scholarly journals Validation of Stainless-Steel CHS Columns Finite Element Models

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1785
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala

Stainless-steel elements are increasingly used in a wide range of load-bearing structures due to their strength, minimal maintenance requirements, and aesthetic appearance. Their response differs from standard steels; therefore, it is necessary to choose a different procedure when creating a correct computational model. Seven groups of numerical models differing in the used formulation of elements integration, mesh density localization, nonlinear material model, and initial geometric imperfection were calibrated. The results of these advanced simulations were validated with published results obtained by an extensive experimental approach on circular hollow sections columns. With regard to the different slenderness of the cross-sections, the influence of the initial imperfection in the form of global and local loss of stability on the response was studied. Responses of all models were validated by comparing the averaged normalized ultimate loads and the averaged normalized deflections with experimentally obtained results.

2021 ◽  
Vol 1203 (3) ◽  
pp. 032048
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala

Abstract The subject of this article is the implementation of new knowledge on material and geometric characteristics obtained from an experimental research program in advanced numerical modelling of compressed columns made of austenitic stainless steel using the ANSYS Classic software. Nonlinear stress–strain curves were obtained using our own experimental program and studied in terms of identifying the most suitable nonlinear material model. Additional material and geometric characteristics were obtained from literature and other independent research. Numerical models differing in mesh density localization, formulation of element integration, non-linear material model, and initial geometric imperfections were created and compared. The aim of the models was the ultimate limit state of a strut of circular hollow cross-section stressed by compression and analysed using the geometrically and materially nonlinear solution with consideration to the influence of initial imperfections. Static resistance and limit state deformations are compared for each model. The paper presents the analysis of model uncertainty by comparing SHELL and SOLID FE models, which must be characterized before the start of the analysis of the random influence of imperfections on the limit states. The mean values and the coefficients of variation are practically the same for both approaches. In summary, the presented models can be considered sufficiently validated and eligible for integration in tandem with simulation sampling methods.


2015 ◽  
Vol 769 ◽  
pp. 331-335
Author(s):  
Jakub Vasek ◽  
Oldrich Sucharda

The paper compares the numerical models of and experiments with a beam. The purpose is to evaluate the nonlinear material model of a steel structure. The steel is modelled as an ideal elastic-plastic material. The FEM and eight-node isoparametric finite elements are considered in the analysis. The 3D calculations use different material constants and several approaches are being tested in order to create the computational models. The calculations are performed in the software application developed by our university.


Author(s):  
Mohammad Anwar-Us-Saadat ◽  
Shameem Ahmed ◽  
Mahmud Ashraf

The design philosophy of stainless steel requires appropriate recognition of observed material nonlinearity and pronounced strain hardening. A rational method namely, the Continuous Strength Method (CSM) has recently been to incorporate these effects but, in its current form, CSM yields better results for stocky sections. Individual capacities (i.e., pure compression and pure bending) for all types of sections and cross-section resistance against combined loading (i.e. compression plus bending) for RHS and I-sections can be predicted using CSM. The current research numerically investigates the performance of stainless steel lipped channel (LC) sections subjected to compression and bending. Nonlinear finite element models are developed and validated using available experimental results, and are consequently used to generate additional results for a wide range of cross-sections through parametric studies. Current CSM guidelines are used to propose a new set of formulations for predicting the section resistance of lipped channel sections subjected to combined loading.


2016 ◽  
Vol 853 ◽  
pp. 301-305
Author(s):  
Shameem Ahmed ◽  
Mahmud Ashraf ◽  
Mohammad Anwar-Us-Saadat

Structural stainless steel design guidelines should appropriately recognise its characteristic beneficial properties such as material nonlinearity and significant strain hardening. The Continuous Strength Method (CSM) exploits those through a strain based approach for both stocky and slender cross-sections. In this paper, a new design method is proposed that combines the CSM with Perry type buckling curves. Numerical models were developed to investigate effects of various parameters on column strength and to develop full column curves. It was observed that material nonlinearity significantly influence column strengths, and hence, different column curves were developed for a total of 20 material property combinations by calibrating imperfection factor and limiting slenderness ratio for each set. Proposed method includes the strain hardening benefits for stocky section, and abolished the necessity of calculating effective cross-sectional properties for slender sections. Performance of the proposed technique is compared against those obtained by the Eurocode EN1993-1-4.


2019 ◽  
Vol 292 ◽  
pp. 140-145
Author(s):  
Pavlina Mateckova ◽  
Lucie Mynarzova ◽  
Oldrich Sucharda ◽  
Vlastimil Bilek

This paper deals with analysis of set of reinforced concrete beams. Loading experiments of these beams were carried out and the results were documented and published earlier. Experiments involve several variants of spans, cross-sections and reinforcement so that various modes of failure of reinforced concrete structures are achieved. This paper compares the resistance of particular beams defined according to valid standard Eurocode 2 with non-linear analysis using advanced spatial 3D numerical models Cementitious material model based on fracture mechanics implemented in ATENA software. This paper outlines the wider evaluation of failure mode of beam and comparison of different calculations of resistance of the cross-section.


