scholarly journals Fracture investigation in starch-based foods

2016 ◽  
Vol 6 (3) ◽  
pp. 20160005 ◽  
Author(s):  
C. G. Skamniotis ◽  
Y. Patel ◽  
M. N. Charalambides ◽  
M. Elliott
Keyword(s):  
Material Model ◽  
Tensile Tests ◽  
Viscoplastic Material ◽  
Rate Dependent ◽  
Highly Nonlinear ◽  
Constitutive Response ◽  
Average Crack ◽  
Damage Law ◽  
Blade Cutting ◽  
Work Of Fracture

The study of oral processing and specifically cutting of the food piece during mastication can lead towards optimization of products for humans or animals. Food materials are complex biocomposites with a highly nonlinear constitutive response. Their fracture properties have not been largely investigated, while the need for models capable of predicting food breakdown increases. In this study, the blade cutting and the essential work of fracture (EWF) methodologies assessed the fracture behaviour of starch-based pet food. Tensile tests revealed rate-dependent stiffness and stress softening effects, attributed to viscoplasticity and micro-cracking, respectively. Cutting data were collected for 5, 10 and 30 mm s −1 sample feed rates, whereas the EWF tests were conducted at 1.7, 3.3 and 8.3 mm s −1 crosshead speeds corresponding to average crack speeds of 4, 7 and 15 mm s −1 , respectively. A reasonable agreement was achieved between cutting and EWF, reporting 1.26, 1.78, 1.76 kJ m −2 and 1.52, 1.37, 1.45 kJ m −2 values, respectively, for the corresponding crack speeds. These toughness data were used in a novel numerical model simulating the ‘first’ bite mastication process. A viscoplastic material model is adopted for the food piece, combined with a damage law that enabled predicting fracture patterns in the product.

scholarly journals A Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Mechanical Behavior ◽  
Lithium Ion ◽  
Material Model ◽  
Tensile Tests ◽  
Element Analysis ◽  
Rate Dependent ◽  
Novel Material ◽  
Li Ion ◽  
Role Based ◽  
Drive Systems

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

A Consistent Implicit Formulation for Nonlinear Finite Element Modeling With Contact and Friction: Part I—Theory

1991 ◽  
Vol 58 (2) ◽  
pp. 499-506 ◽  
Author(s):  
M. J. Saran ◽  
R. H. Wagoner
Keyword(s):  
Finite Element ◽  
Nonlinear Problems ◽  
Material Model ◽  
Test Problems ◽  
Large Strains ◽  
Numerical Verification ◽  
Viscoplastic Material ◽  
Highly Nonlinear ◽  
Complex Boundary ◽  
Consistent Tangent Operator

A formulation for finite element simulation of highly nonlinear problems including friction and contact with arbitrarily shaped rigid surfaces is proposed (CFS approach), prompted by difficulties in robust and accurate simulations of industrial forming processes. Nonlinearities are caused by large strains, plastic flow, and complex boundary conditions with frictional contact. In Part I the theoretical basis is described and the appropriate numerical algorithm is derived. The complete set of the governing relations, comprising equilibrium and interfacial equations, is appropriately linearized; resulting in a consistent tangent operator of the Newton-Raphson algorithm. In Part II, as a numerical verification, plane-strain sheet-forming processes are analyzed using a rigid-viscoplastic material model. Results are presented and discussed for test problems and for complex simulation of reverse drawing by concave tools.

A Thermoelastic-Viscoplastic Model With a Rate-Dependent Yield Strength

1982 ◽  
Vol 49 (2) ◽  
pp. 305-311 ◽  
Author(s):  
M. B. Rubin
Keyword(s):  
Yield Strength ◽  
Second Law Of Thermodynamics ◽  
Yield Function ◽  
Viscoplastic Material ◽  
Rate Dependent ◽  
Recent Developments ◽  
Constitutive Response ◽  
Temperature Rate ◽  
The Moment ◽  
Energy Equations

General nonlinear constitutive equations for a thermoelastic-viscoplastic material that exhibits a rate-dependent yield strength are developed by assuming that the yield function depends explicitly on the total strain rate and temperature rate. Following recent developments in continuum thermodynamics restrictions on the constitutive response functions are imposed to ensure that the moment of momentum and energy equations are identically satisfied and that various statements of the second law of thermodynamics are satisfied for all thermodynamical processes. A particular constitutive equation for a thermoelastic-viscoplastic material is proposed, and an analytical example is considered that examines the rate-dependent plastic response to a deformation history that includes segments of loading, unloading, and reloading, each occurring at varying strain rates.

