scholarly journals Microstructural, Surface Topology and Nanomechanical Characterization of Electrodeposited Ni-P/SiC Nanocomposite Coatings

2019 ◽  
Vol 9 (14) ◽  
pp. 2901 ◽  
Author(s):  
Konstantinos Tsongas ◽  
Dimitrios Tzetzis ◽  
Alexander Karantzalis ◽  
George Banias ◽  
Dimitrios Exarchos ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Computational Models ◽  
Intermetallic Phase ◽  
Three Dimensional ◽  
Surface Topology ◽  
Nanocomposite Coatings ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Heat Treated

In the present study, nickel phosphorous alloys (Ni-P) and Ni-P/ silicon carbide (SiC) nanocomposite coatings were deposited by electrodeposition on steel substrates in order for their microstructural properties to be assessed while using SEM, XRD, and three-dimensional (3D) profilometry as well as nanoindentation. The amorphisation of the as-plated coatings was observed in all cases, whereas subsequent heat treatment induced crystallization and Ni3P intermetallic phase precipitation. Examination of the surface topology revealed that the surface roughness follows the deposition characteristics and heat treatment induced microstructural changes. Additionally, substantial improvements in mechanical properties, including hardness, yield stress, and elasticity modulus, were obtained for the Ni-P, Ni-P/SiC nanocomposites when heat treated as seen from the nanoindentation results. A Finite Element Analysis (FEA) was developed to simulate the nanoindentation tests that enable the precise extraction of the Ni-P and Ni-P/SiC nanocomposite coatings’ stress-strain behavior. It is shown that the correlation between the nanoindentation tests and the computational models was satisfactory, while the stress-strain curves revealed higher yield points for the heat-treated samples.

scholarly journals Field Variable Associations With Scratch Orientation Dependence of UHMWPE Wear: A Finite Element Analysis

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Matthew C. Paul ◽  
Liam P. Glennon ◽  
Thomas E. Baer ◽  
Thomas D. Brown
Keyword(s):  
Finite Element ◽  
Computational Models ◽  
Three Dimensional ◽  
Element Model ◽  
Field Variable ◽  
Orientation Dependence ◽  
Normal Strain ◽  
Stress Strain ◽  
Element Analysis ◽  
Local Direction

Scratches on the metal bearing surface of metal-on-polyethylene total joint replacements have been found to appreciably accelerate abrasive/adhesive wear of polyethylene, and constitute a source of the considerable variability of wear rate seen within clinical cohorts. Scratch orientation with respect to the local direction of relative surface sliding is presumably a factor affecting instantaneous debris liberation during articulation. A three-dimensional local finite element model was developed, of orientation-specific polyethylene articulation with a scratched metal counterface, to explore continuum-level stress/strain parameters potentially correlating with the orientation dependence of scratch wear in a corresponding physical experiment. Computed maximum stress values exceeded the yield strength of ultra-high molecular weight polyethylene (UHMWPE) for all scratch orientations but did not vary appreciably among scratch orientations. Two continuum-level parameters judged most consistent overall with the direction dependence of experimental wear were (1) cumulative compressive total normal strain in the direction of loading, and (2) maximum instantaneous compressive total normal strain transverse to the sliding direction. Such stress/strain metrics could be useful in global computational models of wear acceleration, as surrogates to incorporate anisotropy of local metal surface roughening.

Determination of localized stress–strain behavior of fused silica: Inverse numerical analysis from nanoindentation test

2020 ◽  
pp. 146442072096703
Author(s):  
Suparat Bootchai ◽  
Nitikorn Noraphaiphipaksa ◽  
Nipon Taweejun ◽  
Anchalee Manonukul ◽  
Chaosuan Kanchanomai
Keyword(s):  
Mechanical Properties ◽  
Numerical Analysis ◽  
Three Dimensional ◽  
Fused Silica ◽  
Nanoindentation Test ◽  
Displacement Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Load Displacement

Because the localized mechanical properties of fused silica are unlikely to be obtained via conventional tensile testing, an inverse numerical analysis has been applied to deduce these properties using the load–displacement curve from nanoindentation testing. The mechanical properties were initially assumed, and the load–displacement curve was numerically simulated using three-dimensional elastic–plastic finite element analysis. The mechanical properties were adjusted until the numerical curve corresponded to the experimental curve, and then the localized mechanical properties in the vicinity of an indentation could be estimated. Unfortunately, the inverse numerical analysis requires time-consuming numerical calculation, involving many repetitions, by experienced researchers. In the present work, the influence of mechanical properties on the nanoindentation parameters of fused silica was evaluated, and the systematical adjustment of mechanical properties to obtain a satisfactory load–displacement curve has been proposed. It is considered that this procedure can be applied for the evaluation of localized stress–strain behavior of fused silica.

