Assessment of Elastic–Plastic and Electrical Properties of Printed Silver-Based Interconnects for Flexible Electronics

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Hsien-Chie Cheng ◽  
Ruei-You Hong ◽  
Wen-Hwa Chen
Keyword(s):  
Electrical Properties ◽  
Dimensional Analysis ◽  
Flexible Electronics ◽  
Plastic Material ◽  
Electrical Performance ◽  
Plastic Properties ◽  
Solvent Content ◽  
Representative Strain ◽  
Elastic Plastic ◽  
Wide Range

In this work, the elastic–plastic properties of the printed interconnects on a glass substrate with Ag-filled polymer-conductor ink are evaluated through a theoretical framework based on finite element (FE) modeling of instrumented sharp indentation, experimental indentation, the concept of the representative strain, and dimensional analysis. Besides, the influences of the ink-solvent content and temperature on the elastic–plastic and electrical properties of the printed Ag-based interconnects are also addressed. First of all, parametric FE indentation analyses are carried out over a wide range of elastic–plastic material parameters. These parametric results together with the concept of the representative strain are used via dimensional analysis to constitute a number of dimensionless functions, and further the forward/reverse algorithms. The forward algorithm is used for describing the indentation load–depth relationship and the reverse for predicting the elastic–plastic parameters of the printed Ag-based interconnects. The proposed algorithms are validated through the correct predictions of the plastic properties of three known metals. At last, their surface morphology, microstructure, and elemental composition are experimentally characterized. Results show that the elastic–plastic properties and electrical sheet resistance of the printed Ag-based interconnects increase with the ink-solvent content, mainly due to the increase of carbon element as a result of the increased ink-solvent residue, whereas their elastic–plastic properties and electrical performance decreases with the temperature.

Determining Elastic-Plastic Properties of Al6061-T6 from Micro-Indentation Technique

2013 ◽  
Vol 592-593 ◽  
pp. 610-613
Author(s):  
Sina Amiri ◽  
Nora Lecis ◽  
Andrea Manes ◽  
Davide Mombelli ◽  
Marco Giglio
Keyword(s):  
Manufacturing Process ◽  
Optimization Procedure ◽  
Test System ◽  
Standard Test ◽  
Material Behavior ◽  
Plastic Properties ◽  
Representative Strain ◽  
Elastic Plastic ◽  
Dimensionless Analysis ◽  
Micro Indentation

Different approaches have been proposed in order to determine the material behavior of ductile materials. Since, the mechanical properties of a mechanical component are modified during manufacturing process due to plastic deformation, heat treatment and etc, a non-destructive indentation experimental procedure addressed to predict the elastic-plastic properties of material after manufacturing process is of interest. This is especially true for small size components where it is complex to extract specimens to test on standard test system. Based on dimensionless analysis and the concept of a representative strain, different approaches have been proposed to determine the material properties of power law materials by using indentation process. In this work, the Johnson-Cook (JC) constitutive model of the aluminum alloy Al6061-T6 is characterized by means of a well-defined optimization procedure based on micro-indentation testing and high fidelity finite element models and an optimization procedure but without the concept of dimensionless analysis and a representative strain. This methodology allows determining a set of JC constants for Al6061-T6. The obtained results have good agreement with parameters calibrated by means of universal standard tests and reverse engineering approach.

A combined dimensional analysis and optimization approach for determining elastic–plastic properties from indentation tests

2011 ◽  
Vol 46 (8) ◽  
pp. 749-759 ◽  
Author(s):  
J J Kang ◽  
A A Becker ◽  
W Sun
Keyword(s):  
Mechanical Properties ◽  
Dimensional Analysis ◽  
Optimization Procedure ◽  
Fe Analysis ◽  
Optimization Approach ◽  
Fe Method ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Indentation Tests ◽  
Extensive Computation

Loading–unloading curves obtained from indentation experiments can be used to extract elastic-plastic mechanical properties using the finite element (FE) method. However, extensive computation times are required in such an approach due to the fact that the optimization procedure is based on iterative FE computations. In this study, a combined dimensional analysis and optimization approach is developed for the determination of the elastic-plastic mechanical properties of power law materials, without the need for iterative FE analysis. A parametric study using FE analysis is first conducted to construct the appropriate dimensional functions. The optimization algorithm with either a single indenter or dual indenters is then used to obtain the material properties from the given loading–unloading curves. Different sets of materials properties are used and the accuracy and validity of the predicted mechanical properties using the single indenter or dual indenters are assessed.