A Visco-Hyperelastic Constitutive Model for Multilayer Polymer Membranes and its Application in Packaging Air Cushion

2016 ◽  
Vol 08 (05) ◽  
pp. 1650062
Author(s):  
Yingfeng Liu ◽  
Qiong Rao ◽  
Ming Chen ◽  
Xiongqi Peng ◽  
Shaoqing Shi
Keyword(s):  
Experimental Data ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Packaging Material ◽  
Polymer Membrane ◽  
Rate Dependent ◽  
Highly Nonlinear ◽  
Air Cushion

Air cushion is an important packaging material with admirable cushion property in protecting articles from damage. Polymer membrane in air cushion renders a highly nonlinear elastic and rate dependent mechanical behavior in experimental tensile test. A visco-hyperelastic constitutive model for a polymer membrane of an air cushion is developed by additively decomposing its mechanical response into a hyperelastic portion and a viscoelastic portion. Material parameters are consecutively obtained by matching experimental data of static and dynamic uni-axial tensile tests of the membrane, respectively. Compression test of a single air column of the air cushion is conducted as a means of validation on the proposed constitutive model. By comparing simulation results with experimental data, it is shown that the proposed visco-hyperelastic model can properly characterize the mechanical behavior of the air cushion packaging material. The model can be applied to evaluate cushion performance of air cushions and their optimum design.

A dynamic crash model for energy absorption in braided composite materials - Part II: Implementation and verification

2011 ◽  
Vol 45 (8) ◽  
pp. 867-882 ◽  
Author(s):  
Nathan D. Flesher ◽  
Fu-Kuo Chang ◽  
Nageswara R. Janapala ◽  
J. Michael Starbuck
Keyword(s):  
Composite Materials ◽  
Energy Absorption ◽  
Composite Structures ◽  
Material Model ◽  
Element Model ◽  
Failure Behavior ◽  
Viscoplastic Material ◽  
Braided Composite ◽  
Rate Dependent ◽  
Crash Model

A dynamic crash model is developed and implemented to model the failure behavior and energy absorption of braided composite structures. Part I describes the development and theoretical foundation of a viscoplastic material model that captures the rate-dependent behavior present in braided composite materials. Part II presents the implementation of the model into a finite element model program and the experimental results for tubes crushed from quasi-static to 4000 mm/s rates used to verify the model. Energy absorption decreases sharply with an increase in crush rate, which is reflected in this model. Design concepts are also introduced to increase energy absorption in braided composites.

Strain-Rate-Dependent Constitutive Equations for Concrete

1998 ◽  
Vol 120 (4) ◽  
pp. 398-405 ◽  
Author(s):  
J. W. Tedesco ◽  
C. A. Ross
Keyword(s):  
Strain Rate ◽  
Constitutive Equations ◽  
Split Hopkinson Pressure Bar ◽  
Material Model ◽  
Tensile Tests ◽  
Hopkinson Pressure Bar ◽  
Static Properties ◽  
Rate Dependent ◽  
Split Hopkinson ◽  
Pressure Bar

This paper summarizes the results of a comprehensive experimental study to quantify the effects of strain rate on concrete compressive and tensile strengths. Direct compression and splitting tensile tests were conducted at quasi-static rates (between 10−7/s and 10−5/s) in a standard MTS machine to establish the “static” properties. These same tests were conducted at high strain rates (between 10−1/s and 103/s) on a split-Hopkinson pressure bar (SHPB) to determine the dynamic material properties. A statistical analysis was performed on the data and strain-rate-dependent constitutive equations, both for compression and tension, were developed. These constitutive equations were subsequently employed to modify an existing quasi-static, nonlinear concrete material model.

Study of Material Modeling of Polymers for Impact Analysis

2014 ◽  
Vol 566 ◽  
pp. 474-479 ◽  
Author(s):  
Kunio Takekoshi ◽  
Kazukuni Niwa
Keyword(s):  
Tensile Test ◽  
High Speed ◽  
Impact Analysis ◽  
Material Model ◽  
Tensile Tests ◽  
Material Modeling ◽  
Test Results ◽  
Charpy Test ◽  
Rate Dependent ◽  
Dog Bone

High-speed tensile tests were carried out to investigate strain rate effect on both yield stress and failure strain using ASTM D1822 Type-S specimens made of polycarbonate. Based on test results, parameters for a material model suitable for polymers are determined, and numerical analysis is carried out to simulate test results. The material model is used to simulate tensile test using a dog-bone specimen and Charpy test other than the tensile test of Type-S specimens. It is found that good predictions can be obtained when rate dependent material parameters are used. Further, the high-speed tensile test considered in the present study is suitable for selection of parameters for material modeling of polymers for impact analysis.

