Lab 2 Rock tensile strength: Brazilian test
Summary
TLDRThis video explains the process of performing a tensile strength test using the Brazilian density strength method. The procedure involves applying force to a cylindrical rock sample, measuring its diameter and length, and observing the fracture point. Key steps include sample measurement, setup of the loading frame, alignment checks, and data analysis. The video highlights how to calculate tensile strength based on the peak load and dimensions of the sample, emphasizing the importance of precision during both the testing and analysis phases.
Takeaways
- 🧪 The focus of this lab (Laboratory 2) is on measuring tensile strength using the Brazilian tensile strength test.
- 📏 The sample used in this test is a cylindrical rock with equal length and diameter, and force is applied along the cylindrical side.
- 💥 The test generates tensile strength, causing a fracture in the rock, and the tensile strength is estimated from the peak load and sample dimensions.
- 📊 Steps in the analysis include sample measurement, loading frame setup, fracturing, and data analysis—similar to Laboratory 1.
- 📐 The diameter is measured in different directions to ensure the sample is as circular as possible, while length measurement is less critical compared to Lab 1.
- 🔄 The alignment of the top and bottom parts of the frame is checked to ensure they are parallel using a level tool.
- ⚙️ The control setup monitors two key parameters: the load and displacement, with displacement measurement being optional in this lab.
- ⏩ Two speeds are used in the setup: one for movement and one for displacement, and the lower frame is raised until it touches the upper frame.
- 🛡️ Protective plastic is placed around the sample in case the rock explodes during the test.
- 📸 After the rock fractures, a force drop is observed, and data is captured for further analysis, including calculating tensile strength based on the peak load.
Q & A
What is the main focus of the laboratory experiment discussed in the transcript?
-The main focus of the laboratory experiment is to measure the tensile strength of a cylindrical rock sample using the Brazilian Tensile Strength test method.
What shape is the rock sample used in the tensile strength test?
-The rock sample used in the tensile strength test is cylindrical, with the diameter and length being the same.
How is the tensile strength generated during the test?
-Tensile strength is generated by applying force along the cylindrical side of the sample, which causes a fracture in the rock.
What are the key measurements needed before starting the tensile strength test?
-The key measurements needed are the diameter and the length of the sample. These measurements help in estimating the tensile strength once the peak load is known.
Why is it important to check the circularity of the sample during the preparation phase?
-It is important to check the circularity of the sample to ensure that the sample is as close to a perfect cylinder as possible. An irregular shape may affect the accuracy of the tensile strength measurement.
How does bedding direction influence the tensile strength test?
-Bedding direction can affect the tensile strength of the sample depending on how the stress is applied during the test. It is important to check for bedding direction before proceeding.
Why is it necessary to level the top and bottom parts of the frame before testing?
-It is necessary to level the top and bottom parts of the frame to ensure that the load is applied evenly across the sample. Misalignment could result in inaccurate measurements.
What are the two main parameters controlled during the tensile strength test?
-The two main parameters controlled during the test are the load and the speed of displacement.
What indicates that the sample has fractured during the test?
-The sample is considered to have fractured when the load applied reaches a peak and then suddenly drops.
How is the tensile strength calculated after the test is completed?
-Tensile strength is calculated using the peak load applied during the test, along with the sample's length and diameter measurements.
Outlines
🧪 Introduction to Tensile Strength and Brazilian Density Test
In this section, the speaker introduces the topic of tensile strength testing for cylindrical rock samples, specifically using the Brazilian Density Strength Test. The method involves applying force along the cylindrical side of the sample to generate tensile strength and fracture the rock. The tensile strength can be calculated using the peak load and by measuring the sample's dimensions (length and diameter). The procedure is similar to what was covered in a previous lab session, and involves sample measurement, loading frame setup, fracturing, and data analysis.
🧩 Importance of Sample Measurement and Quality Control
The speaker emphasizes the need for careful sample measurement and quality control. Two key factors are highlighted: ensuring the sample is as circular as possible, and considering the impact of bedding direction on tensile strength. Multiple measurements of the diameter and length are taken to ensure accuracy, although the length is less critical compared to the first lab session. Special attention is given to whether the sample has bedding, as this could affect the results of the tensile strength test.
🔧 Setting Up the Loading Frame
This section covers the setup of the loading frame used in the tensile strength test. The speaker explains that the top and bottom parts of the frame must be parallel, which is checked using a level. Once the frame is properly aligned, the sample can be positioned for testing. The speaker explains the control system, noting that while vertical displacement is not necessary for this test, it can still be measured if additional data is needed. Various functions on the control panel are described for adjusting the speed and monitoring the test.
🚀 Preparing for the Tensile Strength Test
The speaker discusses the final preparation steps before the tensile strength test begins. Two speeds (screen speed and displacement speed) are used to carefully position the sample in the frame. As the lower frame moves up and touches the upper frame, the force increases slightly, signaling that the sample is in place. Safety precautions are also mentioned, including the use of protective plastic around the sample to prevent injury in case the rock explodes during testing.