Magnetomechanical Instabilities in Elastic-Plastic Cylinders, Part II: Plastic Response

1996 ◽  
Vol 63 (3) ◽  
pp. 742-749 ◽  
Author(s):  
D. L. Littlefield
Keyword(s):  
Electric Current ◽  
Plastic Flow ◽  
Plastic Material ◽  
Yield Criterion ◽  
Confining Pressure ◽  
Constitutive Law ◽  
Linear Perturbation ◽  
Uniform Motion ◽  
Elastic Plastic ◽  
Wide Range

The analysis of elastic instabilities in metal cylinders when subjected to electromagnetic fields (Littlefield, 1996a) is extended in this work to include elastic-plastic flow. The cylinder is assumed to be infinitely long and perfectly conducting. The Prandtl-Reuss elastic-plastic material model is the assumed constitutive law, with the von Mises yield criterion employed to limit the effective stress. An axial electric current, assumed to be conducting along the surface of the cylinder, generates a confining pressure, causing plastic flow that is initially assumed to be uniform throughout the cross section. The propagation of small axisymmetric disturbances to this uniform motion is studied by applying linear perturbation theory. Solutions to these equations exhibit a wide range of instability modes, as was the case for the purely elastic results, and the frequency of the oscillating disturbances appears to be suppressed by electromagnetic effects. However, in contrast to the elastic result, no threshold magnetic field exists, and distending instabilities are possible for all levels of electric current. Physical mechanisms resulting in these distinctions are suggested.

Scale Effects on Contact Deformation of Elastic-Plastic Solids

2005 ◽  
Author(s):  
K. Komvopoulos
Keyword(s):  
Scale Effects ◽  
Plastic Material ◽  
Discrete Models ◽  
Contact Deformation ◽  
Roughness Effects ◽  
Length Scales ◽  
Elastic Plastic ◽  
Wide Range ◽  
Asperity Contacts ◽  
Interacting Surfaces

Surface roughness effects result in asperity contacts spanning a wide range of length scales. In view of the multi-scale roughness of real surfaces, contact deformation of solid bodies exhibits strong scale dependence. Therefore, it is essential that contact mechanics analyses account for the evolution of deformation over a range of length scales, similar to that of the wavelengths comprising the topographies of the interacting surfaces. Results from finite element method (FEM) and molecular dynamics (MD) analyses based on continuum and discrete models of the interacting solids, respectively, reveal important effects of topography, length parameters (e.g., indenter tip radius, coating thickness, and penetration depth), surface traction, and elastic-plastic material properties on the deformation behavior at different length scales.

An energy-based method to extract plastic properties of metal materials from conical indentation tests

2005 ◽  
Vol 20 (5) ◽  
pp. 1194-1206 ◽  
Author(s):  
Yan Ping Cao ◽  
Xiu Qing Qian ◽  
Jian Lu ◽  
Zhen Han Yao
Keyword(s):  
Stable Solution ◽  
Strain Hardening Exponent ◽  
Simple Method ◽  
Plastic Properties ◽  
Representative Strain ◽  
Plastic Materials ◽  
Wide Range ◽  
Indentation Tests ◽  
Elastoplastic Materials ◽  
Conical Indentation

Based on dimensional analysis and finite element computations, an energy-based representative strain for conical indentation in elastoplastic materials has been proposed to establish an explicitly one-to-one relationship between the representative stress σr, the indentation loading curvature C, and the ratio of reversible work We to total work Wt performed by the indenter, i.e., σr/C = F0(We/Wt), where σr is the flow stress corresponding to the representative strain. The relationship provides a very simple method to evaluate the representative stress σr from the three directly measurable quantities We, Wt, and C. Numerical examples and further theoretical analysis reveal that a unique, stable solution can be obtained from the present method for a wide range of material properties, including both highly plastic materials (e.g., Ni for which E/σy = 1070) and highly elastic materials (e.g., materials for which E/σy = 25 and n = 0.5), using indenters with different tip apex angles. Based on the representative strains and stresses given by two indenters with different tip apex angles, e.g., (σr,80, ϵr,80) and (σr,65, ϵr,65), the plastic properties of materials, i.e., the yield strength σy and strain hardening exponent n can be further determined.

