The inaccuracy that ration of flaw detection of longitudinal wave law analyses spends assess surely

Ltd, p.

R.

China 330001)Abstract:MEasurement Uncertainty Is So Important In Tesing Works That The International Systems Such As ISO Has Special Requiremet On It.

This Paper Deduces The Errors Sources From The Process Of Ultrasonic Longitudinal Wave Testing And Evaluates Its Uncertainty.

Key Words:MEasurement Uncertainty, vltrasonic Wave, longitudinal Wave, quantitative Analysis.

Introductive uncertainty of measurement (abbreviation inaccuracy is spent surely) it is token of in order to reasonable gift the dispersive sex of measured value, it is the important parameter 〔 that assess measures an outcome 1, 2 〕 , the correct assess that measures an outcome for the standard and use, 7 organizations such as international standardization were made 93 years jointly " uncertainty of measurement conveys guideline " wide application. 96 years home begins to popularize inaccuracy to be spent surely in metric calibrating job, but the application in quantitative analysis is measured in nondestructive check still not extensive. Conform with international to facilitate, the article spends inaccuracy application to detect at nondestructive surely in, discuss with everybody. The source of error of flaw detection of longitudinal wave law wait at use flaw detector, probe, test block, workpiece, couplant, locate measure and uncertainty of measurement all exists in the process such as quantitative analysis in blemish, assess inaccuracy spends the reliable level that can show flaw detection analyses a result surely, have very good promotion value. The fixed position of 1 blemish presses 1: Speed of scanning of N adjustment longitudinal wave, the horizontal scale with right place of blemish wave forward position is worth the F that it is τ , criterion blemish comes of probe be apart from lie between for 〔 3 〕 : Xf=n τ F (1)1.

　 of 1 instrument, workpiece (flaw detector of 1)EPOCH- Ⅱ ultrasonic; (2)2.

25P0.

75 ′ probe; (3)CSK- Ⅰ test block; (Workpiece of 4) ply 100 Mm. 1.

Of 2 positions determine the instrument presses 1 ∶ 1 adjust scanning speed, horizontal scale value is 69.

64, blemish position: Xf=n τ F=69.

64 Mm1.

3 inaccuracy are spent surely judge degree of 　 (because generation of the meeting when the inaccuracy that speed of 1) adjustment scanning causes spends scanning speed to adjust surely shows screen is the smallest the reading error that scale restricts. What use instrument level the smallest scale is 0.

1, criterion reading can come the smallest scale 1 ／ 10 namely reading error distributinging limits is (- 1 ／ 10, + scale of 1 ／ 10) , to distributing equably, standard inaccuracy spends surely (express with spending surely relative to inaccuracy) 〔 4 〕 : ; Its unreliability is 50% , freedom spends V1=(50%)-2=2 　 　 (the fixed position precision that 2) level affects the horizontal linear of the instrument to affect blemish, linear of level of classics calibrating instrument is 5.

7 × 10-3, obedient normal school (K=3) , its standard inaccuracy spends surely: (B kind) : Its value is reliable, freedom spends error of scale of level of V2= ∞ 　 to suffer an instrument to defend oneself rate influence (defend oneself rate 0.

01) , obedience distributings equably, its error is 1 ／ 2 defend oneself rate, distributinging limits (- 0.

005, + 0.

5 〕 of 005) 〔 , its standard inaccuracy spends surely (express) with spending surely relative to inaccuracy: ; (B kind) ; Reading dependability is 50% , freedom spends value of scale of V3=(50%)-2=2 　 level to be measured 10 times respectively, 69 all be worth.

64, standard deviation S=0.

21, its standard inaccuracy spends surely (spend certainly relatively express) : ; (A kind) : Freedom spends scale of V4=n-1=9 　 level to synthesize standard inaccuracy to spend the horizontal linear that is an instrument, instrument to defend oneself surely value of scale of rate, level repeats observation the synthesis that 3 standards inaccuracy spends surely, it is above namely 3 A kind with B kind synthesis: (3) result assess the transfer function of each heft: The fixed position of blemish, its synthesize inaccuracy to spend surely: Effective freedom spends: Take believe level 95% , TP(0.

95)=1.

Position of 96 　 blemish is: Xf(1 ± TPuC(Xf))=69.

64(1 ± 8.

Its do not decide 　 of 8 × 10-3) absolutely degree (synthetic standard) UC(Xf)=Xf.

UC(Xf)=0.

Type calculates under size of equivalent of blemish of analysis of 31272 blemish ration: (2) from type (can see in 2) , blemish equivalent size suffers the effect of ply of blemish position, workpiece, attenuation. 2.

The change of 1 attenuation detects in attenuation changes to wait by attenuation of error of frequency of perpendicular sex, probe, attenuator, couplant, medium cause. 2.

1.

The influence of 1 perpendicular linear gets perpendicular sex and attenuation impact by next type: (In 3) type: H0 -- H1 of 　 of ideal wave height -- actual measurement wave height (the following with H ′ 1 replace H1 to be actual measurement wave height, h ″ 1 replace H1 to be actual measurement wave height 2 times) 　 　 ① the × of influence transfer function of wave height 0.

4342944=10.

9 　 linear error is 4.

