Structural Flakeboards and Composites 



3051 



Figure 24-59. — Shaped particle beam under bending load. (Photo from Geimer and 

 Lehmann 1975.) 



Elmendoif Research, Inc. (1970ab) developed panel products (STONE-TEX 

 and PLY-TEX) platen-pressed from shavings in such a manner that surfaces are 

 textured with pronounced elevations and depressions. This molding is accom- 

 plished through use of resilient platens and the resulting board is more uniform in 

 density across board width and length than particleboards platen-pressed with 

 rigid cauls. 



SHAPED PARTICLE BEAMS 



Geimer and Lehmann (1975) evaluated several forming methods in construct- 

 ing 9.75-inch-deep, 96-inch-long I-beams (fig. 24-59) of wood particles using 

 shaped molds. They found that the forming method holding most promise 

 maintains a level mat during the forming period by utilizing a low-bulk-density 

 fibrous material for the web portion of the beam and aligned flakes with high 

 bulk density for the flange area. Beams having the best bending properties were 

 constructed using aligned 0.020- by 0.5- by 2-inch, disk-cut flakes in the flanges 

 and 0.020- by 2-inch ring flakes randomly dispersed for the web. Such beams 

 had EI of 185,000,000 psi and breaking loads of 10,750 pounds under quarter- 

 span, two-point loading over a 90-inch span. Bending stiffness was comparable 

 to that of a solid lumber beam of equal weight. Bending strength, however, was 

 only half that of a lumber beam. 



