Vibration characteristics of island-bridge structure on porous PDMS substrates for stretchable electronics

2021 ◽  
pp. 1-18
Author(s):  
Xin Song ◽  
Zuguang Bian ◽  
Xiaoliang Zhou ◽  
Zhuye Huang
Keyword(s):  
Analytical Model ◽  
Mechanical Design ◽  
Dynamic Performance ◽  
Structure Design ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Stretchable Electronics ◽  
Bridge Structure ◽  
Element Analysis ◽  
Design And Optimization

Abstract Stretchable electronics employing island-bridge structure design can achieve controllable and reversible stretchability. The use of a porous substrate, which provides excellent breathability for wearable devices bonded to skin, not only satisfies this static superiority but also has a profound impact on the dynamic performance of the stretchable electronics. In this paper, the vibration characteristics of the island-bridge structure based on porous polydimethylsiloxane (p-PDMS) substrates are studied by utilizing an analytical model, which takes account of geometric nonlinearity due to mid-plane stretching, buckling configuration, elastic boundary conditions considering the p-PDMS substrates and the mass of the island. In numerical examples, the accuracy of the analytical model is first verified by finite element analysis (FEA). After that, we investigate the effects of some primary factors, i.e. the prestrain of the substrate, spring stiffnesses at the ends of the interconnect, porosity and thickness of the substrate, and the mass of the island, on the natural frequencies and vibration mode shapes of the island-bridge structure. Results show that the vibration characteristics of the island-bridge structure can be tuned conveniently by adjusting the porosity of the substrate and the mass of the island, which are expected to be helpful to mechanical design and optimization of stretchable electronics in complex noise environments.

Bridge structure design and finite element analysis

2021 ◽  
Author(s):  
Xiaolin Zhang ◽  
Tianyi Guan ◽  
Lei Fan ◽  
Na Wang ◽  
Li Shang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structure Design ◽  
Bridge Structure ◽  
Element Analysis

Updating of Non-Conservative Systems Using Inverse Methods

1997 ◽  
Author(s):  
Ladislav Starek ◽  
Milos Musil ◽  
Daniel J. Inman
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Natural Frequencies ◽  
Eigenvalue Problems ◽  
Model Updating ◽  
Analytical Models ◽  
Mode Shapes ◽  
Element Analysis ◽  
Modal Data

Abstract Several incompatibilities exist between analytical models and experimentally obtained data for many systems. In particular finite element analysis (FEA) modeling often produces analytical modal data that does not agree with measured modal data from experimental modal analysis (EMA). These two methods account for the majority of activity in vibration modeling used in industry. The existence of these discrepancies has spanned the discipline of model updating as summarized in the review articles by Inman (1990), Imregun (1991), and Friswell (1995). In this situation the analytical model is characterized by a large number of degrees of freedom (and hence modes), ad hoc damping mechanisms and real eigenvectors (mode shapes). The FEM model produces a mass, damping and stiffness matrix which is numerically solved for modal data consisting of natural frequencies, mode shapes and damping ratios. Common practice is to compare this analytically generated modal data with natural frequencies, mode shapes and damping ratios obtained from EMA. The EMA data is characterized by a small number of modes, incomplete and complex mode shapes and non proportional damping. It is very common in practice for this experimentally obtained modal data to be in minor disagreement with the analytically derived modal data. The point of view taken is that the analytical model is in error and must be refined or corrected based on experimented data. The approach proposed here is to use the results of inverse eigenvalue problems to develop methods for model updating for damped systems. The inverse problem has been addressed by Lancaster and Maroulas (1987), Starek and Inman (1992,1993,1994,1997) and is summarized for undamped systems in the text by Gladwell (1986). There are many sophisticated model updating methods available. The purpose of this paper is to introduce using inverse eigenvalues calculated as a possible approach to solving the model updating problem. The approach is new and as such many of the practical and important issues of noise, incomplete data, etc. are not yet resolved. Hence, the method introduced here is only useful for low order lumped parameter models of the type used for machines rather than structures. In particular, it will be assumed that the entries and geometry of the lumped components is also known.

scholarly journals Experimental and Numerical Investigation of Resonance Characteristics of Novel Pumping Element Driven by Two Piezoelectric Bimorphs

2019 ◽  
Vol 9 (6) ◽  
pp. 1234 ◽  
Author(s):  
Yu-Chih Lin ◽  
Yu-Hsi Huang ◽  
Kwen-Wei Chu
Keyword(s):  
Speckle Pattern ◽  
Laser Doppler Vibrometer ◽  
Impedance Analysis ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Element Analysis ◽  
Visible Displacement ◽  
Piezoelectric Bimorphs ◽  
Phase Motion

This paper describes the vibration characteristics of a dual-bimorph piezoelectric pumping element under fluid–structure coupling. Unlike the single bimorph used in most previous studies, the proposed device comprises two piezoelectric bimorphs within an acrylic housing. Amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) was used to examine the visible displacement fringes in order to elucidate the anti-phase as well as in-phase motions associated with vibration. Analysis was also conducted using impedance analysis and laser Doppler vibrometer (LDV) based on the measurement of point-wise displacement. The experimental results of resonant frequencies and the corresponding mode shapes are in good agreement with those obtained using finite element analysis. The gain of flow rate obtained by the anti-phase motion of the dual-bimorph pumping element is larger than both those obtained by in-phase motion and the single bimorph pumping element. This work greatly enhances our understanding of the vibration characteristics of piezoelectric pumping elements with two bimorphs, and provides a valuable reference for the further development of bionic pump designs.

