Solution methods for one-dimensional viscoelastic problems

1987 ◽  
Author(s):  
JOHN STUBSTAD ◽  
GEORGE SIMITSES
2018 ◽  
Vol 74 (8) ◽  
pp. 951-960 ◽  
Author(s):  
Chong Zhang ◽  
Kou-Lin Zhang

The bromo-substituted aromatic dicarboxylic acid 5-amino-2,4,6-tribromoisophthalic acid (H2ATBIP) was used to assemble with CdII ions in the presence of the N-donor flexible bipyridyl ligands 3,3′-(diazene-1,2-diyl)dipyridine (mzpy) and 1,3-bis(pyridin-3-ylmethyl)urea (3bpmu), leading to the formation of two chain coordination polymers by adopting solution methods, namely, catena-poly[[[triaqua(5-amino-2,4,6-tribromoisophthalato-κO)cadmium(II)]-μ-3,3′-(diazene-1,2-diyl)dipyridine-κ2 N 1:N 1′] dihydrate], {[Cd(C8H2Br3NO4)(C10H8N4)(H2O)3]·2H2O} n or {[Cd(ATBIP)(mzpy)(H2O)3]·2H2O} n , (1), and catena-poly[[[tetraaquacadmium(II)]-μ-1,3-bis(pyridin-3-ylmethyl)urea-κ2 N 1:N 1′-[diaquabis(5-amino-2,4,6-tribromoisophthalato-κO)cadmium(II)]-μ-1,3-bis(pyridin-3-ylmethyl)urea-κ2 N 1:N 1′] octahydrate], {[Cd(C8H2Br3NO4)(C12H12N4O)(H2O)3]·4H2O} n or {[Cd(ATBIP)(3bpmu)(H2O)3]·4H2O} n , (2). Both complexes were characterized by FT–IR spectroscopic analysis, thermogravimetric analysis (TGA), solid-state diffuse reflectance UV–Vis spectroscopic analysis, and single-crystal and powder X-ray diffraction analysis (PXRD). The mzpy and 3bpmu ligands bridge the CdII metal centres in (1) and (2) into one-dimensional chains, and the ATBIP2− ligands show a monodentate coordination to the CdII centres in both coordination polymers. A discrete water tetramer exists in (1). Within the chains of (1) and (2), there are halogen bonds between adjacent ATBIP2− and mzpy or 3bpmu ligands, as well as hydrogen bonds between the ATBIP2− ligands and the coordinated water molecules. With the aid of weak interactions, the structures of (1) and (2) are further extended into three-dimensional supramolecular networks. An analysis of the solid-state diffuse reflectance UV–Vis spectra of (1) and (2) indicates that a wide indirect band gap exists in both complexes. Complexes (1) and (2) exhibit irreversible and reversible dehydration–rehydration behaviours, respectively, and the solid-state fluorescence properties of both complexes have been studied.


AIAA Journal ◽  
1988 ◽  
Vol 26 (9) ◽  
pp. 1127-1134 ◽  
Author(s):  
John M. Stubstad ◽  
George J. Simitses

Author(s):  
Carlos Yoong ◽  
Anders Thorin ◽  
Mathias Legrand

The Wave Finite Element Method (WFEM) is implemented to accurately capture travelling waves propagating at a finite speed within a bouncing rod system and induced by unilateral contact collisions with a rigid foundation; friction is not accounted for. As opposed to the traditional Finite Element Method (FEM) within a time-stepping framework, potential discontinuous deformation, stress and velocity wave fronts are accurately described, which is critical for the problem of interest. A one-dimensional benchmark with an analytical solution is investigated. The WFEM is compared to two time-stepping solution methods formulated on a FEM semi-discretization in space: (1) an explicit technique involving Lagrange multipliers and (2) a non-smooth approach implemented in the Siconos package. Attention is paid to the Gibb’s phenomenon generated during and after contact occurrences together with the time evolution of the total energy of the system. It is numerically found that the WFEM outperforms the FEM and Siconos solution methods because it does not induce any spurious oscillations or dispersion and diffusion of the shock wave. Furthermore, energy is not dissipated over time. More importantly, the WFEM does not require any impact law to close the system of governing equations.


1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.


Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).


Author(s):  
Peter Sterling

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.


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