Capacitor Characterization Study for a High Power, High Frequency Converter Application

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000174-000181
Author(s):  
William C. Lanter ◽  
Hiroyuki Kosai ◽  
Tyler Bixel ◽  
B. Allen Tolson ◽  
Jeffery Stricker ◽  
...  
Keyword(s):  
Electrical Properties ◽  
High Power ◽  
High Frequency ◽  
Frequency Converter ◽  
Electrical Performance ◽  
Element Analysis ◽  
Device Architecture ◽  
Select Group ◽  
Wide Range ◽  
Simulation Input

Recent advances in SiC power devices and high temperature magnetic and insulation materials has led to an increase in activity to develop compact, high switch rate power system components that can operate at temperatures in excess of 200°C. These efforts have highlighted the need to develop capacitor technology for high power, high frequency power filter applications, which can experience cycling over a wide range of temperature (−55 °C to 250 °C). A modeling and simulation capability was used to investigate device architecture and electrical performance relationships for a select group of wound and stacked devices, which were then evaluated for use in a power conditioning application. A finite element analysis of the device architectures was used to develop a better understanding of how magnetic fields and thermal profiles affect the performance of the capacitors in maintaining a low ripple voltage at high switch rates (>20 kHz). Both predicted electrical properties and empirical data were utilized as SPICE simulation input parameters to evaluate the performance of the different capacitors in an interleaved DC-DC boost converter model. Of interest is developing a better understanding of how the device architecture and its electrical properties affect its performance as a filtering device in a high power, high frequency application.

Masonry: the brittle or plastic material?

2019 ◽  
pp. 22-28
Keyword(s):  
Plastic Material ◽  
Experimental Studies ◽  
Point Of View ◽  
Plastic Properties ◽  
Plastic Deformations ◽  
Base Materials ◽  
Stress States ◽  
Creep Deformations ◽  
Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

Linear electrical properties of striated muscle fibres observed with intracellular electrodes

1964 ◽  
Vol 160 (978) ◽  
pp. 69-123 ◽  
Keyword(s):  
Electrical Properties ◽  
Striated Muscle ◽  
Surface Membrane ◽  
Fibre Surface ◽  
Step Function ◽  
Muscle Fibres ◽  
Appreciable Effect ◽  
Current Application ◽  
Current Path ◽  
Wide Range

The linear electrical properties of muscle fibres have been examined using intracellular electrodes for a. c. measurements and analyzing observations on the basis of cable theory. The measurements have covered the frequency range 1 c/s to 10 kc/s. Comparison of the theory for the circular cylindrical fibre with that for the ideal, one-dimensional cable indicates that, under the conditions of the experiments, no serious error would be introduced in the analysis by the geometrical idealization. The impedance locus for frog sartorius and crayfish limb muscle fibres deviates over a wide range of frequencies from that expected for a simple model in which the current path between the inside and the outside of the fibre consists only of a resistance and a capacitance in parallel. A good fit of the experimental results on frog fibres is obtained if the inside-outside admittance is considered to contain, in addition to the parallel elements R m = 3100 Ωcm 2 and C m = 2.6 μF/cm 2 , another path composed of a resistance R e = 330 Ωcm 2 in series with a capacitance C e = 4.1 μF/cm 2 , all referred to unit area of fibre surface. The impedance behaviour of crayfish fibres can be described by a similar model, the corresponding values being R m = 680 Ωcm 2 , C m = 3.9 μF/cm 2 , R e = 35 Ωcm 2 , C e = 17 μF/cm 2 . The response of frog fibres to a step-function current (with the points of voltage recording and current application close together) has been analyzed in terms of the above two-time constant model, and it is shown that neglecting the series resistance would have an appreciable effect on the agreement between theory and experiment only at times less than the halftime of rise of the response. The elements R m and C m are presumed to represent properties of the surface membrane of the fibre. R e and C e are thought to arise not at the surface, but to be indicative of a separate current path from the myoplasm through an intracellular system of channels to the exterior. In the case of crayfish fibres, it is possible that R e (when referred to unit volume) would be a measure of the resistivity of the interior of the channels, and C e the capacitance across the walls of the channels. In the case of frog fibres, it is suggested that the elements R e , C e arise from the properties of adjacent membranes of the triads in the sarcoplasmic reticulum . The possibility is considered that the potential difference across the capacitance C e may control the initiation of contraction.

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