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D5024-23 – Standard Test Method Technical Guide
ASTM D5024-23 defines the standard methodology for evaluating the dynamic mechanical properties of plastics in compression. It applies to a wide range of materials, including thermoplastic and thermosetting resins, composites, and cellular plastics, using nonresonant forced-vibration techniques.
📐 Specimen Geometry and Types
The test method requires test specimens with a cylindrical cross section. These can be molded directly from the material or cut from sheets, plates, or molded shapes. This allows the standard to be applied to raw materials as well as finished components. Specimens are positioned between two parallel, flat plates or disks for dynamic compression testing. The method is applicable to both solid and cellular (foam) plastic materials.
⚙️ Test Methodology and Conditions
Testing follows the nonresonant, forced-vibration principles established in Practice D4065. The instrument applies a linear oscillatory displacement to the specimen. Testing is controlled by either varying the temperature at a fixed frequency or measuring at multiple frequencies under isothermal conditions. The standard permits a frequency range of 0.01 Hz to 100 Hz.
🔬 Relative vs. Absolute Values: The standard explicitly notes (Section 1.4) that due to possible instrumentation compliance, data generated are intended to indicate relative and not necessarily absolute property values. Despite this, Section 1.5 confirms the data is relevant and appropriate for engineering design purposes. SI units are regarded as the standard (Section 1.6).
📊 Key Measured Properties and Data Reporting
The test generates critical viscoelastic properties as a function of frequency, time, or temperature. Plots of these properties help identify significant thermomechanical transitions such as the glass transition temperature (Tg) and secondary relaxations.
| 🟦 Parameter | 📏 Specification / Range |
|---|---|
| Valid Frequency Range | 0.01 Hz to 100 Hz |
| Specimen Shape | Cylindrical cross section |
| Test Fixture | Parallel flat plates or disks |
| Temperature Mode | Linear variation or isothermal |
| Primary Practice | D4065 |
| 🎯 Measured/Reported Property | 💡 Description |
|---|---|
| Storage Modulus (Elastic) | Measure of the stored elastic energy (stiffness) |
| Loss Modulus (Viscous) | Measure of the dissipated viscous energy (damping) |
| Complex Modulus | Total resistance of the material to deformation |
| Tan Delta (Damping factor) | Ratio of Loss Modulus to Storage Modulus |
⚠️ Standardization Note: Per Note 1 of the standard, there is no known ISO equivalent to ASTM D5024-23. All terminology used must be in accordance with ASTM D4092 (Dynamic Mechanical Properties) and ASTM D883 (Plastics). Conditioning should follow Practice D618.
❓ Frequently Asked Questions
🔍 What types of materials are suitable for D5024 compression testing?
The standard covers thermoplastic and thermosetting resins, composite systems, and cellular plastics in the form of cylindrical specimens molded directly or cut from sheets, plates, or molded shapes.
⚡ What is the standard frequency and temperature testing range?
The standard is valid for a wide range of frequencies, typically from 0.01 Hz to 100 Hz. Temperature testing can be conducted using a linear temperature variation or under isothermal conditions at variable frequencies.
📌 Why does the standard state that data indicates “relative” property values?
Section 1.4 states that due to possible instrumentation compliance between different setups, the data generated is intended to indicate relative and not necessarily absolute property values, though it remains suitable for engineering design.
💡 What standards are most frequently referenced alongside D5024?
The primary referenced standard is Practice D4065 (Procedures). Terminology is taken from D4092 (Dynamic Mechanical Properties) and D883 (Plastics). Conditioning of specimens follows Practice D618.