2019 ◽  
Vol 809 ◽  
pp. 493-499 ◽  
Author(s):  
Dominik Schneider ◽  
Axel Schumacher ◽  
Tobias Donhauser ◽  
Alexander Huf ◽  
Sebastian Schmeer

The design process of fiber-reinforced plastics (FRP) is a challenging task, especially concerning passenger vehicles in crashworthiness applications where manufacturing limitations and requirements regarding passive safety have to be considered. Numerical optimization can be a helpful tool during the design process, but most available methods are not applicable because analytical sensitivities are not available in crash simulations. The Graph and Heuristic based Topology Optimization (GHT) can be utilized to optimize the topology of cross-sections of crashworthiness structures while fulfilling a wide range of manufacturing constraints, but it has to be extended for composites. Since the topology changes during optimization runs, the stress state changes as well. This demands high predictive capabilities on the material model. This paper presents the necessary adjustments to describe composite profile structures within the GHT method. A commercial material model for LS-Dyna is parameterized and used for the calculation process.


2019 ◽  
Vol 8 (11) ◽  
pp. 507 ◽  
Author(s):  
Arseni ◽  
Voiculescu ◽  
Georgescu ◽  
Iticescu ◽  
Rosu

Bathymetric measurements play an important role in assessing the sedimentation rate, deposition of pollutants, erosion rate, or monitoring of morphological changes in a river, lake, or accumulation basin. In order to create a coherent and continuous digital elevation model (DEM) of a river bed, various data interpolation methods are used, especially when single-beam bathymetric measurements do not cover the entire area and when there are areas which are not measured. Interpolation methods are based on numerical models applied to natural landscapes (e.g., meandering river) by taking into account various morphometric and morphologies and a wide range of scales. Obviously, each interpolation method, used in standard or customised form, yields different results. This study aims at testing four interpolation methods in order to determine the most appropriate method which will give an accurate description of the riverbed, based on single-beam bathymetric measurements. The four interpolation methods selected in the present research are: inverse distance weighting (IDW), radial basis function (RBF) with completely regularized spline (CRS) which uses deterministic interpolation, simple kriging (KRG) which is a geo-statistical method, and Topo to Raster (TopoR), a particular method specifically designed for creating continuous surfaces from various elevation points, contour, or polygon data, suitable for creating surfaces for hydrologic analysis. Digital elevation models (DEM’s) were statistically analyzed and precision and errors were evaluated. The single-beam bathymetric measurements were made on the Siret River, between 0 and 35 km. To check and validate the methods, the experiment was repeated for five randomly selected cross-sections in a 1500 m section of the river. The results were then compared with the data extracted from each elevation model generated with each of the four interpolation methods. Our results show that: 1) TopoR is the most accurate technique, and 2) the two deterministic methods give large errors in bank areas, for the entire river channel and for the particular cross-sections.


2011 ◽  
Vol 50-51 ◽  
pp. 599-604 ◽  
Author(s):  
X.Y. Kou ◽  
S.T. Tan ◽  
Hod Lipson

Driven by the wide range of new material properties offered by multi-material 3D printing, there is emerging need to create predictive material models for these materials. A data driven process for estimating nonlinear material model is presented in this paper. In contrast with classical methods which derive the engineering stress-strain relationship assuming constant cross-section area and fixed length of a specimen, the proposed approach takes full advantage of 3D geometry of the specimen to estimate the material models. Give a hypothetical material model, virtual tensile tests are performed using Finite Element Analysis (FEA) method, and the parameters of the material model are estimated by minimizing the discrepancies of the virtual responses and the experimental results. The detailed material models, numerical algorithms as well as the optimization approaches are presented and finally preliminary results are offered.


Author(s):  
John J. Friel

Committee E-04 on Metallography of the American Society for Testing and Materials (ASTM) conducted an interlaboratory round robin test program on quantitative energy dispersive spectroscopy (EDS). The test program was designed to produce data on which to base a precision and bias statement for quantitative analysis by EDS. Nine laboratories were sent specimens of two well characterized materials, a type 308 stainless steel, and a complex mechanical alloy from Inco Alloys International, Inconel® MA 6000. The stainless steel was chosen as an example of a straightforward analysis with no special problems. The mechanical alloy was selected because elements were present in a wide range of concentrations; K, L, and M lines were involved; and Ta was severely overlapped with W. The test aimed to establish limits of precision that could be routinely achieved by capable laboratories operating under real world conditions. The participants were first allowed to use their own best procedures, but later were instructed to repeat the analysis using specified conditions: 20 kV accelerating voltage, 200s live time, ∼25% dead time and ∼40° takeoff angle. They were also asked to run a standardless analysis.


Alloy Digest ◽  
1982 ◽  
Vol 31 (6) ◽  

Abstract Type HN is an iron-chromium-nickel alloy containing sufficient chromium for good high-temperature corrosion resistance and with nickel content in excess of the chromium. This alloy has properties somewhat similar to the more widely used ACI Type HT alloy but with better ductility. Type HN is used for highly stressed components in the 1800-2000 F temperature range. It is used in the aircraft, automotive, petroleum, petrochemical and power industries for a wide range of components and parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: SS-410. Producer or source: Various stainless steel casting companies.


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