1.力传感器的正确安装技术是什么?

传感器相关问题

A very important consideration when mounting force transducers is recognition that force transducers are directional. This means that force transducers are designed to accurately measure force on only one of its two mounting faces, for example labeled TOP and BASE on the PCB model 208 series. This is shown below; a 208 series force transducer is mounted to a 2155G12 rod style stinger. Note that for this model force transducer the TOP of the unit is the designed sensing surface and should be mounted directly to the test article. Some transducers, like the PCB model 288D01 impedance head, have an indication of exactly which side to mount to the structure. In any case, please consult the force transducers user manual for identifying which mounting surface is intended to measure the force accurately. This is due to the fact that the force transducer itself has mass and stiffness. They are designed and calibrated to read force accurately on one of its mounting faces, and thus need to be installed accordingly.

安装力传感器时,一个非常重要的注意事项是认识到,力传感器是“有方向的”。这表示力传感器被设计来精确地测量力,仅仅测量其两个安装表面中的一个面上的力,例如,在PCB 208系列上标识为“顶部”和“基座”。如下面图7所示,显示了一个208系列的力传感器,安装到一个2155G12型的杆状推力杆上。注意,对这个型号的力传感器,零件的“顶部”是设计的敏感面,应该直接安装到被测物体上。有些力传感器,例如PCB 288D01型阻抗头,有一个指示,准确地表明哪一侧安装到结构上。任何情况下,请翻阅力传感器的用户手册来确定哪个安装面旨在准确地测量力。这是因为力传感器本身有质量和刚度。它们在一个安装面上被设计和校准来准确地读取力,于是需要相应地安装。

ShakerFAQ07-01

图7 PCB 208系列力传感器,显示被安装在TMS 2155G12模态推力杆上

Another important consideration is that the force transducer should always be mounted directly to the test structure, between it and the stinger and shaker assembly. If the force gage is mounted on the exciter side, then the dynamics of the stinger become part of the measured function. This is generally only an issue when using conventional shakers for modal applications because modal shakers have the through-hole armature design and would not accommodate mounting the force transducer in such a fashion.

另一个重要的注意事项是,力传感器总是应该直接安装在测试结构上,力传感器安装在结构、推力杆和激振器组件之间。如果力传感器安装在激振器侧,如图8中所示,那么推力杆的动力特性变成了所测函数的一部分。一般来说,这只是对模态应用使用传统的激振器时,是个问题。因为模态激振器有通孔动圈的设计,将不适合于按照这种方式安装力传感器。

ShakerFAQ08-01

图8 – 典型的推力杆设置,显示了相对于测试对象、螺纹推力杆和激振器的正确力传感器位置

The force transducer is usually mounted using a threaded adhesive mounting base, firmly attached to the test structure using dental cement or quick dry epoxy. Dental cement is ideal because it is extremely stiff, providing rigid attachment within the frequency range of typical modal testing. If the test structure can be drilled and tapped with an appropriate thread, directly attaching the force transducer to the structure is the best solution.

通常用一个带螺孔的粘贴安装座来安装,利用牙科粘合剂或者快干环氧树脂牢固地连接到测试结构上。牙科粘合剂是非常理想的,因为它极其坚硬,在典型模态试验的频率范围内提供了刚性连接。如果测试结构可以钻孔,拧一个合适的螺丝,直接连接力传感器到结构上是最优的解决方案。