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ASTM D1822 Tensile-Impact Test To Break Plastics and Electrical Insulating Materials

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ASTM D1822 Tensile Impact Energy to Break Plastics and Electrical Insulating Materials


The ASTM D1822 standard outlines test procedures to find the energy required to rupture tension-impact specimens of plastic or electrical insulating materials. Test materials that are too bendable or too thin to be tested in accordance with the ASTM D256 standard are ideal for this test along with more rigid materials.

ASTM D1822 Tensile-Impact Test To Break Plastics and Electrical Insulating MaterialsASTM D1822 Tensile-Impact Test To Break Plastics and Electrical Insulating Materials


The test uses a pendulum impact testing machine with two pendulum falling arms. The two arms are connected by the testing specimen. 

ASTM D1822 specifies that the pendulum arms are dropped and the machine stops one arm at the lowest point and the kinetic energy of the second arm pull the connecting plastic specimen to failure. The energy that is required to cause the specimen to fail is the tensile impact energy.


Specific Test Method: 

ASTM D1822 uses one single standardized method (similar to ISO 8256 Method B):

The specimen is mounted inside a removable yoke assembly attached to the pendulum.

At impact, the yoke stops suddenly while the pendulum continues moving.

The specimen is pulled in high-speed tension until it fractures.

Result: Tensile-Impact Energy and Tensile-Impact Strength.


Test Specimen information: 

There are two types of test specimens which can be used, long (L) and short (S). Both are 63.5mm (2.5") long, but gauge length areas vary. 

Type L specimens:

with a gauge length of 9.53mm   (0.375") provide a greater differentiation between materials. 

Type S specimens:

which have no true gauge length (see the   picture above) provide a greater occurrence of brittle failures.


Type  
LLebxLoShape
SMethod B  63.5 (2.5”)  25.4 (1")  9.53 or 12.7
  (0.375 or 0.5”)  
3.18±0.03-ASTM D1822 Tensile-Impact Test To Break Plastics and Electrical Insulating Materials
LMethod B63.5 (2.5”)25.4 (1")9.53 or 12.7
  (0.375 or 0.5”)
3.18±0.03
  (0.125± 0.01")  
9.53±0.05  ASTM D1822 Tensile-Impact Test To Break Plastics and Electrical Insulating Materials

L : Length

Le: Free length between grips

b: Width

x: Preferred value of dimension

Lo : Preferred value of dimension


Related Standards

ISO 8256: The direct international equivalent. The main differences lie in specimen geometry details and procedural nuances. Results from the two standards are not directly numerically comparable but serve the same technical purpose.

ASTM D256: Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics. This is a flexural impact test, providing complementary data under a different stress state.

ASTM D638: Standard Test Method for Tensile Properties of Plastics. Provides the quasi-static tensile properties (strength, modulus) which contrast with the high-speed properties from D1822. 


General ASTM D1822 Tensile Impact Test Procedures:

Condition specimens at standard temperature and humidity.

Measure width and thickness of the narrow gauge section.

Mount the specimen in the yoke assembly.

Attach the yoke to the pendulum.

Release the pendulum to perform impact.

Record the energy absorbed.

Test at least 5–10 specimens.

Calculate average tensile-impact energy and strength.

Note fracture type: ductile, brittle, or partial break.


Key Differences between ASTM D1822 and ISO 8256:

ISO 8256 has 2 methods; ASTM D1822 only 1.

ISO 8256 Method B ≈ ASTM D1822 mechanically.

Specimens are different and not interchangeable.

Dimensions, thickness, and geometry differ.

Standards come from different regions (US vs International).

Results cannot be directly compared numerically without conversion.

Related products and device

ASTM D1822 plastic tensile impact tester

LCT plastic tensile impact testing machine is used to execute tensile-impact test of plastics or insulation materials under defined condition, measure the tensile-impact strength and permanent break elongation rate, especially for materials too flexible or too thin to be tested use Charpy or Izod.

