Studies on the Improvement and the practical application of Contact Pressure Measurement by Means of Ultrasonic Waves

在机械设备连接件的设计中，准确掌握接触压力信息是非常重要的。本文提出了一种用普通探头利用超声波定量测量接触压力的方法，用于测量两个层合板或两个层合柱连接状态下的接触压力。进行了实验，得到了以下实验结果。为了定量测量接触压力，通过压缩定标块，研究了在不同表面粗糙度条件下，接触压力与接触面和基座反射波声压之间的关系。随着粗糙度的增加，反射波声压的每一次变化都变小，然后这些校准曲线几乎是线性的。两个矩形平板、一个螺栓接头和由凸台和衬套组成的两个圆柱体在固定载荷作用下被压缩，通过安装在被测体一侧的法向探头测量来自接触面和底座的反射波的声压。根据测量曲线与标定曲线之间的关系，定量地得到了接触压力。并将实验结果与分析结果进行了比较。两个矩形板和螺栓连接的计算结果基本吻合，但两个圆柱体的计算结果尚未得到充分的取值。发现凸台与衬套之间的曲线和表面粗糙度不一定一致是造成两个圆柱体测量误差的原因。从上述结果可以看出，所提出的超声法是测量两层合板间接触压力的实用方法。此外，还将阐明两个叠层圆柱体的测量方法。

In the design of joint parts of machines and apparatus, it is very important to have exact information about the contact pressure. In this paper, a quantitative measurement of contact pressure by means of ultrasonic waves using a normal probe has been proposed to measure the contact pressure at a state in which two laminated plates or two laminated cylinders were connected. The experiment was done and the following experimental results are obtained.1. In order to measure the contact pressure quantitatively, the relations between contact pressure and sound pressures of reflected waves from the contact surface and the base were investigated by compressing calibration blocks under various surface roughnesses, in which the contact surface was flat or curved. Each change in the sound pressure of reflected waves becomes smaller as the roughness increases, and then these calibration curves are almost linear.2. Two rectangular plates, a bolted joint and two cylinders composed of boss and bush were compressed under a fixed load, and the sound pressures of reflected waves from the contact surface and the base were measured by the normal probe set on one side of measuring bodies. From the relation between measured curve and caribration curve, the contact pressure was obtained quantitatively. The experimental results were compared with the analytical one. Both results in the two rectangular plates and the bolted joint agree approximately, but both results in the two cylinders are not yet obtained adequate values.3. The cause of the measured error in the two cylinders is found that the curve and the surface roughness between boss and bush are not necessarily uniform.4. From the results destribed above, it is seen that the proposed ultrasonic method is practically for measuring the contact pressure between two laminated plates. Furthermore, the measuring method of the two laminated cylinders will be clarified.