A theoretical and numerical FSI approach is used to predict the mass flow in a Coriolis flow meter. By comparing with the experimental results according to the relationship between mass flow and the time phase difference at the inlet and outlet of the tubes, the authors could determine the reliability of the present results from a theoretical and numerical approach in this paper. The mass flow has a linear relationship with the time phase difference, which is a unique parameter to measure true mass flow; therefore, for more precise measurement, it should be long enough to detect the signal within the given time resolution afforded by the detecting system and control system. Compact size and manufacturability, which are the important factors that decide the product competitiveness, should also be considered. In this paper, inversed triangle shaped and conventional U shaped Coriolis flow meters are designed, their time phase difference performances are predicted, and the results from experiments are well matched with the predicted results from the above-mentioned analysis.

In this paper, finite element modeling methods for cylindrical composite lattice structures were verified through natural frequency test. Finite element models for cylindrical composite lattice structure were developed using beam, shell and solid elements. Natural frequency test was measured using impact test method under free-boundary condition. The analysis result of the beam element model showed up to 23% errors because the beam element could not consider the degradation of mechanical properties of non-intersection parts of the composite lattice structures. On the other hand, the natural frequencies of finite element analysis for shell and solid element models showed good results with natural frequencies test. From the analysis of the experiment, finite element model for composite lattice structures should use shell or solid element which takes into consideration the intersection and non-intersection parts.

The role of dynamic behavior of operating rotor system in rotor design may or may not be evaluated under the impact of an external force such as earthquake. This article reports the result of an experimental study to resolve the dilemma. First, a sine weep test was performed to determine the first natural frequency of a Jeffcott rotor and compared with the ANSYS mode analysis demonstrating the reliability of experimental tests. The operating rotor vibrations were measured under the impact of sinusoidal forces at several frequencies, generated by the MTS vibration exciter. The experimental data suggest the need for a rotor design considering the dynamic behavior of the operating rotor under exciting external forces.

We have designed the structural shapes of a spiral blade and the frame to be used in an Archimedes wind-power system with the objective of increasing its mechanical strength. A conical roll-bending forming process was introduced to fabricate a metallic spiral blade, based on an incremental stepwise approach. From this process, the complicated spiral blade was constructed, and it could be applied to the wind-power mill. We proposed a few structural design concepts for improvement of the mechanical strength of the blade and frame. Fixing rods between the blades increased the natural frequency of the blades three-fold, compared to the original model with no rods. Also, the strength of the frame was increased by introducing edge-flanges with a height greater than 20 mm. This study will be helpful to industrial engineers interested in the structural design of a wind-power system in understanding the structural design process.

This paper presents a proposed means of frequency-tuning a magnetostrictive energy harvester(EH). This end may be accomplished by decreasing the distance between two permanent magnets (PM) located at free end of the cantilever and at the opposite, resulting in increase of a repulsive force between the PMs. The EH consists of a coil-wound Galfenol cantilever with PMs, a mover connected to the cantilever, and a rotating wheel with PMs. The rotating wheel driven by a motor provides a forced vibration to the EH. To direct inspection, It is noted that the maximum output voltage continually changes depending upon the the distance between the PMs And itmight therefore be deduced that the resonant frequency of the harvester may be adjusted to attain maximum, or optimal, voltage output. The rotational speed of the wheel (for the purpose of attaining maximum output voltage) is changed from 325 rpm to 265 rpm at a distance of 10 mm. It can be concluded that the practice of frequency-tuning with two PMs is a potentially positive application with respect to the EH.

Defining an appropriate flight vibration specification is a critical issue at an initial design phase, for optimized design of components in a surface-to-air missile (SAM). As the related document (MIL-STD-810G) doesn’t provide detailed value, appropriate procedures for estimation of flight vibration specification are required for design of a surface-to-air missile. In this study, the method-making appropriate specification without an actual flight test is introduced. Comparison between a theoretical approach using the beam theory and FEA is conducted to attain a natural vibration frequency under thrust force. Transient response analysis using commercial S/W is conducted to establish an envelope curve for flight vibration.

Recent use of mobile phones as a multimedia device has increased the development of micro-speaker modules having high quality and a compact size. Micro-speakers use polymer diaphragms fabricated by the thermoforming process. To improve the sound quality, micro-speaker diaphragms are usually designed to contain a number of micro-corrugations. This study investigated the effects of the corrugation depth on the acoustic characteristics of the diaphragm, using finite element (FE) analysis. Structural FE analysis was performed to investigate the stiffness change according to the corrugation depth. Modal FE analysis was used to compare the change in natural frequencies for each case. Harmonic response analysis further investigated the resulting variation in acoustic power. The effects of the corrugation depth on the acoustic characteristics of the diaphragm were discussed by reviewing all the FE analysis results synthetically.