Matrix tacticity controlled tuning of microstructure, constitutive behavior and rheological percolation effect of melt‐mixed amino‐functionalized MWCNT/PP nanocomposites

2017 ◽  
Vol 58 (7) ◽  
pp. 1115-1126 ◽  
Author(s):  
Dibyendu Das ◽  
Sucharita Sethy ◽  
Bhabani K. Satapathy
Keyword(s):  
Constitutive Behavior ◽  
Percolation Effect ◽  
Rheological Percolation

Application of QR framework in modeling the constitutive behavior of porcine coronary sinus tissue

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Shahla Zamani ◽  
Sandipan Paul ◽  
Akhilesh A. Kotiya ◽  
John C. Criscione ◽  
Alan D. Freed
Keyword(s):  
Coronary Sinus ◽  
Constitutive Behavior

Micro-Injection Molding of Polymer Nanocomposites Composition-Process-Properties Relationship

2021 ◽  
Vol 36 (3) ◽  
pp. 276-286
Author(s):  
Z. Dekel ◽  
S. Kenig
Keyword(s):  
Mechanical Properties ◽  
Plug Flow ◽  
Volume Resistivity ◽  
Process Conditions ◽  
Polyamide 66 ◽  
Fountain Flow ◽  
Microinjection Molding ◽  
Injection Molded ◽  
Composition Process ◽  
Rheological Percolation

Abstract The mechanical, electrical, thermal, and rheological properties of micro injection molded nanocomposites comprising 2% and 5% carbon nanotubes (CNTs) incorporated in polycarbonate (PC), and polyamide 66 (PA) were studied. The design of experiments method was used to investigate the composition-process – properties relationship. Results indicated that the process variables significantly affected the flow patterns and resulting morphology during the filling stage of the microinjection molding (lIM) process, using 0.45 mm diameter lIM samples. Two distinct flow regimes have been identified in lIM using the low cross-section samples. The first was a conventional “fountain flow,” which resulted in a skin/core structure and reduced volume resistivity up to 10 X cm in the case of 5% CNTs and up to 100 X cm in 2% CNTs, in both polymers, respectively. In addition, inferior mechanical properties were obtained, attributed to polymer degradation under high shear rate conditions, when practicing high injection speeds, high mold temperatures, and high screw rotation velocities. The second was a “plug flow” due to wall slippage, obtained under low injection speeds, low mold temperatures, and low rotation velocities, leading to a substantial increase in modulus of elasticity (60%) with increased electrical resistivity up to 103 X cm for 5% CNTs and 105 X cm for 2% CNTs, respectively. The rheological percolation threshold was obtained at 2% CNTs while the electrical threshold was attained at 0.4% CNTs, in both polymers. It was concluded that in lIM, the process conditions should be closely monitored. In the case of high viscous heating, degradation of mechanical properties was obtained, while skin- core morphology formation enhanced electrical conductivity.

Measured Constitutive Behavior of Several Compositions of PZT

1999 ◽  
Author(s):  
Christopher S. Lynch ◽  
Brandon Davis
Keyword(s):  
Grain Size ◽  
Constitutive Behavior ◽  
Load History ◽  
Hysteresis Behavior

Abstract PZT is often used as an actuator material. The actuation properties are dependent on several factors including composition, grain size, and processing; as well as on loading and load history. The effect of grain size and composition on the hysteresis behavior of PZT was experimentally characterized. The results show the effects of preload stress and temperature on the actuation capability of this class of materials.

A Meso-Electro-Mechanical Model for PMN-PT-BT Ceramics Behavior

2001 ◽  
Author(s):  
Jinghong Fan
Keyword(s):  
Phase Transition ◽  
Mechanical Model ◽  
Three Dimensional ◽  
Constitutive Behavior ◽  
Rate Equations ◽  
State Variables ◽  
Empirical Relationships ◽  
Nonlinear Hysteresis ◽  
Fully Coupled ◽  
Maximum Permittivity

Abstract A three-dimensional, meso-electro-mechanical model has been formulated for description of PMN-PT-BT ceramics. Unlike the experimentally fit models and phenomenological models which are based on state variables and/or empirical relationships, this fully coupled, computational mesomechanics model for polycrystalline PMN-PT-BT ceramics is developed based on considerations of constitutive behavior of single crystals. Specifically, domain wall nucleation and evolution rate equations are proposed in this work to describe the nonlinear hysteresis behavior of these ceramics near the phase transition temperature with maximum permittivity.

Constitutive behavior of porous ductile materials accounting for micro-inertia and void shape

2015 ◽  
Vol 80 ◽  
pp. 324-339 ◽  
Author(s):  
C. Sartori ◽  
S. Mercier ◽  
N. Jacques ◽  
A. Molinari
Keyword(s):  
Constitutive Behavior ◽  
Ductile Materials ◽  
Void Shape
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