7.不进行测试时,应该断开推力杆的连接吗?

模态激振器相关问题

Whenever a modal test is performed using shaker excitation, the shakers should be disconnected from the structure while data is not being acquired, whether it is between different test configurations or during periods of inactivity, for example over a lunch break or overnight. There are many reasons for this. During the set up of the test, there may be some shifting or settling of the test article. Commonly, airbag soft support systems are used to provide a free-free boundary condition during testing. These may lose air over time, shifting the structure. Additionally, an elastic shock cord (bungee) will creep in length over a period of time. In between tests, there may be some reconfiguration of the test article for multiple sets of test data. For instance, a vehicles gas tank may be empty in one test and then filled in another test. Because of this, there may be a general shifting or redistribution of mass in the system, which in turn causes shifting of the test article relative to the original alignment of the shakers to the structure.

无论何时用激振器激励进行模态试验,当不进行数据采集时,激振器都应该从结构上断开,不管是在不同的试验设置之间还是在不活动的间歇,例如在午休时间还是过夜时。这么做有很多原因。在试验设置的过程中,可能会有试件移动或者试件安静下来。通常,在试验过程中用气囊软支持系统来提供自由-自由的边界条件。随着时间进行可能会漏气,使结构方式移动。另外,一个弹性绳(橡皮绳)经过一段时间后会蠕变。例如,在某次测试中汽车油箱可能是空的,而在接下来的另一个试验中,可能是满的。由于这个原因,系统中可能会有质量的常规移动或者重新分布,反过来,它有使得试验对象相对于激振器跟结构的最初的对中发生移动。

If the shakers are attached during down time between tests while the structure undergoes necessary reconfigurations, there may be side loads applied to the stinger attaching the shaker to the structure and the alignment of the system may be disturbed. These side loads will potentially bend the stingers, or worse, cause damage to the shaker armature. In addition, it may become difficult to disassemble the stinger from the structure once the alignment has been disturbed.

在两次试验的停机过程中,如果激振器一直连接着,这时结构经过了必要的重新布置,那么可能会有侧向载荷施加到连接激振器到结构的推力杆上,可能干扰系统的对中。这些侧向载荷可能使推力杆发生弯曲,或者更糟,引起激振器动圈的损坏。另一方面,一旦对中被干扰之后,从结构上拆下推力杆可能会变得困难。

If the shakers are disconnected during periods between test cycles, it will be obvious if any misalignment has occurred upon reattaching the shakers for the next set of tests. If the original shaker alignment is disturbed, then the shaker must be realigned in order to provide a proper attachment to the system.

在两次试验阶段的中间过程中,如果没有连接激振器,对下组试验设置,在重新连接激振器中如果发生了任何的不对中,它会非常明显。如果最初的激振器对中受到干扰,那么为了提供到系统的正确连接,必须重新对中激振器。