scholarly journals Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

ACS Omega ◽  
2021 ◽  
Author(s):  
Takahiro Doi ◽  
Hideaki Takagi ◽  
Nobutaka Shimizu ◽  
Noriyuki Igarashi ◽  
Shinichi Sakurai
Keyword(s):  
Block Copolymers ◽  
Stress Relaxation ◽  
Stress Strain

scholarly journals A Simplified Method for Elastic-Plastic-Creep Structural Analysis

1985 ◽  
Vol 107 (1) ◽  
pp. 231-237 ◽  
Author(s):  
A. Kaufman
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Kinematic Hardening ◽  
Nonlinear Finite Element ◽  
Strain History ◽  
Stress Strain ◽  
Element Analysis ◽  
Inelastic Analysis ◽  
Simplified Method ◽  
Time Required

A simplified inelastic analysis computer program (ANSYMP) was developed for predicting the stress-strain history at the critical location of a thermomechanically cycled structure from an elastic solution. The program uses an iterative and incremental procedure to estimate the plastic strains from the material stress-strain properties and a plasticity hardening model. Creep effects can be calculated on the basis of stress relaxation at constant strain, creep at constant stress or a combination of stress relaxation and creep accumulation. The simplified method was exercised on a number of problems involving uniaxial and multiaxial loading, isothermal and nonisothermal conditions, dwell times at various points in the cycles, different materials, and kinematic hardening. Good agreement was found between these analytical results and nonlinear finite element solutions for these problems. The simplified analysis program used less than 1 percent of the CPU time required for a nonlinear finite element analysis.

Scattering patterns and stress–strain relations on phase-separated ABA block copolymers under uniaxial elongating simulations

Soft Matter ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 926-936 ◽  
Author(s):  
Katsumi Hagita ◽  
Keizo Akutagawa ◽  
Tetsuo Tominaga ◽  
Hiroshi Jinnai
Keyword(s):  
Molecular Dynamics ◽  
Block Copolymers ◽  
Molecular Dynamics Simulations ◽  
Coarse Grained ◽  
Two Dimensional ◽  
Stress Strain ◽  
Uniaxial Stretching ◽  
Dynamics Simulations ◽  
Coarse Grained Molecular Dynamics

To develop molecularly based interpretations of the two-dimensional scattering patterns (2DSPs) of phase-separated block copolymers (BCPs), we performed coarse-grained molecular dynamics simulations of ABA tri-BCPs under uniaxial stretching for block-fractions where the A-segment (glassy domain) is smaller than the B-segment (rubbery domain), and estimated the behaviour of their 2DSPs.

scholarly journals Modelling the Mechanical and Strain Recovery Behaviour of Partially Crystalline PLA

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1342 ◽  
Author(s):  
John Sweeney ◽  
Paul Spencer ◽  
Karthik Nair ◽  
Phil Coates
Keyword(s):  
Finite Element ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Stress Relaxation ◽  
Shape Memory ◽  
Yield Stress ◽  
Amorphous Phase ◽  
Strain Recovery ◽  
Stress Strain

This is a study of the modelling and prediction of strain recovery in a polylactide. Strain recovery near the glass transition temperature is the underlying mechanism for the shape memory in an amorphous polymer. The investigation is aimed at modelling such shape memory behaviour. A PLA-based copolymer is subjected to stress–strain, stress relaxation and strain recovery experiments at large strain at 60 °C just below its glass transition temperature. The material is 13% crystalline. Using published data on the mechanical properties of the crystals, finite element modelling was used to determine the effect of the crystal phase on the overall mechanical behaviour of the material, which was found to be significant. The finite element models were also used to relate the stress–strain results to the yield stress of the amorphous phase. This yield stress was found to possess strain rate dependence consistent with an Eyring process. Stress relaxation experiments were also interpreted in terms of the Eyring process, and a two-process Eyring-based model was defined that was capable of modelling strain recovery behaviour. This was essentially a model of the amorphous phase. It was shown to be capable of useful predictions of strain recovery.

