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ASTM Testing Standards
ASTM C393_Standard Test Method for Shear Strength
Specimen has rectangular in cross-section
Length x Width x Depth - 200 mm x 75 mm x Thickness of Sandwich Construction
Make sure to test at least five specimens per test condition unless you are confident that the results obtained are valid through the use of fewer specimens.
Equipment: ball-interfaced and anvil interface micrometer, deflectometer, conditioning chamber, environmental test chamber are recommended but not required.
Apparatus: The machine will have a stationary and movable head, the machine should be able to indicate the total force being carried by the test specimen, it will either be a 3- or 4-point bend test. Below is what they used
Test at least five specimens.
Condition the specimen in a chamber if the test environment is not the same as a conditioned environment.
Measure the length, width and thickness at three places in the specimen.
Place the specimen into the test fixture and align the fixture so the longitudinal axis of the specimen is perpendicular (within 1 degree) to the longitudinal axes of the loading bars, the bars must also be parallel (within 1 degree) to the plane of the specimen facings.
Attach the deflection transducer.
Apply a compressive force to the specimen until failure or until a deflection equal to the thickness is reached.
It was noted that the speed of testing should be around 6mm/min.
Failure should occur at 3-6 minutes.
3-point or 4-point bend test
Force versus crosshead displacement, force versus deflection data continuously, or at frequent intervals (around 2-3 recordings per second, with a target minimum of 100 recorded data points)
If there are any initial failures, record force, displacement and mode of damage where the failure occurs.
Record mode, area and location of each failure.
Use the failure identification codes
Record the max force, failure force, head displacement and the deflection at the moment of ultimate failure.
For ultimate failure modes, record the mode, area and location of ultimate failure for each material.
Calculations:
For 3-Point Mid-Span Loading:
Core Shear Ultimate Stress
Core Shear Yield Stress
Facing Stress
For 4-Point, Quarter-point loading:
Core Shear Ultimate Stress
Core Shear Yield Stress:
Facing Bending Stress
For 4-Point (Third Point) Loading:
Core Shear Ultimate Stress
Core Shear Yield Stress:
Facing Bending Stress:
these calculations are in the confluence page
ASTM D3039_Standard Test Methods for Tensile Properties
3 Force Indicator, Grips, Strain-Indicating Device, Strain transducer, Extensometer, Strain Gauge, End Tabs.
Tensile Testing machine with a stationary head and a movable head.
Test at least 5 specimens
Measure the specimen in 3 places and report average thickness and width as well as average area.
The speed of testing should be able to have a nearly constant strain rate and it will produce failure within 1 to 10 min.
Tensile Test
Calculate modulus of elasticity
Calculate ultimate tensile strength.
If tensile modulus/ultimate tensile strain will be calculated, get the tensile strain at the indicated displacement at each required data point.
Tensile chord modulus of elasticity.
Poisson’s Ratio by Chord Method.
*All these equations are found in the confluence page*
ASTM D3410_Standard Test Method for Compressive Properties of Polymer Matric Composite Materials
Sampling—Test at least five specimens per test condition unless valid results can be gained through the use of fewer specimens
The test specimen will have a constant rectangular cross section with a specimen width variation of no more than 1% and a specimen thickness variation of no more than 2%, the tables below give more detail.
Below is an equation to get the recommended test thickness
Equipment required:
Micrometers/calipers
Strain-Indicating Device
Bonded Resistance Strain Gauges
Emery cloth
Special Alignment Jig (pictured below)
Compression Testing Fixture(pictured below are schematics and the actual fixture)
Apparatus:
There will be a force indicator
The machine will have two loading heads.
^^^I don’t exactly know what this means (interpret pls)
The drive mechanism will be able to give a controlled displacement rate with respect to the stationary head.
If the atmosphere conditions suck use a conditioning chamber and an environmental test chamber.
If the material is super stiff use an extensometer.
Test at least five specimens per test condition
Get ready because this is a HEFTYYY procedure
General instructions:
Condition specimens before/after strain gaging as required. Condition travelers if they will be used
Apply strain gages/extensometers to both faces of the specimen
The loading rate should produce a failure within 1 to 10 min.
