Authors: Vinh Q.C. Tran, Doekle R. Yntema, Duc V. Le, Paul J.M. Havinga
University of Twente,The Netherlands

Corresponding author: Vinh Q.C. Tran
Contact Information:
q.c.v.tran@utwente.nl





***General Introduction***
Title: Strain data of paper:Testbed Hardware Design to Collect Data for Underground PVC Water Pipe Crack Detection: Challenges and Solutions
paper link:
https://doi.org/10.1145/3560905.3567765.



Keyword(s):
Crack, strain gauges, stress



1. file: rawdata.zip: raw data file
- Data include 21 columns:
+ column 1: time
+ column 2: pressure in mbar
+ columns 3- 21 :  strain gauges values of 19 (from 1 to 19)strain gauges.

Note: the order of some strain gauges in the raw data files are different to figure 3 in the paper.Some of them must be reodered as follow:
In raw data file: [8 9 10 11 12 13 14] (strain gauges number)
In the figure of the paper : [10 14 11 8 9 12 13]] (strain gauges number)

Experimental Context:
1. Purpose: change the input internal water pressure in a pipe (from 1 0 to 5 bars) --> measure 19 strain data, read simulately from Hx7111 
1.1 Investigate the crack impact:
	- Measure the pressure and strain at differerence data points (pressure), a pressure value was change and hold for at least 30sec for stabilization
				file: "crack6org.txt": crack 50mm, depth =1/3 pipewall

	- Create crack 1..6, Measure the pressure and strain at differerence data points,
			. crack 1: data_crack50mm.txt: crack 50mm, depth =1/3 pipewall	
			. crack 2: data_crack100mm_d1.txt: crack 100mm, depth =1/3 pipewall
			. crack 3: data_crack100mm_d2.txt: crack 100mm, depth =2/3 pipewall
			. crack 4: data_crack150mm_d1.txt: crack 150mm, depth =2/3 pipewall
			. crack 5: data_crack180mm_d1.txt: crack 180mm, depth =2/3 pipewall
			. crack 6: data_crack200mm_d1.txt: crack 200mm, depth =2/3 pipewall

1.2 Then the crack pipe (200mm, 2/3 pipewall) were tested at various temperature, with the simalar procesdure pressure variation profile of 1.1:
			. T1_24_6oC.txt: 24.6oC
			. T1_35oC.txt: 35oC
			. T2_23oC.txt:23oC
			. T156oC.txt: 15oC
	
1.3	Then the crack pipe (200mm, 2/3 pipewall) were tested with 4 external external hoop stress level (induced by a round clamp on the pipe wall)
The clamp were placed in the middle of strain gauges 1 and 3
			. crack6org.txt: no external stress
			. clampAtSS3SS1: raw data of 4 external stress
				This file are seperated into 4 file corressponding to 4 stress levels: "clampSS3Lv1".."clampSS3Lv4".csv
		

Data processing:
Software require: Matlab revised 2020a

1. Crack impact analyzation
	1.1 All the data (in section 1.1) are merged  into XCr stored in file:	"indata.mat"

	1.2 At each stable pressure point, 100 samples (or 10sec) from raw data (in section 1.1) are extracted. 
	File: 
	- Code file: "CreatX.m":
		. input:
			"indata.mat": merged data
			"myConstants.mat": settings for processing
		. output:"XCr" stored in 'Xmatrix.mat',
	- These data then be averaged and normalized in code:	"createXavg.m"
	Normalization the strain values uses the range of good data ('crack6org.mat') 
			. input :
				'Xcr' in 'Xmatrix.mat'
				"myConstants.mat": settings for processing
			.output: in file 'XAvgNmatrix.mat':
				'XavgN': normalized data
	- Then, the code 'RandomSlope2.m' contruct the pressure-strain characteristic (PSC) of each strain gauges in each crack regime. 
		Then it calculate the differnce of the PSCs of the crack regimes with the good pipe regimes 
			input
				'XavgN' in 'XAvgNmatrix.mat'
				"myConstants.mat": settings for processing
			.output: in file 'SlopeChange.mat':
				'perChange': the difference of each regime
				index :1 : good pipe vs good pipe
				index :2..7: crack number (1..6) vs good pipe.
	- Then the file "drawSlopechangeAll.m" draw the change as the figure 3c in the paper.
	
2. Temperature impact analyzation:
Context: the pipe with  were taken out for 1 months and then reassembly to investigate the temperature. 
Therefore, we used this condition at ambient temperature (24oC) for reference

3. External stress analyzation
Context: the pipe with  were taken out for 1 months and then reassembly to investigate the temperature. 
we analyze data of strain gauges 1 to 4 which near the clamp
Then we applying data to excel file to draw the figure 4f
calcExternalStress.mlx