7 × 10-2, obedient normal school (K=3) , standard inaccuracy spends surely (opposite inaccuracy spends surely express) : (B kind) ; Its are worth stability, freedom spends V5= ∞ . The 1 ／ that reading error leads to defend oneself 2, obedient and even distributinging limits (- 0.

5, + 0.

5) , standard inaccuracy spends surely (express) with spending surely relative to inaccuracy: ; (B kind) its appraise reads dependability 50% , freedom spends V6=(50%)-2=2 　 the inaccuracy of wave height is spent surely by above two A kind with B kind synthesis, namely: ② of 10-2 　 　 the influence transfer function of 2 wave height 2 times its linear error is wave height 4.

7 × 10-2, its standard inaccuracy spends surely: U7=u5=1.

57 × 10-2(B kind) ; Freedom spends V7=v5= ∞ 　 reading error is same second wave, u8=u6, the inaccuracy that V8=v6 　 linear error produces spends the synthesis that spends surely for inaccuracy of wave height and standard of 2 wave height surely, namely: 2.

1.

The attenuation frequency to attenuation effect that 2 frequency cause: Transfer function: Frequency error 10% , obedient normal school (K=3) , standard inaccuracy spends surely: ; Its are worth stability, freedom spends V9= ∞ to cause the standard inaccuracy of attenuation to spend surely: 2.

1.

2 couplant influence changes couplant ply, measure its attenuation, with statistical method the analysis gets its are not spent certainly (this second experiment frequency is) 10 times, the experiment all must is worth 5.

5 DB, standard deviation S=0.

566, standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: 10-2; The 1 ／ that the error that spends V10=10-1=9 　 reading to cause freely leads to defend oneself 2, obedience distributings equably, its distributing limits is (- 0.

05, + 0.

05) , standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: ; Reading dependability 50% , the influence that spends precision of V11=(50%)-2=2 　 attenuator freely (measure below 12dB) : Attenuator error 0.

5dB, obedient normal school (K=3) , standard inaccuracy spends surely: Express 10-2 with be being spent surely relative to inaccuracy; Its are worth stability, freedom spends V12= ∞ . The inaccuracy that couplant causes attenuation spends surely for above 3 A kind with B kind synthesis: 2.

1.

4 medium attenuation repeats an examination to workpiece (10) , get medium attenuation, all be worth for 5.

3, standard deviation S=0.

2 DB, standard inaccuracy spends calm: Express with spending surely relative to inaccuracy: ; freedom spends the standard inaccuracy that V13=10-1=9 　 reading causes surely: U ′ 14=u11=0.

029 DB(B kind) 　 expresses with spending surely relative to inaccuracy: 10-3; freedom spends the influence of V14=v11=2 　 attenuator: U15=u12=0.

167 DB(B kind) 　 expresses with spending surely relative to inaccuracy: × 10-2; Freedom spends V15=v12= ∞ . The inaccuracy of medium attenuation spends surely for above 3 A kind with B kind synthesis: 2.

1.

5 attenuation repeat the change of observation result to be measured 10 times to workpiece, 6 all be worth.

2, standard deviation S=0.

58, its standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: ; freedom spends the standard inaccuracy that reading error causes V16=10-1=9 　 surely: U17=u11=0.

029 DB(B kind) 　 expresses with spending surely relative to inaccuracy: 10-3; freedom spends the influence of V17=v11=2 　 attenuator, its standard inaccuracy spends surely: U18=u12=0.

167 DB(B kind) 　 expresses with spending surely relative to inaccuracy: 10-2; Its are worth stability, freedom spends V18= ∞ . Synthesize standard inaccuracy to spend surely: So far, the inaccuracy of attenuation of influence of of all kinds element spends surely for: 2.

　 of 2 ply influence is measured 10 times so that all be worth 100, standard deviation S=0.

15 Mm, standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: U ′ 19=4.

74 × - 4; freedom spends V19=10-1=9 　 callipers the smallest reading is 0.

02, its error obedience distributings equably, distributinging limits (- 0.

01, + 0.

01) , its standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: U ′ 20=5.

Freedom of 8 × 10-5; spends inaccuracy of V20=(50%)-2=2 　 callipers surely for 0.

05(k=3) , obedient normal school, standard inaccuracy spends surely: Express with spending surely relative to inaccuracy: 10-4; its value is stable, freedom spends V21= ∞ . Inaccuracy of standard of workpiece ply synthesis is spent surely by above 3 are synthesized, namely: 2.

Big profile of 3 blemish equivalent gives function: Synthesize standard inaccuracy to spend surely: Express with spending surely relative to inaccuracy: Φ of U ′ C() =3.

　 of 08 × 10-2 spends effectively freely: Believe level is taken 95% , enclothe factor: TP(4)=2.

78U=tP.

Uc(Φ F)=2.

78 × 0.

0613=0.

Volume of dimension of 17 　 equivalent is final ＝ of eventuate Φ F 1.

99 ± 0.

17 Mm(among them 0.

The uncertainty of measurement that 17 Mm is test result) the computation of the uncertainty of measurement that 3 conclusion pass quantitative to flaw detection of longitudinal wave law analysis and assess, ration of knowable dawn flaw detection analyses the degree of reliability of the result, can decide the influence degree of experiment process and the source of error that analyse as a result and result of its knot test. The assess of uncertainty of measurement regards an experiment as the main component of the result, applicable measures each domains of quantitative analysis at nondestructive check. CNC Milling CNC Machining