BS EN 61788-19:2014
$189.07
Superconductivity – Mechanical properties measurement. Room temperature tensile test of reacted Nb3Sn composite superconductors
| Published By | Publication Date | Number of Pages |
| BSI | 2014 | 48 |
IEC 61788-19:2013 covers a test method detailing the tensile test procedures to be carried out on reacted Cu/Nb3Sn composite superconducting wires at room temperature. The object of this test is to measure the modulus of elasticity and to determine the proof strength of the composite due to yielding of the copper and the copper tin components from the stress versus strain curve. Furthermore, the elastic limit, the tensile strength, and the elongation after fracture can be determined by means of the present method, but they are treated as optional quantities because the measured quantities of the elastic limit and the elongation after fracture have been reported to be subject to significant uncertainties according to the international round robin test. The sample covered by this test procedure should have a bare round or rectangular cross-section with an area between 0,15 mm2 and 2,0 mm2 and a copper to non-copper volume ratio of 0,2 to 1,5 and should have no insulation. Key words: supraconductivity, mechanical properties
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 9 | INTRODUCTION |
| 10 | 1 Scope 2 Normative references 3 Terms and definitions |
| 12 | 4 Principles 5 Apparatus 5.1 General 5.2 Testing machine 5.3 Extensometer 6 Specimen preparation 6.1 General 6.2 Length of specimen |
| 13 | 6.3 Removing insulation 6.4 Determination of cross-sectional area (S0) 7 Testing conditions 7.1 Specimen gripping 7.2 Setting of extensometer 7.3 Testing speed 7.4 Test |
| 14 | 8 Calculation of results 8.1 Modulus of elasticity (E) |
| 15 | 8.2 0,2 % proof strength (Rp0,2-0 and Rp0,2-U) 9 Uncertainty of measurand 10 Test report 10.1 Specimen |
| 16 | 10.2 Results 10.3 Test conditions |
| 17 | Figures FigureĀ 1 ā Stress-strain curve and definition of modulus of elasticity and 0,2Ā % proof strengths for Cu/Nb3Sn wire |
| 18 | Annex A (informative) Additional information relating to Clauses 1 to 10 A.1 Scope A.2 Extensometer A.2.1 Double extensometer FigureĀ A.1 ā Light weight ultra small twin type extensometer |
| 19 | A.2.2 Single extensometer FigureĀ A.2 ā Low mass averaging double extensometer |
| 20 | A.3 Optical extensometers FigureĀ A.3 ā An example of the extensometer provided with balance weight and vertical specimen axis |
| 21 | A.4 Requirements of high resolution extensometers FigureĀ A.4 ā Double beam laser extensometer |
| 22 | A.5 Tensile stress Relasticmax and strain Aelasticmax FigureĀ A.5 ā Load versus displacement record of a reacted Nb3Sn wire |
| 23 | A.6 Functional fitting of stress-strain curve obtained by single extensometer and 0,2 % proof strength (Rp0,2-F) FigureĀ A.6 ā Stress-strain curve of a reacted Nb3Sn wire |
| 24 | A.7 Removing insulation A.8 Cross-sectional area determination A.9 Fixing of the reacted Nb3Sn wire to the machine by two gripping techniques |
| 25 | A.10 Tensile strength (Rm) FigureĀ A.7 ā Two alternatives for the gripping technique. FigureĀ A.8 ā Details of the two alternatives of the wire fixing to the machine |
| 26 | A.11 Percentage elongation after fracture (Af) A.12 Relative standard uncertainty |
| 27 | Tables TableĀ A.1 ā Standard uncertainty value results achieved ondifferent Nb3Sn wires during the international round robin tests |
| 28 | A.13 Determination of modulus of elasticity E0 TableĀ A.2 ā Results of ANOVA (F-test) for the variations of E0 |
| 29 | A.14 Assessment on the reliability of the test equipment A.15 Reference documents |
| 30 | Annex B (informative) Uncertainty considerations B.1 Overview B.2 Definitions B.3 Consideration of the uncertainty concept |
| 31 | TableĀ B.1 ā Output signals from two nominally identical extensometers TableĀ B.2 ā Mean values of two output signals TableĀ B.3 ā Experimental standard deviations of two output signals |
| 32 | B.4 Uncertainty evaluation example for TC 90 standards TableĀ B.4 ā Standard uncertainties of two output signals TableĀ B.5 ā Coefficient of Variations of two output signals |
| 33 | B.5 Reference documents of Annex B |
| 35 | Annex C (informative) Specific examples related to mechanical tests C.1 Overview C.2 Uncertainty of the modulus of elasticity FigureĀ C.1 ā Measured stress-strain curve |
| 36 | C.3 Evaluation of sensitivity coefficients |
| 37 | C.4 Combined standard uncertainties of each variable TableĀ C.1 ā Load cell specifications according to manufacturerās data sheet |
| 38 | TableĀ C.2 ā Uncertainties of displacement measurement |
| 39 | TableĀ C.3 ā Uncertainties of wire diameter measurement TableĀ C.4 ā Uncertainties of gauge length measurement |
| 40 | C.5 Uncertainty of 0,2 % proof strength Rp0,2 TableĀ C.5 ā Calculation of stress at 0Ā % and at 0,1Ā % strain using the zero offset regression line as determined in FigureĀ C.1 (b) |
| 41 | FigureĀ C.2 ā Stress-strain curve |
| 42 | TableĀ C.6 ā Linear regression equations computed for the three shifted linesand for the stressāstrain curve in the region where the lines intersect TableĀ C.7 ā Calculation of strain and stress at the intersections of the three shifted lines with the stressāstrain curve |
| 43 | TableĀ C.8 ā Measured stress versus strain data and the computed stress based on a linear fit to the data in the region of interest |
| 45 | Bibliography |
