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

在机械和仪器的连接部件的设计中，获得准确的接触压力信息是非常重要的。本文提出了一种用普通探头测量两层合板或两层合柱连接状态下接触压力的超声波定量测量方法。进行了实验，得到了以下实验结果：为了定量测量接触面压力，在不同表面粗糙度下，通过压缩标定块，研究了接触面与底座反射波的声压与接触面压力的关系。随着粗糙度的增大，反射波声压的每一次变化都变小，校正曲线基本是线性的。在固定载荷作用下，将两个矩形板、一个螺栓连接和由凸台和衬套组成的两个圆柱体压缩，通过设置在测量体一侧的法向探头测量接触面和基座反射波的声压。根据实测曲线与标定曲线的关系，定量地得到了接触压力。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结果大致一致，但两个圆柱体的结果还没有得到足够的值。发现两缸测量误差的原因是凸台与衬套之间的曲线和表面粗糙度不一定均匀。从上述结果可以看出，所提出的超声波测量方法对于测量两个层合板之间的接触压力是实用的。进一步阐明了两层压圆柱体的测量方法。

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.