Effects of statistical pore characteristics on mechanical performance of selective laser melted parts: X-ray computed tomography and micromechanical modeling

2022 ◽  
pp. 142515
Author(s):  
Xue Wang ◽  
Liping Zhao ◽  
Jerry Ying Hsi Fuh ◽  
Heow Pueh Lee
Keyword(s):  
Computed Tomography ◽  
Mechanical Performance ◽  
Micromechanical Modeling ◽  
Pore Characteristics ◽  
X Ray ◽  
X Ray Computed

scholarly journals Effect of Porosity on Mechanical Properties of 3D Printed Polymers: Experiments and Micromechanical Modeling Based on X-Ray Computed Tomography Analysis

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1154 ◽  
Author(s):  
Wang ◽  
Zhao ◽  
Fuh ◽  
Lee
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Micromechanical Model ◽  
Micromechanical Modeling ◽  
X Ray ◽  
Fused Deposition ◽  
3D Printed ◽  
X Ray Computed

Additive manufacturing (commonly known as 3D printing) is defined as a family of technologies that deposit and consolidate materials to create a 3D object as opposed to subtractive manufacturing methodologies. Fused deposition modeling (FDM), one of the most popular additive manufacturing techniques, has demonstrated extensive applications in various industries such as medical prosthetics, automotive, and aeronautics. As a thermal process, FDM may introduce internal voids and pores into the fabricated thermoplastics, giving rise to potential reduction on the mechanical properties. This paper aims to investigate the effects of the microscopic pores on the mechanical properties of material fabricated by the FDM process via experiments and micromechanical modeling. More specifically, the three-dimensional microscopic details of the internal pores, such as size, shape, density, and spatial location were quantitatively characterized by X-ray computed tomography (XCT) and, subsequently, experiments were conducted to characterize the mechanical properties of the material. Based on the microscopic details of the pores characterized by XCT, a micromechanical model was proposed to predict the mechanical properties of the material as a function of the porosity (ratio of total volume of the pores over total volume of the material). The prediction results of the mechanical properties were found to be in agreement with the experimental data as well as the existing works. The proposed micromechanical model allows the future designers to predict the elastic properties of the 3D printed material based on the porosity from XCT results. This provides a possibility of saving the experimental cost on destructive testing.

scholarly journals Fiber orientation quantification utilizing X-ray micro-computed tomography

2020 ◽  
pp. 002199832096255
Author(s):  
Jennifer M Sietins ◽  
Jessica C Sun ◽  
Daniel B Knorr Jr
Keyword(s):  
Computed Tomography ◽  
Fiber Orientation ◽  
Mechanical Performance ◽  
Ct Scans ◽  
Micro Computed Tomography ◽  
Orientation Data ◽  
Orientation Analysis ◽  
X Ray ◽  
Software Analysis ◽  
X Ray Computed

It is well known that the mechanical performance of composite materials is highly dependent on the fiber orientation. Several techniques have historically been used to quantify fiber orientation experimentally. Newer methods have involved 3 D X-ray computed tomography (CT) scans due to the high resolution that is now achievable within a laboratory setting. The accuracy of the analysis, however, is a function of the resulting scan image quality and the specific parameters influencing the resulting orientation analysis. This report summarizes a methodology to quantify fiber orientation from 3 D CT scans. Optimal scanning parameters are presented taking into account both the necessary resolution, geometric unsharpness, and the scan volume size. The influence of varied software analysis parameters and their effects on the resulting orientation data is discussed. The selection of software analysis parameters was independently validated with optical microscopy on a sample with only two fibers. Lastly, the orientation analysis was applied to a 0/+45/−45/90 composite to demonstrate this technique on a larger scale.

Soil pore effects on spatial patterns of extracellular enzymes: combined X-ray computed tomography and 2D zymography

2021 ◽  
Author(s):  
Archana Juyal ◽  
Andrey Guber ◽  
Alexandra Kravchenko
Keyword(s):  
Computed Tomography ◽  
Enzyme Activity ◽  
Spatial Patterns ◽  
Extracellular Enzymes ◽  
Cropping Systems ◽  
Pore Characteristics ◽  
X Ray ◽  
Preliminary Results ◽  
Computed Tomography Scanning ◽  
X Ray Computed

