scholarly journals Resonance Frequency of Longitudinal Vibration as a Parameter for Prediction of Young's Modulus of Structural Timbers.

1993 ◽  
Vol 42 (473) ◽  
pp. 121-125
Author(s):  
Nobuo SOBUE ◽  
Kiyoshi MIZUKAMI
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wen-Jen Liu ◽  
Yung-Huang Chang ◽  
Sin-Liang Ou ◽  
Yuan-Tsung Chen ◽  
You-Cheng Liang ◽  
...  

In this study, a Co40Fe40W20 alloy was sputtered onto Si (100) with thicknesses (tf) ranging from 18 to 90 nm, and the corresponding structure, magnetic properties, adhesive characteristics, and nanomechanical properties were investigated. X-ray diffraction (XRD) patterns of the Co40Fe40W20 films demonstrated a significant crystalline body-centered cubic (BCC) CoFe (110) structure when the thickness was 42 nm, and an amorphous status was shown when the thickness was 18 nm, 30 nm, 60 nm, and 90 nm. The saturation magnetization (Ms) showed a saturated trend as tf was increased. Moreover, the coercivity (Hc) showed a minimum 1.65 Oe with 30 nm. Hc was smaller than 4.5 Oe owing to the small grain size distribution and amorphous structure, indicating that the Co40Fe40W20 film had soft magnetism. The low-frequency alternating current magnetic susceptibility (χac) decreased as the frequency was increased. The χac revealed a thickness effect when greater thicknesses had a large χac. The maximum χac and optimal resonance frequency (fres) of Co40Fe40W20 were investigated. The maximum χac indicated the spin sensitivity and was maximized at the optimal resonance frequency. The 90 mm thickness had the highest χac 0.18 value at an fres of 50 Hz. The contact angles of the Co40Fe40W20 films are less than 90°, which indicated that the film had a good wetting effect and hydrophilicity. The surface energy was correlated with the adhesion and displayed a concave-down trend. CoFeW films can be used as a seed or buffer layer; therefore, the surface energy and adhesion are very important. The highest surface energy was 30.12 mJ/mm2 at 42 nm and demonstrated high adhesion. High surface energy has corresponding strong adhesive performance. The increased surface roughness can induce domain wall pinning effect and high surface energy, causing a high coercivity and strong adhesion. The increase of hardness and Young’s modulus could be reasonably inferred from the thinner CoFeW films. The hardness and Young’s modulus of CoFeW films are also displayed to saturated tendency when increasing thickness.


2010 ◽  
Vol 26-28 ◽  
pp. 936-939
Author(s):  
Li Zhang ◽  
Ying Cheng Hu

In this paper, the poplar LVL was reinforced with multilayer fiberglass mesh. The reinforcing effect of adding position of fiberglass mesh on improving the static MOE was studied. And three different nondestructive testing (NDT) methods, such as the longitudinal transmission method, longitudinal vibration method and flexural vibration method (out-plane and in-plane), were used to test the dynamic properties of the reinforced poplar LVL. The correlation analysis was implemented between the dynamic Young’s modulus and the static MOE of the reinforced poplar LVL. It can be concluded that the three NDT methods are useful for predicting the MOE of reinforced LVL, but the flexural and longitudinal vibration methods had better accuracy to estimate the MOE.


2011 ◽  
Vol 380 ◽  
pp. 348-351 ◽  
Author(s):  
Jiang Chang ◽  
Xue Gong ◽  
Zhi Hui Sun

In this paper the vibration testing and Fast Fourier Transform(FFT) analysis detection on the basis of nondestructive testing method were analyzed. The dynamic Young’s modulus of the regeneration pre-sensitized offset plate were obtained by using the nondestructive testing methods, including the dynamic Young’s modulus by longitudinal vibration method, the dynamic Young’s modulus by out-plane flexural vibration method, and the dynamic Young’s modulus by in-plane flexural vibration method. The linear correlativity was investigated between the dynamic Young’s modulus and the modulus of elasticity(MOE) for the regeneration pre-sensitized offset plate.The linear correlations between the dynamic Young’s modulus and the MOE were good. So it is feasible to predict and analyze the plate mechanical properties put forward the nondestructive testing method of key mechanical performance parameters.