Related Standard

ISO 8256 for plastics tensile impact testing

ISO 8256:2023 Plastics — Determination of tensile-impact strength


ISO 8256 specifies two methods (method A and method B) for the determination of the tensile-impact strength of plastics under defined conditions. The tests can be described as tensile tests at relatively high strain rates. These methods can be used for rigid materials (as defined in ISO 472), but are especially useful for materials too flexible or too thin to be tested with impact tests conforming to ISO 179 or ISO 180.These methods are used for investigating the behaviour of specified specimens under specified impact velocities, and for estimating the brittleness or the toughness of specimens within the limitations inherent in the test conditions. Similar with standard ASTM D1822. 

These methods are applicable both to specimens prepared from moulding materials and to specimens taken from finished or semi-finished products (for example mouldings, films, laminates, or extruded or cast sheets).

Frequently Asked Questions (FAQs) about Tensile-Impact Testing (ASTM D1822 / ISO 8256)

Q1: What is the main purpose of a tensile-impact test, and how is it different from a Charpy or Izod test?

A: The tensile-impact test measures the energy to break a specimen under a high-speed pulling (tensile) force. Charpy and Izod tests apply a high-speed bending (flexural) force. The stress state and failure mode are fundamentally different. A material can be tough in bending but brittle in tension, making this test crucial for applications involving sudden snatch loads.


Q2: Are ASTM D1822 and ISO 8256 the same test? Can I directly compare results?

A: They are technically equivalent in principle and purpose—both measure tensile-impact strength. However, they are not identical. Key differences exist in:

Specimen Geometry: The dumbbell shapes (Type L/S in ASTM vs. Type 1A/1B in ISO) have different dimensions.

Striker/Pendulum Design: Slight variations in machine design may exist.

Calculation Details: Procedures for correcting for friction and windage loss may differ.

Therefore, numerical results from the two standards are not directly comparable. You must report which standard was used.


Q3: Why would I choose a tensile-impact test over the more common Izod test?

A: Choose tensile-impact when your product's real-world failure risk is from a sudden pulling or stretching action, not a bending impact. It is particularly relevant for films, fibers, tapes, straps, snap-fit closures, and any component that might experience rapid tensile deformation. It provides a more accurate toughness assessment for that specific loading condition.


Q4: The specimens look like standard tensile dumbbells. Are they the same?

A: They are similar in shape but not identical. Tensile-impact specimens are typically shorter and have a different neck geometry optimized for high-speed failure. Using a quasi-static tensile specimen (e.g., from ISO 527) in an impact tester will likely yield invalid results. Always use the precise specimen dimensions mandated by the standard.


Q5: What are common sources of error or variability in this test?

A: High variability is common and can stem from:

Specimen Preparation: Nicks, scratches, or imperfect machining in the critical neck region.

Misalignment: If the specimen is twisted or not aligned axially in the clamps, it creates bending stresses.

Clamping Pressure: Too little pressure causes slippage; too much can crush or pre-stress the specimen.

Incorrect Calibration: Failure to properly account for the machine's friction and windage losses.


Q6: Can I test very brittle or very ductile materials with this method?

A: Yes, but with caveats.

For very brittle materials, the energy absorbed is very low, and the test may not distinguish well between materials. The result primarily reflects crack initiation energy.

For very ductile materials, the specimen may stretch significantly without cleanly breaking, or the clamp may slip. The test measures the total energy to yield and tear. The standard specifies that the specimen must break completely within the pendulum's swing.


Q7: What does a higher tensile‑impact value mean?

A: A higher value means the material absorbs more energy before breaking under high‑speed tension — so it is tougher, more ductile, and more resistant to sudden tensile failure.


Q8: What does a low tensile‑impact value mean?

A: A low value indicates the material is more brittle under high strain rates and may fail suddenly and catastrophically in dynamic tensile applications.


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