Investigation on local structure response of dense and loose sand subjected to shearing based on DEM simulations

Author(s):  
Qing Chen ◽  
Yan Gao
Author(s):  
Jianhua Pan ◽  
Xuedong Chen ◽  
Zhibin Ai ◽  
Huifeng Jiang

High-rise towers are very sensitive to wind loads because of their high flexibility. Wind-induced resonance vibrations due to Karman vortex street have great impact on these structures, especially for the high empty cylindrical shell towers. In a petrochemical enterprise, a few local cracks were detected in some empty towers and the wind-induced resonance vibrations were considered to be responsible for that. In this paper, by employing software SW6 and ANSYS, the tower cracking cause was analyzed with emphasis on the simulation of local structure response for an empty tower under wind loads. It can be found that the stress level was quite severe at the head-skirt conjunctions which were consistent with those actual cracking positions.


2014 ◽  
Vol 90 (17) ◽  
Author(s):  
A. Iadecola ◽  
B. Joseph ◽  
M. Bendele ◽  
G. Aquilanti ◽  
H. Takeya ◽  
...  

Author(s):  
G.E. Ice

The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. With new x-ray optics these microprobes can achieve micron and submicron spatial resolutions. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature will have important applications to materials science. For example, x-ray fluorescent microanalysis of materials can reveal elemental distributions with greater sensitivity than alternative nondestructive probes. In materials, segregation and nonuniform distributions are the rule rather than the exception. Common interfaces to whichsegregation occurs are surfaces, grain and precipitate boundaries, dislocations, and surfaces formed by defects such as vacancy and interstitial configurations. In addition to chemical information, an x-ray diffraction microprobe can reveal the local structure of a material by detecting its phase, crystallographic orientation and strain.Demonstration experiments have already exploited the penetrating nature of an x-ray microprobe and its inherent elemental sensitivity to provide new information about elemental distributions in novel materials.


1982 ◽  
Vol 43 (C9) ◽  
pp. C9-43-C9-46 ◽  
Author(s):  
A. Sadoc ◽  
A. M. Flank ◽  
D. Raoux ◽  
P. Lagarde

1986 ◽  
Vol 47 (C8) ◽  
pp. C8-423-C8-426
Author(s):  
H. OYANAGI ◽  
Y. TAKEDA ◽  
T. MATSUSHITA ◽  
T. ISHIGURO ◽  
A. SASAKI

1986 ◽  
Vol 47 (C8) ◽  
pp. C8-403-C8-406
Author(s):  
N. MOTTA ◽  
A. BALZAROTTI ◽  
P. LETARDI
Keyword(s):  

2020 ◽  
Author(s):  
Adam Sapnik ◽  
Duncan Johnstone ◽  
Sean M. Collins ◽  
Giorgio Divitini ◽  
Alice Bumstead ◽  
...  

<p>Defect engineering is a powerful tool that can be used to tailor the properties of metal–organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal–linker bonds, generating more coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially</p><p>retained, even in the amorphised material. We find that the solvent toluene stabilises the MIL-100 (Fe) framework against collapse and leads to a substantial rentention of porosity over the non-stabilised material.</p>


2018 ◽  
Author(s):  
Kyle Hall ◽  
Zhengcai Zhang ◽  
Christian Burnham ◽  
Guang-Jun Guo ◽  
Sheelagh Carpendale ◽  
...  

<p>The broad scientific and technological importance of crystallization has led to significant research probing and rationalizing crystallization processes, particularly how nascent</p> <p>crystal phases appear. Previous work has generally neglected the possibility of the molecular-level dynamics of individual nuclei coupling to local structures (e.g., that of the nucleus and its</p> <p>surrounding environment). However, recent experimental work has conjectured that this can occur. Therefore, to address a deficiency in scientific understanding of crystallization, we have</p> <p>probed the nucleation of prototypical single and multi-component crystals (specifically, ice and mixed gas hydrates). Here, we establish that local structures can bias the evolution of nascent</p> <p>crystal phases on a nanosecond timescale by, for example, promoting the appearance or disappearance of specific crystal motifs, and thus reveal a new facet of crystallization behaviour.</p> <p>Analysis of the crystallization literature confirms that structural biases are likely present during crystallization processes beyond ice and gas hydrate formation. Moreover, we demonstrate that</p> <p>structurally-biased dynamics are a lens for understanding existing computational and experimental results while pointing to future opportunities.</p>


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