Avaliação das propriedades acústicas de mogno africano ( Khaya ivorensis ) submetido a tratamento térmico em estufa e autoclave

Materia

article

Francisco Antonio Lopes Laudares¹  Alexandre Miguel do Nascimento¹  Renata Nunes Oliveira¹  Rogério Rodrigues dos Santos¹  Fabrizia Dias Guedes Moura¹ 

[1] Universidade Federal Rural do Rio de Janeiro

关键词: Resonance frequency;    Impulse Excitation;    logarithmic damping decrement;    Acoustic attenuation;    Dynamic modulus of elasticity;   

DOI  :  10.1590/1517-7076-RMAT-2023-0035

学科分类：工程和技术（综合）

来源: Universidade Federal do Rio de Janeiro * Coordenacao dos Programas de Pos-Graduacao de Engenharia

【 摘 要 】

The present work evaluated the effect of thermal treatment on the acoustic behavior of african mahogany wood (Khaya ivorensis A. Chev.) submitted to two types of thermal treatments called dry treatment, carried out in an oven at temperatures of 130, 160 and 190 °C, and wet treatment, using steam in an autoclave at temperatures and pressures of 123 °C and 1.2 kgf.cm−2 and 160 °C and 6.0 kgf.cm−2, respectively. Conjugated treatments were also carried out, where part of the samples first went through wet treatment and after that, through dry treatment. After treatments, the samples were submitted to acoustic evaluation through mechanical vibration tests, using the transverse impulse excitation technique, as reported for in the ASTM-E1876 standard. The fundamental resonance frequency (fr), the specific transverse dynamic (Espe), the logarithmic decrement of damping (LDD) and the acoustic conversion efficiency (ACE) were determined. According to the results obtained, the wood treated only by steam in an autoclave at 123 °C stood out in relation to the other treatments, including the conjugated was. An increase of 7.3 % was verified for the fr, 10.8 % for Eesp and 26.4 % for ECA, and reduction of 11.9 % for Dl. It was observed the optimization of African mahogany’s acoustic properties.

【 授权许可】

CC BY