{K_L{K}_T}N{\mathrm{\σ}}_O,$ So $P=\frac{E}{2(1+\mathrm{\μ})}\frac{K_L{K}_T{P}^M}{N{\mathrm{\σ}}_O}\mathrm{\ϵ},$ P=Φ * ε then,

The part shape coefficient is: $\mathrm{\Φ}=\frac{E}{2+(1+\mathrm{\μ})}\frac{K_L{K}_T{P}^M}{N{\mathrm{\σ}}_O}.$

This method is a kind of extremely useful force measuring method, promptly to the load actual measurement of some excess levels, need not remove to process the pressure transducer of a costliness, thereby more need not the tired brain of demarcation.The photoelectricity composite algorithm has been arranged,, just can directly obtain operating load as long as can measure ε on the primary structure member at the scene.Both rapidly accurately, it was economical to save time again in this measurement.

Description of drawings

The full-bridge strain paster synoptic diagram of Fig. 1 for pasting on the flakelet;

Fig. 2 is the luxuriant instrumentation logic design frame chart of making according to this method.

Embodiment

Connect with 2030 Baosteel Cold Rolling, 2030 hot rollings acid and to wash that 2030 new pickling planisher groups are example on the production line.After new pickling planisher group is installed, find to have casting flaw on the planisher frame through nondestructive examination.Because the existence of defective makes that the real work load (being roll-force) of 2030 new pickling planishers is more much smaller than rated load like this, has influenced production output and progress.For to 2030 exerting oneself property of planisher frame evaluations, at first to know the real work roll-force of this planisher.Owing on frame, traditional sensor can't be installed, for this reason, adopt the compound force measuring method of this method-photoelectricity.In 1: 25 ratio processing photoelasticity frame model, by photoelastic analysis, find out the position of best flakelet, promptly find the part stress stress gradient to change little position, as framework pillar; Make a flakelet, its material is identical with framework pillar, is 40G, its size is long * wide * thick be 25 * 1.2 * 100 (mm), determine Φ=12.636 * 10 ⁹On flakelet, paste selected resistance strain gage, form measuring bridge, flakelet is demarcated, obtain calibration coefficient

Use 502 glue (or epoxy resin) flakelet to be pasted the measuring point place of framework pillar then; Strain value ε when recording equipment work; As shown in Figure 2, the ε input signal through amplification, A/D conversion, multiplier, relatively amplify, enter behind the amplification driver computer multiplier and obtain roll-force P with multiplying each other by above-mentioned determined Φ _Survey=2500KN, the actual roll-force P that records through the scene _Real=2520KN.Both have only 0.8% at error.And should actual roll-force only account for 25% of specified roll-force, so if there is not degree of impairment in 2030 planisher frames, then the rolling potentiality of frame are very big.Then pass through fracture mechanics analysis and FEM (finite element) calculation etc. again, conclusion is the intensity that the defective of this frame does not influence frame, and the roll-force of this milling train can be brought up to specified roll-force, thereby improves output, obtains the approval and the favorable comment of manufacturer for this reason.

Claims (1)

1, the compound force measuring method of a kind of photoelectricity is characterised in that, the steps include:

1) getting vital part on the plant equipment that need are surveyed is object, is processed into photoelastic model, and model is applied the similar power that acts on the plant equipment, obtains the shape coefficient of the part at similar measuring point place: $\mathrm{\Φ}=\frac{E}{2(1+\mathrm{\μ})}\frac{K_L{K}_T{P}^M}{{\mathrm{N\σ}}_O}$

The elastic feel quantity of E-part; The Poisson ratio of μ-part

K _LThe shape ratio of-part and photoelastic model; K _T-part and photoelastic model

The thickness ratio; P ^M-similar power; The fringe order of N-photoelastic model;

σ _o-stress fringe value;

2) make a flakelet, its material is pasted selected resistance strain gage with the crucial material of part in addition of plant equipment on flakelet, form measuring bridge, connects the input/output signal line;

3) flakelet is demarcated, obtained calibration coefficient Use glue (or epoxy resin) flakelet to be pasted the measuring point place of crucial mechanical component then;

4) by the resistance strain gage on the flakelet on the crucial mechanical component, the strain value ε when recording equipment work;

5) being multiplied each other in multiplier by shape coefficient Φ and strain value ε is P=Φ * ε, finishes mechanical force measurement.

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