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ASTM Testing Standards

ASTM C393_Standard Test Method for Shear Strength

 Test Specimen Requirements
  • 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.

 Equipment and Apparatus:
  • Apparatus: Universal Testing Machine (UTM)

Figure 1: Universal Testing Machine (UTM)

 Procedure:
  1. Condition the specimen in a chamber if the test environment is not the same as a conditioned environment.

  2. Measure the length, width and thickness at three places in the specimen.

  3. Place the specimen into the test fixture as shown in the equipment and apparatus section.

  4. Attach the deflection transducer (if we choose to use one).

  5. Apply a compressive force to the specimen until failure or until a deflection equal to the thickness is reached.

Variable

Quantity

Load rate

6mm/min

Failure occurence

3-6 minutes

Support bar separation

150 mm

 Basic Description:
  • 3-point or 4-point bend test

Figure 3: 3-Point Bend Test

Figure 4: 4-Point Bend Test

 Reported during the 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, shown in the figure below.

  • 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:

    • For 4-Point, Quarter-point loading:

    • For 4-Point (Third Point) Loading:

ASTM D3039_Standard Test Methods for Tensile Properties

 Test Specimen Requirements
  • Test at least 5 specimens

 Equipment and Apparatus:
  • Apparatus: Universal Testing Machine (UTM)

Figure 1: Universal Testing Machine (UTM)

 Procedure:
  1. Measure the specimen in 3 places and report average thickness and width as well as average area. 

  2. Place the specimen into the grips of the testing machine

  3. Apply the force until failure occurs

Variable

Quantity

Failure occurence

1 to 10 min

Head displacement

2mm/min

 Basic Description:
  • Tensile Test

 Reported during test:

Variable

Symbol

Percent Bending

By

Ultimate Tensile Strength

F tu

Tensile Strain at ith Data Point

Ɛi

Tensile chord modulus of elasticity

Echord

Poisson’s Ratio by Chord Method

v

 ASTM D3410_Standard Test Method for Compressive Properties of Polymer Matric Composite Materials

 Test Specimen Requirements
  • Test at least 5 specimens

 Equipment and Apparatus:
  • Equipment required:

    • Special Alignment Jig as shown in the figure below.

  • Apparatus will be a compression test fixture as shown in the figures below.

 Procedure:

  • Condition specimens

  • Apply strain gages/extensometers to both faces of the specimen(if we choose to).

  • Monitor test temperature using thermocouples (if we choose to).

  • 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. 

  • 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. 

  • Attach strain transducers if they will be used. 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).

  • Apply the force to the fixture at the specified rate until failure while recording data.

Variable

Quantity

Strain Rate

0.01 min-1

Crosshead Displacement

1.5 mm/min

Failure occurence

1-10 min

 Basic Description:

This video is a good example of this test being carried out.

 Reported during test:
  • Failure modes:

    • Record them by giving a code as shown in figure 9, below:


  • There are a few unacceptable failure modes including end-crushing and euler buckling. 

Variable

Symbol

Compressive Stress/ Ultimate Compressive Stress

F cu

Compressive strain/ Ultimate Compression Strain

Ɛi c

Compressive Modulus of Elasticity

E chord

Compressive Poison’s ratio

v c

Transition Strain

μ E

ASTM D3518_Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test

 Test Specimen Requirements
  • Test at least five specimens per test condition

  • Same as ASTM D3039 standard along with the following:

 Equipment and Apparatus:
  • Same as ASTM D3039

 Procedure:
  • Same as ASTM D3039 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. 

 Basic Description:
  • Tensile Test

 Reported during test:

Variable

Symbol

Max Shear Stress

t12m

Shear Stress

t12i

Shear Strain

y12i

Max Shear Strain

y12m

Shear Modulus of Elasticity

G12chord

Offset Shear Strength

F12o

ASTM D903_Standard Test Method for Peel or Stripping Strength of Adhesive Bonds

 Test Specimen Sampling and Geometry
  •   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.

 Equipment and Apparatus:
  • I believe that we can use a UTM but I’m not 100% sure about it.

  • A picture of the testing apparatus is shown in the figure below:

Figure 1: 90-degree peel tester

Figure 2: UTM I think but, this setup is a vertical peel test.

 Procedure:
  • Prep the specimen.

  • Precondition the test specimen.

  • Test the specimen as soon as possible after conditioning

  • Place the specimen in the test apparatus

  • Wait until failure

Variable

Quantity

Grip Separation

About 1 Inch

Stripping angle

180 degrees.

 Basic Description:
  • Peel Test, which is very similar to a tensile test (in my opinion). A video of this test being carried out is shown below.

https://www.youtube.com/watch?v=m6Rd6I-XMMg

 Reported during test:

Note that none of these variables have symbols/formulas.

Variable

Average peel/stripping strength

Max and Min strength values of the series

Type of failire

ASTM D905_Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading (for adhesives on wood)

 Test Specimen Requirements
  • Will conform to the following geometry:

  • At least 20 specimens shall be tested, representing at least four different joints

 Equipment and Apparatus:

Testing apparatus shown in figure 1, below.

 Procedure:

  • Prepare the test specimens.

  • Place the test specimen in the apparatus.

  • Apply a load onto the test specimens until failure occurs.

Variable

Quantity

Load Rate

5 mm/min

Specific Gravity of maple blocks

0.65

 Basic Description:
  • Shearing tool/shearing tester. The following video shows what this testing apparatus looks like.

https://www.youtube.com/watch?v=iRBkWFmCyco

 Reported during test:

Note that none of these had associated calculations/symbols

Variable

Shear Stress at failure

Max and min shear stress at failure and percentages of wood failure

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

 Test Specimen Requirements
  • Use these dimensions if you can:

  • Test 10 test specimens for each adhesive

 Equipment and Apparatus:
  • Apparatus:

Figure 1: Pendulum-type testing apparatus

 Procedure:
  • Put the specimen in the jig that is 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.

 Basic Description:
  • Pendulum-type test

 Reported during test:


Note that none of these have symbols.

Variable

Joules of energy absorbed in producing failure of the specimen

Percentages of cohesion, adhesion, and contact failure. This will be based on visual inspection

Impact strength of the specimen over the bonded area. 

ASTM D5868_Standard Test Method for Lap Shear Adhesion for Fiber Reinforced Plastic (FRP) Bonding

 Test Specimen Requirements
  • Prepare a minimum of 5 lap shear samples in each case and test.

  • See figure 1 below for the recommended geometry of the lap shear samples

 Equipment and Apparatus:
  • UTM

 Procedure:

  • 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.

  • Condition the test specimens

  • Place specimens in UTM

  • Wait for failure

Variable

Quantity

Grip Separation

75mm

load rate

13mm/min

 Basic Description:
  • Tensile test.

 Reported during test:

Note that none of the following are calculations

Variable

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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