scholarly journals Three-Dimensional Finite Element Analysis and Characterization of Quasi-Surface Acoustic Wave Resonators

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1118
Author(s):  
Wen Chen ◽  
Linwei Zhang ◽  
Shangshu Yang ◽  
Wenhan Jia ◽  
Songsong Zhang ◽  
...  

In this work, three-dimensional finite element analysis (3D FEA) of quasi-surface acoustic wave (QSAW) resonators with high accuracy is reported. The QSAW resonators consist of simple molybdenum (Mo) interdigitated transducers (IDT) on solidly mounted stacked layers of AlN/Mo/Si. Different to the SAW resonators operating in the piezoelectric substrates, the reported resonators are operating in the QSAW mode, since the IDT-excited Rayleigh waves not only propagate in the thin piezoelectric layer of AlN, but also penetrate the Si substrate. Compared with the commonly used two-dimensional (2D) FEA approach, the 3D FEA method reported in this work shows high accuracy, in terms of the resonant frequency, temperature coefficient of frequency (TCF), effective coupling coefficient (keff2) and frequency response. The fabricated QSAW resonator has demonstrated a keff2 of 0.291%, series resonant frequency of 422.50 MHz, and TCF of −23.418 ppm/°C in the temperature range between 30 °C and 150 °C, for the design of wavelength at 10.4 μm. The measurement results agree well with the simulations. Moreover, the QSAW resonators are more mechanically robust than lamb wave devices and can be integrated with silicon-based film bulk acoustic resonator (FBAR) devices to offer multi-frequency function in a single chip.

Holzforschung ◽  
2016 ◽  
Vol 70 (6) ◽  
pp. 539-546 ◽  
Author(s):  
Jung-Pyo Hong ◽  
Jun-Jae Lee ◽  
Hwanmyeong Yeo ◽  
Chul-Ki Kim ◽  
Sung-Jun Pang ◽  
...  

Abstract This study is aiming at the simulation of wood compression (C) at a macroscopic level by means of a three-dimensional finite element analysis (3D-FEA) of solid wood and evaluation of the capability and limitations of this approach. C-Tests were carried out on Douglas fir according to ASTM D 143. The specimens included the 25×25×100 mm3 cuboid bars for longitudinal (L), radial (R) and tangential (T) directions and the conventional 50×50×150 mm3 blocks for the perpendicular to grain (⊥) direction. Two sets of wood parameters were developed and the 3D-FEA was implemented for the two types of specimens. The 3D-FEA worked successfully provided that the stress state coming from the total wood C was uniform. However, in case of the dominance of local compressive behaviour such as bearing, crushing and fibre shear, a microscopic-level modelling technique is needed for correction of the material parameters. More details on the limitations and difficulties of 3D-FE implementation for wood were discussed.


2020 ◽  
Vol 28 (6) ◽  
pp. 603-613 ◽  
Author(s):  
Efe Can Sivrikaya ◽  
Mehmet Sami Guler ◽  
Muhammed Latif Bekci

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.


2019 ◽  
pp. 0000-0000 ◽  
Author(s):  
Karina Albino Lencioni ◽  
Pedro Yoshito Noritomi ◽  
Ana Paula Macedo ◽  
Ricardo Faria Ribeiro ◽  
Rossana Pereira Almeida

This study analyzed the biomechanical behavior of rigid and non-rigid tooth-implant supported fixed partial dentures. Different implants were used in order to observe the load distribution over teeth, implants, and adjacent bone using three-dimensional finite element analysis. A simulation of tooth loss of the first and second right molars was created with an implant placed in the second right molar and a prepared tooth with simulated periodontal ligament (PDL) in the second right premolar. Configurations of two types of implants and their respective abutments, i.e., external hexagon (EX) and Morse taper (MT), were transformed into a 3D format. Metal-ceramic fixed partial dentures were constructed with rigid and non-rigid connections. Mesh generation and data processing were performed on the 3D FEA results. Static loading of 50 N (premolar) and 100 N (implant) were applied. When an EX implant was used, with a rigid or non-rigid connection, there was intrusion of the tooth in the distal direction with flexion of the periodontal ligament. Tooth intrusion did not occur when the MT implant was used independent of a rigid or non-rigid connection. The rigid or non-rigid connection resulted in a higher incidence of compressive forces at the cortical bone and stress in the abutment/pontic area, regardless of whether EX or MT implants were used. MT implants have a superior biomechanical performance in tooth-implant supported fixed partial dentures. This prevents the intrusion of the tooth independent of the connection. Both types of implants that were studied caused a greater tendency of compressive forces at the crestal area.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


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