<p>Extracellular enzymes play an important role in soil biochemical processes as they are the key regulators of litter and soil organic matter degradation. However, understanding of the factors influencing their activity and fate in soil is still limited. In this study, we examined the relationship between soil pores and spatial patterns of extracellular enzyme activity in soils from two bioenergy cropping systems: monoculture switchgrass (Panicum virgatum L.) and restored prairie. Intact soil cores (5 cm Ø x 5 cm height) were collected at two contrasting topographical positions (depression and slope) within large topographically diverse fields where the switchgrass and prairie were grown since 2008. The cores were subjected to X-ray computed tomography scanning at 18 µm resolution. After the scanning, a switchgrass seedling was planted in these cores and allowed to grow for three months. Then the plants were terminated and the cores were rescanned. Pore characteristics were assessed using the image information, and b-glucosidase activity was characterized via 2D zymography. Preliminary results showed that soil of the prairie system had greater volumes of 60-180 mm Ø size pores compared to monoculture switchgrass system. However, enzyme activity was higher in the soil of monoculture switchgrass. Our preliminary results indicate that the soil pore size distribution and enzyme activity differ depending on the type of the bioenergy cropping system. Further analysis is conducted to determine microbial abundance, total C in soil and microbial biomass in these cropping systems to understand the effect of pores on microbial activity associated with C processes in soil.</p>

Estimating the depth of the restrictive layer of soil in a cranberry field based on CT scan images

2020 ◽  
Author(s):  
Elnaz Shahriarinia ◽  
Silvio Jose Gumiere ◽  
Christian Dupuis
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Fine Particles ◽  
Pore Network ◽  
Imaging Method ◽  
Pore Characteristics ◽  
Soil Particles ◽  
X Ray ◽  
Soil Media ◽  
X Ray Computed

<p><strong>Estimating the depth of the restrictive layer of soil in a cranberry field based on CT scan images</strong></p><p> </p><p>Cranberry production is a dominant culture in Québec, Canada. In cranberry production, there is a substantial need for water whether for irrigation, harvesting, or frost control. Some farms are implementing subirrigation procedures in order to reduce water use and increase fruit yields. However, this irrigation method may impose hydraulic stresses on soil particles which results in the movement of fine particles. The accumulation of the soil particles in narrow pore throats leads to the formation of restrictive layers in soil.  In this respect, we are going to study the changes in soil media and its porosity based on X-ray computed tomography (CT) which is a non-destructive imaging method. Consequently, X-ray CT has become a great asset to analyze soil physical properties. With the analysis of the images captured by the use of X-ray computed tomography, it is possible to visualize and analyze the pore network structure in the soil media.</p><p> </p><p>This study reports the results of subirrigation experiments for four different sandy soils. These column experiments aimed to reproduce the effects of subirrigation in cranberry fields for 40 years. Seven different time steps were taken with a medical CT scanner SOMATOM Definition AS+ 128 (Siemens, Germany). The 2-D horizontal 16-bit gray-scale images were captured by an X-ray energy level of 140 KeV. For each column, we got 1677 images of 512  512 pixels with a voxel size of 0.1 × 0.1 × 0.6 mm (x, y, z). Studying our images for further analysis, we used several global and local methods to find the most reliable and efficient one to binarize our images. Results show that the methods and the image analysis neighborhood have a great impact on the accuracy of the image segmentation. We were able to reconstruct a 3-D visualization of the soil pore network for each column. We used this reconstruction to demonstrate that the variation of porosity and soil pore characteristics can be studied over time. We find that the transport of soil particles tends to be highest when there are fine sandy soil particles on top of a layer of coarse soil. These finer particles have sufficient energy to be remobilized within the pore network while coarser particles remain in place. Our results show that soil particle transport can be assessed using time-lapse imagery and thus makes it possible to approximate the depth and amount of time that will be required for these restrictive layers to form in different soil profiles. Finally, it would be possible to find the best structure of soil in construction of a cranberry field in the future.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p>

scholarly journals Analysis of strength property and pore characteristics of Taihang limestone using X-ray computed tomography at high temperatures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shi Liu ◽  
Zhe Huang
Keyword(s):  
Computed Tomography ◽  
High Temperature ◽  
Strength Property ◽  
Mechanical Test ◽  
Test Method ◽  
High Temperature Treatment ◽  
Pore Characteristics ◽  
X Ray ◽  
Limestone Sample ◽  
X Ray Computed

