Experimental Modal Analysis Vrije Universiteit （sccp试验模态分析）.pdfVIP

Experimental Modal Analysis A Simple Non-Mathematical Presentation Peter Avitabile, University of Massachusetts Lowell, Lowell, Massachusetts Often times, people ask some simple questions regarding responds to the frequency where peaks in the frequency re- modal analysis and how structures vibrate. Most times, it is sponse function reach a maximum (Figure 4). So you can see impossible to describe this simply and some of the basic un- that we can use either the time trace to determine the frequency derlying theory needs to be addressed in order to fully explain at which maximum amplitude increases occur or the frequency some of these concepts. However, many times the theory is just response function to determine where these natural frequen- a little too much to handle and some of the concepts can be cies occur. Clearly the frequency response function is easier described without a rigorous mathematical treatment. This to evaluate. article will attempt to explain some concepts about how struc- Most people are amazed at how the structure has these natu- tures vibrate and the use of some of the tools to solve struc- ral characteristics. Well, what’s more amazing is that the de- tural dynamic problems. The intent of this article is to sim- formation patterns at these natural frequencies also take on ply identify how structures vibrate from a nonmathematical a variety of different shapes depending on which frequency is perspective. With this being said, let’s start with the first ques- used for the excitation force. tion that is usually asked: Now let’s see what happens to the deformation pattern on the structure at each one of these natural frequencies. Let’s