Strain-Controlled Tests, standard strain rate of 0.01 min/1 ?? I think the unit may be wrong here. I think it's supposed to be mm/min??
Constant Head-Speed Tests, A standard crosshead displacement of 1.5mm.min.
Monitor test temp by placing a thermocouple within 25mm of the specimen gauge section. You can also tape the thermocouple(s) to the test specimen and travelers.
Fixture Installation:
Place the lower wedge housing block on the lower platen, then attack the upper wedge housing block to the upper crosshead/insert it into the upper wedge housing holding fixture, centered over the lower wedge housing block.
Move a crosshead to close the distance between the 2 housing blocks while guiding the bearing guide rods into the mating bearing of the companion housing block. The lower housing block can be fitted with guide rods long enough to allow the rods to remain in the bearings while the wedges or specimen assembly is loading into and out of the housing blocks.
Specimen Insertion:
If needed, move the testing machine crosshead to open the distance between the 2 housing blocks so both the upper and lower wedge rip assemblies may be accessed.
I’m so sorry but idk how to summarize the following thing :(
If the specimen will be aligned with the wedge grips in the fixture housing block, the lower jaws should be raised so that grip-faces open to allow specimen insertion.
If we need to, free the upper wedge grips so they are in the fully open position. Moving the crosshead, close the distance between the housing blocks and guide the upper end of the specimen into the opening between the upper wedge grips.
Close the upper grips manually to check the specimens vertical displacement. Do it with the lower grips as well. The upper grips should be in full contact with the wedge when closed. Repeat if we need to.
Keep the grips closed and slowly close the distance between the housing blocks by moving the crosshead, watch the force indicator at this time. Stop the crosshead when the specimen begins to take a compressive force.
Transducer Installation:
If the strain-transducer(s) other than strain gages will be used, attach them to the specimen at the mid-span, mid-width location. Then, attach the strain recording instrumentation to the strain gages or other transducers on the specimen. Then, remove any remaining preload and zero the transducer(s).
Loading:
Apply the force to the fixture at the specified rate until failure while recording data.
https://www.youtube.com/watch?v=qfHoq9w3glE I really like this video Tommy found and I believe it should give a really good idea of the test.
Failure modes:
Record them by giving a code as shown below:
There are a few unacceptable failure modes including end-crushing and euler buckling.
Calculations:
Compressive Stress/Ultimate Compressive Stress.
Compressive Strain and Ultimate Compression Strain.
Compressive Modulus of Elasticity
Compressive Poisson’s Ratio
Transition Strain
The following should be noted:
Ultimate compressive strength
Ultimate compressive strain
Compressive (linear or chord) modulus of elasticity
Poisson’s ratio in compression
Transition strain
*remember all these formulas will be in the astm document for finding the above values*
ASTM D3518_Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test
Will be the same as the above standard along with the following:
Same as the above standard.
Test at least five specimens per test condition
Same as the above standard as well as:
This test will have normal strain instrumentation in both the longitudinal and transverse directions. It will also have a continuous/nearly continuous force normal strain data recording.
Same as the above standard.
Calculations:
Max shear stress/shear stress
Shear strain/max shear strain
Shear modulus of Elasticity
Offset Shear Strength
Various statistics
*Again, all these formulas will be in the confluence page*
ASTM D903_Standard Test Method for Peel or Stripping Strength of Adhesive Bonds
The above is the diagram of the geometry
Test at least 10 test specimens for each adhesive.
Discard specimens that give out of line test results due to obvious flaws and then retest.
Apart from the testing apparatus, the only equipment needed is a conditioning room/desiccators
The following is a picture of the testing apparatus:
Hehe…remember this…yeah it still makes no sense :C
Ummm...help
These are the only values needed to be reported (they don’t seem like they’re calculations)
Average peel/stripping strength.
Max and Min strength values of the series.
Type of failure.
