Third-Order Polynomials Model for Analyzing Multilayer Hard/Soft Materials in Flexible Electronics

2016 ◽  
Vol 83 (8) ◽  
Author(s):  
Xianhong Meng ◽  
Boya Liu ◽  
Yu Wang ◽  
Taihua Zhang ◽  
Jianliang Xiao
Keyword(s):  
Mechanical Properties ◽  
Flexible Electronics ◽  
Virtual Work ◽  
Soft Materials ◽  
Normal Strain ◽  
Stress Distributions ◽  
Third Order ◽  
Inorganic Semiconductors ◽  
Design And Optimization ◽  
Good Agreement

In flexible electronics, multilayer hard/soft materials are widely used to utilize both the superior electrical properties of inorganic semiconductors and robust mechanical properties of polymers simultaneously. However, the huge mismatch in mechanical properties of the hard and soft materials makes mechanics analysis challenging. We here present an analytical model to study the mechanics of multilayer hard/soft materials in flexible electronics. Third-order polynomials are adopted to describe the displacement field, which can be used to easily derive both strain and stress fields. Then, the principle of virtual work was used to derive the governing equations and boundary conditions, which can be solved numerically. Two types of loadings, pure bending and transverse shear, are studied. The normal strain distributions along thickness direction in the bimaterial regions clearly show zigzag profiles, due to the huge mismatch in the mechanical properties of the hard and soft materials. The effect of very different mechanical properties of the hard and soft materials on shear stress distributions can also be predicted by this model. The results from this analytical mode show good agreement with finite-element modeling (FEM). This model can be useful in systems with multilayer hard/soft materials, to predict mechanical behavior and to guide design and optimization.

A Coupled Zig-Zag Third-Order Theory for Piezoelectric Hybrid Cross-Ply Plates

2004 ◽  
Vol 71 (5) ◽  
pp. 604-614 ◽  
Author(s):  
S. Kapuria
Keyword(s):  
Electric Potential ◽  
Virtual Work ◽  
Piecewise Linear ◽  
Three Dimensional ◽  
Order Theory ◽  
Piecewise Linear Approximation ◽  
Shear Stresses ◽  
Normal Strain ◽  
Third Order ◽  
Hybrid Cross

A new zig-zag coupled theory is developed for hybrid cross-ply plates with some piezoelectric layers using third-order zig-zag approximation for the inplane displacements and sublayer wise piecewise linear approximation for the electric potential. The theory considers all electric field components and can model open and closed-circuit boundary conditions. The deflection field accounts for the transverse normal strain due to the piezoelectric d33 coefficient. The displacement field is expressed in terms of five displacement variables (which are the same as in FSDT) and electric potential variables by satisfying exactly the conditions of zero shear stresses at the top and bottom, and their continuity at layer interfaces. The governing equations are derived from the principle of virtual work. Comparison of the Navier solutions for the simply-supported plates with the analytical three-dimensional piezoelasticity solutions establishes that the present efficient zig-zag theory is quite accurate for moderately thick plates.

Experimental and Theoretical Study on Mechanical Properties of Porous PDMS

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
Chen Huang ◽  
Zuguang Bian ◽  
Chengfeng Fang ◽  
Xiaoliang Zhou ◽  
Jizhou Song
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexible Electronics ◽  
Poisson’S Ratio ◽  
Mechanical Design ◽  
Homogenization Method ◽  
Poisson's Ratio ◽  
Design And Optimization ◽  
Volume Porosity ◽  
Asymptotic Homogenization Method

Polydimethylsiloxane (PDMS) is extensively used in clinical flexible electronics, due to its biocompatibility and stability. When it is employed in a stretchable epidermal sensor for long-term monitoring, PDMS must have open pores within it to assure the sweat penetration. In the present paper, we focus on the mechanical properties of porous PDMS with different volume porosities at different temperatures. The emulsion polymerization technique is applied to fabricate porous PDMS. By controlling the ratio of water to PDMS prepolymer, different porosities of PDMS were obtained, and elastic moduli of such porous PDMS were measured in experiment. Results indicate that the elastic modulus increases nonlinearly as its temperature rises from 0 °C to 40 °C (a temperature range frequently encountered in clinical applications). Meanwhile, an asymptotic homogenization method (AHM) is employed to theoretically predict the elastic modulus and Poisson's ratio of porous PDMS, whose reliability is testified by comparing the results with experimentally measured data. Further theoretical discussions on mechanical properties are carried out, and results show that the pore size of porous PDMS has almost no effect on the elastic modulus and Poisson's ratio for certain porosities. Porosity of porous PDMS, however, has significant effect on both of these two mechanical parameters. Two fitted nonlinear formulas are then proposed to estimate the elastic modulus and Poisson's ratio of porous PDMS for any volume porosity less than 50%. All the results in the present paper are essential for mechanical design and optimization of clinical flexible electronics based on porous PDMS.

