scholarly journals A Mixed Iteration Method to Determine the Linear Material Parameters in the Study of Creep Behavior of the Composites

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2907
Author(s):  
Mostafa Katouzian ◽  
Sorin Vlase ◽  
Maria Luminița Scutaru
Keyword(s):  
Composite Materials ◽  
Creep Behavior ◽  
Iteration Method ◽  
Viscoelastic Behavior ◽  
Calculation Algorithm ◽  
Nonlinear Parameters ◽  
Material Parameters ◽  
Different Temperatures ◽  
Classical Models ◽  
Linear Material

This paper presents and applies a mixed iteration method to determine the nonlinear parameters of the material used to study a composite’s creep behavior. To describe the research framework, we made a synthetic presentation of the viscoelastic behavior of composite materials by applying classical models. Further, the presented method was based on a calculation algorithm and program, which was applied on several types of materials. In a consecutive procedure of experiments and calculations, we determined the material parameters of the studied materials. The method was further applied to two composite materials in which the nonlinearity factors at different temperatures were determined.

scholarly journals A Phenomenological Primary–Secondary–Tertiary Creep Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2353
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Creep Behavior ◽  
Reference Model ◽  
Creep Model ◽  
Creep Process ◽  
Validation Dataset ◽  
Testing Conditions ◽  
Proposed Model ◽  
Testing Data ◽  
Bonded Composite

This study develops a unified phenomenological creep model for polymer-bonded composite materials, allowing for predicting the creep behavior in the three creep stages, namely the primary, the secondary, and the tertiary stages under sustained compressive stresses. Creep testing is performed using material specimens under several conditions with a temperature range of 20 °C–50 °C and a compressive stress range of 15 MPa–25 MPa. The testing data reveal that the strain rate–time response exhibits the transient, steady, and unstable stages under each of the testing conditions. A rational function-based creep rate equation is proposed to describe the full creep behavior under each of the testing conditions. By further correlating the resulting model parameters with temperature and stress and developing a Larson–Miller parameter-based rupture time prediction model, a unified phenomenological model is established. An independent validation dataset and third-party testing data are used to verify the effectiveness and accuracy of the proposed model. The performance of the proposed model is compared with that of an existing reference model. The verification and comparison results show that the model can describe all the three stages of the creep process, and the proposed model outperforms the reference model by yielding 28.5% smaller root mean squared errors on average.

scholarly journals The Influence of Composite Polymeric Materials Topology Over the Shearing Modulus Using Virtual Instruments

2018 ◽  
Vol 55 (4) ◽  
pp. 524-530
Author(s):  
Marinela Marinescu ◽  
Larisa Butu ◽  
Claudia Borda ◽  
Delicia Arsene ◽  
Mihai Butu
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Virtual Instrument ◽  
Mechanical Characteristics ◽  
Polymeric Materials ◽  
Mechanical Impedance ◽  
Impedance Analysis ◽  
Cross Linking ◽  
Labview Software ◽  
Different Temperatures

This study presents research regarding the calculation of the mechanical characteristics of composite polymeric materials. By using LabVIEW� software a virtual instrument was created used for monitoring in real time the process of cross-linking the composite polymeric materials. The experiments were realized based on composite materials containing epoxy/fiberglass resin of different topologies. By means of the virtual instrument and of a sensor created based on the mechanical impedance analysis, implanted in the composite material, it was determined the G shearing module of the composite material at different temperatures.

scholarly journals Reliability and micromechanics of Composite Materials

1992 ◽  
Vol 1 (3) ◽  
pp. 096369359200100 ◽  
Author(s):  
Zhanjun Gao
Keyword(s):  
Composite Materials ◽  
Structural Reliability ◽  
Global Response ◽  
Micromechanical Analysis ◽  
Material Parameters ◽  
Micro Level

A methodology is proposed to evaluate the reliability of composites. Micromechanical analysis is utilized as a basis for the representation of the effects of constituent properties on global response. The analysis is then combined with the models of structural reliability to study the influence of micro-level material parameters on reliability of composites under static loadings.

Study on High-Temperature Creep Behavior of T23 and T24 Steels

2018 ◽  
Vol 789 ◽  
pp. 182-186
Author(s):  
Jin Ping Pan ◽  
Shu Heng Tu ◽  
Ding Jun Chu ◽  
Xin Wei Zhu ◽  
Bin Hu ◽  
...  
Keyword(s):  
High Temperature ◽  
Creep Behavior ◽  
Rupture Strength ◽  
Progressive Increase ◽  
High Temperature Creep ◽  
Creep Tests ◽  
Theoretical Simulation ◽  
Temperature Creep ◽  
Piping Systems ◽  
Different Temperatures

A progressive increase of plant efficiency calls for new requirements of heat-resistantsteels used in the boiler and piping systems. In this paper, high-temperature creep behavior of T23and T24 steels were studied. Creep tests over a long period of time have been conducted for bothsteels at different temperatures. The creep mechanisms of the two steels have been clarified byanalyzing the minimum creep rate versus stress data. Besides, the creep rupture data from the creeptests were in good accordance with theoretical simulation on the basis of the CDM model over a longtime. Creep temperature has great effects on the rupture strength of the two steels. By creep ruptureexperiments and appropriate modelling, the high-temperature creep behavior can be well described.

