scholarly journals Multiscale FE-MD Coupling: Influence of the Chain Length on the Mechanical Behavior of Coarse-Grained Polystyrene

2021 ◽  
Author(s):  
M. Ries ◽  
F. Weber ◽  
M. Striegel ◽  
P. Steinmann ◽  
S. Pfaller
Keyword(s):  
Mechanical Behavior ◽  
Chain Length ◽  
Coarse Grained

scholarly journals Percolation Phase Transition from Ionic Liquids to Ionic Liquid Crystals

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shen Li ◽  
Yanting Wang
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Chain Length ◽  
Complex Fluids ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length

Abstract Due to their complex molecular structures and interactions, phase behaviors of complex fluids are quite often difficult to be identified by common phase transition analysis methods. Percolation phase transition, on the other hand, only monitors the degree of connection among particles without strict geometric requirements such as translational or orientational order, and thus suitable for pinpointing phase transitions of complex fluids. As typical complex fluids, ionic liquids (ILs) exhibit phases beyond the description of simple liquid theories. In particular, with an intermediate cationic side-chain length, ILs can form the nanoscale segregated liquid (NSL) state, which will eventually transform into the ionic liquid crystal (ILC) structure when the side chains are adequately long. However, the microscopic mechanism of this transformation is still unclear. In this work, by means of coarse-grained molecular dynamics simulation, we show that, with increasing cationic side-chain length, some local pieces of non-polar domains are gradually formed by side chains aligned in parallel inside the NSL phase, before an abrupt percolation phase transition happens when the system transforms into the ILC phase. This work not only identifies that the NSL to ILC phase transition is a critical phenomenon, but also demonstrates the importance of percolation theory to complex fluids.

Nanostructured Shape Memory TiNi Alloy Processed by Severe Electroplastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 507-512 ◽  
Author(s):  
Vladimir V. Stolyarov
Keyword(s):  
Cold Rolling ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Fracture Strain ◽  
Coarse Grained ◽  
Tini Alloy ◽  
Current Effect ◽  
Electroplastic Rolling ◽  
Ultrafine Grained ◽  
A Current

Electropulse current effect during cold rolling on deformability, nanostructure formation and mechanical behavior in coarse-grained (CG) and ultrafine-grained (UFG) TiNi alloys enriched by nickel is investigated. The UFG sample subjected to cold rolling with current has a fracture strain (е = 1.91) which is higher than that without a current (е = 0.59). As a result of cold rolling with a current and a subsequent annealing at 400-450 °C, nanostructure is formed in both alloys, which leads to a significant enhancement of yield and ultimate stresses. It has been shown that the efficiency of electroplastic rolling depends on the purity of the alloys.

scholarly journals Experimental Study on Mechanical Behavior of Lean Cemented Sand and Gravel Material in Unloading and Reloading Paths

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jie Yang ◽  
An-yu Yang ◽  
Yan-gong Shan ◽  
Miao-miao Yang ◽  
Jin-lei Zhao ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Hysteresis Loop ◽  
Triaxial Test ◽  
Volumetric Strain ◽  
Rate Of Change ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Water Drainage ◽  
Cemented Sand ◽  
Sand And Gravel

Lean cemented sand and gravel (LCSG) materials are subjected to unloading-loading when an LCSG dam is opened for water drainage and then refilled or a roadbed base is subjected to repeated wheel loads. To investigate the behavior of the LCSG materials under loading-unloading, previous studies utilized the complete loading triaxial test. In contrast, in this study, the consolidated drained triaxial tests in the unloading and reloading paths for materials with cementing agent contents of 60 and 100 kg/m3 under different confining pressures, for which each curve generates three loading-unloading cycles, were applied to investigate the unloading and reloading mechanical behavior. Experimental results indicated that the unloading and reloading behavior of the LCSG materials produced stress-strain curves exhibiting a crescent-shaped hysteresis loop, which differs from that exhibited by coarse-grained soil. Although the shape of the crescent-like hysteresis loop was preserved as stress levels increasing, it gradually expanded. Compared with that of the typical triaxial test, the cohesive force and the increasing internal friction angle increased. Further, as the confining pressure increased, the crescent-like hysteresis loops tapered, shear strength increased linearly, and the modulus of resilience increased nonlinearly; the latter’s rate of change, however, decreased. The change in volumetric strain was small during unloading as the stress level changed.

Mechanical and Functional Properties of Titanium Alloys Processed by Severe Plastic Deformation

2011 ◽  
Vol 683 ◽  
pp. 137-148 ◽  
Author(s):  
Vladimir V. Stolyarov
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Mechanical Behavior ◽  
Titanium Alloys ◽  
Functional Properties ◽  
Coarse Grained ◽  
Cyclic Loads ◽  
Metallic Materials ◽  
Ultrafine Grained

Systematized literature data related to the study of mechanical and functional properties of ultrafine-grained and nanostructured metallic materials processed by deformation methods are presented. Special attention is given to the mechanical behavior of titanium materials under tension, as well as under impact and cyclic loads. The advantage of the materials under investigation over their coarse-grained analogues is shown.

The statistical and dynamics properties of hard-sphere polymer chains

2015 ◽  
Vol 29 (18) ◽  
pp. 1550091 ◽  
Author(s):  
Zi-Wen Huang ◽  
Ji-Xuan Hou ◽  
Chun Xie ◽  
Hao Zhang
Keyword(s):  
Relaxation Time ◽  
Chain Length ◽  
Hard Sphere ◽  
Dynamic Properties ◽  
Polymer Chains ◽  
Coarse Grained ◽  
Power Exponent ◽  
Polymer Model ◽  
Time Saving ◽  
Scaling Relationship

We investigated a highly coarse-grained polymer model — hard-sphere (HS) model. This model is characterized by its time-saving computation and strictly guaranteed uncrossability of polymer chains. Regarding the statistical and dynamic properties of HS model, our simulating results perfectly coincide with pre-existing scaling theory. Additionally, we point out that the power exponent of scaling relationship between its relaxation time and chain length is 2.2.

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