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结构物的原型和模型振动试验,通常利用电磁式激振器作为产生激振力的换能器件。电磁式激振器的输出特性,往往用力常数来表达。根据输入电流及力常数来确定电磁式激振器施于试验物体上的激振力是相当粗糙的。因为,在振动频率较高的情况下,一方面,电磁式激振器本身的运动部分已不再是一个简单的单自由度体系,输出力的情况较复杂;另一方面,激振力在通过传力杆传递的过程中,由于传力杆本身的弹性变形,也将损耗一部分能量。此外,还由于安装不妥的原因,也将产生相当大的摩擦损耗。而且,上述这些因素通常随频率而变。所以,电磁式激振器的输出力并不等于传至试验物体上的激振力,同时,激振力的波形与输入电流的波形也有失真观象。为了保证试验结果可靠正确,必须直接测定电磁式激振器施于试验体上的激振力。为此,在吸收国外动态测力传感器研制经验的基础上,应用国产压电陶瓷材料,研制成了TDJ-30动态测力传感器。本文将介绍它的结构,工作原理及主要特性。
Structural Prototypes and Model Vibration Tests Electromagnetic exciters are commonly used as transducing devices that generate exciting forces. The output characteristics of the electromagnetic exciter, often expressed in force constant. According to the input current and force constant to determine the excitation force applied to the test object electromagnetic exciter is quite rough. Because, at high vibration frequency, on the one hand, the moving part of the electromagnetic exciter itself is no longer a simple single degree of freedom system, the output force of the situation is more complicated; on the other hand, the exciting force in Passing the dowel bar in the process of transmission, due to the dowel bar itself elastic deformation, will also be part of the loss of energy. In addition, due to improper installation, it will also generate considerable friction loss. Moreover, these factors generally vary with frequency. Therefore, the output force of the electromagnetic exciter does not equal to the excitation force transmitted to the test object, at the same time, the waveform of the excitation force and the input current waveform distortion phenomenon. In order to ensure that the test results are reliable and correct, the excitation force exerted by the electromagnetic exciter on the test body must be directly determined. To this end, on the basis of absorbing the experience of the development of dynamic force sensors abroad, the application of domestic piezoelectric ceramic materials has been developed into a TDJ-30 dynamic force sensor. This article will introduce its structure, working principle and main features.