Improved Prediction Method for Estimating Notch Elastic-Plastic Strain

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Three Dimensional ◽  
Prediction Method ◽  
Inelastic Strain ◽  
Stress Concentrations ◽  
Stress Strain ◽  
Element Analysis ◽  
Simple Method ◽  
Elastic Plastic ◽  
Strain Behavior ◽  
Notch Stress

Notch stress-strain conversion (NSSC) rules are widely used to estimate nonlinear and history-dependent stress-strain behavior of the notch components or structures. This paper focuses on the estimation of stress and strain using the conventional NSSC rules and linear elastic analysis by considering the entire relaxation locus of the component during inelastic action. On the basis of local effects, net-section collapse, and reference stress, a simple method for estimating inelastic strain in the vicinity of stress concentrations is proposed. The accuracy of the method is compared with elastic-plastic finite element analysis for several notch configurations exhibiting two-dimensional and three-dimensional effects.

Cord/Rubber Material Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 830-856 ◽  
Author(s):  
R. J. Cembrola ◽  
T. J. Dudek
Keyword(s):  
Finite Element ◽  
Material Model ◽  
Rubber Composites ◽  
Stress Strain ◽  
Element Analysis ◽  
Rubber Layer ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Interlaminar Shear ◽  
Mechanics Of Composite Materials

Abstract Recent developments in nonlinear finite element methods (FEM) and mechanics of composite materials have made it possible to handle complex tire mechanics problems involving large deformations and moderate strains. The development of an accurate material model for cord/rubber composites is a necessary requirement for the application of these powerful finite element programs to practical problems but involves numerous complexities. Difficulties associated with the application of classical lamination theory to cord/rubber composites were reviewed. The complexity of the material characterization of cord/rubber composites by experimental means was also discussed. This complexity arises from the highly anisotropic properties of twisted cords and the nonlinear stress—strain behavior of the laminates. Micromechanics theories, which have been successfully applied to hard composites (i.e., graphite—epoxy) have been shown to be inadequate in predicting some of the properties of the calendered fabric ply material from the properties of the cord and rubber. Finite element models which include an interply rubber layer to account for the interlaminar shear have been shown to give a better representation of cord/rubber laminate behavior in tension and bending. The application of finite element analysis to more refined models of complex structures like tires, however, requires the development of a more realistic material model which would account for the nonlinear stress—strain properties of cord/rubber composites.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Hyperelastic Muscle Simulation

2007 ◽  
Vol 345-346 ◽  
pp. 1241-1244 ◽  
Author(s):  
Mohd. Zahid Ansari ◽  
Sang Kyo Lee ◽  
Chong Du Cho
Keyword(s):  
Skeletal Muscle ◽  
Silicone Rubber ◽  
Soft Tissues ◽  
Material Model ◽  
Incompressible Material ◽  
Material Behavior ◽  
Rubber Tube ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior

Biological soft tissues like muscles and cartilages are anisotropic, inhomogeneous, and nearly incompressible. The incompressible material behavior may lead to some difficulties in numerical simulation, such as volumetric locking and solution divergence. Mixed u-P formulations can be used to overcome incompressible material problems. The hyperelastic materials can be used to describe the biological skeletal muscle behavior. In this study, experiments are conducted to obtain the stress-strain behavior of a solid silicone rubber tube. It is used to emulate the skeletal muscle tensile behavior. The stress-strain behavior of silicone is compared with that of muscles. A commercial finite element analysis package ABAQUS is used to simulate the stress-strain behavior of silicone rubber. Results show that mixed u-P formulations with hyperelastic material model can be used to successfully simulate the muscle material behavior. Such an analysis can be used to simulate and analyze other soft tissues that show similar behavior.

