Описание
xvi Preface
This book is meant to focus on the practical aspects of experimental modal analysis. Only
limited theory is presented in the text in order to illustrate or expound upon certain methodologies of experimental modal testing that have their roots in the underlying theory. In many
cases, the theory (or final equation of a long derivation) is just presented; this text is not about
developing the details of the theory but rather applying the theory to solve real problems. There
are an abundance of good textbooks in the area of vibrations but very few contain even a small
piece of the content of this book. There are some textbooks on experimental modal analysis but
most concentrate on the theoretical side of modal analysis assuming the implementation of a
real test is easy and straightforward.
Back in the late 1990s, the Society for Experimental Mechanics had a series in Experimental Techniques magazine entitled “Modal Space – Back to Basics” – that series published for 17
continuous years. The series addressed very simple problems commonly encountered by experimental modal analysis testers. The articles were never more than 2 pages and had a variety of
experimental modal analysis topics addressed. But the material was scattered from one article
to the next and they were just intended to be “snip-its” of information that resulted from years
and years of teaching industry modal seminars, teaching in-house modal seminars and many,
many emails received over 20 or more years working in this area. This book is about pulling all
that information together and providing a more complete treatment of that material.
So this text is laid out in two parts – the first part is more of the traditional theory related to
analytical and experimental modal analysis whereas the second part is about the practical issues
related to experimental modal tests followed by appendices with additional useful information.
Chapter 1 is a very simple overview of the entire experimental modal test to set the stage for
the entire text; this is extremely useful to the new folks starting into modal analysis. Chapter 2
through 5 have some of the cornerstones of basic information. Chapter 2 has all the pertinent
theory summarized related to single degree of freedom systems to multiple degree of freedom
systems with equations presented in the physical domain, modal domain, Laplace domain and
the frequency domain. Chapter 3 presents a good summary of all the pertinent digital signal
processing techniques that are needed for the acquisition of measured data; sampling issues to
frequency data to noise are all addressed here. Chapter 4 presents the most common excitation
techniques used for modal testing today – impact and shaker excitation. Chapter 5 contains
some of the rudimentary information necessary for modal parameter estimation. Chapter 6
through 9 have a more practical side of the material. Chapter 6 is related to the issues related
to setting up a test from start to finish. Chapter 7 has many examples related to impact testing
which is the most widely used excitation technique for traditional experimental modal tests.
Chapter 8 further discusses shaker excitation techniques and issues related to running these
types of tests as well as multiple input multiple output testing. Chapter 9 provides some very
practical insights into the reduction of the data collected using different modal parameter estimation approaches. Chapter 10 and 11 have a variety of different issues related to modal testing
that are difficult to place in one of the previous chapters because they span more than one topic
or were just not appropriate for a particular chapter. There are several appendices that have
some very simple analytical models that help to show the math in action. A few more appendices have a scattering of broad information that may be useful to the modal test engineer. And
a few final chapters have some data sets that have been used for modal parameter estimation
with results for the user to try to decompose with their own software used in their lab; the data
sets are available in universal file format on the book webpage so that they can be downloaded
and processed and compared to the users results.
Finally, there are the thanks to so many that have crossed paths during my time spent in
this modal community. I started working in the mid-seventies and early on came across John
O’Callahan and G. Dudley Shepard up at then the University of Lowell (the former Lowell Tech).
Детали
- Год издания
- 2018
- Format