9 Stresses and strains below the proportional limit as indices of non-destructive testing of wood

The Paper shows that non-destructive tests of timber below the so-called elastic limit can be used to estimate the breaking load, and that stress/strain relationships, bending tests and the use of modulus of elasticity are promising methods of estimating breaking loads and safety factors.

It is especially important that wood with its variation in mechanical properties should be tested non-destructively, i.e. instead of very expensive and unreliable destructive tests, non-destructive tests are introduced in the material testing. Many approaches have been made, most of which were a failure.

2. If any wooden constructional part is loaded, the following situation exists. The load, of course reduced to the cross section in tension and compression and with complication in bending, means stress. Stress always produces strains, i.e. deformation.