If you are irritated by every rub, how will your mirror be polished? Rumi
Idea Transcript
TE-MSC
• • • • •
Salvador Ferradas Troitiño (TE-MSC-MDT) Jose Luis Rudeiros Fernandez (TE-MSC-LMF) Jose Ferradas Troitiño (TE-MSC-MDT) Juan Carlos Perez (TE-MSC-MDT) Susana izquierdo Bermúdez (TE-MSC-MDT)
TE-MSC
Contents 1.
Introduction
2.
Proposed Analysis
3.
Experimental discussion
4.
Main concerns and bonus
5.
To be launched
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1. Introduction In order to measure the mechanical properties in transverse direction of the different Racetrack coils, a series of modifications of an existing press need to be implemented. Main Objectives: • Characterisation of the mechanical behaviour in transversal direction. Measurement of the stiffness of the structure. • Back-calculation of the equivalent modulus of a cable block. • Validation of 10 stack measurements, FE and analytical models. • Determination of the nominal size of the coil to reach the required azimuthal pre-stress. • Experimental verification of the shim sizes.
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Upper Block
Lower Block
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2. Proposed steps Aim: Try to exploit as much as possible the expertise gained with the 11T E-Modulus Press. 1. Setup closest as possible to standard uniaxial compression tests. 2. Finite element modelling of the proposed setup. Analytical verification. 3. Calibration / Verification using two reference materials. 4. Compliance correction / Verification. 5. Measurements and analysis. 1Standard, A.
S. T. M. "E9-09." Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature. ASTM International (2009). 2Standard, A. S. T. M. "E111–04. ", Standard Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus. ASTM International (2010).
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2. Proposed Setup Use of a video extensometer 1.
2. 3. 4. 5.
Displacement measured between to marks using a video extensometer Force measured using commercial Load Cell. Parallelism ensured by means of the parallel structure and ball seat. Needed: Avoid buckling and delamination on the first pole turn. If buckling is not a problem, tooling and assumptions are minimized ⇢ Uniaxial compression test
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2. Proposed Setup Same principle as 11T E-Modulus Press. 1. 2. 3. 4. 5.
Displacement measured using LVDTs. Force measured using commercial Load Cell. Parallelism ensured by means of the parallel structure and ball seat. Needed: Avoid buckling and delamination on the first pole turn. If buckling is not a problem, tooling and assumptions are minimized ⇢ Uniaxial compression test
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2. Proposed verification Material properties • Characterisation of the Young’s modulus in compression of the two materials used for the E-modulus press: 1.4104 and EN AW-6082 T651 • Tests carried out in a tensile-compression testing machine, equipped with a 200 kN load cell and video-extensometer, according to ASTM E9. Determination of Young’s modulus based on a straight line fitted to the data in a given stress range by the method of least squares calculated, according to ASTM E111. • Five samples per each material.
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3. Experimental – E-modulus press Compliance correction • Contrary to the 11T EModulus press case, boundary conditions of the calibration/test are simpler. The theoretical curve can be analytically obtained as a first order approximation. • Theoretical curves to be compared to measurements, will be also exported from an FE 3D model. 1Standard, A.
S. T. M. "E9-09." Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature. ASTM International (2009).
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3. Experimental – E-modulus press 20 18 16
𝛿𝑐 𝐹
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Load (KN)
Compliance correction • Assuming that the compliance is constant or directly proportional to the force leads to obvious errors. • Compliance shall be considered as a non-linear function of the Force. • Correction function to be computed as the difference between the measured curve and the theoretical curve1.
12 Aluminium Fit Theoretical curve
10 8 6
4 2 0
1Kalidindi,
S. R., A. Abusafieh, and E. El-Danaf. "Accurate characterization of machine compliance for simple compression testing." Experimental mechanics 37.2 (1997): 210-215.
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0.00
0.10 0.20 Displacement (mm)
0.30
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3. Experimental – E-modulus press Measurements sequence (= 11T) 1. Test of calibration blocks (Steel coils have been chosen for this purpose). Three consecutive measurements are taken. 2. Test of coil. Three consecutive measurements are taken for each position. Measurements are taken every 100 mm along the axis of the coil. 3. After measuring the coil, the calibration blocks are measured again, three times consecutively. The final calibration curve is taken as the average of all measurements of calibration blocks. 10/3/2017
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4. Main concerns & Bonus The main concerns arising from the design are :
• •
Wrong parallelism between both coil mid-planes can cause delamination in the first pole turn. If we minimize the tooling, parallelism must be ensured ⇢ Ball socket
We can profit from the open and simpler setup: • •
Using Video Extensometers. Using In-House developed Matlab code + Commercial camera to reproduce the measurements of Video Extensometers.
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5. To be launched: • Buckling analysis. • Analytical and FE calculations. • •
Required force to get desired stress level. Stress distribution.