Dynamic model is necessary to predict the product performance in numerical simulation; strength of structure, noise and vibration. An experiment must be performed to identify the model parameter such as structural properties of installed or completed products because of preventing deterioration of prediction accuracy accompanying product dispersion and aging deterioration. Although several identification methods for elastic beams with frequency equation have been proposed in the previous studies. In these methods, the structural properties were derived from natural frequencies of the beam with/ without additional weights. The structural properties are not uniquely determined due to various factors such as boundary conditions and additional weights. Especially, no study deals with experimental conditions to enable the high prediction accuracy. This paper proposes novel methods to identify the structural properties of elastic beams of homogeneous, uniform cross-section in the lengthwise direction with free-free condition. In addition, the effects of controllable experimental parameters on the accuracy are examined. Two identification methods of the structural properties are derived; one is based on the frequency equation of the beam and the other is mass response method. It is necessary to measure natural frequencies of the beam with/ without additional weights on the beam to use both methods. The former can treat the change of mode shapes due to the additional weights, whereas the latter assumes that the mode shapes are unchanged. Finite element models are developed for validation of both methods. Various experimental conditions are adopted and the accuracy of the identified parameters by the both methods is compared. The mode shapes of the free-free beam are changed with additional weights. Thus, the method using the frequency equation is more applicable to the beam with the additional weights. Finally, the method based on the frequency equation of the beam is validated through the experiments.

In numerical simulation, dynamic model is necessary to predict the product performance such as strength of structure, noise, and vibration. The prediction accuracy depends on the accuracy of parameter identification. For installed or completed products, an experiment must be done to identify structural properties such as Young's modulus or density. This experiment allows us to accurately predict the product performance regardless of product dispersion and aging deterioration. Hence there are many studies about identification methods of the structural parameters of beams. In these studies, the structural parameters were derived from natural frequencies of a beam with/without an additional mass. However, no study can obtain the parameters under unknown boundary conditions. In this study, we proposed a new simple method to identify line density of beams. This method assumes that mode shapes of a beam do not change regardless of additional masses. This study proposes an experimental method for arrangements of additional masses, which can keep mode shapes unchanged. In the numerical analysis, a finite element method is used to obtain the natural frequencies of a beam with/without additional masses. The natural frequencies and the weight of the additional masses are used to identify line density of the beams. We also verify the method through experiment.

The propagation properties of Love-type magneto-surface acoustic waves (MSAW) in FeB/SiOx multilayers (0.5 pmxl0) have been studied. The insertion loss of MSAW devices was found to vary with the applied field strength and orientation angle in an approximately periodic fashion. When the acoustic aperture was restricted to a narrow strip along the center line of a square magnetic film (1 cm x 1 cm), the oscillations of the insertion loss were greatly reduced. Calculation of the demagnetizing field showed that the resultant inhomogeneity of the internal field can produce the delay difference of the partial waves up to 1.5-2 wavelengths (h =36 pm), and cause their interference at the output transducer.

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