scholarly journals Numerical Analysis of Time‐Dependent Conduit Magma Flow in Dome‐Forming Eruptions With Application to Mount St. Helens 2004–2008

2019 ◽  
Vol 124 (11) ◽  
pp. 11251-11273 ◽  
Author(s):  
Ying‐Qi Wong ◽  
Paul Segall
2006 ◽  
Vol 508 ◽  
pp. 199-204 ◽  
Author(s):  
Marc Hainke ◽  
Sonja Steinbach ◽  
Johannes Dagner ◽  
Lorenz Ratke ◽  
Georg Müller

The solidification microstructure is the consequence of a wide range of process parameters, like the growth velocity, the temperature gradient and the composition. Although the influence of these parameters is nowadays considerably well understood, an overall theory of the influence of convection on microstructural features is still lacking. The application of time dependent magnetic fields during directional solidification offers the possibility to create defined solidification and flow conditions. In this work, we report about solidification experiments in the ARTEMIS and ARTEX facilities including rotating magnetic fields (RMF). The effect of the forced melt flow on microstructural parameters like the primary and secondary dendrite arm spacing is analyzed for a wide range of magnetic field parameters. The experimental analysis is supported by a rigorous application of numerical modeling. An important issue is hereby the prediction of the resulting macrosegregation, i.e., differences in the composition on the scale of the sample (macroscale) due to the RMF. For the considered configuration and parameters an axial enrichment of Si is found beyond a certain magnetic field strength. The results are compared to available theories and their applicability is discussed.


1998 ◽  
Vol 66 (1) ◽  
pp. 39-46 ◽  
Author(s):  
P. Persephonis ◽  
A. Ioannou ◽  
J. Parthenios ◽  
C. Georgiades ◽  
V. Giannetas

2014 ◽  
Vol 14 (02) ◽  
pp. 1350065 ◽  
Author(s):  
K. LIU ◽  
N. ZHANG ◽  
H. XIA ◽  
G. DE ROECK

The interaction between a bridge and a train moving on the bridge is a coupled dynamic problem. The equations of motion of the bridge and the vehicle are coupled by the time dependent contact forces. At each time step, the motion of the bridge influences the forces transferred to the vehicle and this, in turn, changes the forces acting on the bridge. In this paper, a comparison of three different time domain solution algorithms for the coupled equation of motion of the train–bridge system is presented. Guidelines are given for a good choice of the time step.


Author(s):  
Nicolas Von Bandel ◽  
Mikhael Myara ◽  
Baptiste Chomet ◽  
Mohamed Sellahi ◽  
Tahar Souici ◽  
...  

2017 ◽  
Vol 21 (10) ◽  
pp. 1495-1509 ◽  
Author(s):  
Bo Wu ◽  
Jinsong Liu ◽  
Xiaomei Chen

In this article, numerical analysis has been conducted for multi-story reinforced concrete frames under different fire scenarios to investigate the time-dependent lateral displacement of beam-column joint, which is almost the same as the lateral displacement at column end. Based on the numerical results, an empirical model has been proposed to approximately determine the time-dependent lateral displacement of the beam-column joint, and the calculated results using this model are compared with the numerical and test results provided by other researchers. Finally, the fire performance of axially-and-rotationally restrained reinforced concrete columns with time-dependent sidesway is numerically analyzed and compared with that without sidesway. It is found that (1) when the target floor is on fire, the influence of its non-adjacent floors’ exposure to fire on the lateral displacement of the joints at the target floor can be neglected, and the biggest error induced by this neglect is less than 10%; but the exposure of its adjacent floor(s) to fire leads to larger lateral displacement of these joints; and (2) fire endurance of the restrained reinforced concrete column with high nominal axial load ratio (e.g. 0.6) decreases significantly with the increasing of the column’s sidesway.


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