scholarly journals A model for aging under deformation field, residual stresses and strains in soft glassy materials

Soft Matter ◽  
2015 ◽  
Vol 11 (16) ◽  
pp. 3198-3214 ◽  
Author(s):  
Yogesh M. Joshi
Keyword(s):  
Residual Stress ◽  
Relaxation Time ◽  
Simple Model ◽  
Residual Stresses ◽  
Yield Stress ◽  
Shear Banding ◽  
Stress And Strain ◽  
Glassy Materials ◽  
Soft Glassy Materials ◽  
Residual Stresses And Strains

A simple model is proposed that explicitly considers the effect of evolving relaxation time and modulus on various rheological behaviors of soft glassy materials including thixotropy, yield stress, shear banding, and residual stress and strain.

Shear banding and yield stress in soft glassy materials

2008 ◽  
Vol 77 (4) ◽  
Author(s):  
P. C. F. Møller ◽  
S. Rodts ◽  
M. A. J. Michels ◽  
Daniel Bonn
Keyword(s):  
Yield Stress ◽  
Shear Banding ◽  
Glassy Materials ◽  
Soft Glassy Materials

scholarly journals A multi-component lattice Boltzmann approach to study the causality of plastic events

2020 ◽  
Vol 378 (2175) ◽  
pp. 20190403
Author(s):  
Pinaki Kumar ◽  
Roberto Benzi ◽  
Jeannot Trampert ◽  
Federico Toschi
Keyword(s):  
Yield Stress ◽  
Lattice Boltzmann ◽  
Soft Matter ◽  
Scaling Laws ◽  
System A ◽  
Plastic Event ◽  
Glassy Materials ◽  
Couette Cell ◽  
Soft Glassy Materials ◽  
Concentrated Emulsions

Using a multi-component lattice Boltzmann (LB) model, we perform fluid kinetic simulations of confined and concentrated emulsions. The system presents the phenomenology of soft-glassy materials, including a Herschel–Bulkley rheology, yield stress, ageing and long relaxation time scales. Shearing the emulsion in a Couette cell below the yield stress results in plastic topological re-arrangement events which follow established empirical seismic statistical scaling laws, making this system a good candidate to study the physics of earthquakes. One characteristic of this model is the tendency for events to occur in avalanche clusters, with larger events, triggering subsequent re-arrangements. While seismologists have developed statistical tools to study correlations between events, a process to confirm causality remains elusive. We present here, a modification to our LB model, involving small, fast vibrations applied to individual droplets, effectively a macroscopic forcing, which results in the arrest of the topological plastic re-arrangements. This technique provides an excellent tool for identifying causality in plastic event clusters by examining the evolution of the dynamics after ‘stopping’ an event, and then checking which subsequent events disappear. This article is part of the theme issue ‘Fluid dynamics, soft matter and complex systems: recent results and new methods’.

Residual Stress and Strain Responses of Welded Piping Joints Under Low-Cycle Fatigue Loading

2009 ◽  
Author(s):  
Pei-Yuan Cheng ◽  
Tasnim Hassan
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fatigue Failure ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Stress And Strain ◽  
Weld Toe ◽  
Strain Responses

It is well known that residual stress of welded joints influence their fatigue lives. This influence of residual stress is manifested through strain ratcheting response at the weld toe. Among many other reasons, strain ratcheting at the weld toe is anticipated to be a reason of many premature fatigue failure of welded joints. Hence, accurate simulations of weld toe residual stress and strain responses are essential for fatigue life simulation of welded joints. This paper presents results form an ongoing study on fatigue failure of welded piping joints. A modeling scheme for simulating weld toe residual stress and strain response is developed. Uncoupled, thermo-mechanical, finite element analyses are employed for imitating the welding procedure, and thereby simulating the temperature history during welding and initial residual stresses. Simulated residual stresses are validated by comparing against the measured residual stresses. Finite element simulations indicate that both residual stress and resulting strain responses near the weld toe are the key factors in inducing fatigue cracks at the weld toe. Research needs in revealing the fatigue failure mechanisms at the weld toe are discussed.

