scholarly journals A numerical analysis of skin–PPE interaction to prevent facial tissue injury

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rikeen D. Jobanputra ◽  
Jack Hayes ◽  
Sravani Royyuru ◽  
Marc A. Masen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Tissue Injury ◽  
Soft Materials ◽  
Element Model ◽  
Healthcare Systems ◽  
Skin Injury ◽  
Energy Density Distribution ◽  
The World ◽  
The Face

AbstractThe use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on healthcare systems around the world, leading to medical professionals using high-grade PPE for prolonged durations, resulting in device-induced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometric and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviour (e.g. many elastomers) should be avoided.

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

2021 ◽  
Author(s):  
Rikeen D. Jobanputra ◽  
Jack Hayes ◽  
Sravani Royyuru ◽  
Marc A. Masen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Tissue Injury ◽  
Soft Materials ◽  
Element Model ◽  
Medical Professionals ◽  
High Grade ◽  
Skin Injury ◽  
Energy Density Distribution ◽  
The Face

Abstract The use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on the healthcare system, leading to medical professionals using high-grade PPE for prolonged times, resulting in device-insduced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometry and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviours (e.g. most elastomers) should be avoided.

The Debond Fracture of Sandwich Plate with Corrugated Core Using Cohesive Zone Element

2012 ◽  
Vol 525-526 ◽  
pp. 117-120
Author(s):  
Guang Ping Zou ◽  
Peng Fei Yang ◽  
Jie Lu ◽  
Yong Gui Li
Keyword(s):  
Tensile Test ◽  
Cohesive Zone ◽  
Strain Energy ◽  
Sandwich Plate ◽  
Strain Energy Release ◽  
Element Model ◽  
Mode I Fracture Toughness ◽  
The Face ◽  
Open Displacement ◽  
Cohesive Element Model

In this paper, flatwise tensile test (FWT) and modified double cantilever beam (DCB) experiment were conducted to investigated the debond fracture of sandwich plate with corrugated core. In the experiment, the crack always stays at the face/core interfacial. Tensile bond strength of face core can be given from the flatwise tensile test and we can get the mode I fracture toughness GIC from DCB tests. It is found that the trends of curves change greatly at the beginning, with the propagation of crack, load against open displacement curves change smoothly. In order to simulate the face/core failure of sandwich plate with corrugated core, the cohesive element model is used. Tensile strength and strain energy release rate measured by the experiments presented in this paper are used in as parameters for simulation of the debond fracture. By comparing with the experiment results, the model can express the face/core failure of sandwich plate with corrugated core validly.

scholarly journals Mechanism by Which Backfill Body Reduces Amount of Energy Released in Deep Coal Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Wenyue Qi ◽  
Jixiong Zhang ◽  
Nan Zhou ◽  
Zhongya Wu ◽  
Jun Zhang
Keyword(s):  
Energy Density ◽  
Coal Mining ◽  
Coal Mine ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Mining Area ◽  
Filling Material ◽  
Ultrahigh Energy ◽  
Energy Density Distribution ◽  
Working Face

Deep coal mining is unavoidable, and the complex mining environments and the increasing dangers associated with ultrahigh energy accumulation and release from mining disturbances renders it extremely difficult to maintain a safe and stable stope. Solid backfilling technology directly uses coal gangue and other solid wastes in the mining area to fill the gob after mining. Support from the backfill body can inhibit the movement of overlying rock strata and significantly alleviate the influence of mining. In this study, the correlations between the deformation of gangue filling material and the characteristics of energy dissipation were examined under lateral uniaxial compression. The strain energy density distributions of backfilling and caving mining methods were simulated using numerical modeling. The results showed that the strain energy density distribution of backfilling mining was less concentrated, and its peak value was lower than that of caving mining by 51.0%, indicating that backfilling could effectively reduce the amount of energy released from mining rocks. The dense backfill mining area of the No. 9301 face in Tangkou Coal Mine was used as a case study. Measures for controlling the backfill body compaction for reducing the amount of energy released from mining rocks were proposed. These measures include optimizing the support structure and filling material formula, controlling the preroof subsidence, and ensuring an appropriate number of tamping strokes. The monitoring results of the backfilling quality, surface subsidence, and microseismic energy of No. 9301 working face in Tangkou Coal Mine showed that when the backfill body filling ratio control value was 82.28%, the total number of microseisms and the amount of energy released from the mining working face were significantly lower compared to those of the caving method. This study demonstrated that the backfill body could effectively reduce the amount of energy released from mining rocks, thereby realizing management of mine earthquake and sustainable deep coal mining.

The effect of cement mantle thickness on strain energy density distribution and prediction of bone density changes around cemented acetabular component

2018 ◽  
Vol 232 (9) ◽  
pp. 912-921 ◽  
Author(s):  
Devismita Sanjay ◽  
Subrata Mondal ◽  
Richa Bhutani ◽  
Rajesh Ghosh
Keyword(s):  
Energy Density ◽  
Density Distribution ◽  
Acetabular Component ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Cement Mantle ◽  
Thickness Variation ◽  
Acetabular Cup ◽  
Energy Density Distribution ◽  
Mantle Thickness

Cement mantle thickness is known to be one of the important parameters to reduce the failure of the cemented acetabular component. The thickness of the cement mantle is also often influenced by the positioning of the acetabular cup. The aim of this study is to determine the effect of uniform and non-uniform cement mantle thickness on strain energy density distribution and prediction of the possibility of bone remodelling around the acetabular region. Furthermore, tensile stress distribution in the cement mantle due to non-uniform cement mantle thickness was also investigated. Three-dimensional finite element models of intact and 17 implanted pelvic bone were developed based on computed tomography data sets. Results indicate that implantation with non-uniform cement thickness variation in the anterior–posterior direction has a significant influence on strain energy density distribution around the acetabulum as compared to thickness variation in the superior–inferior direction. Increase in density is predicted at the anterior part of the acetabulum, whereas density decrease is predicted at the posterior, inferior and superior part of the acetabulum. The non-uniform cement mantle thickness affected the tensile stress distribution in the cement mantle, in particularly superiorly placed acetabular cup. This study concludes that uniform cement thickness is desired for the longer success of the cemented acetabular component.

Topology Optimization and Robust Analysis of Welding Spot Layout for a Heavy Duty Truck Cab Based on Element Strain Energy Density

2014 ◽  
Vol 887-888 ◽  
pp. 1284-1289 ◽  
Author(s):  
An Cui ◽  
Shi Zhan Zhang ◽  
Li Juan Xu ◽  
Hui Zi Liu
Keyword(s):  
Topology Optimization ◽  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Element Model ◽  
Optimization Method ◽  
Heavy Duty ◽  
Static Stiffness ◽  
Heavy Duty Truck ◽  
Welding Spot

The static stiffness and numerical modal are analyzed with the finite element model of a heavy duty truck cab. Considering the influence of welding spots on static stiffness, strength and first order modal frequency, the welding spots of the heavy duty truck cab are divided into two areas based on element strain energy density. And welding spot layout of the two areas is optimized by topology optimization method respectively. Then the robustness of welding spot layout before and after optimization is analyzed. The results show that the number of welding spots after optimization is reduced with the performance maintained and welding spot layout robustness of the cab is improved.

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