A Theoretical Examination of Mems Microactuator Responses with an Emphasis on Materials and Fabrication

1994 ◽  
Vol 360 ◽  
Author(s):  
D.E. Glumac ◽  
T.G. Cooney ◽  
L.F. Francis ◽  
W.P. Robbins
Keyword(s):  
Material Properties ◽  
Elastic Moduli ◽  
Beam Theory ◽  
Core Layer ◽  
Metal Electrode ◽  
Force Output ◽  
Free Standing ◽  
Element Analysis ◽  
The Core ◽  
Core Thickness

AbstractA free standing cantilever beam consisting of a support structural material (polysilicon/silicon nitride), a piezoelectric PZT ceramic layer, and metal electrode layers has been analyzed. Beam theory and finite element analysis were used to model the electric field induced deflections of this structure, and provided information as to how material choices influenced actuator function. Both support material and PZT thicknesses varied from 0-1.0 gim, and bulk piezoelectric coefficients and elastic moduli were assumed. The beam theory uses known (or assumed) material properties to predict actuator responses. Conversely, if device responses can be measured, material properties may be inferred from the theory. For a PZT thickness of 0.3 μm, a core layer thickness of 0.13 μm was found to maximize displacement. Also, the force output was found to be more dependent on the core thickness than that of the PZT. This information can then be used to predict the response of a more complex microactuator.

Design with Nonhomogeneous Materials—Part I: Pure Bending of Prismatic Bars

1987 ◽  
Vol 109 (1) ◽  
pp. 82-86 ◽  
Author(s):  
V. K. Stokes
Keyword(s):  
Tensile Test ◽  
Material Properties ◽  
Elastic Moduli ◽  
Mechanical Response ◽  
Mechanical Design ◽  
Beam Theory ◽  
Pure Bending ◽  
Strongly Coupled ◽  
Point To Point ◽  
Nonhomogeneous Materials

Because material properties vary from point to point in nonhomogeneous materials, there is some question as to what “properties” are measured in tests such as the tensile test, and how such “properties” can be used in the mechanical design process. In this paper, the mechanical response of nonhomogeneous prismatic bars in pure bending has been shown to depend on parameters that are strongly coupled combinations of geometry and material properties. The purely geometry based inertia tensor in homogeneous beam theory is replaced in the nonhomogeneous case by the rigidity tensor, which combines geometry and material properties. Interpretations for the average elastic moduli, which would be determined by tests on nonhomogeneous materials, have been explored. Also discussed is the usefulness of such average moduli for predicting the mechanical response of nonhomogeneous bars.

scholarly journals NASTRAN Analysis of a Turbine Blade and Comparison With Test and Field Data

1975 ◽  
Author(s):  
J. M. Allen ◽  
L. B. Erickson
Keyword(s):  
Turbine Blade ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Mode Shapes ◽  
Stress Distributions ◽  
Free Standing ◽  
Element Analysis ◽  
Metallographic Examination ◽  
Stiffening Effect ◽  
Generalized Beam Theory

A NASTRAN finite element analysis of a free standing gas turbine blade is presented. The analysis entails calculation of the first four natural frequencies, mode shapes, and relative vibratory stresses, as well as deflections and stresses due to centrifugal loading. The stiffening effect of the centrifugal force field was accounted for by using NASTRAN’s differential stiffness option. Natural frequencies measured in a rotating test correlated well with computed results. Areas of maximum vibratory stress (fundamental mode) coincided with the three zones of crack initiation observed in a metallographic examination of a fatigue failure. Airfoil stress distributions were found to be significantly different from that predicted by generalized beam theory, especially near the airfoil-platform junction.

Vibration Analysis and Optimization of Sandwiched Beam Structure Using Higher Order Variation of Core Layer Displacement

2012 ◽  
Author(s):  
Jasrobin Singh Grewal ◽  
Ramin Sedaghati ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Linear Model ◽  
Linear Models ◽  
Core Layer ◽  
Higher Order ◽  
Order Model ◽  
Various Boundary Conditions ◽  
The Core ◽  
Parametric Studies ◽  
Beam Type ◽  
Core Thickness

Vibration characteristic of a sandwiched beam type structure is analyzed using the finite element method based on a higher order model for displacement field in the core layer of the structure. Results of the higher order and linear models were compared with those of experimental ones reported in literature and shown that higher order model provides more accurate results than the linear model. The parametric studies for the developed model are presented to indicate the effect of the core thickness on the loss factor and the natural frequencies, and the results are compared with those obtained for the linear model. Finally, using the higher order model, an optimization problem is formulated to find the optimal distribution and the number of partial treatments in order to achieve highest damping value in the sandwiched beam with various boundary conditions.

scholarly journals Finite Element Analysis of a Spur Gear Considering Mass Relief Strategies

2021 ◽  
Vol 31 (2) ◽  
pp. 36-49
Author(s):  
Lauro Miguel Lima Rocha ◽  
Marco Túlio Santana Alves
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Local Stress ◽  
Spur Gear ◽  
Spur Gears ◽  
Element Analysis ◽  
The Core ◽  
Core Thickness ◽  
Structural Influence ◽  
Maximum Stresses

This paper deals with analyzing the structural influence of mass reliefs in spur gears. For this purpose, a system composed of pinion and a gear was designed, such that for gear several geometries were designed with different reliefs shapes and soul thicknesses. From the proposed geometries, finite element analysis (FEA) was performed, and the tooth stresses of each model were compared with the solid gear. From the results, it was observed that the tooth stresses are reduced in some cases. Besides, from the aforementioned cases, it is possible to observe that the maximum stresses may take place in its core instead of the teeth (rim area). On the other hand, based on other cases, the core thickness plays an important role as a criterion that defines the local stress.