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

scholarly journals Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1036
Author(s):  
Eduardo Colin García ◽  
Alejandro Cruz Ramírez ◽  
Guillermo Reyes Castellanos ◽  
José Federico Chávez Alcalá ◽  
Jaime Téllez Ramírez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Energy Impact ◽  
Treatment Conditions ◽  
Mold Casting ◽  
Grade 3 ◽  
Good Agreement

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.

scholarly journals High elasticity and strength of ultra-thin metallic transition metal dichalcogenides

2021 ◽  
Author(s):  
Ali Sheraz ◽  
Naveed Mehmood ◽  
Mert Mirac Cicek ◽  
İbrahim Ergün ◽  
Hamid Reza Rasouli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Transition Metal ◽  
Flexible Electronics ◽  
Transition Metal Dichalcogenides ◽  
High Elasticity ◽  
Metal Dichalcogenides

Mechanical properties of transition metal dichalcogenides (TMDCs) are relevant to their prospective applications in flexible electronics. So far, the focus has been on the semiconducting TMDCs, mostly MoX2 and WX2...

Heat and Mass Diffusion Including Shrinkage and Hygrothermal Stress during Drying of Holed Ceramics Bricks

2011 ◽  
Vol 312-315 ◽  
pp. 971-976 ◽  
Author(s):  
J. Barbosa da Silva ◽  
G. Silva Almeida ◽  
W.C.P. Barbosa de Lima ◽  
Gelmires Araújo Neves ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Moisture Content ◽  
Three Dimensional ◽  
Average Moisture Content ◽  
Stress Distributions ◽  
Drying Process ◽  
Convective Boundary ◽  
Volume Method ◽  
Hygrothermal Stress ◽  
Thermo Physical Properties ◽  
Good Agreement

The Aim of this Work Is to Present a Three-Dimensional Mathematical Modelling to Predict Heat and Mass Transport inside the Industrial Brick with Rectangular Holes during the Drying Including Shrinkage and Hygrothermalelastic Stress Analysis. the Numerical Solution of the Diffusion Equation, Being Used the Finite-Volume Method, Considering Constant Thermo-Physical Properties and Convective Boundary Conditions at the Surface of the Solid, it Is Presented and Analyzed. Results of the Temperature, Moisture Content and Stress Distributions, and Drying and Heating Kinetics Are Shown and Analyzed. Results of the Average Moisture Content and Surface Temperature of the Brick along the Drying Process Are Compared with Experimental Data (T = 80.0oC and RH = 4.6 %) and Good Agreement Was Obtained. it Was Verified that the Largest Temperature, Moisture Content and Stress Gradients Are Located in the Intern and External Vertexes of the Brick.

Modelling the nano indentation behaviour of recast layer and heat affected zone on reverse micro EDMed hemispherical feature

2021 ◽  
pp. 1-15
Author(s):  
Tribeni Roy ◽  
Anuj Sharma ◽  
Prabhat Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Heat Affected Zone ◽  
Parent Material ◽  
Recast Layer ◽  
Machined Surface ◽  
Nano Indentation ◽  
Fea Simulation ◽  
Load Displacement ◽  
Good Agreement

Abstract Electrical discharge machined surfaces inherently possess recast layer on the surface with heat affected zone (HAZ) beneath it and these have a detrimental effect on the mechanical properties viz. hardness, elastic modulus, etc. It is very difficult to experimentally characterise each machined surface. Therefore, an attempt is made in this study to numerically calculate the mechanical properties of the parent material, HAZ and the recast layer on a hemispherical protruded micro feature fabricated by reverse micro EDM (RMEDM). In the 1st stage, nano indentation was performed to experimentally determine the load-displacement plots, elastic modulus and hardness of the parent material, HAZ and the recast layer. In the 2nd stage, FEA simulation was carried out to mimic the nano indentation process and determine the load-displacement plots for all the three cases viz. parent material, recast layer and HAZ. Results demonstrated that the load'displacement plots obtained from numerical model in each case was in good agreement with that of the experimental curves. Based on simulated load-displacement plots, hardness was also calculated for parent material, HAZ and the recast layer. A maximum of 11% error was observed between simulated values of hardness and experimentally determined values.