🔨 Conducting the Fracture Test
In this section, the speaker explains the process of conducting the fracture test. The lower part of the frame is moved up to increase the load on the sample. As the load increases, it will reach a peak before dropping when the rock fractures. The test is stopped once the force drops, and a picture of the fractured sample is taken. The data collected is stored for further analysis.
📊 Data Analysis and Tensile Strength Calculation
The final section covers data analysis and the calculation of tensile strength. Using the previously measured length and diameter of the sample, along with the peak load recorded during the test, the tensile strength of the rock can be calculated. The speaker concludes by mentioning that this data will be used for reporting and further analysis.
Mindmap
Keywords
💡Tensile Strength
💡Brazilian Test
💡Cylindrical Sample
💡Fracture
💡Load Cell
💡Sample Measurement
💡Loading Frame
💡Bedding Direction
💡Displacement
💡Data Analysis
Highlights
Introduction to tensile strength and the Brazilian density strength test.
Description of using a frame to apply force on a cylindrical sample.
Explanation of how force is applied along the cylindrical side to generate tensile strength and fracture.
Method to estimate tensile strength based on peak load, sample length, and diameter.
Steps for analysis: sample measurement, loading frame setup, fracturing, and data analysis.
Importance of quality checking the sample to ensure it is as circular as possible.
Impact of bearing direction on tensile strength depending on stress application.
Measuring sample diameter in different directions to check circularity.
Less criticality of parallel faces for length measurement compared to laboratory 1.
Checking for bedding direction in the sample.
Ensuring the frame's top and bottom parts are parallel using a level.
Setting the sample and controlling parameters: load and displacement.
Using two speeds: screen speed and displacement speed for the frame.
Protective measures: placing protective plastic around the sample during measurement.
Observing load increase and drop during fracturing to determine fracture.
Stopping analysis, capturing fracture data, and structuring the data file for the report.
Calculating tensile strength using sample dimensions and highest applied load.
Transcripts
this talk is going to be
for the laboratory number two in our
attorney number two
we are going to talk about tensile
strength
the method that we use to measure
that inside strength is called brazilian
density
strength test in here
we use a frame to apply a force on a
cylindrical sum
in this cylindrical sample diameter and
length
have the same length
and the force that we are applying
is along the cylindrical side
of the sample in this case
when we apply the load we generate
a tensile strength generating the
fracture
in the rock we can estimate
the tensile strength based on the
peak load and by the sample and
by knowing the length and the diameter
of the
ceiling
the steps that we are going to
[Music]
use to for this analysis
are the same that we already seen in
laboratory 1
which are sample measurement loading
frame setup
fracturing and data analysis
what we observe is that again we need to
measure and quality check the sample
that we are going to use in our analysis
the main points in here are two first
samples are not going to be perfectly
selenium
this case we have to check that the
sample
or the cylinder is as circular as
possible
second that is
if we have bearing bearing
direction may affect the tensile
strength
depending on how we apply the stress on
the sample
to analyze the sample we are going to
measure
two values diameter
d and length
l in the case of the diameter
we are going to measure in different
directions
just to check that the side that the
sample is
circular and we are going to use the
address
for the length we are going to measure
at different directions
in this case compared to our retina re1
we don't need the sample to be to have
parallel
and faces so length
measuring is not as critical as we
observe
in laboratory one however we have to
check
whether we have bedding and if we have
bedding direction
so now we are going to
analyze and
to check if the frame is
a properly settled for the work
first we have to check if
the top and the bottom part of the frame
are parallel or not to check that
we use a level and what we check is
actually is that
the level at the top and the bottom are
aligned one exit with each other
then we can proceed to sit in the sample
again as in our 31 we are going to
have the the control
where we check two main parameters first
the load a second displacement
in the laboratory two this vertical
displacement
is not going to be necessary however you
can measure
it in case that you need some additional
information
to measure whether we are moving
the sample up or down we can use
develops up or down and to control the
speed
we can check speed and go to the menu
here f2 is going to you to be used
to control the digits while f3 and
f4 are going to check where to
increase or decrease the digit that we
are
stepping on once we confirm the speed
we just hit speed to go back to the menu
before
in this work again we are going to use
two speeds
screen speed and displacement speed
using certain speed then we can
sit ourselves it means that
we are going to move up
our lower frame until
it touches the upper part of the frame
when that happens we'll see that the
force
slightly increases now we are ready to
do the measurement so
we just have to place protective plastic
around
in case that the frag that the rock is
so
explodes during the measurement
so now that we have the leveling check
and that we see the sample we are going
to go
to a factory the fracturing what we are
going to do is
just we are going to keep moving up the
lower part of the frame
but we are going to observe an
increase in the load that we are
applying
this load is going to reach a minimum
and then
it's going to have a drop when the
fractal fades
when the rock phase and
by the end of the after the data
analysis
we can see a video where we are applying
and strength on the sample until it
fractures
so as i mentioned before we have to move
up
we expect to see a forced rope and then
we immediately stop the analysis
take a picture of the fracture and
struck the data file
for our report finally
we can proceed with our data analysis
to calculate the tensile strength we
already have the length
and the diameter of the sample so we
have to
[Music]
find which was the highest load
that we are applied in our load cell
and from this value we can calculate
that inside strength
you
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