SOP Procedure Template .ubc.ca



STANDARD OPERATING PROCEDURE

Composite research Network

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SOP for

Fabric Pure Bending Tester (FPBT)

ADOPTION AND NIMS COMPLIANCE REVIEW

|Signature | |Printed Name | |Title | |Date |

|Signature | |Printed Name | |Title | |Date |

|Signature | |Printed Name | |Title | |Date |

|Signature | |Printed Name | |Title | |Date |

Record of Change

|Change No. |Description |Change Date |Approved By |

|001 |Update after first usage |11/12/2018 | |

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Purpose

The purpose of this SOP is to describe the FPBT device and how to use it. Parts and test procedure will be discussed in this SOP.

DESCRIPTION

Overview

The Fabric Pure Bending Tester (FPBT) is a device that measures the bending properties of woven fabrics and thin films. The output of this device is moment-curvature curve of the fabric or thin film. The device is containing electrical and mechanical parts. Main parts of the device are shown and described in Figure 1.

Fabric or Thin film sample will be held between two grippers. The rotating gripper will be moved by the motor to -90 and then to +90 degrees. At the same time, load-cell will read the reaction force on the fixed griper due to bending and send the data to the indicator that can be sent to the computer.

[pic]

Figure 1 Device Parts

Functions and roles

Here, roles and functions of the parts of device are listed.

• Load-cell: (AEP TCA S Type load cell) reads the reaction force from the fixed gripper and send the data to indicator

• Indicator: (AEP DFX microprocessor indicator) receives the data from load-cell, remove the noise and send the data to computer

• Servo motor: (Dynamixel AX-12) rotates the rotating gripper to certain degrees (device has been set for -90 and +90 degrees of bending, although these angles can be changed from 0-150 and -150-0 degrees. This is described in the software section.)

• Main shaft: linking the motor to rotating gripper

• Rotating gripper: clamping one end of the sample and applying bending to it

• Fixed gripper: clamping another end of the sample

• Lever: is transferring the reaction force to load-cell. It’s center of gravity is located on the joint. Lever has a horizontal small movement due to bending.

• Balance weight: keeps the center of gravity of the lever on the joint. It can be repositioned for different gauge lengths to keep the balance of the lever.

• Joint: is connecting the lever to a long vertical shaft that transfers the load to load-cell. Friction between the joint and lever must be as low as possible, for that reason, a linear bearing is used as a joint.

sample

Preparation

Preparing a sample for pure bending test includes cutting the material to a desired size. Width of the sample can be from 1 cm to 5 cm. The test length of the sample can be between 0.5 cm to 3 cm. Always cut the sample about 1cm to 2cm longer (length wise) than the size you want to test, because the extra length will be clamped in the grippers.

Samples can be cut in main directions of the fibers in fabric (warp and weft) or in any directions depending on the purpose of the test. A typical sample prepared for bending test is shown in Figure 2.

[pic]

Figure 2 Sample Preparation

Limitations

The loadcell used for this device has a 2kg force capacity. Samples which generate higher loads can not be tested on this device. In order to test stiff materials, make sure that you are using a smaller width and if the load exceed 2 kg, reduce the maximum bend angle or resize your sample to a more narrow sample.

Mounting The Sample

In order to mount the sample on device, operator needs to follow tasks below:

1. Unscrew the eight clamp screws shown in Figure 3.

2. Remove top part of the rotating and fixed grippers.

3. Place the sample on the grippers so that about 0.5cm of the sample would be clamped by the grippers.

4. Make sure that the direction of the fibers is as desired. (for testing fine fabrics in main directions (warp and weft), pull out one yarn in the opposite direction of the test and use it as a control.)

5. Put the top parts back in place.

6. Screw the eight clamp screws shown in Figure 3.

[pic]

Figure 3 Grippers

Gauge length

Gauge length of the device is the distance between two grippers or the length of the test sample. This length is one of the most important parameters in the pure bending test and will affect the results in a significant way. Gauge length has an optimum value for each fabric depending on its stiffness. In general, longer length are used for stiffer materials and vice versa. For example, the optimum gauge length for Twintex® is 1cm and for Carbon fiber is 8mm.

how to change it?

This device has the capability of changing the gauge length. This action is feasible by:

1. Loosening the gauge screw shown in Figure 3

2. Moving part c-2 further from part c-1

3. Tighten the gauge screw

4. Move the fixed gripper back by the same amount as part c-2, so that the sample is centered about the main shaft

5. Displace the balance weight to make the lever balanced

Note:

The center of test sample must be aligned with the center of the main shaft. Make sure that the distance between the center of the main shaft and the tip of rotating gripper, and the distance between the center of the main shaft and the tip of the fixed gripper are equal.

connections

In this section, the connections are described. Before starting a test, the operator needs to make sure that the following connections are made:

• Load cell to indicator

Load cell can be connected to the indicator via an R232 serial cable. The only cable on the load cell needs to be connected to the serial port #1 as shown in Figure 4.

• Indicator to computer

Indicator needs to be connected to the computer to save the data. Connections have been made based on Figure 4. The DB9 female RS232 host on DFX has been linked to another DB9 female RS232 host which is then connected to the computer.

