Mechanical Properties of Ion-Irradiated Stainless Steel Determined by Nanoindentation Tests and Finite Element Analyses

2020 ◽  
Author(s):  
Jae Min Sim ◽  
Yoon-Suk Chang ◽  
Byeong Seo Kong ◽  
Changheui Jang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Test Data ◽  
Radiation Effects ◽  
Ion Irradiation ◽  
Nanoindentation Test ◽  
Finite Element Analyses ◽  
Stress Strain ◽  
Term Operation ◽  
Constitutive Parameters

Abstract While austenitic stainless steels (ASSs) have been widely adopted for reactor vessel internals because of their excellent material properties, diverse ageing-related degradation may occur due to high temperature, corrosive and neutron radiation environments during operation. In particular, since the change of mechanical properties is a major concern in long-term operation but it is difficult to prepare and handle standard specimens influenced by neutrons, most of experimental researches for enhanced understanding of the radiation effects have been focused on high-energetic ion-irradiation and tests of small specimens. In this study, systematic finite element analyses were carried out to quantify changing mechanical properties based on both virgin and ion-irradiated nanoindentation test data of typical ASS material. First of all, numerical analysis was carried out to obtain unirradiated material constitutive parameters by using trial set along the miniature specimen and comparing test data, and then indentation stress-strain (ISS) curve was derived. Subsequently, ISS was converted into uniaxial stress-strain response taking into account simple correlation. Finally, with regard to the irradiated material, similar analytical procedures were established. 304 SS was irradiated with 2 MeV proton and radioactivity is being measured. Comparison between analysis result and experimental one will be carried out, of which details and key findings will be discussed.

Three Types of Stress-Strain Relationship’s Comparison of Circular Tubed Reinforced Concrete in FEA

2012 ◽  
Vol 204-208 ◽  
pp. 930-933
Author(s):  
Xiao Hu ◽  
Zhen Lin Chen
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Uniaxial Stress ◽  
Steel Tube ◽  
Finite Element Analyses ◽  
Stress Strain ◽  
Concrete Filled Steel Tube ◽  
Bearing Analysis

The paper introduces 3 types of uniaxial stress-strain relationships of concrete filled steel tube by Pan Youguang, Susantha and Saenz, and performs finite element analyses of the axial strengths of 18 CTRC columns, studies the characters of three models, and comprises between the axial strengths from FEA and existed experiments. Results show these 3 types of model are all suitable for bearing analysis, but Pan’s model is more accurate.

scholarly journals Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Test Data ◽  
Element Model ◽  
Finite Element Models ◽  
Anisotropic Model ◽  
Material Models ◽  
Material Parameters ◽  
Constitutive Parameters

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.

Verification of Specimens for Low-Cycle Fatigue and Cyclic Plasticity Testing

1979 ◽  
Vol 101 (4) ◽  
pp. 321-327
Author(s):  
C. C. Schultz ◽  
H. M. Zien
Keyword(s):  
Finite Element ◽  
Low Cycle Fatigue ◽  
Cyclic Plasticity ◽  
Cycle Fatigue ◽  
Finite Element Analyses ◽  
Stress Strain ◽  
Inelastic Analysis ◽  
Analysis Methods ◽  
Strain Data

The results of inelastic finite element analyses of several uniaxial specimens used for low-cycle fatigue and cyclic plasticity testing are presented. The test specimens studied include both hourglass and uniform gage-type geometries. These results indicate that normally used hourglass specimens may significantly underestimate the strain for a given stress. Uniform gage specimens with commonly used length-to-diameter ratios are shown to provide adequate stress-strain data. Two extensively strain-gaged uniform gage specimens were tested to provide data to confirm the acceptability of the inelastic analysis methods.

Computational mechanical property determination of viscoelastic/plastic materials from nanoindentation creep test data

2009 ◽  
Vol 24 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
Jianjun Wang ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Test Data ◽  
Plastic Material ◽  
Test Method ◽  
Element Formulation ◽  
Unknown Parameters ◽  
Plastic Materials

Nanoindentation is a widely accepted test method for materials characterization. On account of the complexity of contact deformation behavior, design of parametric constitutive models and determination of the unknown parameters is challenging. To address the need for identification of mechanical properties of viscoelastic/plastic materials from nanoindentation data, a combined numerical finite element/optimization-based indentation modeling tool was developed, fully self-contained, and capable of running on a PC as a stand-alone executable program. The approach uses inverse engineering and formulates the material characterization task as an optimization problem. The model development consists of finite element formulation, viscoelastic/plastic material models, heuristic estimation to obtain initial solution boundaries, and a gradient-based optimization algorithm for fast convergence to extract mechanical properties from the test data. A four-parameter viscoelastic/plastic model is presented, then a simplified three-parameter model with more rapid convergence. The end result is a versatile tool for indentation simulation and mechanical property analysis.