Stress Relaxation of Sugi (Cryptomeria japonica D.Don) Wood in Radial Compression under High Temperature Steam

Holzforschung ◽  
1999 ◽  
Vol 53 (5) ◽  
pp. 541-546 ◽  
Author(s):  
W. Dwianto ◽  
T. Morooka ◽  
M. Norimoto ◽  
T. Kitajima
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Cryptomeria Japonica ◽  
Chain Scission ◽  
Strain Recovery ◽  
Crystalline Lattice ◽  
Compressive Deformation ◽  
Radial Compression ◽  
Stress Strain ◽  
Permanent Fixation

Summary To clarify the mechanism of the permanent fixation of compressive deformation of wood by high temperature steaming, stress relaxation and stress-strain relationships in the radial compression for Sugi (Cryptomeria japonica D.Don) wood were measured under steam at temperatures up to 200°C. The stress relaxation curves above 100°C were quite different in shape from those below 100°C, showing a rapid decrease in stress with increasing temperature. In the stress-strain relationships measured above 140°C, the stress reduced as pre-steaming time increased when compared at the same strain. The recovery of compressive deformation (strain recovery) was decreased with steaming time and reached almost 0 in 10 min at 200°C. The relationship between the residual stress and the strain recovery at the end of relaxation measurements could be expressed by a single curve regardless of time and temperature. The permanent fixation of deformation by steaming below 200°C was considered to be due to chain scission of hemicelluloses accompanying a slight cleavage of lignin. In some cases, the increase in regularity of the crystalline lattice space of microfibrils or the formation of crosslinks between the cell wall polymers seemed to play an important role in the permanent fixation of compressive deformation.

Modelling Recovery and Recrystallisation Kinetics after Intercritical Deformation in 0.19 wt% C 1.5 wt% Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 329-334 ◽  
Author(s):  
A. Smith ◽  
A. Miroux ◽  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag
Keyword(s):  
Stress Relaxation ◽  
Stress Distribution ◽  
Strain Distribution ◽  
Local Stress ◽  
Stress Strain ◽  
Simple Modification ◽  
Single Grain ◽  
Grain Model ◽  
Mn Steel ◽  
Kinetics Of

The softening kinetics of a 0.19 wt% C 1.5 wt% Mn steel deformed at two intercritical temperatures have been characterised using the stress relaxation technique. Recrystallisation of intercritical austenite has been modelled using a single grain model (Chen et al., 2002 [1]), whilst recovery of both intercritical austenite and ferrite has been modelled using a model in the literature [Verdier et al., 1999 [2]). The models are combined to predict the overall softening kinetics with a rule of mixtures formulation. Comparison of the model with experiment shows significant deviations. The reasons are discussed with reference to the mixture rule and to the local stress-strain distribution which exists in the deformed samples. A simple modification to the model is proposed which takes into account the effect of a local stress distribution in deformed austenite.

Tensile Stress—Strain and Stress Relaxation Behavior of Raw Elastomers Using a High Speed Tester

1974 ◽  
Vol 47 (2) ◽  
pp. 307-317 ◽  
Author(s):  
H. H. Bowerman ◽  
E. A. Collins ◽  
N. Nakajima
Keyword(s):  
Stress Relaxation ◽  
High Speed ◽  
Strain Rates ◽  
Time Behavior ◽  
Stress Strain ◽  
Strain Behavior ◽  
Relaxation Measurements ◽  
Ultimate Properties ◽  
Short Time ◽  
Acrylonitrile Copolymers

Abstract A high-speed, tensile-testing device was used to determine the stress—strain behavior of uncompounded butadiene—acrylonitrile copolymers over a range of temperatures and deformation rates. The strain rates were varied from 267 to 26,700 per cent/sec and the temperature was varied from 25 to 97° C. The high-speed tester was also used for stress—relaxation measurements by applying the strain nearly instantly in conformity with theoretical requirements in order to obtain the short time behavior. The WLF equation was obtained from the stress—relaxation data and then used to reduce the ultimate properties to one temperature over four decades of the strain rates. The ultimate properties could be represented by a failure envelope similar to those obtained for vulcanizates.

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