Non-Linear Large Deformation Kinetics of Polymeric Gel

2013 ◽  
Vol 535-536 ◽  
pp. 338-341 ◽  
Author(s):  
William Toh ◽  
Teng Yong Ng ◽  
Zi Shun Liu
Keyword(s):  
Transient Heat Conduction ◽  
Element Model ◽  
Initial State ◽  
Linear Deformation ◽  
Deformation Kinetics ◽  
Polymeric Gels ◽  
Free Swelling ◽  
Non Linear ◽  
Kinetics Of ◽  
Fixed Cylinder

The transient swelling process of polymeric gels is studied and a finite element model is introduced to simulate the phenomena based on existing hyperelastic theory for inhomogeneous swelling of gels and analogies made to transient heat conduction analysis. Examples of free swelling of a cube and a fixed cylinder were investigated, showing the highly non-linear deformation present during transition from the initial state to equilibrium.

INHOMOGENEOUS LARGE DEFORMATION KINETICS OF POLYMERIC GELS

2013 ◽  
Vol 05 (01) ◽  
pp. 1350001 ◽  
Author(s):  
WILLIAM TOH ◽  
ZISHUN LIU ◽  
TENG YONG NG ◽  
WEI HONG
Keyword(s):  
Large Deformation ◽  
Soft Matter ◽  
Inner Core ◽  
Kinetic Studies ◽  
Fe Model ◽  
One Dimensional ◽  
Simplified Approach ◽  
Deformation Kinetics ◽  
Polymeric Gels ◽  
Kinetics Of

This work examines the dynamics of nonlinear large deformation of polymeric gels, and the kinetics of gel deformation is carried out through the coupling of existing hyperelastic theory for gels with kinetic laws for diffusion of small molecules. As finite element (FE) models for the transient swelling process is not available in commercial FE software, we develop a customized FE model/methodology which can be used to simulate the transient swelling process of hydrogels. The method is based on the similarity between diffusion and heat transfer laws by determining the equivalent thermal properties for gel kinetics. Several numerical examples are investigated to explore the capabilities of the present FE model, namely: a cube to study free swelling; one-dimensional constrained swelling; a rectangular block fixed to a rigid substrate to study swelling under external constraints; and a thin annulus fixed at the inner core to study buckling phenomena. The simulation results for the constrained block and one-dimensional constrained swelling are compared with available experimental data, and these comparisons show a good degree of similarity. In addition to this work providing a valuable tool to researchers for the study of gel kinetic deformation in the various applications of soft matter, we also hope to inspire works to adopt this simplified approach, in particular to kinetic studies of diffusion-driven mechanisms.

Finite Element Analysis for J-Integral of Axial Through-Wall Cracked Elbow Under Bending Moment

2011 ◽  
Author(s):  
Wei-Ju Liu ◽  
Bor-Jiun Tsai ◽  
Jien-Jong Chen ◽  
Yan-Shiun Du ◽  
Wei-Sheng Liu
Keyword(s):  
Finite Element ◽  
Fracture Behavior ◽  
Bending Moment ◽  
Element Model ◽  
J Integral ◽  
Element Analysis ◽  
Linear Deformation ◽  
Proposed Model ◽  
Non Linear ◽  
Leak Before Break

Leak-before-break (LBB) assessment of nuclear piping involves ductile fracture analysis of pipes or elbows with postulated through-wall cracks. Due to the fact that the crown part of an elbow is one of the positions that crack initiation occurs in most frequently, the calculation of J-integrals to investigate fracture behavior are important research topics. This paper proposes a 3-D finite element model of an elbow embedded with an axial through-wall crack to estimate the J-integral parameters under bending moment. The J-integral values can be calculated by using ABAQUS and taking into account the effects of geometrical and model of material in non-linear analysis. The results show that the non-linear deformation and contact condition of crack surfaces play important roles for the J-integral values. In addition, the J values estimated by the proposed model are more conservative and realistic than previous studies.

Fracture Toughness of Laminated Composites – A Non-Linear Analysis

2012 ◽  
Vol 20 (8) ◽  
pp. 711-716
Author(s):  
V. Rizov ◽  
A. Mladensky
Keyword(s):  
Test Specimen ◽  
Crack Opening ◽  
Laminated Composite ◽  
Element Model ◽  
Linear Deformation ◽  
Linear Character ◽  
Linear Fracture ◽  
Non Linear ◽  
Laminated Composite Materials ◽  
Dry Conditions

Non-linear fracture behaviour of laminated composite materials under mode I (crack opening) loading conditions was studied experimentally and theoretically. For this purpose, single edge notched tension (SENT) tests were carried-out using displacement-controlled loading under room temperature dry conditions. It was found that the load-displacement diagram had non-linear character prior to onset of macroscopic crack propagation. Thus, the main objective of this paper was to study the fracture properties using non-linear fracture mechanics. A two-dimensional finite element model was set-up in order to analyze the non-linear response of the SENT test specimen. Non-linear deformation due to damage was simulated using the Tsai-Hill failure criterion. The failure analysis revealed that the damage was localized in the vicinity of the crack tip. The fracture response was characterized using a J-integral. It was shown that a realistic appraisal of the potential for crack growth should include the effects of non-linear material deformation. It was found that taking into account the non-linear deformation increased the fracture resistance. This finding was attributed to the increased strain energy dissipation due to the damage induced non-linear behaviour of the SENT test specimen.

scholarly journals Evaluation of Moisture and Decay Models for a New Design Framework for Decay Prediction of Wood

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 721
Author(s):  
Jonas Niklewski ◽  
Philip Bester van Niekerk ◽  
Christian Brischke ◽  
Eva Frühwald Hansson
Keyword(s):  
Service Life ◽  
Wood Decay ◽  
Element Model ◽  
Digital Design ◽  
Design Guideline ◽  
Digital Performance ◽  
Detail Design ◽  
Non Linear ◽  
Service Life Design ◽  
Life Design

Performance-based, service-life design of wood has been the focus of much research in recent decades. Previous works have been synthesized in various factorized design frameworks presented in the form of technical reports. Factorization does not consider the non-linear dependency between decay-influencing effects, such as between detail design and climate variables. The CLICKdesign project is a joint European effort targeting digital, performance-based specification for service-life design (SLD) of wood. This study evaluates the feasibility of using a semi-empirical moisture model (SMM) as a basis for a digital SLD framework. The performance of the SMM is assessed by comparison against a finite element model (FEM). In addition, two different wood decay models (a logistic, LM, and simplified logistic model (SLM)) are compared. While discrepancies between the SMM and FEM were detected particularly at high wood moisture content, the overall performance of the SMM was deemed sufficient for the application. The main source of uncertainty instead stems from the choice of wood decay model. Based on the results, a new method based on pre-calculated time series, empirical equations, and interpolation is proposed for predicting the service life of wood. The method is fast and simple yet able to deal with non-linear effects between weather variables and the design of details. As such, it can easily be implemented as part of a digital design guideline to provide decision support for architects and engineers, with less uncertainty than existing factorized guidelines.

Kinetics of microdamage accumulation in low-carbon steel in the initial state and after ECAP

2020 ◽  
Author(s):  
I. O. Sinev ◽  
E. N. Beletsky ◽  
M. R. Tyutin ◽  
L. R. Botvina ◽  
O. V. Rybalchenko ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Initial State ◽  
Microdamage Accumulation ◽  
Kinetics Of
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