Determination of the Flow Stress–Strain Curves of Aluminum Alloy and Tantalum Using the Compressive Load–Displacement Curves of a Hat-Type Specimen

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Jae-Ha Lee ◽  
Hyunho Shin ◽  
Jong-Bong Kim ◽  
Ju-Young Kim ◽  
Sung-Taek Park ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Compressive Load ◽  
Type Specimen ◽  
Displacement Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Optimization Function ◽  
Load Displacement ◽  
Constitutive Parameters

The load–displacement curves of an aluminum alloy and tantalum were determined using a hat-type specimen in the compression test. Based on the results of finite element analysis, the employed geometry of the hat-type specimen was found to yield a load–displacement curve that is nearly independent of the friction between the specimen and the platen. The flow stress–strain curves of the alloy and tantalum were modeled using the Ludwik and Voce constitutive laws, respectively; furthermore, simulation of the compression event of the hat-type specimen was performed by assuming appropriate constitutive parameters. The constitutive parameters were varied via an optimization function built in matlab until the simulated load–displacement curves reasonably fit the experimental curve. The optimized constitutive parameters obtained in this way were then used to construct friction-free flow stress–strain curves of the two materials.

Estimation of transverse tensile behavior of Zircaloy pressure tubes using ring-tensile test and finite element analysis

2012 ◽  
Vol 227 (6) ◽  
pp. 1177-1186 ◽  
Author(s):  
MK Samal ◽  
KS Balakrishnan ◽  
J Parashar ◽  
GP Tiwari ◽  
S Anantharaman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Tests ◽  
Tensile Specimen ◽  
Displacement Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Transverse Tensile ◽  
Pressure Tubes ◽  
Load Displacement

Determination of transverse mechanical properties from the ring type of specimens directly machined from the nuclear reactor pressure tubes is not straightforward. It is due to the presence of combined membrane as well as bending stresses arising in the loaded condition because of the curvature of the specimen. These tubes are manufactured through a complicated process of pilgering and heat treatment and hence, the transverse properties need to be determined in the as-manufactured condition. It may not also be possible to machine small miniaturized specimen in the circumferential direction especially in the irradiated condition. In this work, we have performed ring-tensile tests on the un-irradiated ring tensile specimen using two split semi-cylindrical mandrels as the loading device. A three-dimensional finite element analysis was performed in order to determine the material true stress–strain curve by comparing experimental load–displacement data with those predicted by finite element analysis. In order to validate the methodology, miniaturized tensile specimens were machined from these tubes and tested. It was observed that the stress–strain data as obtained from ring tensile specimen could describe the load–displacement curve of the miniaturized flat tensile specimen very well. However, it was noted that the engineering stress–strain as directly obtained from the experimental load–displacement curves of the ring tensile tests were very different from that of the miniaturized specimen. This important aspect has been resolved in this work through the use of an innovative type of 3-piece loading mandrel.

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.

scholarly journals Stress-Softening in Particle-Filled Polyurethanes under Cyclic Compressive Loading

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1588
Author(s):  
Wenshuai Xu ◽  
Mangong Zhang ◽  
Yu Liu ◽  
Hao Zhang ◽  
Meng Chen ◽  
...  
Keyword(s):  
Compressive Loading ◽  
Compressive Load ◽  
Soft Materials ◽  
Constitutive Parameter ◽  
Spherical Indentation ◽  
Mullins Effect ◽  
Stress Softening ◽  
Loading And Unloading ◽  
Load Displacement ◽  
Constitutive Parameters

Elastomer compositions containing various particulate fillers can be formulated according to the specific functions required of them. Stress softening—which is also known as the Mullins effect—occurs during high loading and unloading paths in certain supramolecular elastomer materials. Previous experiments have revealed that the load–displacement response differs according to the filler used, demonstrating an unusual model of correspondence between the constitutive materials. Using a spherical indentation method and numerical simulation, we investigated the Mullins effect on polyurethane (PU) compositions subjected to cyclic uniaxial compressive load. The PU compositions comprised rigid particulate fillers (i.e., nano-silica and carbon black). The neo-Hooke model and the Ogden–Roxburgh Mullins model were used to describe the nonlinear deformation behavior of the soft materials. Based on finite element methods and parameter optimization, the load–displacement curves of various filled PUs were analyzed and fitted, enabling constitutive parameter prediction and inverse modeling. Hence, correspondence relationships between material components and constitutive parameters were established. Such relationships are instructive for the preparation of materials with specific properties. The method described herein is a more quantitative approach to the formulation of elastomer compositions comprising particulate fillers.