The Vibration Characteristics of a Large Flexible Vibration Isolation Structure with Finite Element Analysis and Modal Test

2011 ◽  
Vol 199-200 ◽  
pp. 858-864 ◽  
Author(s):  
Liu Bin Zhou ◽  
Tie Jun Yang ◽  
Wan Peng Yuan ◽  
Hui Shi ◽  
Zhi Gang Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Vibration Isolation ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Element Analysis ◽  
Modal Test ◽  
The Finite Element Analysis

A large flexible vibration isolation structure is presented in this thesis, and experimental modal test based on the finite element analysis is carried out in order to find out the vibration characteristics of it. Results show that the natural frequencies and mode shapes calculated by finite element method basically conform to those measured from experimental modal test. Some suggestion to vibration active control in further research is also provided.

Structure Design and Optimization of Vacuum Vessel for Spacecraft Thermal Test

2013 ◽  
Vol 390 ◽  
pp. 665-669
Author(s):  
Xiao Han ◽  
Bo Tao Liu ◽  
Shi Zeng Lyu ◽  
Yan Qi ◽  
Feng Guo
Keyword(s):  
External Pressure ◽  
Structure Design ◽  
The Body ◽  
Space Environment ◽  
Design Parameters ◽  
Main Body ◽  
Vacuum Vessel ◽  
Element Analysis ◽  
Design And Optimization ◽  
Thermal Test

The space environment simulator is a facility used to conduct thermal test for spacecraft, and vacuum vessel is the main body of it. During the test process, the vacuum vessel is exerted an external pressure of 0.1MPa, and there are various pipe orifices on the body of the vessel, therefore the intensity and stability should be taken into account carefully. This paper introduces three approaches for the design of structure intensity and stability of vacuum vessel, and takes GVU-600 space environment simulator as an example, which is the first aerospace facility developed by China for Russia. One approach is calculation by rules, and the second method utilizing finite element analysis, which could check details of the structure, but the efficiency of the previous two methods is low. In the end, a mathematics approach is introduced, which utilizes the optimization model, and the design parameters could be calculated accurately and efficiently.

scholarly journals Buckling of a stiff thin film on an elastic graded compliant substrate

2017 ◽  
Vol 473 (2208) ◽  
pp. 20170410 ◽  
Author(s):  
Zhou Chen ◽  
Weiqiu Chen ◽  
Jizhou Song
Keyword(s):  
Thin Film ◽  
Analytical Model ◽  
Compressive Strain ◽  
Period Doubling ◽  
Stretchable Electronics ◽  
Element Analysis ◽  
Compliant Substrate ◽  
Material Parameters ◽  
Plane Compression ◽  
Critical Buckling Strain

The buckling of a stiff film on a compliant substrate has attracted much attention due to its wide applications such as thin-film metrology, surface patterning and stretchable electronics. An analytical model is established for the buckling of a stiff thin film on a semi-infinite elastic graded compliant substrate subjected to in-plane compression. The critical compressive strain and buckling wavelength for the sinusoidal mode are obtained analytically for the case with the substrate modulus decaying exponentially. The rigorous finite element analysis (FEA) is performed to validate the analytical model and investigate the postbuckling behaviour of the system. The critical buckling strain for the period-doubling mode is obtained numerically. The influences of various material parameters on the results are investigated. These results are helpful to provide physical insights on the buckling of elastic graded substrate-supported thin film.

scholarly journals Study on Influence of Multi-Parameter Variation of Bladed Disk System on Vibration Characteristics

2021 ◽  
Vol 11 (7) ◽  
pp. 3084
Author(s):  
Honggang Pan ◽  
Yunshi Wu ◽  
Tianyu Zhao
Keyword(s):  
Finite Element ◽  
Vibration Mode ◽  
Fine Sand ◽  
Structure Design ◽  
Vibration Characteristics ◽  
Disk System ◽  
Element Analysis ◽  
Bladed Disk ◽  
Rotor Disk ◽  
Aero Engines

