Table 13 . -Selected performance goals for structural flakeboard 



Component Thickness MOE 1 MOE 



Inches Psi Psi 



STATIC BENDING 



Floor 5/8 

 Id C/C 5/h 



3 800,000 



A "7 C f\dr\ 



475, 000 



4,000 

 3 , 000 



Roofs 1/2 

 24" c/c 5/8 



725,000 

 375,000 



3 4,500 

 3,000 



wai i s j/ id 

 16" c/c 3/8 



5UU , UUU 

 300,000 



1 , 500 

 2,200 



RESIDUAL BENDING STRENGTH AFTER 

 ACCELERATED AGING: 

 50 PERCENT OF INITIAL 







TENSILE STRENGTH PERPENDICULAR TO 

 SURFACE (INTERNAL BOND) 

 Strength- -Dry 



--After accelerated aging 



70 lb/in 2 

 35 lb/in 2 





RELATIVE HUMIDITY) 







Allowable linear expansion 



(in plane of panel) 

 Allowable thickness swelling 



0.25 percent 

 8 percent 





INTERLAMINAR SHEAR 

 Strength 



250 lb/in 2 





EDGEWISE SHEAR 

 Strength 



1,000 lb/in 2 





Values are average values with a variability consideration. 

 Values are near -minimum values. 



Values governing a single maximum performance panel. 



Alining wood flakes or strands in one direction produces structural flakeboards of 

 even higher strength and stiffness (Elmendorf 1965; Snodgrass and others 1973). To 

 obtain adequate linear stability and strength in the nonalined direction, three- layer 

 alined boards are suggested. The importance of this is reflected in figure 10, where 

 expansion perpendicular to the alined direction can be very high unless restrained 

 (Geimer and others 1975b) . The cores consist of either random flakes or cross-alined 

 flakes (Geimer, and others 1975a; Saunders and others 1975) . , (The alined panel patent 

 (Elmendorf 1965) restricts commercial production of this panel type.) Typical surfaces 

 of random and alined boards are shown in figure 11. 



16 