[pic]

Figure 4 loadcell connections

Table 1. Loadcell-computer connections

|DFX |Computer |

|5 |5 |

|1 |4 |

|2 |3 |

|3 |2 |

• Motor to computer

In order to connect motor to PC, the motor is linked to the U2D2 using a 3-pin TTL connector. Then, the U2D2 is linked with the PC using a USB cable shown in Figure 5.

• Power to motor

Servo motor is connected to the power supply using a power supply adapter shown in Figure 5.

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Figure 5 Motor Connections

Software

Introduction

National Instruments Labview is used to control the device. Front panel of the program written for this device is shown in Figure 6.

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Figure 6 Software Front Panel

Followings tasks need to be done to run the device:

✓ Open Controller.vi

✓ Choose COM ports for motor and load cell (#1 shown in Figure 6)

✓ Choose goal positions for motor. In Figure 6, selected positions are representing 0, -90, 90 and 0 degrees, respectively. (#2 shown in Figure 6)

✓ Choose speed of the test ~ 10*rpm (#3 shown in Figure 6)

✓ Choose the gauge length set for the test (#4 shown in Figure 6)

✓ Start the test by clicking on item #5 shown in Figure 6

✓ After running the test, motor position and load cell data will be illustrated in item #6 and item #7 shown in Figure 6, respectively.

✓ When the test is done, results will be show in tabs with item #8.

o Position-Time tab

o Load-Time tab

o Hysteresis tab

o Hysteresis 2 tab

o Moment-curvature tab

o Moment-curvature 2 tab

✓ All the results can be exported to excel files.

✓ Test can be stopped anytime by clicking on the stop button #9 shown in Figure 6.

Possible errors

Calculations

Curvature

First step to calculate the curvature is to convert the position of the motor to angles of the motor using Equation 1. Then convert it to bending angle or sample angle using Equation 2. Afterwards, using the bending angle calculated in Equation 3, curvature can be obtained. A geometrical explanation has been illustrated in Figure 7 for bending angle.

Motor angle vs. motor position and sample angle vs. motor position chart is shown in Figure 8.

[pic] Equation 1

[pic] Equation 2

[pic] Equation 3

[pic]

Figure 7 Curvature analysis

[pic]

Figure 8 Motor position vs Motor angle and Sample angle

Moment

Moment can be calculated by multiplying the force read by load cell, by the distance between the joint and center of sample which is 7cm as shown in Equation 4.

[pic] Equation 4

In the equation above, moment’s unit is ‘gf.cm’. This unit can be normalized by the number of yarns in the sample or by the width of the sample, in those cases, unit of moment is ‘gf.cm/yarn’ and ‘gf.cm/cm’ respectively.

results

Position-Time

One of the results that can be obtained, is the position of the motor vs. time. A typical result for the motor position is shown in Figure 9.

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Figure 9 Typical result for motor position

Load-Time

Load recorded by the load cell vs. time is saved on the load-time tab. A typical result for load vs. time is shown in Figure 10.

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Figure 10 Typical result for load

Hysteresis

In the hysteresis tab, position vs. load is drawn. A typical curve for load-position is shown in Figure 11.

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Figure 11 Typical result for load vs. position

Hysteresis 2

To make the results smoother, a filter has been applied on the data points. A typical curve for filtered load vs. position is shown in Figure 12.

[pic]

Figure 12 Typical result for modified load vs. position

Moment-Curvature

Normalized moment calculated for the setting of the device vs. curvature calculated based on the input information is drawn on moment-curvature tab. A typical moment-curvature curve is shown in Figure 13.

[pic]

Figure 13 Typical result for moment vs. curvature

Moment-Curvature 2

A filter has been applied to the data points of the moment-curvature curve and modified moment-curvature curve is shown in moment-curvature 2 tab. A typical modified moment-curvature curve is potted in Figure 14.

[pic]

Figure 14 Typical result for modified moment vs. curvature

Quick start guide

Below are the steps to start a test:

1. Check all the connections and make sure they are all connected

2. Turn on the indicator

3. Prepare the sample

4. Mount the sample on the device

5. Set indicator to zero

6. Open “Controler.vi” on the computer

7. Set the gauge length and speed

8. Select the COM ports

9. Start the test

Export results to excel files

POSIBBLE POSITIONS OF MOTOR

|Position |Motor Angle |Sample Angle |

|512 |150 |0 |

|518 |151 |1 |

|525 |153 |3 |

|531 |155 |5 |

|536 |157 |7 |

|542 |158 |8 |

|543 |159 |9 |

|546 |160 |10 |

|555 |162 |12 |

|561 |164 |14 |

|564 |165 |15 |

|568 |166 |16 |

|570 |167 |17 |

|576 |168 |18 |

|580 |170 |20 |

|584 |171 |21 |

|588 |172 |22 |

|596 |174 |24 |

|597 |175 |25 |

|605 |177 |27 |

|613 |179 |29 |

|618 |181 |31 |

|626 |183 |33 |

|628 |184 |34 |

|636 |186 |36 |

|640 |187 |37 |

|647 |189 |39 |

|649 |190 |40 |

|654 |191 |41 |

|658 |192 |42 |

|666 |195 |45 |

|670 |196 |46 |

|674 |197 |47 |

|678 |198 |48 |

|682 |200 |50 |

|691 |202 |52 |

|696 |204 |54 |

|705 |206 |56 |

|712 |208 |58 |

|718 |210 |60 |

|722 |211 |61 |

|725 |212 |62 |

|729 |213 |63 |

|732 |214 |64 |

|739 |216 |66 |

|741 |217 |67 |

|744 |218 |68 |

|750 |219 |69 |

|755 |221 |71 |

|758 |222 |72 |

|763 |223 |73 |

|768 |225 |75 |

|777 |227 |77 |

|779 |228 |78 |

|783 |229 |79 |

|787 |230 |80 |

|791 |231 |81 |

|792 |232 |82 |

|797 |233 |83 |

|800 |234 |84 |

|803 |235 |85 |

|806 |236 |86 |

|811 |237 |87 |

|816 |239 |89 |

|820 |240 |90 |

|822 |241 |91 |

|835 |244 |94 |

|840 |246 |96 |

|847 |248 |98 |

|853 |250 |100 |

|859 |251 |101 |

|865 |253 |103 |

|872 |255 |105 |

|878 |257 |107 |

|882 |258 |108 |

|888 |260 |110 |

|896 |262 |112 |

|903 |264 |114 |

|908 |266 |116 |

|915 |268 |118 |

|923 |270 |120 |

|929 |272 |122 |

|939 |275 |125 |

|945 |277 |127 |

|951 |278 |128 |

|956 |280 |130 |

|962 |282 |132 |

|970 |284 |134 |

|975 |285 |135 |

|982 |287 |137 |

|986 |289 |139 |

|993 |291 |141 |

|999 |292 |142 |

|1001 |293 |143 |

|1007 |295 |145 |

|1010 |296 |146 |

|1015 |297 |147 |

|1019 |298 |148 |

|1023 |300 |150 |

|0 |0 |-150 |

|5 |1 |-149 |

|10 |2 |-148 |

|13 |3 |-147 |

|14 |4 |-146 |

|19 |5 |-145 |

|23 |6 |-144 |

|25 |7 |-143 |

|30 |8 |-142 |

|31 |9 |-141 |

|38 |11 |-139 |

|45 |13 |-137 |

|52 |15 |-135 |

|57 |16 |-134 |

|58 |17 |-133 |

|62 |18 |-132 |

|65 |19 |-131 |

|70 |20 |-130 |

|76 |22 |-128 |

|84 |24 |-126 |

|88 |25 |-125 |

|90 |26 |-124 |

|95 |27 |-123 |

|98 |28 |-122 |

|99 |29 |-121 |

|107 |31 |-119 |

|111 |32 |-118 |

|116 |34 |-116 |

|125 |36 |-114 |

|130 |38 |-112 |

|134 |39 |-111 |

|142 |41 |-109 |

|146 |42 |-108 |

|153 |44 |-106 |

|159 |46 |-104 |

|165 |48 |-102 |

|171 |50 |-100 |

|177 |51 |-99 |

|183 |53 |-97 |

|189 |55 |-95 |

|195 |57 |-93 |

|203 |59 |-91 |

|208 |60 |-90 |

|213 |62 |-88 |

|215 |63 |-87 |

|223 |65 |-85 |

|230 |67 |-83 |

|235 |68 |-82 |

|237 |69 |-81 |

|241 |70 |-80 |

|246 |72 |-78 |

|252 |73 |-77 |

|255 |74 |-76 |

|257 |75 |-75 |

|264 |77 |-73 |

|272 |79 |-71 |

|274 |80 |-70 |

|277 |81 |-69 |

|284 |83 |-67 |

|290 |85 |-65 |

|294 |86 |-64 |

|300 |87 |-63 |

|304 |89 |-61 |

|312 |91 |-59 |

|315 |92 |-58 |

|318 |93 |-57 |

|321 |94 |-56 |

|324 |95 |-55 |

|329 |96 |-54 |

|333 |97 |-53 |

|337 |98 |-52 |

|341 |100 |-50 |

|350 |102 |-48 |

|354 |103 |-47 |

|362 |106 |-44 |

|367 |107 |-43 |

|373 |109 |-41 |

|379 |111 |-39 |

|386 |113 |-37 |

|389 |114 |-36 |

|397 |116 |-34 |

|401 |117 |-33 |

|409 |119 |-31 |

|416 |121 |-29 |

|419 |122 |-28 |

|422 |123 |-27 |

|426 |124 |-26 |

|431 |126 |-24 |

|438 |128 |-22 |

|446 |130 |-20 |

|449 |131 |-19 |

|454 |133 |-17 |

|462 |135 |-15 |

|470 |137 |-13 |

|476 |139 |-11 |

|484 |141 |-9 |

|487 |142 |-8 |

|493 |144 |-6 |

|495 |145 |-5 |

|500 |146 |-4 |

|506 |148 |-2 |

Manuals

Dynamixel ax12



Dfx



Tca



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