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Table of Contents

ASTM C393_Standard Test Method for Shear Strength

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titleTest Specimen Requirements
  • Specimen is 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.

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titleEquipment and Apparatus:
  • Apparatus: Universal Testing Machine (UTM) with a deflection transducer, as shown in the figure below.

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Figure 1: Universal Testing Machine (UTM)Image Removed

Figure 2: Deflection transducer setup in a 3-point bend test

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titleProcedure:
  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 specimeninto 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

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

Figure 3: 3-Point Bend Test

Figure 4: 4-Point Bend Test

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titleReported 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

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

Image Added

Figure 1: Universal Testing Machine (UTM)

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titleProcedure:
  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

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titleBasic Description:
  • Tensile Test

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

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titleTest Specimen Requirements
Image AddedImage Added
  • Test at least 5 specimens

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titleEquipment 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.

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titleProcedure:

  • 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

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titleReported 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

*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

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titleReported 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

*Again, all these formulas will be in the confluence page*

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

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titleTest 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.

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titleProcedure:

  • 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

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