scholarly journals An Improved Johnson–Cook Constitutive Model and Its Experiment Validation on Cutting Force of ADC12 Aluminum Alloy During High-Speed Milling

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1038
Author(s):  
Xinxin Meng ◽  
Youxi Lin ◽  
Shaowei Mi
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Constitutive Model ◽  
Strain Rate ◽  
Cutting Force ◽  
High Speed ◽  
Cutting Speed ◽  
Experimental Results ◽  
Element Analysis

Because of the massive work and high cost of milling experiments, finite element analysis technology (FEA) was used to analyze the milling process of ADC12 aluminum alloy. An improved Johnson–Cook (J–C) constitutive equation was fitted by a series of dynamic impact tests in different strain rates and temperatures. It found that the flow stress gradually increases as the strain rate rises, but it decreases as the test temperature rises. Compared with the J–C constitutive model, the predicted flow stress by the improved J–C constitutive model was closer to the experimental results when the strain rate was larger than 8000 s−1 and the temperature was higher than 300 °C. A two-dimensional cycloidal cutting simulation model was constructed based on the two J–C constitutive equations which was validated by milling experiments at different cutting speeds. The simulation results based on the improved J–C constitutive equation were closer to the experimental results and showed the cutting force first increased and then decreased, with cutting speed increasing, reaching a maximum at 600 m/min.

Establishment of Stress-Strain Relationships of Tailor-Welded Tubes via DIC Method Based on Uniaxial Tensile Tests

2014 ◽  
Vol 611-612 ◽  
pp. 475-482 ◽  
Author(s):  
Hui Ji Jia ◽  
Lian Fa Yang ◽  
Jian Wei Liu
Keyword(s):  
Image Correlation ◽  
Uniaxial Tensile ◽  
Displacement Curve ◽  
Stress Strain ◽  
Material Parameters ◽  
Rule Of Mixtures ◽  
Strain Relationship ◽  
Load Displacement ◽  
Relationship Of ◽  
Strain Method

Tailor-welded tubes are widespread in aircraft and automotive industries due to their advantages of low cost, reduction in part weight and flexibility in mass production. It is necessary to obtain the stress-strain relationship of tailor-welded tubes to study deformation behaviors of tubes and simulate deformation tests of tubes. Then a method via digital image correlation (DIC) method based on uniaxial tensile test (UTT) is proposed in this paper to establish stress-strain relationship of tailor-welded tubes. Material parameters of tailor-welded tubes obtained from three methods, i.e. the method based on UTT, the iso-strain method based on a rule of mixtures and the proposed method, were compared in this paper. To assess the accuracy of material parameters obtained from these three methods, UTTs were simulated, and load-displacement curves and maximal loads obtained from simulations were compared with those obtained from UTTs. In simulations of UTTs, finite element models of specimens of sole parent metal and mixed specimens were established, respectively. The results show that: When HAZ included in the specimen has large proportion of the specimen, the proposed method is more reliable than the iso-strain method based on a rule of mixtures on determining the material parameters of the weld; load-displacement curve and maximal load obtained from the proposed method are more close to those obtained from UTT than those obtained from the method based on UTT.