Effect of Model Pollutants on the Recycling of PE/PS Plastic Blends

2003 ◽  
Vol 19 (2) ◽  
pp. 61-76 ◽  
Author(s):  
Tasnim Kallel ◽  
Valérie Massardier-Nageotte ◽  
Mohamed Jaziri ◽  
Jean-François Gérard ◽  
Boubaker Elleuch
Keyword(s):  
Mechanical Properties ◽  
Ethylene Glycol ◽  
Molar Mass ◽  
Polar Molecule ◽  
Dispersed Phase ◽  
Automotive Applications ◽  
Absorbed Energy ◽  
Third Phase ◽  
The Impact ◽  
Good Agreement

PE/PS blends have been extensively studied with the objective of improving their recycling. The objective of the present study was to investigate the effect of potential pollutants on properties of high density polyethylene (HDPE)/polystyrene (PS) plastic blends. The pollutants selected were a polar molecule of low molar mass, i.e. ethylene glycol, and an oil for engine which can be considered as less polar higher molar mass molecules. Such study can be considered for the recycling of polymer wastes from automotive applications. The compatibilizer used for PE/PS blends was a non-grafted Styrene-Ethylene Butene-Styrene copolymer (SEBS). Rheological properties, morphology and mechanical properties were analyzed. Study of the morphologies and of the mechanical properties shows that a small polar molecule such as ethylene glycol can form a third phase whereas an oil can improve compatibilization (lower diameter of the dispersed phase, better adhesion). Morphologies are in good agreement with mechanical behavior. For PE/PS blends, the lower adhesion due to the presence of ethylene glycol induced a decrease of the viscosity and absorbed energy. On the opposite, the presence of oil decreases the diameter of the dispersed phase, which leads to a significant improvement of the impact properties.

Collapse of Tubes Under Combined Bending and Axial Compression Loads

2018 ◽  
Author(s):  
Shan Jin ◽  
Shuai Yuan ◽  
Yong Bai
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Axial Compression ◽  
Local Buckling ◽  
Practical Application ◽  
Buckling Modes ◽  
Combined Loads ◽  
Bending Loads ◽  
Good Agreement

In practical application, pipelines will inevitably experience bending and compression during manufacture, transportation and offshore installation. The mechanical behavior of tubes under combined axial compression and bending loads is investigated using experiments and finite element method in this paper. Tubes with D/t ratios in the range of 40 and 97 are adopted in the experiments. Then, the ultimate loads and the local buckling modes of tubes are studied. The commercial software ABAQUS is used to build FE models to simulate the load-shortening responses of tubes under combined loads. The results acquired from the ABAQUS simulation are compared with the ones from verification bending experiment, which are in good agreement with each other. The models in this paper are feasible to analyze the mechanical properties of tubes under combined axial compression and bending loads. The related results may be of interest to the manufacture engineers.

A Refined Theory for Laminated Anisotropic, Cylindrical Shells

1974 ◽  
Vol 41 (2) ◽  
pp. 471-476 ◽  
Author(s):  
J. M. Whitney ◽  
C.-T. Sun
Keyword(s):  
Shear Deformation ◽  
Shell Theory ◽  
Theory Of Elasticity ◽  
Small Radius ◽  
Refined Theory ◽  
Normal Strain ◽  
Governing Equations ◽  
Transverse Normal Strain ◽  
Anisotropic Cylindrical Shell ◽  
Good Agreement

A set of governing equations and boundary conditions are derived which describe the static deformation of a laminated anisotropic cylindrical shell. The theory includes both transverse shear deformation and transverse normal strain, as well as expansional strains. The validity of the theory is assessed by comparing solutions obtained from the shell theory to results obtained from exact theory of elasticity. Reasonably good agreement is observed and both shear deformation and transverse normal strain are shown to be of importance for shells having a relatively small radius-to-thickness ratio.

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