Determination of acoustical material properties (BeKAM)

现在和未来都将以新型混合聚合物材料的开发为标志，与旧材料相比，这种材料在成本效益方面要优越得多。越来越多地使用此类材料在基于超声波的测量技术领域中带来了新的可能性，但也带来了加剧的因素。合成材料为结构性和声学功能元件的设计提供了更大的自由度。它们相当复杂的声学品质是不利的。与金属不同，频率和主要与方向相关的声速、吸声和声阻抗随温度、年龄或含水量的变化很大。了解这些变化的材料属性的范围非常重要，以便在设计过程中考虑这一点。目前，这些材料特征量既没有标准化，也没有达到必要的规模。对于基于波导的测量系统，所有相关的声学材料特性都应仅通过条件良好的标准化测试样本来确定，并在数据库中提供。

The presence is and the future will be marked by the development of new hybrid polymer materials, which considerably are superior in terms of cost effectiveness in comparison to the old material generation. Increasing use of such materials leads in the area of the ultrasound based measuring technology both to new possibilities and to aggravating factors. Synthetic materials offer substantially more degrees of freedom to design constructive as well as acoustically functional elements. Their considerably more complex acoustic qualities are adverse. The frequency and mostly direction-dependent sound velocity, sound absorption and acoustical impedance vary considerably with the temperature, the age or the water content differently than at metals. It is important to know the range of these changed material properties to consider that during the design process. At present, such material characteristic quantities are neither standardized nor available on the necessary scale. With a wave guide based measurement system all relevant acoustical material properties shall be determined with only a well-conditioned, standardized test specimen and made available in a database.