Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5868-01 – Standard Test Method Technical Guide
🎯 Purpose and Scope
This standard, designated ASTM D5868 −01 (Reapproved 2023), establishes a standardized lap shear test method for measuring the bonding characteristics of adhesives used to join fiber-reinforced plastics (FRP) to themselves and to metals. It is specifically applicable to both random and fiber-oriented FRP composites. The primary objective is to provide a means for generating comparative apparent shear strength data, allowing users to evaluate different FRP materials, adhesives, and surface treatments.
The method is explicitly designed to complement Test Method D1002, extending the single-lap shear test methodology to FRP adherends. This addresses the growing need for standardized testing in adhesively-bonded FRP applications, which offer significant advantages over mechanically-fastened joints, particularly in the alleviation of stress risers and stress cracking.
💡 Technical Note: This test method is intended to generate comparative data for FRP joints. For comprehensive guidance on the interpretation of lap shear test results, users should refer to ASTM Guide D4896. Always consider the specific fiber orientation and substrate properties when analyzing results.
⚙️ Test Procedure and Referenced Standards
The test procedure describes a single-lap shear configuration under tension loading. The standard incorporates several critical ASTM and SAE documents that define the terminology, scope, and quality control practices necessary for conducting the test and classifying its results. Understanding these references is essential for the correct application of D5868.
| 🔗 Standard Designation | 📋 Title and Application |
|---|---|
| D907 | Terminology of Adhesives |
| D1002 | Apparent Shear Strength of Single-Lap-Joint (Metal-to-Metal) |
| D2093 | Preparation of Surfaces of Plastics Prior to Adhesive Bonding |
| D3163 | Strength of Adhesively Bonded Rigid Plastic Lap-Shear Joints |
| D4896 | Guide for Use of Adhesive-Bonded Single Lap-Joint Specimen Test Results |
| D5573 | Classifying Failure Modes in Fiber-Reinforced-Plastic (FRP) Joints |
| E4 | Practices for Force Verification of Testing Machines |
| SAE J1525 | Lap Shear Test for Automotive-Type Adhesives for FRP Bonding |
⚠️ Critical Requirement: According to Section 1.3 of the standard, values stated in inch-pound units are to be regarded as standard. SI units provided in parentheses within the text are mathematical conversions for information purposes only and are not considered the primary reporting metric.
📊 Key Measured Properties and Significance
The significance of D5868 lies in its specific focus on adhesively-bonded fiber-reinforced plastics. As the use of bonded FRP increases in structural applications, this test method provides a critical, repeatable framework for comparing joint performance. The measured apparent shear strength serves as a primary comparative metric for adhesives and surface preparation methods.
Users must be aware of specific interferences. The apparent shear strength is not solely an adhesive property; it is significantly influenced by the substrate’s characteristics, including its moisture absorption and inherent strength.
| 📐 Parameter | 🎯 Specification |
|---|---|
| Standard Designation | D5868 −01 (Reapproved 2023) |
| Test Configuration | Single-Lap Shear under Tension Loading |
| Primary Adherends | FRP (Random or Fiber-Oriented) and Metal |
| Primary Unit System | Inch-Pound (Standard) |
| Secondary Unit System | SI (Mathematical conversion, informational) |
| Key Interference Factors | Substrate moisture absorption & strength |
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D5868?
The test method is designed to measure the lap shear bonding characteristics of adhesives for joining fiber-reinforced plastics (FRP) to themselves and to metals. It is specifically used to generate comparative apparent shear strength data for evaluating different FRP materials, adhesives, and surface treatments.
💡 How