scholarly journals Experimental Characterization of the Viscoplastic Material Behaviour of Thermosets and Thermoplastics

2010 ◽  
Vol 24-25 ◽  
pp. 195-200 ◽  
Author(s):  
Markus Kaestner ◽  
Swen Blobel ◽  
Martin Obst ◽  
Karin Thielsch ◽  
Volker Ulbricht
Keyword(s):  
Material Model ◽  
Small Strain ◽  
Tensile Tests ◽  
Material Behaviour ◽  
Viscoplastic Material ◽  
Experimental Procedure ◽  
Inelastic Material ◽  
Clear Identification ◽  
Relaxation Experiments

In this contribution the mechanical behaviour of polymeric matrix materials is analysed for both thermoplastics (Polypropylene) and thermosets (RTM6, RIM935). The results obtained from tensile tests carried out at different velocities indicate a nonlinear, inelastic material behaviour with strainrate dependence. For the clear identification and quantification of the nonlinearities, the experimental procedure has been extended to relaxation experiments and deformation controlled loading-unloadingprocesses with intermediate relaxations. Based on the experimental observations a small-strain viscoplastic material model is derived and material parameters are identified. The stress-strain-curves computed for different load histories are compared to the experimental results.

ECAE of Al-4%Cu Alloys: Experimental Study Assisted by Polycrystalline-FEM Simulations

2005 ◽  
Vol 495-497 ◽  
pp. 775-784 ◽  
Author(s):  
Javier Signorelli ◽  
R. Logé ◽  
P.A. Turner ◽  
V. Sordi ◽  
E.A. Vieira ◽  
...  
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Extrusion Direction ◽  
Material Model ◽  
Tensile Tests ◽  
Orientation Distribution ◽  
Viscoplastic Material ◽  
Fem Simulations ◽  
Pole Figures ◽  
Deformation Processes ◽  
Strain Paths

The present work reports on the results obtained on equal channel angular extrusion experiments (ECAE) done on a laboratory-cast Al-4%Cu alloy, in the T4 condition, and the use of Polycrystalline-FEM simulations to assist in the interpretation of the experiments. The experimental setup consists on a die of approximately 15 x 15 mm2 sections intersecting at 120o. Deformation at room temperature consisted of up to 5 passes with no rotation between passes. After each extrusion pass, the samples were cut from the deformed billet along planes parallel to the extrusion direction and the preferential orientations were measured on surface and middle layers. Three pole figures, (111), (200) and (220) were measured by conventional x-ray diffraction techniques and used for Orientation Distribution Function calculation and analysis. In addition tensile tests and optical microscopy have been performed in each sample to provide a good estimation of the parameters that enter in the modeling process. A finite element code specially developed to model large deformation processes (Forge3Ò) was used with tetrahedral elements and an elastic-viscoplastic material model to investigate the influence of the different strain paths sustained by different areas of the samples. The calculated distribution of deformations agrees well with the theoretical result. The simulation was used to assist in the selection of sample-cutting procedures for texture measurements and to provide the strain paths needed for self-consistent polycrystal modeling of texture development.

A dynamic crash model for energy absorption in braided composite materials. Part I: Viscoplastic material model

2011 ◽  
Vol 45 (8) ◽  
pp. 853-865 ◽  
Author(s):  
Nathan D. Flesher ◽  
Fu-Kuo Chang ◽  
Nageswara R. Janapala
Keyword(s):  
Composite Materials ◽  
Energy Absorption ◽  
Composite Structures ◽  
Material Model ◽  
Failure Behavior ◽  
Structural Level ◽  
Viscoplastic Material ◽  
Braided Composite ◽  
Rate Dependent ◽  
Crash Model

A dynamic crash model is developed and implemented to model the failure behavior and energy absorption of braided composite structures. Part I describes the development and theoretical foundation of a viscoplastic material model that captures the rate-dependent behavior present in braided composite materials. Part II presents the implementation of the model into a FEM program and contains experimental results for tubes crushed from quasi-static rate to 4000 mm/s rates used to verify the model. The model is presented from the mesoscale to the structural scale, starting with the constitutive model applied to composite tow segments. Tow segment response is homogenized to determine the response of the braided unit cell, while consideration for braider tow rotation and stress concentration appear at the structural level.

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