Different Force Conditions on Nonlinear Finite Element Analysis of Small Concrete Hollow Block Wall with Failure Modes of Influence

2013 ◽  
Vol 788 ◽  
pp. 602-605
Author(s):  
Hong Yi Chen ◽  
Fu Ma
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Modes ◽  
Failure Pattern ◽  
Displacement Curve ◽  
Relative Deformation ◽  
Element Analysis ◽  
Block Wall ◽  
Load Displacement ◽  
Bending Failure

This paper mainly studies small hollow concrete block wall sets a certain level of reinforcement, vertical bar, core column and high aspect ratio, vertical and horizontal load, changes in load point height wall by shear form and bending failure pattern changes and shear capacity and flexural capacity. Nonlinear analysis simulation using ANSYS finite element analysis software of the specimen, mainly analysis and predict the failure modes of the different loading conditions wall. Obtained by calculating the failure pattern of the specimen, the load-displacement curve, the various stages of the load-displacement values and calculated the relative deformation and ductility factor of the wall under various loading height. Comparative analysis of the load-displacement curve variation of the shear failure and bending failure form, draw the conclusion that bending failure energy consumption better performance.

Design of uni-axially loaded components fabricated from tough fibre-reinforced ceramic matrix composites

1991 ◽  
Vol 434 (1891) ◽  
pp. 383-397 ◽  
Keyword(s):  
Damage Mechanics ◽  
Strain Curve ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Stress Redistribution ◽  
Tension Stress ◽  
Displacement Curve ◽  
Stress Strain ◽  
Approximate Methods ◽  
Load Displacement

A simple model for the stress-strain behaviour of a tough fibre-reinforced ceramic matrix composite, based on a single continuum damage mechanics parameter, has been used to study the behaviour of two kinematically determinate, one-dimensional, structures. The structures have been chosen to represent a class of components in which the fibre axes coincide predominantly with the maximum principal tension stress direction. It has been shown that the damage evolution due to the monotonic application of load results in stress redistribution, and that the load displacement characteristics of the structures reflect the characteristics of the stress—strain curve. The size of the predominant load bearing section influences the stress redistribution and hence the smoothness of the load-displacement curve. Approximate methods, based on the concepts of representative materials and structures, have been developed for the rapid prediction of the load-displacement characteristics which can be used at the early, or conceptual, stages of design.

scholarly journals Stress-Strain Compression of AA6082-T6 Aluminum Alloy at Room Temperature

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alexandre da Silva Scari ◽  
Bruno Cesar Pockszevnicki ◽  
Jánes Landre Junior ◽  
Pedro Americo Almeida Magalhaes Junior
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Room Temperature ◽  
Fe Analysis ◽  
Damage Analysis ◽  
Compression Tests ◽  
Stress Strain ◽  
Element Analysis ◽  
Real Value ◽  
Hollomon Equation

Short cylindrical specimens made of AA6082-T6 aluminum alloy were studied experimentally (compression tests), analytically (normalized Cockcroft-Latham criteria—nCL), and numerically (finite element analysis—FEA). The mechanical properties were determined with the stress-strain curves by the Hollomon equation. The elastic modulus obtained experimentally differs from the real value, as expected, and it is also explained. Finite element (FE) analysis was carried out with satisfactory correlation to the experimental results, as it differs about 1,5% from the damage analysis by the nCL concerning the experimental data obtained by compression tests.

Constitutive Equations for 6061 Aluminum Alloy at Elevated Temperature

2017 ◽  
Vol 898 ◽  
pp. 387-391
Author(s):  
Zhi Shen
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Constitutive Equations ◽  
Type Equation ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Stress Strain ◽  
6061 Aluminum Alloy ◽  
Gleeble 3500

Isothermal compression tests were conducted on 6061 aluminum alloy using a Gleeble-3500 thermal simulator under constant strain rates and at deformation temperatures ranging from 623 to 773K, up to a 60% height reduction of the sample. The high temperature deformation behavior of 6061 aluminum alloy was characterized based on an analysis of the stress-strain curves. A set of constitutive equations for 6061 aluminum alloy were proposed by employing an Arrhenius-type equation. Material constants, A, n and activation energy Q were found to be functions of strain. The equations revealed the dependence of flow stress on strain, strain rate and temperature. In order to evaluate the accuracy of the deformation constitutive equations, the mean errors of flow stress between the experimental data and predicted results were plotted. The results showed that the predicted data agreed well with the experimental stress-strain curves.

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