Why measure strain ? Strain coils Magnetic Coupling Transmitter - - PowerPoint PPT Presentation

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Why measure strain ? Strain coils Magnetic Coupling Transmitter - - PowerPoint PPT Presentation

Nov 21, 2022 151 likes •368 views

Why measure strain ? Strain coils Magnetic Coupling Transmitter Coil Oscillator Meter Receiver Coil Strain Coil setup in 3d Y X Transmitting coil Receiving coils Z Strain Coil 3d array stack Direction of travel 75 mm 75 mm At

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SLIDE 1

Why measure strain ?

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SLIDE 2

Strain coils

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SLIDE 3

Magnetic Coupling

Oscillator Transmitter Coil Receiver Coil Meter

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SLIDE 4

Z X Y

Transmitting coil Receiving coils

Strain Coil setup in 3d

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SLIDE 5

Strain Coil 3d array stack

75 mm 75 mm 75 mm

Direction of travel At UGM/Asphalt interface

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SLIDE 6

Strain Coil Stack Configuration

Aggregate Subgrade

Strain Coil

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SLIDE 7
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SLIDE 8

Strain Coil Array excavation

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SLIDE 9

Strain Coil array up close

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SLIDE 10

Strain Coil Calibration

coil volts vs. mm 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 70 71 72 73 74 75 76 77 78 79 80 81 Displacement (mm) Output (Volts) coil volts vs. mm

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SLIDE 11

The Calibration Jig

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SLIDE 12

Simple calibration with jig

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SLIDE 13

Logarithmic transfer Function

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SLIDE 14

Strain Coil Electronics

  • Based on NI Hardware
  • ‘Off the shelf' products
  • Leverages on high quality

measurement instrumentation

  • Long term stability – no drift
  • Coils use a similar principle

to standard LVDT’s

  • Therefore can use NI LVDT

module.

  • Labview Software
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SLIDE 15

Modes of Operation: 1- Static

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SLIDE 16

Modes of Operation: 2 - Dynamic

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SLIDE 17

Vertical Displacement (mm)

11/12/2015 12:23 NaCl 1 Ignacio Barrios mm filtered 73,62 73,64 73,66 73,68 73,7 73,72 73,74 73,76 1 261 521 781 1041 1301 1561 1821 2081 2341 2601 2861 3121 3381 3641 3901 4161 4421 4681 4941 5201 5461 5721 5981 6241 6501 6761 7021 7281 7541 7801

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SLIDE 18

Vertical Displacement (Strain)

11/12/2015 12:23 NaCl 1 Ignacio Barrios

  • 1200
  • 1000
  • 800
  • 600
  • 400
  • 200

200 1 262 523 784 1045 1306 1567 1828 2089 2350 2611 2872 3133 3394 3655 3916 4177 4438 4699 4960 5221 5482 5743 6004 6265 6526 6787 7048 7309 7570 7831

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SLIDE 19

Longitudinal Strain

11/12/2015 12:23 NaCl 1 Ignacio Barrios

  • 150
  • 100
  • 50

50 100 150 200 250 300 1 260 519 778 1037 1296 1555 1814 2073 2332 2591 2850 3109 3368 3627 3886 4145 4404 4663 4922 5181 5440 5699 5958 6217 6476 6735 6994 7253 7512 7771

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SLIDE 20

Transverse Strain

11/12/2015 12:23 NaCl 1 Ignacio Barrios

  • 50

50 100 150 200 250 300 1 259 517 775 1033 1291 1549 1807 2065 2323 2581 2839 3097 3355 3613 3871 4129 4387 4645 4903 5161 5419 5677 5935 6193 6451 6709 6967 7225 7483 7741 7999