Avaliação não destrutiva de peças estruturais de madeira empregando o ensaio de vibração longitudinal

Abstract

The longitudinal vibration test is a non-destructive method. The non-destructive methods can be measure the physical and mechanical properties of materials and structural components without damage or compromise the future usage. The longitudinal vibration test can be accomplished by two approach: by measurement of first resonance frequency r by stress wave method. Hence, the aim study were evaluate the results by two approaches of longitudinal vibration test at to determination the modulus of elasticity of lumber. For this, twenty eight boards of Pinus elliotti, with dimision 2 cm x 15 cm and 2,5 m length were sorted being, half graded as S2 and S3 by (group 1) and the remaining boards (group 2) without knots. The modulus of elasticity was measured both by longitudinal vibration test as bending static test. In both groups, a strong correlation was observed between static and dynamic the modulus of elasticity obtained by natural frequency, with R² = 0,86 for group 1 and R² = 0,92 for group 2. The results obtained with stress wave test method also show a good correlation with static bending tests for group 2 (R² = 0,80). However, for group 1, no correlation was found between static and dynamic modulus of elasticity measured with stress wave test method (R² = 0,09). The suggested to non-correlation between static and dynamic modulus of elasticity measured with stress wave test method of group 1, is that the length that the stress wave ran through the board were different that the wood board’s length.