scholarly journals Three-dimensional analysis model of electric heating fabrics considering the skin metabolism

2021 ◽  
Vol 16 ◽  
pp. 155892502110479
Author(s):  
Xiao Li ◽  
Bo Kuai ◽  
Xikai Tu ◽  
Jiahao Tan ◽  
Xuan Zhou
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Surface Temperature ◽  
Three Dimensional ◽  
Electric Heating ◽  
Skin Surface ◽  
Skin Tissue ◽  
Skin Surface Temperature ◽  
Analysis Model ◽  
Element Analysis

In low temperature environment, electric heating clothing can provide extra heat for human body through built-in heat source, so it has better thermal insulation effect. The thermal analysis is the initial step for electric heating clothing design. The current thermal analysis of electric heating textiles focuses on the fabric itself instead of the effect of skin tissue metabolism and heat production. In order to improve the accuracy of skin surface temperature prediction, the biological heat transfer need be modeled to analyze the internal temperature distribution of the heating suit system. In this paper, a three-dimensional (3D) thermal analysis model of electric heating clothing combined with human skin tissue is established. Firstly, the coupling analysis of Fourier heat conduction and Pennes biological heat transfer equation is carried out. Then the reliability of the 3D thermal analysis model is verified by finite element analysis (FEA). The results show that the fitting error between the three-dimensional model analysis data and FEA simulation data is 5°C, which proves that the model can accurately predict the system temperature. Finally, we make further research about the effects of ambient temperature, clothing layer thickness, and input power on the maximum skin surface temperature. This study provides theoretical foundation for the design of wearable thermal management fabric.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

Analysis of a Virtual Prototype First-Stage Rotor Blade Using Integrated Computer-Based Design Tools

2006 ◽  
Author(s):  
Michel Arnal ◽  
Christian Precht ◽  
Thomas Sprunk ◽  
Tobias Danninger ◽  
John Stokes
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Loading ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Life Assessment ◽  
Element Analysis ◽  
Pressure Losses ◽  
Cooling Channels ◽  
Internally Cooled

The present paper outlines a practical methodology for improved virtual prototyping, using as an example, the recently re-engineered, internally-cooled 1st stage blade of a 40 MW industrial gas turbine. Using the full 3-D CAD model of the blade, a CFD simulation that includes the hot gas flow around the blade, conjugate heat transfer from the fluid to the solid at the blade surface, heat conduction through the solid, and the coolant flow in the plenum is performed. The pressure losses through and heat transfer to the cooling channels inside the airfoil are captured with a 1-D code and the 1-D results are linked to the three-dimensional CFD analysis. The resultant three-dimensional temperature distribution through the blade provides the required thermal loading for the subsequent structural finite element analysis. The results of this analysis include the thermo-mechanical stress distribution, which is the basis for blade life assessment.

scholarly journals Biomechanical assessment of different fixation methods in mandibular high sagittal oblique osteotomy using a three-dimensional finite element analysis model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles Savoldelli ◽  
Elodie Ehrmann ◽  
Yannick Tillier
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Fixation Methods ◽  
Oblique Osteotomy ◽  
Von Mises

AbstractWith modern-day technical advances, high sagittal oblique osteotomy (HSOO) of the mandible was recently described as an alternative to bilateral sagittal split osteotomy for the correction of mandibular skeletal deformities. However, neither in vitro nor numerical biomechanical assessments have evaluated the performance of fixation methods in HSOO. The aim of this study was to compare the biomechanical characteristics and stress distribution in bone and osteosynthesis fixations when using different designs and placing configurations, in order to determine a favourable plating method. We established two finite element models of HSOO with advancement (T1) and set-back (T2) movements of the mandible. Six different configurations of fixation of the ramus, progressively loaded by a constant force, were assessed for each model. The von Mises stress distribution in fixations and in bone, and bony segment displacement, were analysed. The lowest mechanical stresses and minimal gradient of displacement between the proximal and distal bony segments were detected in the combined one-third anterior- and posterior-positioned double mini-plate T1 and T2 models. This suggests that the appropriate method to correct mandibular deformities in HSOO surgery is with use of double mini-plates positioned in the anterior one-third and posterior one-third between the bony segments of the ramus.

