Thermomechanical Analysis of Epidermal Electronic Devices Integrated With Human Skin

2017 ◽  
Vol 84 (11) ◽  
Author(s):  
Yuhang Li ◽  
Jianpeng Zhang ◽  
Yufeng Xing ◽  
Jizhou Song
Keyword(s):  
Human Skin ◽  
Analytical Model ◽  
Temperature Increase ◽  
Electronic Devices ◽  
Vital Signs ◽  
Thermomechanical Analysis ◽  
Design Guidelines ◽  
Thermomechanical Model ◽  
Element Analysis ◽  
The Maximum Principle

Epidermal electronic devices (EEDs) are very attractive in applications of monitoring human vital signs for diagnostic, therapeutic, or surgical functions due to their ability for integration with human skin. Thermomechanical analysis is critical for EEDs in these applications since excessive heating-induced temperature increase and stress may cause discomfort. An axisymmetric analytical thermomechanical model based on the transfer matrix method, accounting for the coupling between the Fourier heat conduction in the EED and the bio-heat transfer in human skin, the multilayer feature of human skin and the size effect of the heating component in EEDs, is established to study the thermomechanical behavior of the EED/skin system. The predictions of the temperature increase and principle stress from the analytical model agree well with those from finite element analysis (FEA). The influences of various geometric parameters and material properties of the substrate on the maximum principle stress are fully investigated to provide design guidelines for avoiding the adverse thermal effects. The thermal and mechanical comfort analyses are then performed based on the analytical model. These results establish the theoretical foundation for thermomechanical analysis of the EED/skin system.

Transient thermomechanical analysis of epidermal electronic devices on human skin

2019 ◽  
Vol 137 ◽  
pp. 103097
Author(s):  
Jianpeng Zhang ◽  
Yuhang Li ◽  
Yufeng Xing ◽  
Jizhou Song
Keyword(s):  
Human Skin ◽  
Electronic Devices ◽  
Thermomechanical Analysis

Parametric Studies of Effects of Solder Bump Pitch, Package Size, and Molding Compound and Substrate Thicknesses on Warpage of PBGA Packages

2014 ◽  
Vol 2014 (1) ◽  
pp. 000044-000049
Author(s):  
Sungbum Kang ◽  
I. Charles Ume
Keyword(s):  
Solder Bump ◽  
Electronic Devices ◽  
Design Guidelines ◽  
Element Analysis ◽  
Molding Compound ◽  
Factors Affecting ◽  
Package Design ◽  
Plastic Ball ◽  
Package Size ◽  
Parametric Finite Element Analysis

Plastic ball grid array (PBGA) is one of the most widely used types of chip packages in various electronic devices such as network servers, microcontrollers, and memory devices. As the demand for higher performance electronic devices grows, the I/O densities of PBGA packages are increasing while requiring superior reliability. Warpage induced during the reflow assembly process is one of the crucial factors affecting the thermo-mechanical reliability of PBGA packages; therefore, accurate warpage prediction is an important task for package design processes. In this study, the effects of four geometric factors (the solder bump pitch, package size, and molding compound and substrate thicknesses) of the PBGA package on its warpage are assessed by using parametric finite element analysis. The correlation between PBGA warpage and the four factors is studied using the regression method. These results are expected to provide design guidelines for in-house PBGA designers.

scholarly journals Development of Simulation Based p-Multipliers for Laterally Loaded Pile Groups in Granular Soil Using 3D Nonlinear Finite Element Model

2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Muhammad Bilal Adeel ◽  
Muhammad Asad Jan ◽  
Muhammad Aaqib ◽  
Duhee Park
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Design Guidelines ◽  
American Petroleum Institute ◽  
Winkler Foundation ◽  
Group Effect ◽  
Pile Groups ◽  
Element Analysis ◽  
Laterally Loaded Pile ◽  
Laterally Loaded

The behavior of laterally loaded pile groups is usually accessed by beam-on-nonlinear-Winkler-foundation (BNWF) approach employing various forms of empirically derived p-y curves and p-multipliers. Averaged p-multiplier for a particular pile group is termed as the group effect parameter. In practice, the p-y curve presented by the American Petroleum Institute (API) is most often utilized for piles in granular soils, although its shortcomings are recognized. In this study, we performed 3D finite element analysis to develop p-multipliers and group effect parameters for 3 × 3 to 5 × 5 vertically squared pile groups. The effect of the ratio of spacing to pile diameter (S/D), number of group piles, varying friction angle (φ), and pile fixity conditions on p-multipliers and group effect parameters are evaluated and quantified. Based on the simulation outcomes, a new functional form to calculate p-multipliers is proposed for pile groups. Extensive comparisons with the experimental measurements reveal that the calculated p-multipliers and group effect parameters are within the recorded range. Comparisons with two design guidelines which do not account for the pile fixity condition demonstrate that they overestimate the p-multipliers for fixed-head condition.