As the main components of the rotor system of aero-engines and other rotating machinery equipment, the bladed disk system has high requirements on its structure design, safety and stability. Taking the rotor disk system of aero-engines as the research object, modal calculation of the rotor disk system was based on the group theory algorithm, and using the fine sand movement on the experimental disk to express the disk vibration shape. The experimental vibration mode is used to compare with the finite element calculation results to verify the reliability of the finite element analysis. Study on the effect of dissonance parameter changes on the bladed disk system vibration characteristics concluded that the vibration mode trends of the blisk system and the disc are, basically, consistent. As the mass of the blade increases, the modal frequencies of the entire blisk system gradually decrease, and the amplitude slightly increases. When the mass increases at different parts of the blade, the effect on the modal frequencies of the bladed disk system are not obvious. When the bladed disk system vibrates at low frequency, the disc will not vibrate and each blade will vibrate irregularly. The bladed disk should be avoided to work in this working area for a long time, so as not to cause fatigue damage or even fracture of some blades.

scholarly journals Design and optimization of main reducer based on Baja racing

2021 ◽  
Vol 260 ◽  
pp. 03015
Author(s):  
Taiyu Ning ◽  
Chao He ◽  
Jifei Chen ◽  
Xueyuan Liu ◽  
Wengang Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Reliability ◽  
Dynamic Performance ◽  
3D Models ◽  
Transmission Ratio ◽  
Main Function ◽  
Element Analysis ◽  
Ratio Distribution ◽  
Design And Optimization ◽  
Main Component

The main reducer is the main component of the whole vehicle, and its main function is to realize deceleration and torque increase. For Baha racing car, in order to improve the dynamic performance of the whole car, the main reducer is designed from the aspects of layout, transmission ratio distribution, shift mode, overall size and shell structure. Calculate the transmission ratio range of reducer according to the performance parameters of transmission parts, and verify the rationality of transmission ratio; Then determine the parameters of gear according to the transmission ratio and related parameters, and finally design the parameters of gear according to the transmission ratio and related parameters, and finally design the parameters of other parts of reducer. Based on the determined parameters, 3D modeling software UG is used to build 3D models of various parts of the reducer, and finite element analysis software ANSYS is used to simulate and analyze the parts to check whether the comprehensive mechanical properties meet the requirements. In this paper, the design of the main reducer realizes the comprehensive design of small size, light weight, reasonable transmission ratio distribution, high reliability, shifting gears during driving, and the comprehensive mechanical properties also meet the requirements.

Modal Analysis of Boring and Milling Machine

2011 ◽  
Vol 105-107 ◽  
pp. 204-207
Author(s):  
Jian Dong Shang ◽  
Jun Qi Guo ◽  
Dong Fang Hu
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Great Influence ◽  
Element Model ◽  
Mode Shapes ◽  
Machining Accuracy ◽  
Element Analysis ◽  
Modes Of Processing

The vibration is a high-precision machine tool components in the design of the major issues, facing its precision has a great influence, so column parts of its modal analysis is necessary. Creating three-dimensional finite element model of the column, using finite element analysis software ANSYS modal analysis of the column, which can reached the first five natural frequencies and mode shapes. Column Part of our understanding of dynamic performance and improve the machining accuracy is helpful. Modal analysis method is the dynamic performance of the column on the main approach, which mainly is to determine the vibration characteristics of the column that is the natural frequency and vibration mode, which we can determine the modes of processing accuracy, and thus the relevant parts of the machine column can be optimized so that it meet the requirements.

Improved Lawnmower Blade Design and Optimization

2009 ◽  
Author(s):  
Robert White ◽  
Jackie Seaman ◽  
Xuejun Fan ◽  
Paul R. Corder
Keyword(s):  
Mechanical Design ◽  
Strain Analysis ◽  
High Strength ◽  
Power Input ◽  
Mechanical Efficiency ◽  
Design Decision ◽  
Element Analysis ◽  
Design And Optimization ◽  
Undergraduate Engineering ◽  
Academic Benefits

With an estimated three billion man-hours of use each year, improvements to the mechanical efficiency of lawnmower systems may yield significant reductions in emissions. Modifications to either the blade geometry or material have been considered in order to achieve the desired gains in efficiency. Specifically, focus is placed upon identification of a more efficient edge shape, reduction of required power input to the blade, and extending the life of the blade sharpness. Using software packages such as Parametric Technology Corporation’s (PTC’s) Pro/Engineer the students were able to increase the quality of design via finite element analysis (FEA) programs such as MSC. Nastran or PTC’s Mechanica. AISI 440C stainless steel was selected as a possible candidate based upon several appealing properties such as high strength, hardness, and resistance to corrosion. It does however have a lower fracture toughness and therefore presents a higher susceptibility to brittle fracture. When both the traditional stress analysis and fracture analysis were considered, opposing results were found. Due to this, other criteria such as cost of material, machining costs, and carbon footprint were considered before making a final design decision. Enhancing education in engineering by diversifying design criteria and encouraging students to address contemporary, real-world design problems was a primary goal of this project. The traditional mechanical design approach relies on stress-strain analysis in order to predict potential failure scenarios, and is the primary technique presented in most undergraduate engineering curricula. Despite its significance, the fracture mechanics approach is not often presented in great detail at the undergraduate level. The academic benefits of including these more universal considerations in the undergraduate engineering curriculum are illustrated in this paper.

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