Comparative study on measurement of elastic constants of wood-based panels using modal testing: choice of boundary conditions and calculation methods

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 4 Elastic constants of OSB and MDF measured by dynamic methods with different boundary conditions and static methods

Panel #	Elastic constants measured by dynamic methods (MPa)									Elastic constants measured by static methods (MPa)
	FFFF^a			SFFF			SFSF			Elastic constants measured by static methods (MPa)
	E _x	E _y	G _xy	E _x	E _y	G _xy	E _x	E _y	G _xy	E _x	E _y	G _xy
OSB1	7769	3534	1790	6533	3168	2092	7496	3177	2045	6424	2654	2504
OSB2	7740	3530	1820	6818	3060	1929	7334	3071	2162	6732	2520	2589
OSB3	8231	3848	1935	6994	3434	2119	7542	3319	2243	6376	2627	2450
OSB4	7678	3483	1768	6820	3225	1897	6921	3049	1959	6808	2574	2488
OSB5	7782	3700	1872	7223	3789	1763	7386	3222	2155	6694	2555	2637
Mean	7840	3619	1837	6878	3335	1960	7336	3167	2113	6607	2586	2534
COV (%)	6.4	6.5	7.1	6.5	9.7	9.9	6.3	8.1	8.8	10.7	14.9	7.5
Diff. (%)	16.9	39.9	−27.5	2.5	29.0	−22.6	9.4	22.5	−16.6	–	–	–
MDF1	3323	3282	1394	3273	2818	1324	3297	3216	1341	3073	3162	1626
MDF2	3290	3188	1377	3233	2938	1319	3210	2906	1411	2929	3078	1450
MDF3	3460	3423	1459	3276	3072	1406	3473	3185	1492	3371	3453	1568
MDF4	3221	3182	1353	3050	2848	1359	3055	3017	1280	3041	3231	1492
MDF5	3440	3310	1446	3280	3031	1434	3403	3200	1526	3078	3251	1477
Mean	3347	3277	1406	3222	2942	1368	3288	3105	1410	3098	3235	1522
COV (%)	4.0	3.6	3.9	5.3	4.5	4.9	5.4	7.3	7.3	6.7	6.0	8.1
Diff. (%)	8.0	1.3	−7.6	4.0	−9.1	−10.1	6.1	−4.0	−7.7	–	–	–

COV is short for the coefficient of variation. Diff. refers to the difference in percentage based on corresponding static value. The dynamic elastic constants of four panel specimens cut from the same full-size panel specimen were averaged as the representatives of each full-size panel specimen. OSB and MDF are short for oriented strand board, and medium density fiberboard, respectively. FFFF represents the boundary condition of all sides free, SFFF represents the boundary condition of one side simply supported and the other three free and SFSF represents the boundary condition of a pair of opposite sides along minor strength direction simply supported and the other pair along major strength direction free
^aResults of FEM updating