Ebe K, Griffin M J
Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, UK.
Ergonomics. 2000 Jun;43(6):771-90. doi: 10.1080/001401300404742.
Judgements of overall seating comfort in dynamic conditions sometimes correlate better with the static characteristics of a seat than with measures of the dynamic environment. This study developed qualitative models of overall seat discomfort to include both static and dynamic seat characteristics. A dynamic factor that reflected how vibration discomfort increased as vibration magnitude increased was combined with a static seat factor which reflected seating comfort without vibration. The ability of the model to predict the relative and overall importance of dynamic and static seat characteristics on comfort was tested in two experiments. A paired comparison experiment, using four polyurethane foam cushions (50, 70, 100, 120 mm thick), provided different static and dynamic comfort when 12 subjects were exposed to one-third octave band random vertical vibration with centre frequencies of 2.5 and 5.5 Hz, at magnitudes of 0.00, 0.25 and 0.50 m x s(-2) rms measured beneath the foam samples. Subject judgements of the relative discomfort of the different conditions depended on both static and dynamic characteristics in a manner consistent with the model. The effect of static and dynamic seat factors on overall seat discomfort was investigated by magnitude estimation using three foam cushions (of different hardness) and a rigid wooden seat at six vibration magnitudes with 20 subjects. Static seat factors (i.e. cushion stiffness) affected the manner in which vibration influenced the overall discomfort: cushions with lower stiffness were more comfortable and more sensitive to changes in vibration magnitude than those with higher stiffness. The experiments confirm that judgements of overall seat discomfort can be affected by both the static and dynamic characteristics of a seat, with the effect depending on vibration magnitude: when vibration magnitude was low, discomfort was dominated by static seat factors; as the vibration magnitude increased, discomfort became dominated by dynamic factors.
在动态条件下，对座椅整体乘坐舒适性的判断有时与座椅的静态特性相关性更好，而不是与动态环境的测量值相关性更好。本研究开发了整体座椅不适的定性模型，以纳入静态和动态座椅特性。一个反映振动不适如何随振动幅度增加而增加的动态因素，与一个反映无振动时座椅舒适性的静态座椅因素相结合。该模型预测动态和静态座椅特性对舒适性的相对和总体重要性的能力在两个实验中进行了测试。一项配对比较实验，使用四个聚氨酯泡沫坐垫（厚度分别为50、70、100、120毫米），当12名受试者暴露于中心频率为2.5和5.5赫兹、在泡沫样品下方测量的均方根值为0.00、0.25和0.50米×秒（-2）的1/3倍频程带随机垂直振动时，提供了不同的静态和动态舒适性。受试者对不同条件下相对不适的判断取决于静态和动态特性，其方式与模型一致。使用三个不同硬度的泡沫坐垫和一个刚性木座椅，在六个振动幅度下对20名受试者进行了量级估计，以研究静态和动态座椅因素对整体座椅不适的影响。静态座椅因素（即坐垫刚度）影响振动影响整体不适的方式：刚度较低的坐垫比刚度较高的坐垫更舒适，对振动幅度变化更敏感。实验证实，座椅整体不适的判断可能受到座椅静态和动态特性的影响，其影响取决于振动幅度：当振动幅度较低时，不适主要由静态座椅因素主导；随着振动幅度增加，不适则主要由动态因素主导。