Effect of interface pressure and skin surface temperature on pressure injury incidence: a turning schedule pilot study

2021 ◽  
Vol 30 (8) ◽  
pp. 632-641
Author(s):  
Sumiati Tarigan ◽  
Saldy Yusuf ◽  
Yuliana Syam
Keyword(s):  
Pilot Study ◽  
Surface Temperature ◽  
Clinical Trial Design ◽  
Randomised Clinical Trial ◽  
Skin Surface ◽  
Injury Incidence ◽  
Skin Surface Temperature ◽  
Interface Pressure ◽  
High Dependency ◽  
Pressure Injury

Objective: This study aimed to evaluate the interface pressure and skin surface temperature in relation to the incidence of pressure injury (PI) using three different turning schedules. Method: This was a pilot study with a three-armed randomised clinical trial design. Participants at risk of PI and treated in the high dependency care unit in a regional hospital in Makassar, Indonesia participated in this study. Patients were repositioned at three different turning schedules (two-, three- and four-hourly intervals). Interface pressure measurement and skin surface temperature were measured between 14:00 and 18:00 every three days. The incidence of PI was assessed during the two-week observation period. Results: A total of 44 participants took part in the study. A one-way ANOVA test revealed no difference in interface pressure among the three different turning schedule groups within two weeks of observations: day zero, p=0.56; day four, p=0.95; day seven, p=0.56; day 10, p=0.63; and day 14, p=0.92. Although the average periumbilical temperature and skin surface temperature were not significant (p>0.05), comparison between these observation sites was significant on all observation days (p<0.05). Regarding the incidence of PI, the proportional hazard test for the development of PI in the three groups was considered not different (hazard ratio: 1.46, 95% confidence interval: 0.43–4.87, p=0.54). Conclusion: No difference in interface pressure and incidence of PI on the three turning schedules was observed; however, there was a potential increase in skin surface temperature in comparison with periumbilical temperature for all three turning schedules.

Heat transfer of three-dimensional micropolar fluid on a Riga plate

2020 ◽  
Vol 98 (1) ◽  
pp. 32-38 ◽  
Author(s):  
S. Nadeem ◽  
M.Y. Malik ◽  
Nadeem Abbas
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Differential Equations ◽  
Surface Temperature ◽  
Ordinary Differential Equations ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Nonlinear Ordinary Differential Equations ◽  
Exponential Order ◽  
Riga Plate

In this article, we deal with prescribed exponential surface temperature and prescribed exponential heat flux due to micropolar fluids flow on a Riga plate. The flow is induced through an exponentially stretching surface within the time-dependent thermal conductivity. Analysis is performed inside the heat transfer. In our study, two cases are discussed here, namely prescribed exponential order surface temperature (PEST) and prescribed exponential order heat flux (PEHF). The governing systems of the nonlinear partial differential equations are converted into nonlinear ordinary differential equations using appropriate similarity transformations and boundary layer approach. The reduced systems of nonlinear ordinary differential equations are solved numerically with the help of bvp4c. The significant results are shown in tables and graphs. The variation due to modified Hartman number M is observed in θ (PEST) and [Formula: see text] (PEHF). θ and [Formula: see text] are also reduced for higher values of the radiation parameter Tr. Obtained results are compared with results from the literature.

Simulation of Nine-Spacer Nozzle’s Flow Field of Al Roll-Casting Using Coupled Fluid-Thermal Finite Element Analysis

2010 ◽  
Vol 159 ◽  
pp. 697-702
Author(s):  
Ying Zhou ◽  
Ya Xi Tan
Keyword(s):  
Thermal Analysis ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Flow Field ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Cooling Capacity ◽  
Element Analysis ◽  
Roll Casting ◽  
Element Simulation

A three-dimensional coupled fluid-thermal finite element simulation model has been developed to provide analyzing distribution of velocity and temperature of nine-spacer nozzle by using FEM simulation of FLOTRAN module in ANSYS 6.0. To explore fluid-thermal analysis of the flow fields of nine-spacer nozzle of aluminum roll-casting, stricter analysis of postprocessing result was conducted by MATLAB. It was concluded that flow field of nine-spacer nozzle was able to match cooling capacity of cast rollers, but nine-spacer nozzle’s geometric flaw didn’t suit for working in the case of speed increasing of the drawing-sheet and thickness reducing of the aluminium sheet during roll casting.

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