What is ASTM D198?
ASTM D198 is an international testing standard used to determine the mechanical properties of structural wood components, including: ✔ Sawn lumber
✔ Glued laminated timber (glulam)
✔ Composite lumber
✔ Pre-fabricated I-joists
This standard includes various test methods, such as flexure (bending), compression, tension, and torsion testing. Among these, flexure testing is one of the most commonly applied methods.
ASTM D198 Test Methods
Flexure (Bending) Test
This test measures the flexural strength of a wooden beam by applying a load under two configurations: 🔹 Center-point loading – Load applied at the midpoint.
🔹 Third-point loading – Load applied at two equidistant points along the span.
The beam is subjected to a controlled rate of deflection until rupture occurs.
Importance of Flexure Testing:
✅ Ensures structural wood components comply with safety standards.
✅ Aids in designing wood structures for construction, furniture, and engineering applications.
✅ Determines the wood’s resistance to bending forces.
Testing Equipment for ASTM D198
Fixtures Used
🔹 Bend Fixtures –
Designed for measuring flexural properties in rigid and semi-rigid materials. Available in various spans and widths for 3-point and 4-point bending tests.
Recommended Universal Testing Machines (UTMs)
We recommend UTMs with a force capacity of 5kN to 600kN, depending on material strength.
VEW 2308 – Universal Testing Machine
✅ High-precision electronic motor for controlled loading.
✅ Capable of flexure, tension, compression, bending, shear, and peel tests.
✅ Suitable for wood, rubber, plastics, textiles, aerospace materials, and more.
ASTM D198 Test Procedure
1️⃣ Prepare the wood specimen as per ASTM D198 guidelines.
2️⃣ Adjust the flexure fixture to match the specimen size and test type.
3️⃣ Secure the specimen in the flexure fixture.
4️⃣ Apply the flexure load at a constant speed.
5️⃣ Record critical data points until failure, including:
✔ First failure
✔ Maximum load
✔ Load-deflection behavior
Key Measurements in ASTM D198
📌 Modulus of Rupture (MOR) – Measures maximum load capacity before breaking.
📌 Apparent Modulus of Elasticity (MOE) – Determines wood stiffness and bending resistance.