Study on the Mechanical Properties of Sapphire by Numerical Simulation and Nanoindentation Technology

2009 ◽  
Vol 69-70 ◽  
pp. 103-107 ◽  
Author(s):  
Ke Hua Zhang ◽  
Dong Hui Wen ◽  
Tao Hong ◽  
Ju Long Yuan
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Plastic Region ◽  
Nanoindentation Test ◽  
Fe Modeling ◽  
The Finite Element Method ◽  
Simulation And Experiment ◽  
Abrasive Process

This paper presents a finite element (FE) modeling of the nanoindentation test of sapphire, in which the finite element method was employed to study the mechanical characteristic of sapphire under the nanoindentation process. The results demonstrated that the nanoindentation FE models were able to simulate the indentation loading-unloading curves of the sapphire. The load and unload displacement curves of the simulation and experiment results can match with each other well, and then the properties used in the simulation should be the actual properties of the sapphire. The Mises stress field distribution of the sapphire sample was calculated to reveal the alteration from elastic region to plastic region, which are useful for indentifying the ductile to brittle change in the sapphire abrasive process.

Improving Axle Performance

2013 ◽  
Author(s):  
Steven L. Dedmon ◽  
Jay M. Galbraith ◽  
James M. Pilch
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Finite Element ◽  
Corrosion Resistance ◽  
Analytical Methods ◽  
Surface Damage ◽  
Finite Element Analyses ◽  
Fretting Corrosion ◽  
Freight Car ◽  
Number Of Cycles

North American freight car axle performance is affected by load and number of cycles, fretting corrosion resistance, mitigation of surface damage and repair practices once damage has occurred. Manufacturers also affect axle performance through chemistry balance, melting practice, forging, and heat treatment and machining techniques. In this investigation, the authors describe several ways axle life has been improved by manufacturers and an assessment of each technique using appropriate analytical methods, including evaluation of mechanical properties and finite element analyses.

scholarly journals On the evaluation of mechanical properties of honeycombs by using finite element analyses

2015 ◽  
Vol 7 (3) ◽  
pp. 135-150 ◽  
Author(s):  
SOROHAN Stefan ◽  
◽  
SANDU Marin ◽  
CONSTANTINESCU Dan Mihai ◽  
SANDU Adriana Georgeta ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Finite Element Analyses

Determining Stress-Strain Behavior of Zr60Cu10Al15Ni15 Bulk Metallic Glass Using Object Oriented Finite Element Analysis

2017 ◽  
Vol 29 ◽  
pp. 1-8 ◽  
Author(s):  
Ketul Arvindbhai Patel ◽  
Ganesh R. Karthikeyan ◽  
S. Vincent
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Metallic Glass ◽  
Strain Analysis ◽  
Indentation Test ◽  
Object Oriented ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior

Determining mechanical properties of Bulk Metallic Glasses (BMGs) requires synthesizing of the alloys in bulk form. However obtaining metallic glass in bulk form is quite challenging due to its tendency towards crystallization. In such circumstances it is beneficial to determine the mechanical properties of materials using finite elemental analysis of microstructures. Thus, in the present investigation, using Object Oriented Finite Element Analysis (OOF2) software package, Stress-Strain analysis has been carried out on Zr60Cu10Al15Ni15 BMG to determine such mechanical properties. Specimen of Zr60Cu10Al15Ni15 BMG exhibiting three microstructurally distinct regions amorphous, partial crystalline and crystalline regions was used for this analysis. The Stress-Strain relationship have been estimated for each of the three distinct phases and the results are validated by determining the Modulus of Elasticity for all the phases and comparing it with the available experimental results from Nano-indentation test.

scholarly journals Effects of Flotage on Immersion Indentation Results of Bone Tissue: An Investigation by Finite Element Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Mingxing Zhou ◽  
Zunqiang Fan ◽  
Zhichao Ma ◽  
Yue Guo ◽  
Liguo Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Nanoindentation Test ◽  
Liquid Media ◽  
Depth Sensing ◽  
Element Analysis ◽  
Fea Simulation ◽  
The Difference

In reality, nanoindentation test is an efficient technique for probing the mechanical properties of biological tissue that soaked in the liquid media to keep the bioactivity. However, the effects of flotage imposed on the indenter will lead to inaccuracy when calculating mechanical properties (for instance, elastic modulus and hardness) by using depth-sensing nanoindentation. In this paper, the effects of flotage on the nanoindentation results of cortical bone were investigated by finite element analysis (FEA) simulation. Comparisons of nanoindentation simulation results of bone samples with and without being soaked in the liquid media were carried out. Conclusions show that the difference of load-displacement curves in the case of soaking sample and without soaking sample conditions varies widely based on the change of indentation depth. In other words, the nanoindentation measurements in liquid media will cause significant error in the calculated Young’s modules and hardness due to the flotage. By taking into account the effect of flotage, these errors are particularly important to the accurate biomechanics characterization of biological samples.

Refined FEM Analysis of 1000MW Generator Stator during Integral Transportation on Railway

2014 ◽  
Vol 1025-1026 ◽  
pp. 143-147
Author(s):  
Chun Ge Nie ◽  
Yue Dong Wang ◽  
Wen Zhong Zhao
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Load Condition ◽  
Fem Analysis ◽  
Numerical Results ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
The Third ◽  
Generator Stator

A new designed 1000MW generator stator was planned to be transported by DQ45 Schnabel car with end shield mode. In order to ensure the safety of transportation, three design schemes of end shield were proposed。In this paper, refined finite element models were established including frame of stator with different end shield, and nonlinear finite element analyses according to load condition of transportation on railway were performed subsequently. The numerical results indicated that load condition of structure could be improved significantly by using the third proposed end shield with tension bar, and the safety of transportation could be guaranteed. At last, the numerical results of the third scheme were compared with test data, and the reliability of finite element models was confirmed.

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