ASTM D905_Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading (for adhesives on wood)
Will conform to the following geometry:
At least 20 specimens shall be tested, representing at least four different joints
No equipment listed, just apparatus:
The machine will have a capacity of no less than 6810kg in compression and shall be fitted with a shearing tool containing a self-aligning seat to ensure uniform lateral distribution of the load.
It will be able to maintain a uniform rate of loading so the load may be applied with a continuous motion. The apparatus is pictured below:
At least 20 specimens should be tested, they will represent at least four different joints.
We will have to prep the test joints:
They will be hard maple blocks, having a minimum specific gravity of 0.65 based on oven-dry weight and volume shall be selected. Below is a picture of the test joints and how they should be cut?
I don’t really get how to explain this one to be honest help :C
Calculations:
Shear stress at failure.
Max and min shear stress at failure and percentages of wood failure.
The standard deviation of all individual test values.
Average shear stress at failure and the average percentage of wood failure.
ASTM D950_Standard Test Method for Impact Strength of Adhesive Bonds
Use these if you can:
Test 10 test specimens for each adhesive
Equipment:
Desiccators
Conditioning chambers
Apparatus:
Use a pendulum-type impact machine (pictured below).
Use a jig to hold the specimen as shown below.
Use a vise/bolts to hold the jig rigid.
Put the specimen in the jig in the vise of the machine so the specimen butts squarely against the end of the jig.
Rest the impact head against the specimen and adjust the jig so the head fits squarely against the impact face.
Raise the impact head and release the safety catch.
We will then note the impact energy absorbed.
A pendulum will fall and hit our specimen and test the adhesive strength
Joules of energy absorbed in producing failure of the specimen
Percentages of cohesion, adhesion, and contact failure. This will be based on visual inspection.
Calculation:
Impact strength of the specimen over the bonded area.
*the calculations will be available in the confluence page*
ASTM D5868_Standard Test Method for Lap Shear Adhesion for Fiber Reinforced Plastic (FRP) Bonding
Substrates—Fiber reinforced plastic (FRP) as specified, with metal composition (heat treat, temper, and condition) and roughness as specified when bonding FRP to metal. (I don’t know what this means)
Cut fiber-reinforced plastic parts into flat coupons 1 by 4 in. (25.4 by 100 mm) at a nominal thickness of 0.1 in. (2.5 mm). In the case of FRP-to-metal bonding, use metal with a nominal thickness of 0.06 in. (1.5 mm). It is recommended that a diamond tip water-cooled saw blade be used, or a cutting method capable of producing sharp cut edges.
Joint Geometry—Control joint geometry by appropriate fixturing, using glass beads or other suitable means to control a 0.03-in. (0.76-mm) adhesive bondline thickness. Use the minimum number of glass beads in the glue line needed to hold bondline thickness. Fixturing pressure is allowed. Lap shear overlap will be 1 by 1 in. (25.4 by 25.4 mm) See Figure 1 below.
Prepare a minimum of 5 lap shear samples in each case and test.
No equipment is outlined, only an apparatus which is said to most likely just be a simple tensile tester like pictured below
Prepare a minimum of 5 lap shear samples in each case and test.
Prep the surface of the FRP as recommended by the adhesive manufacturer. If there is no recommendation, prep the surface as outlined in practice D2093.
Apply the adhesive in accordance with the adhesive suppliers recommendations.
Adhesive Cure—Cure the adhesive at room temperature or elevated temperature using prescribed conditions determined by the adhesive supplier.
The initial grip separation is 75mm, with a minimum of 25.4mm of each sample end held in the test grips.
The load rate is 13mm/min.
This load rate is said to be an important difference compared to other standards.
Tensile test.
Complete identification of the adhesive tested, this includes the type and manufacturers code number.
Complete identification of the substrates used. This includes the type of resin and fiber orientation as well as the method of surface prep prior to bonding.
Cure schedule time and temperature for bonding sample.
Individual peak load values, and averages by maximum and minimum values.
Test temperature and conditions.
Type of failure whether it be fiber tear, cohesive, adhesive.
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