ASTM D5023 Standard Test Method for Plastics: Dynamic Mechanical Properties in Flexure (Three-Point Bending)

Get Certified ASTM D5023 Testing for Reliable Dynamic Mechanical Property Evaluation

ASTM D5023 testing is a method for characterizing the thermomechanical and viscoelastic behavior of plastic materials and composite systems under controlled three-point bending conditions. Results may be utilized for quality control, R&D, material comparison, process optimization, and engineering design. The method is also capable of measuring changes in modulus as a function of temperature or frequency, processing effects, resin cure and damping characteristics, formulation additives, annealing, fiber reinforcement orientation, and filler effects. If the applicable material specification gives other information for specimen preparation, conditioning, dimensions, or testing parameters that override the default conditions of ASTM D5023, testing should be done in accordance with the material specification.

• Material: Thermoplastic and thermosetting resins, plastics, and composite systems.
• Specimen form: Rectangular bars molded directly or cut from sheets, plates, or molded shapes.
• Test mode: Dynamic three-point bending using nonresonant forced vibration.
• Frequency: Typically 0.01 Hz to 100 Hz.
• Measured properties: Storage modulus, loss modulus, complex modulus, and tan delta.
• Variables: Dynamic mechanical properties can be evaluated as functions of temperature, frequency, or time.
• Applications: Quality control, research and development, processing optimization, and engineering design.
• Limitations: Because instrumentation compliance can affect measurements, results are intended to indicate relative rather than necessarily absolute property values.

What are the Uses of ASTM D5023 Testing?

The controlled three-point bending method described in ASTM D5023 can be used to assess the dynamic mechanical and thermomechanical properties of plastic materials. Thus, the results can be used by engineers to characterize the material response and explore changes that can be related to temperature, frequency, processing, formulation, and reinforcement. The ASTM D5023 standard-

• Measures the storage modulus of plastic materials under flexural dynamic load.
• Measures loss modulus and damping of plastic compounds.
• Measures the complex modulus and tan delta at the test conditions.
• Evaluates the modulus as a function of temperature or frequency.
• Determines the influence of material processing conditions on material response.
• Evaluates relative resin characteristics: cure and damping.
• Assesses the impact of the type of substrate and the orientation of the material on the modulus.
• Discusses the effects of fillers and formulation additives on modulus and glass-transition behavior.
• Helps with quality control, research and development, and optimization of processing conditions.
• Offers thermomechanical information that can be used to aid engineering design.

Which materials can be tested under ASTM D5023?

ASTM D5023 is applicable to thermoplastic and thermosetting resins and composite systems which can be fabricated into appropriate rectangular bars for three-point bending. Specimens can be molded to the desired size and shape or simply cut from sheets, plates, or molded shapes. When applicable, the material specification should be checked prior to testing, as the specimen preparation, specimen conditioning, dimensions, and/or testing parameters are of higher priority. Representative sampling is extremely important for meaningful dynamic mechanical results for small specimen geometries.

Why is ASTM D5023 Important?

The stiffness and damping of plastic materials can be highly sensitive to temperature, frequency, time, processing, and formulation. ASTM D5023 establishes a controlled method to characterize these changes by performing dynamic three-point bending measurements. The method is used to measure elastic and loss response and is able to identify changes in thermomechanical performance through changes in modulus and tan delta. The information obtained aids the analysts in understanding the material behavior under certain conditions and in comparing between different plastic materials with the same test parameters. Since the values measured are influenced by the experimental conditions and the potential compliance of the instrumentation, it is crucial that the test conditions are reported in full for meaningful interpretation.

ASTM D5023 Testing Process and Data Collection

ASTM D5023 involves the three-point bending of a rectangular sample with a controlled linear dynamic displacement at a chosen frequency. As the specimen responds to the applied deformation, the instrument measures the applied force, the amount of deflection, frequency, and temperature. Temperature sweeps or frequency measurements can be performed by the analysts, depending on the goal of the evaluation. From this response, the storage modulus, loss modulus, complex modulus and tan delta are calculated. The test conditions need to be recorded because the response measured will be dependent on the test conditions and may be influenced by instrumentation compliance.

Common Challenges and Troubleshooting

Common challenges with ASTM D5023 include using nonrepresentative specimens, incorrect specimen dimensions, improper support positioning, excessive deformation outside the linear elastic region, inadequate preload, and inconsistent temperature or frequency conditions. When comparing results, it is also important to have complete documentation of instrument compliance because this can also influence the measured response. Thus, technicians must check the dimensions of the specimen, position the specimen properly, ensure that the specimen support geometry is adequate, select deformation amplitude within the linear range, and control temperature and frequency during the test. Material specifications are also applicable and should be reviewed prior to testing because the specimen preparation, conditioning, specimen size, or testing parameters may supersede the default ASTM D5023 conditions.

• The laboratory documents the conditioning data, dimensions, material, and identification of the specimens.
• The operator writes down the frequency applied, the amplitude of deformation, temperature conditions, and other test parameters.
• Analysts determine the storage modulus, loss modulus, complex modulus, and tan delta from the measured response.
• Technicians compare the changes in the modulus and damping behavior with respect to temperature, frequency, or time.
• Results may be applied to quality control, R&D, processing optimization, material comparison, and engineering design.

Link to ASTM D5023