Effects of Frequency, Temperature and Test Duration in the Viscoelasticity of Brazilian Hardwoods Used in Handmade Musical Instruments

This study aims to make a comprehensive analysis on the viscoelastic behavior of typical tropical hardwoods and its influences in making musical instruments. For that a Dynamic-Mechanical Analysis was done and the mechanical parameters dependence on test control parameters like temperature, frequency and test duration time were measured. For Dalbergia Nigra the final value of Module of Elasticity (MOE) was 17551.0MPa and 0.022020 for tangent delta (tg(δ)), but a great variation in those parameters was observed during the tests, for all species the MOE increases and tg(δ) decreases, even with constant temperatures, which may be caused by water loss. Besides that, a discussion was made relating the obtained data and historical knowledge about the usages of the studied woods for musical instruments manufacture, and density was shown as the main variable for that purpose.本研究旨在对典型热带阔叶材的黏弹性行为及其在乐器制作中的影响开展全面分析。为此本研究开展了动态力学分析（Dynamic-Mechanical Analysis），并测定了力学参数对温度、频率、试验时长等试验控制参数的依赖特性。针对黑黄檀（Dalbergia Nigra），其弹性模量（Module of Elasticity, MOE）最终值为17551.0MPa，损耗角正切（tangent delta, tg(δ)）最终值为0.022020；但试验过程中上述参数呈现出显著波动：所有受试树种的MOE均随试验推进呈上升趋势，tg(δ)则呈下降趋势，即便在恒温条件下亦是如此，该现象或由水分流失所致。此外，本研究将试验所得数据与学界关于受试木材在乐器制作领域的传统应用认知相结合展开讨论，结果表明木材密度是该应用场景下的核心影响变量。