Hole-Drilling Method for Residual Stress Measurement - Consideration of Elastic-Plastic Material Properties

2013 ◽  
Vol 768-769 ◽  
pp. 174-181 ◽  
Author(s):  
David von Mirbach
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Yield Stress ◽  
Material Properties ◽  
Plastic Material ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Elastic Plastic Material ◽  
Ring Core

Two commonly used mechanical methods for the determination of residual stresses are the hole-drilling method and the ring-core method, which can be regarded as semi-destructive. The most restricting limitation for the general applicability of both methods, according to the current state of science and technology, is the fact that the scope for relatively low residual stress under 60% of the yield stress is limited.This is a result of the notch effect of the hole or ring core, which leads to a plastification around and on the bottom of the hole and ring shaped groove already at stresses well below the yield stress of the material. The elastic evaluation of the resulting plastic strains leads consequently to an overestimation of the delineated residual stresses. In this paper the influence of elastic-plastic material properties no the specific calibration function for the hole-drilling method using the differential method is studied, and the method of adaptive calibration functions is presented.

Residual Stress of Gear Meshing under Shakedown Condition with Direct Analysis

2012 ◽  
Vol 152-154 ◽  
pp. 877-882
Author(s):  
Yuan Yuan ◽  
Peng Fei Li ◽  
Kai Liu
Keyword(s):  
Mathematical Model ◽  
Residual Stress ◽  
Residual Stresses ◽  
Direct Method ◽  
Direct Analysis ◽  
Numerical Approach ◽  
Operating Life ◽  
Operator Split ◽  
Gear Contact ◽  
Residual Stresses And Strains

A shakedown mathematical model of gear contact has been developed. A direct method is applied to solve the mathematical model. Local coordinates are constructed on different meshing points because curvature of gear profile is not constant. Distributions of residual stresses and strains are given base on variable curvature surface. The numerical approach consists of an operator split technique, which transforms the elastic-plastic problem into a purely elastic problem and a residual problem with prescribed eigenstrains. The eigenstrains are determined using an incremental projection method. Contact stresses and contact residual stresses of meshing gear teeth with standard and modified profile are computed. The results show compressive residual stress can improve capacity of gear and operating life. This aspect may contribute to future developments in the understanding of gear durability.

scholarly journals Shear banding, aging and noise dynamics in soft glassy materials

Soft Matter ◽  
2009 ◽  
Vol 5 (12) ◽  
pp. 2378-2382 ◽  
Author(s):  
S. M. Fielding ◽  
M. E. Cates ◽  
P. Sollich
Keyword(s):  
Shear Banding ◽  
Glassy Materials ◽  
Soft Glassy Materials

scholarly journals Modeling and Calculating of Residual Stress and Strain of Butt Welded Joint

2021 ◽  
Vol 31 (5) ◽  
pp. 58-67
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welded Joint ◽  
The Finite Element Method ◽  
Force Method ◽  
Stress Components ◽  
Residual Stresses And Strains ◽  
Element Method

The non-uniform thermal expansion and contraction resulting from welding processes cause residual stresses and strains. Experimental studies on measuring welding residual stresses and strains of structure are costly and sometimes they are not possible. Previously, analytical methods with idealized models were developed to determine the welding residual stresses and strain. Recently, numerical methods are constructed to analyze the stresses and the strains in welded structures. This paper presents the calculation results of residual stress and welding strain in butt welded joint of S355J2G3 carbon steel of 5 mm thickness made by MAG welding process with a single pass. The calculation is performed by two methods: the imaginary force method and the finite element method. In the finite element method, the SYSWELD software is used to simulate and to determine residual stresses and strain of this welded joint. The results of finite element method are compared with those of imaginary force method to show the rationality and the advantages of finite element method. The study results have shown that in this welded joint, only the longitudinal and transverse stress components are important and the other stress components are negligible.

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