|Test Method: Annual Book of ASTM Standards, 1989, D 1037 -Standard Methods Of Evaluating the Properties of Wood-Base Fiber and Particle Panel Material, pp. 167-196.
Internal bond is a fundamental measure of the adhesive performance in wood composites. This strength is in large part determined by the effectiveness of the glue application in the composite manufacture, but is also affected by other variables such as wood particle size and density of the composite. The internal bond specimen size is 2x2 inches (50x50 mm) by the composite thickness. Aluminum test blocks are glued to the top and bottom surfaces of the specimen using hot-melt glue. The test machine fixture grips the aluminum blocks and applies tension perpendicular to the specimen surface until the specimen fails. Internal bond is then reported as the maximum recorded load divided by the cross sectional area of the specimen.
Internal bond gluing station. Internal bond specimens cool on the cold plate in the foreground while the hot plate melts glue on aluminum blocks in the background.
Applying tensile load to internal bond specimen. Also shown is failed specimen.
|Static bending refers to tests performed in which a bending stress is applied to the specimen to determine the stiffness, or modulus of elasticity of the specimen as well as the amount of force required to cause the specimen to fail, expressed as the modulus of rupture. The specimen size is dependent on the testing standard used, the material type, the original size and intended end-use of the material being tested.|
|Test Methods: Based on the method of Nicholas (Dr. Darrel D. Nicholas, Dr. Zhongwei Jin. 1996. Use of Compression Strength Loss For Measuring Decay in the Soil Block Test.
This test was designed to provide compressive strength data for small-sized wood specimens, since the larger size specimens required for the standard ASTM test method cannot always be obtained. One inch cube specimens are conditioning to 12% MC. Then, the specimen is positioned under the test machine compression plate for an applied load perpendicular to the tangential face of the specimen. The specimen is preloaded to 10 lbs, and then compressed until 5% strain is achieved. The load at 5% strain is recorded.