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<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 8 Calculation of results 8.1 Modulus of elasticity (E) <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 8.2 0,2 % proof strength (Rp0,2-0 and Rp0,2-U) 9 Uncertainty of measurand 10 Test report 10.1 Specimen <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 10.2 Results 10.3 Test conditions <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | Figures Figure\u00a01 \u2013 Stress-strain curve and definition of modulus of elasticity and 0,2\u00a0% proof strengths for Cu\/Nb3Sn wire <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | Annex A (informative) Additional information relating to Clauses 1 to 10 A.1 Scope A.2 Extensometer A.2.1 Double extensometer Figure\u00a0A.1 \u2013 Light weight ultra small twin type extensometer <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | A.2.2 Single extensometer Figure\u00a0A.2 \u2013 Low mass averaging double extensometer <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | A.3 Optical extensometers Figure\u00a0A.3 \u2013 An example of the extensometer provided with balance weight and vertical specimen axis <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | A.4 Requirements of high resolution extensometers Figure\u00a0A.4 \u2013 Double beam laser extensometer <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | A.5 Tensile stress Relasticmax and strain Aelasticmax Figure\u00a0A.5 \u2013 Load versus displacement record of a reacted Nb3Sn wire <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | A.6 Functional fitting of stress-strain curve obtained by single extensometer and 0,2 % proof strength (Rp0,2-F) Figure\u00a0A.6 \u2013 Stress-strain curve of a reacted Nb3Sn wire <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | A.10 Tensile strength (Rm) Figure\u00a0A.7 \u2013 Two alternatives for the gripping technique. Figure\u00a0A.8 \u2013 Details of the two alternatives of the wire fixing to the machine <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | A.11 Percentage elongation after fracture (Af) A.12 Relative standard uncertainty <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Tables Table\u00a0A.1 \u2013 Standard uncertainty value results achieved ondifferent Nb3Sn wires during the international round robin tests <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | A.13 Determination of modulus of elasticity E0 Table\u00a0A.2 \u2013 Results of ANOVA (F-test) for the variations of E0 <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | A.14 Assessment on the reliability of the test equipment A.15 Reference documents <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | Annex B (informative) Uncertainty considerations B.1 Overview B.2 Definitions B.3 Consideration of the uncertainty concept <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Table\u00a0B.1 \u2013 Output signals from two nominally identical extensometers Table\u00a0B.2 \u2013 Mean values of two output signals Table\u00a0B.3 \u2013 Experimental standard deviations of two output signals <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | B.4 Uncertainty evaluation example for TC 90 standards Table\u00a0B.4 \u2013 Standard uncertainties of two output signals Table\u00a0B.5 \u2013 Coefficient of Variations of two output signals <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | B.5 Reference documents of Annex B <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Annex C (informative) Specific examples related to mechanical tests C.1 Overview C.2 Uncertainty of the modulus of elasticity Figure\u00a0C.1 \u2013 Measured stress-strain curve <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | C.3 Evaluation of sensitivity coefficients <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | C.4 Combined standard uncertainties of each variable Table\u00a0C.1 \u2013 Load cell specifications according to manufacturer\u2019s data sheet <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Table\u00a0C.2 \u2013 Uncertainties of displacement measurement <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Table\u00a0C.3 \u2013 Uncertainties of wire diameter measurement Table\u00a0C.4 \u2013 Uncertainties of gauge length measurement <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | C.5 Uncertainty of 0,2 % proof strength Rp0,2 Table\u00a0C.5 \u2013 Calculation of stress at 0\u00a0% and at 0,1\u00a0% strain using the zero offset regression line as determined in Figure\u00a0C.1 (b) <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | Figure\u00a0C.2 \u2013 Stress-strain curve <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Table\u00a0C.6 \u2013 Linear regression equations computed for the three shifted linesand for the stress\u2013strain curve in the region where the lines intersect Table\u00a0C.7 \u2013 Calculation of strain and stress at the intersections of the three shifted lines with the stress\u2013strain curve <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | Table\u00a0C.8 \u2013 Measured stress versus strain data and the computed stress based on a linear fit to the data in the region of interest <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Superconductivity – Mechanical properties measurement. Room temperature tensile test of reacted Nb3<\/sub>Sn composite superconductors<\/b><\/p>\n |