An interlocked flexible piezoresistive sensor with 3D micropyramidal structures for electronic skin applications

Soft Matter ◽  
2018 ◽  
Vol 14 (33) ◽  
pp. 6912-6920 ◽  
Author(s):  
N. Khalili ◽  
X. Shen ◽  
H. E. Naguib
Keyword(s):  
Finite Element ◽  
Silicon Mold ◽  
Flexible Sensor ◽  
Constriction Resistance ◽  
Electronic Skin ◽  
Piezoresistive Sensor ◽  
Resistance Model ◽  
Etched Silicon

An interlocked micropyramidal flexible sensor was fabricated using an anisotropically-etched silicon mold and modelled using a finite-element-assisted constriction resistance model.

scholarly journals Microstructure-Based Interfacial Tuning Mechanism of Capacitive Pressure Sensors for Electronic Skin

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Weili Deng ◽  
Xinjie Huang ◽  
Wenjun Chu ◽  
Yueqi Chen ◽  
Lin Mao ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Sensors ◽  
Pressure Response ◽  
Analysis Method ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
Tuning Mechanism ◽  
Electronic Skin ◽  
Further Development

In order to investigate the interfacial tuning mechanism of electronic skin (e-skin), several models of the capacitive pressure sensors (CPS) with different microstructures and several sizes of microstructures are constructed through finite element analysis method. The simulative pressure response, the sensitivity, and the linearity of the designed CPS show that the sensor with micropyramids has the best performance in all the designed models. The corresponding theoretically predicted sensitivity is as high as 6.3 × 10−7 fF/Pa, which is about 49 times higher than that without any microstructure. Additionally, these further simulative results show that the smaller the ratios ofL/Hof pyramid, the better the sensitivity but the worse the linearity. When the ratio ofL/Hof pyramid is about2, the sensitivity and the linearity could reach a balance point. The simulative results evidently provide the important theoretically directive significance for the further development ofe-skin.

A Constriction Resistance Model in Thermal Analysis of Solder Ball Joints in Ball Grid Array Packages

1999 ◽  
Author(s):  
T. M. Ying ◽  
K. C. Toh
Keyword(s):  
Thermal Analysis ◽  
Solder Joint ◽  
Solder Ball ◽  
Heat Dissipation ◽  
Ball Grid Array ◽  
Internal Resistance ◽  
Ball Joint ◽  
Constriction Resistance ◽  
Resistance Model ◽  
Ball Joints

Abstract The constriction resistance model is employed for the thermal analysis at the solder ball joint of a Ball Grid Array (BGA) package. The behavior of heat dissipation in solder joint is also analyst through Finite Element Modeling (FEM) and compared with the analytical model. The principle of constriction and spreading resistances is analyzed in detail because of the geometrical complexity encountered in BGA solder joints. The total resistance across the solder joint includes the internal resistance and external resistance. The internal resistance, which is the main focus of the analysis, consists of material resistance and constriction resistance. It is a function of material conductivity, thermal boundary conditions and geometric parameters. FEM solutions are in good agreement with analytical results of thermal resistance for single solder ball joint and multiple solder ball joints. The analytical resistance provides an accurate prediction on the temperature drop across the array of solder balls and hence the overall performance of the BGA packages. The pitch size is the main parameter in the investigation to study the heat dissipation of solder ball joints.

Comparison of Track-Beam Interaction among Chinese Code, Eurocode and Japanese code

2019 ◽  
Author(s):  
Gonglian Dai ◽  
Kan Dang ◽  
Y. Frank Chen ◽  
Tianpei Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reaction Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Resistance Model ◽  
Live Loads ◽  
Beam Interaction ◽  
Braking Force ◽  
Track Beam

<p>After the continuously welded rail (CWR) is laid on the bridge, relative displacements between beam and track under the action of temperature, creep, vertical live load, and braking force will occur. Due to the constraint between beam and track, the longitudinal forces are generated in the track, beam, and pier. This paper aims to compare the differences in rack-beam interaction between the Japanese code, the Eurocode and the Chinese code. Particularly the distinctions in track resistance models, braking forces, temperature loads, and vertical live loads. For example, the Chinese code and Eurocode use a nonlinear resistance model, but the Japanese code uses a constant resistance model. A representative bridge example is used to demonstrate the differences, where the finite element analysis is adopted. In the finite element analysis, nonlinear bars or constant bars are used to simulate the track resistance, beam elements with rigid links are used to simulate the bridge, and the mechanical model for the ballasted track was is established. Continuous simply- supported beam is assumed in the analysis.</p><p>Based on the calculation results, it is found that the additional longitudinal stress, the relative displacement, and the reaction force caused by the temperature, vertical live loads, and braking force are higher as calculated by the Eurocode compared to the Chinese code and the Japanese code.</p>

scholarly journals Transparent and Flexible Mayan-Pyramid-based Pressure Sensor using Facile-Transferred Indium tin Oxide for Bimodal Sensor Applications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Minhyun Jung ◽  
Sujaya Kumar Vishwanath ◽  
Jihoon Kim ◽  
Dae-Kwan Ko ◽  
Myung-Jin Park ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Pressure Sensor ◽  
Indium Tin Oxide ◽  
Motion Tracking ◽  
Pressure Sensors ◽  
Water Soluble ◽  
Plastic Substrate ◽  
Silicon Mold ◽  
Sensor Applications ◽  
Electronic Skin

Abstract Transparent and conducting flexible electrodes have been successfully developed over the last few decades due to their potential applications in optoelectronics. However, recent developments in smart electronics, such as a direct human-machine interface, health-monitoring devices, motion-tracking sensors, and artificially electronic skin also require materials with multifunctional properties such as transparency, flexibility and good portability. In such devices, there remains room to develop transparent and flexible devices such as pressure sensors or temperature sensors. Herein, we demonstrate a fully transparent and flexible bimodal sensor using indium tin oxide (ITO), which is embedded in a plastic substrate. For the proposed pressure sensor, the embedded ITO is detached from its Mayan-pyramid-structured silicon mold by an environmentally friendly method which utilizes water-soluble sacrificial layers. The Mayan-pyramid-based pressure sensor is capable of six different pressure sensations with excellent sensitivity in the range of 100 Pa-10 kPa, high endurance of 105 cycles, and good pulse detection and tactile sensing data processing capabilities through machine learning (ML) algorithms for different surface textures. A 5 × 5-pixel pressure-temperature-based bimodal sensor array with a zigzag-shaped ITO temperature sensor on top of it is also demonstrated without a noticeable interface effect. This work demonstrates the potential to develop transparent bimodal sensors that can be employed for electronic skin (E-skin) applications.

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