AbstractRising temperature will cause the changes of pore characteristics and strength property in rock. This research takes the limestone produced in Taihang Mountains as the research object, and performs high-temperature treatment within 25–1000 °C. The high-resolution X-ray computed tomography (CT) scanning test method is used to visually reconstruct the three-dimensional image of the sample, and obtain the spatial distribution status of the mesoscopic parameters of the bones, pores/cracks, etc. The results show that when the temperature exceeded 700 °C, the samples appeared milky white in appearance and as the temperature increased, the color gradually turned white, macroscopic cracks began to appear on the surface, while the meso-pores connected rapidly, reflecting a typical progressive destruction process from inside to outside. The change law of volume porosity with temperature has a consistent trend with that of the apparent morphology of the sample. Similarly, the mechanical test results suggest that 700 °C is also the turning temperature for strength deterioration and brittle-plastic transformation of sample. Based on the results of high-temperature test, CT test and mechanical test, there are enough evidences to show that, for the limestone sample, 700 °C is probably to be the mutation temperature of physical–mechanical behavior.

scholarly journals Relationship between percolation mechanism and pore characteristics of recycled permeable bricks based on X-ray computed tomography

2021 ◽  
Vol 60 (1) ◽  
pp. 207-215
Author(s):  
Songsong Lian ◽  
Tao Meng ◽  
Hongqi Song ◽  
Zhongjia Wang ◽  
Jiabin Li
Keyword(s):  
Computed Tomography ◽  
Effective Porosity ◽  
Recycled Concrete ◽  
Pore Characteristics ◽  
X Ray ◽  
Nonlinear Channels ◽  
Porosity And Permeability ◽  
Porous Permeable Material ◽  
X Ray Computed ◽  
The Relationship

Abstract The relationship between percolation mechanism and pore characteristics for recycled permeable bricks with different porosities is investigated in this study based on X-ray computed tomography (X-CT). Permeability coefficients are measured and some characteristics including size, amount, and distribution of the pore are analysed. The results show that the effective porosity and permeability coefficient of the recycled permeable bricks exhibit a linear relationship first and then a quadratic curve relationship, where the critical effective porosity is 12%. Meanwhile, we discovered that nonlinear channels in permeable bricks are larger and fewer compared with linear percolation channels, regardless of whether the percolation stage is linear or nonlinear. Additionally, when the area and number ratios of the linear and nonlinear percolation channels reached 80% and 10%, respectively, the overall percolation state of the permeable bricks changed from linear to nonlinear percolation. This research is helpful to improve the mechanical and percolation properties of recycled concrete bricks and promote the application of porous permeable material.

scholarly journals Analyzing the Mechanical Performance of Solid Oxide Fuel Cells at Interfacial Anode/Electrolyte Regions Using Sub-Micron Resolution 3D X-Ray Computed Tomography

2017 ◽  
Vol 78 (1) ◽  
pp. 2317-2321 ◽  
Author(s):  
Thomas M. M. Heenan ◽  
James B. Robinson ◽  
Xuekun Lu ◽  
Josh J Bailey ◽  
Daniel J.L. Brett ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Mechanical Performance ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
X Ray ◽  
X Ray Computed

SULFUR DISPERSION QUANTITATIVE ANALYSIS IN ELASTOMERIC TIRE FORMULATIONS BY USING HIGH RESOLUTION X-RAY COMPUTED TOMOGRAPHY

2021 ◽  
Author(s):  
Dayakar Penumadu ◽  
Jun-Cheng Chin ◽  
Stephen Young ◽  
Frederick Ignatz-Hoover ◽  
Tom Floyd ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Mechanical Performance ◽  
Domain Size ◽  
Failure Criteria ◽  
Rubber Matrix ◽  
Mixing Efficiency ◽  
X Rays ◽  
X Ray ◽  
X Ray Computed

ABSTRACT Good dispersion of compounded ingredients in a rubber formulation is important for mechanical performance. After mixing, certain materials can remain undispersed within the rubber matrix, which could lead to critical flaws, influencing performance according to the Griffith failure criteria. High resolution X-ray computed tomography (XCT) offers a unique opportunity to measure phase domain size and distributions. Fillers such as carbon black or silica can be differentiated from sulfur or zinc oxide, providing an opportunity to determine dispersion characteristics of the various phases. The XCT technique has become an important characterization tool for three-dimensional and higher dimension material science due to the availability of polychromatic micro-focus x-ray sources and efficient high spatial resolution detectors with superior scintillators. High resolution XCT provides very rich data quantifying mixing efficiency of particulates in a matrix, such as insoluble sulfur or silica particles in rubber. Imaging with X-rays provides attenuation, phase, or scattering contrast and will prove to be a critical method for evaluating the field of rubber crosslinking, considering realistic environments in situ. This paper highlights methodology development and validation and provides insight on the dispersion of polymeric (insoluble) sulfur in rubber formulations. Dispersion assessment is compared using three techniques: high resolution XCT, population survival analysis in tensile testing, and optical microscopy.

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