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020 ◽  
pp. 136943322098170
Author(s):  
Michele Fabio Granata ◽  
Antonino Recupero
Keyword(s):  
Analytical Model ◽  
Prestressed Concrete ◽  
3D Analysis ◽  
Box Girders ◽  
Element Analysis ◽  
Cross Sectional ◽  
Interaction Domains ◽  
Global And Local ◽  
Resultant Forces

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

scholarly journals Systematic Review on Human Skin-Compatible Wearable Photoplethysmography Sensors

2021 ◽  
Vol 11 (5) ◽  
pp. 2313
Author(s):  
Inho Lee ◽  
Nakkyun Park ◽  
Hanbee Lee ◽  
Chuljin Hwang ◽  
Joo Hee Kim ◽  
...  
Keyword(s):  
Systematic Review ◽  
Health Care ◽  
Real Time ◽  
Human Skin ◽  
State Of The Art ◽  
Electronic Devices ◽  
Semiconducting Materials ◽  
Physiological Conditions ◽  
Technological Developments ◽  
Monitoring Technologies

The rapid advances in human-friendly and wearable photoplethysmography (PPG) sensors have facilitated the continuous and real-time monitoring of physiological conditions, enabling self-health care without being restricted by location. In this paper, we focus on state-of-the-art skin-compatible PPG sensors and strategies to obtain accurate and stable sensing of biological signals adhered to human skin along with light-absorbing semiconducting materials that are classified as silicone, inorganic, and organic absorbers. The challenges of skin-compatible PPG-based monitoring technologies and their further improvements are also discussed. We expect that such technological developments will accelerate accurate diagnostic evaluation with the aid of the biomedical electronic devices.

scholarly journals Heart Rate monitor based on IP networking

2018 ◽  
Vol 210 ◽  
pp. 01006
Author(s):  
Miguel G. Molina ◽  
Priscila E. Garzón ◽  
Carolina J. Molina ◽  
Juan X. Nicola
Keyword(s):  
Heart Rate ◽  
Real Time ◽  
Electronic Devices ◽  
Vital Signs ◽  
Well Being ◽  
Heart Rate Monitor ◽  
Ip Address ◽  
Health Concept ◽  
New Applications ◽  
Threat Situation

With the uprising of Internet of Things (IoT) networks, new applications have taken advantage of this new concept. Having all devices and all people connected 24/7 have several advantages in a variated amount of disciplines. One of them is medicine and the e-health concept. The possibility of having a real time lecture of the vital signs of people can prevent a live threat situation. This paper describes the realization of a device capable of measuring the heart rate of a person and checking for abnormalities that may negatively affect the patient’s well-being. This project will make use of electronic devices known as microcontrollers, specifically from the Arduino family, enabling us to capture data, and, with the help of a network card and a RJ-45 cable, transfer it to a PC and visualize the heart rate in real time over its assigned IP address.

An Accurate Thermomechanical Model for Laser-Driven Microtransfer Printing

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Yuyan Gao ◽  
Yuhang Li ◽  
Rui Li ◽  
Jizhou Song
Keyword(s):  
Size Effect ◽  
Theoretical Basis ◽  
System Optimization ◽  
Engineering Systems ◽  
Transfer Printing ◽  
Thermomechanical Model ◽  
Element Analysis ◽  
Mechanics Model ◽  
Interfacial Fracture Mechanics ◽  
Printing Technique

A recently developed transfer printing technique, laser-driven noncontact microtransfer printing, which involves laser-induced heating to initiate the separation at the interface between the elastomeric stamp (e.g., polydimethylsiloxane (PDMS)) and hard micro/nanomaterials (e.g., Si chip), is valuable to develop advanced engineering systems such as stretchable and curvilinear electronics. The previous thermomechanical model has identified the delamination mechanism successfully. However, that model is not valid for small-size Si chip because the size effect is ignored for simplification in the derivation of the crack tip energy release rate. This paper establishes an accurate interfacial fracture mechanics model accounting for the size effect of the Si chip. The analytical predictions agree well with finite element analysis. This accurate model may serve as the theoretical basis for system optimization, especially for determining the optimal condition in the laser-driven noncontact microtransfer printing.

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