2012 ◽  
Vol 503 ◽  
pp. 308-311
Author(s):  
Han Chen ◽  
Hua Rong

Large-scale measurement of material property is not suit for the MEMS thin-film. Research the in-situ measuring method for material property of the MEMS thin-film is urgently. A center-anchored circular plate is adopted as the test structure here. The resonance frequency of the circular plate is measured to extract the Young’s modulus of a MEMS thin-film. The accuracy of this non-contact in-situ measuring method has been verified by CoventorWare. The inferences of the stress gradient have been analyzed. The advantages of the test structure and the measuring method present here also have been discussed.


2020 ◽  
Vol 34 (26) ◽  
pp. 2050232
Author(s):  
Xiaofei Lei ◽  
Peng Chen ◽  
Heping Hou ◽  
Shanhui Liu ◽  
Peng Liu

In this paper, a novel composite acoustical hyperstructure of Bragg structure with local resonator is investigated theoretically for discussing the scattering performance of longitudinal vibration wave, its bandgaps are calculated using the established mathematical model. For confirming the veritable existence of bandgap and verifying the correctness of established mathematical model, the transmission spectrum of composite acoustical hyperstructure is also studied using finite-element method, and comparing the vibration transmission spectrum with bandgaps, the results indicate that the established theoretical model can correctly predict longitudinal wave bandgaps. Moreover, the bandgaps and modes shapes are calculated and compared with an unalloyed Bragg structure for probing the dispersion mechanics of composite acoustical hyperstructure, it turned out that local resonator can add one bandgap at the base of Bragg structure and the total bandgaps can be broadened. Further, for discussing the effect of spring of local resonator on bandgaps, bandgap of local resonator with different spring is calculated, the results showed that the total width of BG is larger when Young’s modulus is 1E and 16E, the total width are 772.48 and 774.30 Hz, respectively; as Young’s modulus is 0.5E and 2E, the width of BG are lower, 753.79 and 754.23 Hz, respectively. In view of longitudinal vibration wave inducing structural distortion and vibration energy conversion, the dynamic properties of composite acoustical hyperstructure are studied via strain energy density, the results indicate that reaction formation of local resonator can dissipate strain energy, when the local resonator is not activated (or waveless along with Bragg structure), un-dissipation strain energy.


2010 ◽  
Vol 129-131 ◽  
pp. 588-591
Author(s):  
Li Zhang ◽  
Ying Cheng Hu

In this paper, the poplar LVL was reinforced with monolayer fiberglass mesh. The reinforcing effect of lay angle between the weft of fiberglass mesh and the veneer grain was studied. And three different nondestructive testing (NDT) methods, such as the longitudinal transmission method, longitudinal vibration method and flexural vibration method (out-plane and in-plane), were used to test the dynamic Young’s modulus of the reinforced poplar LVL. The correlativity was investigated between the dynamic Young’s modulus and the static MOE of the reinforced poplar LVL. The reinforcing effect was best when the lay angle of fiberglass mesh was 30°. And the flexural vibration method and longitudinal vibration method had better accuracy to estimate the static MOE.


2020 ◽  
Vol 52 (4) ◽  
pp. 400-409
Author(s):  
Yoshitaka Kubojima ◽  
Satomi Sonoda ◽  
Hideo Kato

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4769 ◽  
Author(s):  
Spetzler ◽  
Golubeva ◽  
Müller ◽  
McCord ◽  
Faupel

In recent years the delta-E effect has been used for detecting low frequency and low amplitude magnetic fields. Delta-E effect sensors utilize a forced mechanical resonator that is detuned by the delta-E effect upon application of a magnetic field. Typical frequencies of operation are from several kHz to the upper MHz regime. Different models have been used to describe the delta-E effect in those devices, but the frequency dependency has mainly been neglected. With this work we present a simple description of the delta-E effect as a function of the differential magnetic susceptibility χ of the magnetic material. We derive an analytical expression for χ that permits describing the frequency dependency of the delta-E effect of the Young’s modulus and the magnetic sensitivity. Calculations are compared with measurements on soft-magnetic (Fe90Co10)78Si12B10 thin films. We show that the frequency of operation can have a strong influence on the delta-E effect and the magnetic sensitivity of delta-E effect sensors. Overall, the delta-E effect reduces with increasing frequency and results in a stiffening of the Young’s modulus above the ferromagnetic resonance frequency. The details depend on the Gilbert damping. Whereas for large Gilbert damping the sensitivity continuously decreases with frequency, typical damping values result in an amplification close to the ferromagnetic resonance frequency.


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