Thermal Processing of Polycrystalline NiTi Shape Memory Alloys

2004 ◽  
Vol 855 ◽  
Author(s):  
Carl P. Frick ◽  
Alicia M. Ortega ◽  
Jeff Tyber ◽  
Ken Gall ◽  
Hans J. Maier ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Hot Rolling ◽  
Rolling Process ◽  
Heat Treatments ◽  
Treatment Temperature ◽  
Precipitate Size ◽  
Stress Strain ◽  
Transformation Temperatures ◽  
Strain Behavior

ABSTRACTThe objective of this study is to examine the effect of heat treatment on polycrystalline Ti-50.9 at.%Ni subsequent to hot-rolling. In particular we examine microstructure, transformation temperatures and mechanical behavior of deformation processed NiTi. The results constitute a fundamental understanding of the effect of heat treatment on thermal/stress induced martensite, which is critical for optimizing mechanical properties. The high temperature of the hot-rolling process caused recrystallization, recovery, and hindered precipitate formation, essentially solutionizing the NiTi. Subsequent heat treatments were carried out at various temperatures for 1.5 hours. Transmission Electron Microscopy (TEM) observations revealed that Ti3Ni4 precipitates progressively increased in size and changed their interface with the matrix from being coherent to incoherent with increasing heat treatment temperature. Accompanying the changes in precipitate size and interface coherency, transformation temperatures were observed to systematically shift, leading to the occurrence of the R-phase and multiple-stage transformations. Room temperature stress-strain tests illustrated a variety of mechanical responses for the various heat treatments, from pseudoelasticity to shape memory. The changes in stress-strain behavior are interpreted in terms of shifts in the primary martensite transformation temperatures, rather then the occurrence of the R-phase transformation. The results confirm that Ti3Ni4 precipitates can be used to elicit a desired isothermal stress-strain behavior in polycrystalline NiTi.

Thermomechanical Transient Analysis and Conceptual Optimization of a First Stage Bucket

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Alfonso Campos-Amezcua ◽  
Zdzislaw Mazur-Czerwiec ◽  
Armando Gallegos-Muñoz
Keyword(s):  
Transient Analysis ◽  
Computational Models ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Thermomechanical Analysis ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Calculated Stress ◽  
Three Dimensional Models ◽  
Almost All

This paper presents a thermomechanical analysis of a first stage bucket during a gas turbine startup. This analysis uses two simulation techniques, computational fluid dynamics (CFD) for the conjugate heat transfer and flow analysis, and finite element analysis (FEA) for the thermostructural analysis. Computational three-dimensional models were developed using two commercial codes, including all elements of the real bucket to avoid geometric simplifications. An interface was developed to transfer the three-dimensional behavior of bucket temperatures during turbine startup from CFD analysis to subsequent FEA analysis, imposing them as a thermal load. This interface virtually integrates the computational models, although they have different grids. The results of this analysis include temperature evolution and related stresses, as well as the thermomechanical stresses and zones where they are present. These stresses are dominated by thermal mechanisms, so a new temperature startup curve is proposed where the maximum calculated stress decline around 100 MPa, and almost all stresses are lower throughout the transient analysis. The results are compared with experimental data reported in the literature obtaining acceptable approximation.

Transverse Young's modulus of carbon/glass hybrid fiber composites

2019 ◽  
Vol 54 (7) ◽  
pp. 947-960
Author(s):  
Ganesh Venkatesan ◽  
Maximilian J Ripepi ◽  
Charles E Bakis
Keyword(s):  
Finite Element ◽  
Glass Fiber ◽  
Fiber Composites ◽  
Stress Model ◽  
Hybrid Fiber ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
The Matrix ◽  
Transverse Modulus

Hybrid fiber composites offer designers a means of tailoring the stress–strain behavior of lightweight materials used in high-performance structures. While the longitudinal stress–strain behavior of unidirectional hybrid fiber composites has been thoroughly evaluated experimentally and analytically, relatively little information is available on the transverse behavior. The objective of the current investigation is to present data on the transverse modulus of elasticity of unidirectional composites with five different ratios of carbon and glass fiber and to compare the data with predictive and fitted models. The transverse modulus increases monotonically with the proportion of glass fiber in the composite. Finite element analysis was used to evaluate different ways to model voids in the matrix and allowed the unknown transverse properties of the carbon fibers to be backed out using experimental data from the all-carbon composite. The finite element results show that the transverse modulus can be accurately modeled if voids are modeled explicitly in the matrix region and if modulus is calculated based on stress applied along the minimum interfiber distance path between adjacent fibers arranged in a rectangular array. The transverse modulus was under-predicted by the iso-stress model and was well predicted by a modified iso-stress model and a modified Halpin–Tsai model.

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