Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5083-17 – Standard Test Method Technical Guide
📐 Scope and Specimen Configuration
ASTM D5083-17 establishes a standardized procedure for determining the tensile properties of thermosetting reinforced plastics using straight-sided specimens of uniform nominal width. Based on current experience, this method is primarily validated for glass-reinforced thermoset systems (Note 1). The standard applies to materials with a thickness up to 14 mm (0.55 in.) (Section 1.2). Reducing the thickness of thicker materials by machining is generally discouraged to avoid disturbing the reinforcement structure (Note 3). The constant-rate-of-crosshead-movement (CRCM) type of test is specified, though the standard explicitly acknowledges its theoretical limitations regarding true strain rate measurement (Note 2).
| 🟦 Parameter | 📏 Specification |
|---|---|
| Specimen Type | Straight-sided, uniform width |
| Material Scope | Thermosetting reinforced plastics (glass typical) |
| Maximum Thickness | 14 mm (0.55 in.) |
| Testing Machine | Constant-Rate-of-Crosshead-Movement (CRCM) |
⚠️ Precision Limitation: As highlighted in Note 2, this CRCM test method is not intended for precise physical procedures. Variations between crosshead speed and strain rate across the gauge length are expected. For applications requiring high precision, or where directly comparable results are needed, all samples should be of equal thickness to control surface-to-volume ratio variations.
| 🎯 Differentiating Feature | ASTM D5083 | ISO 527-4 |
|---|---|---|
| Specimen Shape | Straight-sided | Type I Dogbone |
| Allowable Thickness | Up to 14 mm | 2 mm to 10 mm |
| Holes in Tabs | Not permitted | Permitted |
| Property Definitions | Standard definitions apply | Different definitions apply |
⚙️ Testing Procedure and Conditioning
Testing must occur under strictly defined conditions of pretreatment, temperature, humidity, and machine speed. Conditioning of all test specimens shall be performed in accordance with Practice D618. The physical dimensions of the specimens must be measured according to Test Methods D5947. A critical consideration is that variations in specimen thickness—which are permitted within the 14 mm limit—can alter the surface-to-volume ratio and influence results. Therefore, the standard emphasizes that all samples should be of equal thickness when directly comparable results are required (Note 2).
💡 Material Characterization Guidance: This test method is not designed for high-modulus fiber composites. For materials reinforced with fibers exhibiting a modulus greater than 20 GPa (3.0 × 10⁶ psi), strictly use Test Method D3039/D3039M or ISO 527-5 for valid results (Note 5).
📊 Key Measured Properties and Engineering Design
The data generated from this test method is explicitly recognized as relevant and appropriate for use in engineering design (Section 1.3). Key properties include tensile strength and modulus. Users must be acutely aware that the technical definitions and calculations for tensile strength and modulus in ASTM D5083 differ from those in ISO 527-4 (Note 4d). The standard mandates that SI units are the standard, with inch-pound units provided for reference only (Section 1.4).
❓ Frequently Asked Questions
🔍 What is the maximum specimen thickness allowed?
The maximum allowable thickness for a specimen under this standard is 14 mm (0.55 in.). Testing materials beyond this thickness is not recommended by the standard (Section 1.2, Note 3).
💡 How does this standard differ from ISO 527-4?
ISO 527-4 utilizes a Type I dogbone specimen, restricts thickness to 10 mm, and permits holes in gripping tabs. ASTM D5083 uses straight-sided specimens, allows up to 14 mm, and prohibits holes in tabs. Furthermore, the definitions of tensile properties differ between the two standards (Note 4).
⚡ Is this test method valid for carbon fiber composites?
No. The scope focuses on thermosetting plastics, with experience limited to glass reinforcement. For composites using high-modulus fibers (> 20 GPa), such as carbon fiber or aramid, Test Method D3039/D3039M must be employed (Note 5).
📌 Why must all test specimens have equal thickness for valid comparisons?
Variations in thickness, even within the permissible 14 mm range, directly affect the surface-to-volume ratio of the specimen. This geometric variation can significantly skew the tensile test results, making equal thickness a prerequisite for generating directly comparable data across a sample set (Note 2).