The Canadian Space Agency recently performed the Modal Analysis of a RADARSAT Satellite using five modal shakers. It is important to obtain the modal analysis of the unit-under-test because information about the natural frequencies, damping coefficients and mode shapes can be used to optimize its design and improve its structural behavior.

A Ground Vibration Test (GVT) involves carrying out modal analysis of an aircraft and its sub-assembly components to analyze and detect any changes in their structural properties. The modal parameters determined through this testing are used to validate analytical models. The modal characteristics are also used to predict the flutter of the aircraft in order to create a safe flight envelope before flight operation. Thus, GVT is a crucial process in the design and development cycle of aircrafts.

To acquire FRFs of an engine, it is hung with bungee cords to imitate free-free boundary conditions. Two modal shakers were used to excite the V6 engine block. Shaker excitation provides better consistency and repeatability than a modal hammer. It also produces a cleaner data set because of a greater average. Multiple sensors are roved through the engine to obtain the vibration characteristics.

This article examines the acquisition of modal characteristics from a bullet train wheel by performing experimental modal analysis. The wheel vibrations affect the dynamics of the wheel-rail interactions. Understanding these vibration characteristics will help mitigate the vibration and noise at high speeds.

This article examines the acquisition of modal characteristics from a disc brake rotor by performing experimental modal analysis. Brake systems are required for safe vehicle operation. The major component of a brake system is the disc brake rotor. While braking, the excitation frequency level can match natural frequencies and this phenomenon of resonance can cause the brake to squeal, potentially generating unpleasant vibration and noise.

Extracting the natural frequencies, damping shapes, and mode shapes of a structure aids in improving the design of the unit under test. In this case, the modal characteristics of a license plate is acquired by performing a modal analysis.

A MIMO FRF test is carried out using a pair of modal shakers and 14 accelerometers to obtain the vibration characteristics. The shakers impart energy to the structure for a longer period, which ensures an increased data set. The higher quality of the measurements also aids in the better estimation of the modal parameters.

This section describes the orbit plot feature in the vibration visualization function. In-depth details about the workflow of the vibration visualization process will be discussed in the later portion of the article. The orbit plot is not only used to understand the magnitude of the vibration during a vibration test but also to observe the phase relationship between the different channels used to acquire the response of the unit under test. This is understood more clearly using a test case.

Operational Modal Analysis (OMA) is commonly used to monitor and evaluate the health of building structures to investigate for any damage [1]. Studying the modal parameters of the structure can assist in observing changes in the dynamic properties which can further help in predicting error in certain elements which might need some repair or modification.

In this case, the modal characteristics of an airplane model is acquired by performing experimental modal analysis. A SIMO FRF test is carried out using a single modal shaker and multiple sensors to obtain the vibration characteristics. Shaker excitation provides better consistency and repeatability than a modal hammer. It also produces a cleaner data set because of a greater average. The higher quality measurements lead to a better estimation of the modal parameters.