Measurement of the loss tangent of low-density polyethylene with a nanoindentation technique

2000 ◽  
Vol 15 (5) ◽  
pp. 1195-1198 ◽  
Author(s):  
J. L. Loubet ◽  
W. C. Oliver ◽  
B. N. Lucas
Keyword(s):  
Loss Tangent ◽  
Arrhenius Equation ◽  
Viscoelastic Behavior ◽  
Low Density ◽  
Diamond Indenter ◽  
Different Temperatures ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Two Temperatures ◽  
Good Agreement

This paper describes experimental measurements of the linear viscoelastic behavior of the surface of low-density (LD) polyethylene in contact with a pyramidal Berkovich diamond indenter. The experiments were carried out at two different temperatures, 15.9 and 27.2 °C, between frequencies of 0.1 and 800 Hz. Using the shift of the loss tangent between the two temperatures at frequencies lower than 20 Hz and an Arrhenius equation, an activation energy of 105 ± 2 kJ/mol was obtained. This value is in good agreement with the bulk value of the a relaxation of LD polyethylene reported in the literature.

Superplastic Behaviour of AZ61-F Magnesium Composite Materials

2017 ◽  
Vol 36 (3) ◽  
pp. 279-283 ◽  
Author(s):  
Michal Besterci ◽  
Katarína Sülleiová ◽  
Oksana Velgosová ◽  
Beáta Balloková ◽  
S.-J. Huang
Keyword(s):  
Grain Size ◽  
Composite Materials ◽  
Strain Rate ◽  
Magnesium Alloys ◽  
Equal Channel Angular Pressing ◽  
Strain Rates ◽  
Maximum Strain ◽  
Plastic Deformations ◽  
Angular Pressing ◽  
Different Temperatures

AbstractDeformation of AZ61-F magnesium alloys with 1 wt % of Al2O3phase was tested at different temperatures and different strain rates. It was shown that at temperatures 473–523 K and the highest strain rate applied from 1×10–2s–1to 1×10–4s–1, a significant ductility growth was observed. The grain size of 0.6–0.8 μm was reached by severe plastic deformations by means of equal channel angular pressing (ECAP). Secondary Mg17Al12and Al2O3phases were identified. Maximum strain was gained at temperature of 473 K and strain rate of 1×10–4s–1.

Interface Controlled Diffusional Creep of Cu + 2.8 at.% Co Solid Solution

2012 ◽  
Vol 322 ◽  
pp. 33-39 ◽  
Author(s):  
Sergei Zhevnenko ◽  
Eugene Gershman
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Surface Tension ◽  
High Temperature ◽  
Creep Behavior ◽  
Pure Copper ◽  
Diffusional Creep ◽  
High Temperature Creep ◽  
Temperature Range ◽  
Different Temperatures

High-temperature creep experiments were performed on a Cu-2.8 ат.% Co solid solution. Cylindrical foils of 18 micrometers thickness were used for this purpose. Creep tests were performed in a hydrogen atmosphere in the temperature range of about from 1233 K to 1343 K and at stresses lower than 0.25 MPa. For comparison, a foil of pure copper and Cu-20 at.% Ni solid solution were investigated on high temperature creep. Measurements on the Cu foil showed classical diffusional creep behavior. The activation energy of creep was defined and turned out to be equal 203 kJ/mol, which is close to the activation energy of bulk self-diffusion of copper. There was a significant increase in activation energy for the Cu-20 at.% Ni solid solution. Its activation energy was about 273 kJ/mol. The creep behavior of Cu-Co solid solution was more complicated. There were two stages of diffusional creep at different temperatures. The extremely large activation energy (about 480 kJ/mol) was determined at relatively low temperature and a small activation energy (about 105 kJ/mol) was found at high temperatures. The creep rate of Cu-Co solid solution was lower than that of pure copper at all temperatures. In addition, the free surface tension of Cu-2.8 ат.% Co was measured at different temperatures from 1242 K to 1352 K. The surface tension increases in this temperature range from 1.6 N/m to 1.75 N/m. There were no features on the temperature dependence of the surface tension.

scholarly journals 3D-Simulation of Topology-Induced Changes of Effective Permeability and Permittivity in Composite Materials

2007 ◽  
Vol 2007 ◽  
pp. 1-8 ◽  
Author(s):  
B. Hallouet ◽  
R. Pelster
Keyword(s):  
Composite Materials ◽  
Effective Permeability ◽  
Filling Factor ◽  
Effective Permittivity ◽  
Matrix Material ◽  
Systematic Difference ◽  
Material Parameters ◽  
Effective Medium Model ◽  
Permittivity And Permeability ◽  
Induced Changes

We have performed 3D simulations of complex effective permittivity and permeability for random binary mixtures of cubic particles below the percolation threshold. We compare two topological classes that correspond to different spatial particle arrangements: cermet topology and aggregate topology. At a low filling factor off=10%, where most particles are surrounded by matrix material, the respective effective material parameters are indistinguishable. At higher concentrations, a systematic difference emerges: cermet topology is characterized by lower effective permittivity and permeability values. A distinction between topological classes might thus be a useful concept for the analysis of real systems, especially in cases where no exact effective-medium model is available.

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