Abstract Impact sound performance below 100 Hz forms part of a design criterion that is particularly important for multi-story timber buildings. An ISO tapping machine, which is predominantly used for impact sound measurement, has properties that may result in less measurement accuracy in the low frequency range, down to 20 Hz, than in its traditional measurement range above 100 Hz. The characteristics of the pistons’ impact are dissimilar to the impact of a human foot in this lower range. This may cause low signal-to-noise ratios in field measurements and the test data may also be less representative due to the test objects’ possible structural nonlinearities affecting impact sound transmission. The ISO rubber ball has shown to bear a close resemblance to a human’s excitation in the low frequency range, which makes it a suitable excitation device from this perspective. To support correlations between simulations and measurements, measuring impact forces in order to extract frequency response functions would be beneficial. To enable measurements of impact forces that stem from the ISO rubber ball, equipment for field measurements of forces and potentially point mobilities has been manufactured and evaluated. Furthermore, an investigation has been conducted into the repeatability of the rubber ball’s low frequency force spectrum for floors with different mobilities. Impact force measurements have been made on lightweight timber floors as well as on concrete floors. Within the frequency range up to around 55 Hz, it appears to be possible to use a prescribed force spectrum for the ISO ball, together with impact sound measurements, to create accurate impact force to sound frequency response functions for different floors. Also, instrumenting the impact point with an accelerometer enables estimates to be made of direct point mobilities.

中文翻译：

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利用ISO橡胶球测量轻质木地板低频冲击声频响函数及振动特性

摘要 低于 100 Hz 的冲击声性能是设计标准的一部分，这对多层木结构建筑尤为重要。主要用于冲击声测量的 ISO 攻丝机的特性可能会导致低频范围（低至 20 Hz）的测量精度低于 100 Hz 以上的传统测量范围。在这个较低的范围内，活塞的冲击特性与人脚的冲击不同。这可能会导致现场测量中的低信噪比，并且由于测试对象的可能结构非线性影响冲击声传输，测试数据也可能不太具有代表性。ISO 橡皮球已显示出在低频范围内与人类的激励非常相似，从这个角度来看，这使其成为合适的励磁装置。为了支持模拟和测量之间的相关性，测量冲击力以提取频率响应函数将是有益的。为了能够测量源自 ISO 橡胶球的冲击力，已经制造和评估了用于力和潜在点移动性的现场测量的设备。此外，还对具有不同移动性的地板的橡胶球低频力谱的可重复性进行了调查。已经在轻质木地板和混凝土地板上进行了冲击力测量。在高达 55 Hz 左右的频率范围内，似乎可以对 ISO 球使用规定的力谱以及撞击声测量，为不同楼层的声音频率响应函数创建准确的冲击力。此外，使用加速度计检测撞击点可以估计直接点的移动性。