scholarly journals Large Deformation Finite Element Analyses for 3D X-ray CT Scanned Microscopic Structures of Polyurethane Foams

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 949
Author(s):  
Makoto Iizuka ◽  
Ryohei Goto ◽  
Petros Siegkas ◽  
Benjamin Simpson ◽  
Neil Mansfield
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Foam Cell ◽  
Parent Material ◽  
Polyurethane Foams ◽  
Compression Tests ◽  
Polymer Foam ◽  
Element Analysis ◽  
X Ray ◽  
Wide Range

Polyurethane foams have unique properties that make them suitable for a wide range of applications, including cushioning and seat pads. The foam mechanical properties largely depend on both the parent material and foam cell microstructure. Uniaxial loading experiments, X-ray tomography and finite element analysis can be used to investigate the relationship between the macroscopic mechanical properties and microscopic foam structure. Polyurethane foam specimens were scanned using X-ray computed tomography. The scanned geometries were converted to three-dimensional (3D) CAD models using open source, and commercially available CAD software tools. The models were meshed and used to simulate the compression tests using the implicit finite element method. The calculated uniaxial compression tests were in good agreement with experimental results for strains up to 30%. The presented method would be effective in investigating the effect of polymer foam geometrical features in macroscopic mechanical properties, and guide manufacturing methods for specific applications.

Polyurethane Foams Behaviour. Experiments versus Modeling

2008 ◽  
Vol 399 ◽  
pp. 123-130 ◽  
Author(s):  
Liviu Marsavina ◽  
Tomasz Sadowski ◽  
Dan Mihai Constantinescu ◽  
Radu Negru
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Polyurethane Foam ◽  
Polyurethane Foams ◽  
Experimental Program ◽  
High Porosity ◽  
Compression Tests ◽  
Element Analysis ◽  
Micromechanical Models

. Polyurethane foam materials are widely used as cores in sandwich composites, for packing and cushioning. The main characteristics of foams are light weight, high porosity, high crushability and good energy absorption capacity. The paper presents the experimental results obtained for the mechanical properties of polyurethane foams in different loading conditions and the influence of impregnation on the mechanical properties. A 200 kg/m3 density polyurethane foam was investigated in the experimental program in three different Strength of Materials laboratories from Lublin, Bucharest and Timisoara. The paper assesses the possibility to describe the polyurethane foam behaviour trough compression tests, micromechanical models and Finite Element Analysis (FEA). The micromechanical models and Finite Element Analysis could be used successfully for representing the engineering stress – strain behaviour if the compression tests provide reliable material parameters.

scholarly journals Three-Dimensional (3D) Microstructure-Based Modeling of a Thermally-Aged Cast Duplex Stainless Steel Based on X-ray Microtomography, Nanoindentation and Micropillar Compression

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 688
Author(s):  
Qingdong Zhang ◽  
Kai Zhu ◽  
Arun Sundar S. Singaravelu ◽  
Weizhao Sun ◽  
Tao Jing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Three Dimensional ◽  
Compression Tests ◽  
Element Analysis ◽  
X Ray ◽  
3D Microstructure ◽  
Individual Phase ◽  
Micropillar Compression

Finite element analysis was conducted on a thermally-aged cast duplex stainless steel based on the true three-dimensional (3D) microstructure obtained from X-ray microtomography experiments and using the constitutive behavior of each individual phase extracted from nanoindentation on single-crystal and bicrystal micropillar compression tests. The evolution of the phase morphology, the mechanical properties and the boundary deformation behavior during the aging process are highlighted. Quantitative analysis in terms of the distribution and evolution of the stress and strain in both the as received and aged conditions was performed. The experimental results show that aging at an intermediate temperature has a negligible influence on the morphology of the two phases in cast duplex stainless steel (CDSS). Results from simulations reveal that the mechanical behavior of this material were seriously affected by the microstructure and the mechanical properties of the individual phase and the necking deformation tend to form in the area with less large ferrite grains after aging. In addition, stress localization tends to form at the austenite/ferrite interface, in the narrow region of ferrite grains and in the small ferrite grains.

scholarly journals CHARACTERIZATION OF THE NONLINEAR BEHAVIOR OF FLEXIBLE ROAD PAVEMENTS

2020 ◽  
Vol 15 (12) ◽  
Author(s):  
Irfan Ullah
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Laboratory Test ◽  
Asphalt Concrete ◽  
Viscoelastic Behavior ◽  
Virtual Model ◽  
Element Analysis ◽  
X Ray ◽  
Nonlinear Viscoelastic ◽  
Actual Geometry

In this paper, the Asphalt Concrete is analyzed by finite element modeling in Abaqus. The nonlinear viscoelastic behavior of Asphalt Concrete is simulated in Finite Element Analysis (FEA). The X-Ray Computed Tomography scans of the laboratory specimen are converted to a 3D virtual model in image processing software (Simpleware Scan IP). The 3D model is used in FEA by applying boundary conditions and giving mechanical properties, considering the Asphalt Concrete as a viscoelastic material. The mechanical properties of the Asphalt Concrete were determined from the laboratory test performed on the same sample. Three different types of model were analyzed. The representative 3D meshed model and Abaqus meshed model were analyzed for recovery of stress under constant strain and compared. It was concluded that the analysis on a model without considering the actual geometry of the Asphalt Concrete, gives a similar pattern of results but differ by 18% than a laboratory test. The actual 3D geometry of Asphalt Concrete specimen can be obtained by converting 2D X-ray CT scans. It was also found that the nonlinear viscoelastic analysis on a 3D virtual model of Asphalt Concrete gives 96% similar results to the laboratory tests.

scholarly journals Novel Ring Compression Test Method to Determine the Stress-strain Relations and Mechanical Preperties of Metallic Materials

2021 ◽  
Author(s):  
Guang-Zhao Han ◽  
lixun Cai ◽  
Chen Bao ◽  
Bo Liang ◽  
Yang Lv ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Test Method ◽  
Metallic Materials ◽  
Compression Tests ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Ring Compression ◽  
Wide Range

Abstract Although there are methods for testing the stress–strain relation and strength, which are the most fundamental and important properties of metallic materials, their application to small size specimens is limited. In this study, a new dimensionless elastoplastic load–displacement (EPLD-Ring) model for compressed metal rings with isotropy and constitutive power law is proposed to describe the relation between the geometric dimensions, Hollomon law parameters, load, and displacement based on energy density equivalence. Furthermore, a novel test method for the rings is developed to obtain the elastic modulus, stress–strain relation, yield strength, and tensile strength. The universality and accuracy of the model are verified within a wide range of imaginary materials via finite element analysis (FEA), and the results show that the stress–strain relations obtained with the model are more consistent with those inputted in the FEA software. Additionally, for seven metallic materials, a series of ring compression tests with various dimensions were performed. It was found that the stress–strain relations and mechanical properties predicted by the model are in agreement with the normal tensile test results. It is believed that the new method is reliable and effective for testing the mechanical properties of small size materials and tube components.

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

1995 ◽  
Vol 39 ◽  
pp. 109-117
Author(s):  
Burkhard Beckhoff ◽  
Birgit Kanngießer
Keyword(s):  
High Intensity ◽  
Focal Plane ◽  
Bragg Reflection ◽  
Pyrolytic Graphite ◽  
Trace Element Analysis ◽  
Detection Sensitivity ◽  
Element Analysis ◽  
X Ray ◽  
Wide Range ◽  
Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

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