Optimal Structural Design of Multi Chip Package to Reduce the Failure in Substrate

2005 ◽  
Vol 297-300 ◽  
pp. 912-917 ◽  
Author(s):  
Dong Kil Shin ◽  
Seung Woo Kim ◽  
Shin Kim ◽  
Seok Won Lee ◽  
Hee Kook Choi
Keyword(s):  
Numerical Analysis ◽  
Structural Design ◽  
Thermal Loading ◽  
Three Dimensional ◽  
Chip Thickness ◽  
Core Layer ◽  
Component Level ◽  
The Core ◽  
Out Of Plane ◽  
Core Thickness

In this study, epoxy molded multi chip package was investigated and a highly reliable structure against failure of copper trace on PCB substrate was proposed. Function failure caused by the pattern crack during component level thermal cycle test was considered. In-plane and out-of-plane movements of package during thermal loading were measured by moiré interferometry and shadow moiré. Measured data were compared with numerical analysis results. Two dimensional and three dimensional numerical analysis were performed considering visco-elastic material properties. Tensile stress in the core layer was analyzed quantitatively and qualitatively. Analysis showed that the reliability of pattern crack could be improved by decreasing the chip thickness and increasing the core thickness, and that the material property of die adhesive was important.

scholarly journals Effects of SiO2 Filler in the Shell and Wood Fiber in the Core on the Thermal Expansion of Core–Shell Wood/Polyethylene Composites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2570
Author(s):  
Lichao Sun ◽  
Haiyang Zhou ◽  
Guanggong Zong ◽  
Rongxian Ou ◽  
Qi Fan ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Wood Fiber ◽  
Core Layer ◽  
Element Analysis ◽  
Linear Coefficient ◽  
Anisotropic Thermal Expansion ◽  
The Core ◽  
Expansion Behavior ◽  
Polyethylene Composites

The influence of nano-silica (nSiO2) and micro-silica (mSiO2) in the shell and wood fiber filler in the core on the thermal expansion behavior of co-extruded wood/polyethylene composites (Co-WPCs) was investigated to optimize the thermal expansion resistance. The cut Co-WPCs samples showed anisotropic thermal expansion, and the thermal expansion strain and linear coefficient of thermal expansion (LCTE) decreased by filling the shell layer with rigid silica, especially nSiO2. Finite element analysis indicated that the polymer-filled shell was mainly responsible for the thermal expansion. The entire Co-WPCs samples exhibited a lower thermal expansion strain than the cut Co-WPCs samples due to protection by the shell. Increasing the wood fiber content in the core significantly decreased the thermal expansion strain and LCTE of the Co-WPCs. The Co-WPCs whose core layer was filled with 70% wood fiber exhibited the greatest anisotropic thermal expansion.

scholarly journals Numerical Analysis of Sandwich Composite Deep Submarine Pressure Hull Considering Failure Criteria

2019 ◽  
Vol 7 (10) ◽  
pp. 377 ◽  
Author(s):  
Mahmoud Helal ◽  
Huinan Huang ◽  
Defu Wang ◽  
Elsayed Fathallah
Keyword(s):  
Numerical Analysis ◽  
Core Layer ◽  
Failure Criteria ◽  
Control Surface ◽  
Sandwich Composite ◽  
Minor Role ◽  
Analysis And Design ◽  
The Core ◽  
Hull Design ◽  
Core Thickness

The pressure hull is the primary element of submarine, which withstands diving pressure and provides essential capacity for electronic systems and buoyancy. This study presents a numerical analysis and design optimization of sandwich composite deep submarine pressure hull using finite element modeling technique. This study aims to minimize buoyancy factor and maximize deck area and buckling strength factors. The collapse depth is taken as a base in the pressure hull design. The pressure hull has been analyzed using two composite materials, T700/Epoxy and B(4)5505/Epoxy, to form the upper and lower faces of the sandwich composite deep submarine pressure hull. The laminated control surface is optimized for the first ply failure index (FI) considering both Tsai–Wu and maximum stress failure criteria. The results obtained emphasize an important fact that the presence of core layer in sandwich composite pressure hull is not always more efficient. The use of sandwich in the design of composite deep submarine pressure hull at extreme depths is not a safe option. Additionally, the core thickness plays a minor role in the design of composite deep submarine pressure hull. The outcome of an optimization at extreme depths illustrates that the upper and lower faces become thicker and the core thickness becomes thinner. However, at shallow-to-moderate depths, it is recommended to use sandwich composite with a thick core to resist the shell buckling of composite submarine pressure hull.

scholarly journals A Simple Energy-based Approach of Stent Elastic Properties

2020 ◽  
Vol 319 ◽  
pp. 02002
Author(s):  
Shuai Wang ◽  
Kaifa Zhou ◽  
Zhong Li
Keyword(s):  
Energy Conservation ◽  
Young’S Modulus ◽  
Elastic Moduli ◽  
Young's Modulus ◽  
Cell Structure ◽  
Beam Theory ◽  
Numerical Data ◽  
Grid Structure ◽  
Element Analysis ◽  
Energy Conservation Principle

Simple closed-form expressions were derived for the elastic moduli of lozenge grid structure based on the convenient beam theory and energy conservation principle. Finite element analysis was employed to validate the analytical estimates of the Young’s modulus. The theoretic results were also compared with the numerical data in the literature. The results show that the calculation method of Young’s modulus obtained by energy conservation is feasible, which provides a new way for stress analysis of sandwich structures. At the same time, the cell structure proposed in this paper provides a new scheme for the design of vascular stent.

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