Investigation of the viscoelastic response of high temperature <scp>AS4</scp>‐12<scp>K/RP46</scp> composites using a micromechanical approach

Sayyidmousavi, Alireza; Bougherara, Habiba; Sawi, Ihab El

doi:10.1002/pc.23309

Cited by 6 publications

(4 citation statements)

References 32 publications

(28 reference statements)

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“…All stiffness tensors must be positive semi-definite to yield the thermodynamic consistency. [35] Time-temperature superposition principle is generally used to evaluate properties of polymers at different temperatures, [36,37] namely the mechanical behavior C of the material at temperature T can be derived by shifting its property C ref at the reference temperature T ref as:…”

Section: Temperature Dependent Viscoelastic Constitutive Modelmentioning

confidence: 99%

“…Time–temperature superposition principle is generally used to evaluate properties of polymers at different temperatures, [ 36,37 ] namely the mechanical behavior

C

of the material at temperature

T

can be derived by shifting its property

{boldC}^{ref}

at the reference temperature

T^{ref}

as:

C (t; T) = {boldC}^{ref} (\frac{t}{a_{T}}; T^{ref}),

where,

a_{T}

denotes the shift factor. When the temperature is within the glass transition temperature

T_{g}

and

T_{g} + 100 ° C

, [ 38 ] the Williams‐Landel‐Ferry (WLF) model is commonly used to mathematically describe

a_{T}

, [ 39 ] which is expressed as:

\log a_{T} = - \frac{C_{1} (T - T_{ref})}{C_{2} + (T - T_{ref})},

where,

C_{1}

and

C_{2}

denote universal constants.…”

Section: Introductionmentioning

confidence: 99%

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A dual‐scale three‐dimensional thermo‐viscoelastic model for the hot stamping simulation of thermoplastic composites

et al. 2022

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Existing hot stamping simulations are performed at the macroscopic scale, making optimizing process parameters for a new composite system time‐consuming. This paper develops a dual‐scale three‐dimensional thermos‐viscoelastic model based on a numerical homogenization approach to accurately predict the structural deformation of thermoplastic composite laminates during hot stamping. The viscoelastic homogenization model is developed on representative volume elements using temperature‐dependent viscoelastic parameters determined from thermo‐mechanical tests. The effective properties of the composites are identified from the homogenization results, which are then combined with the experimentally measured thermal behavior into a numerical model of the hot stamping process. The developed model is validated by the agreement between the finite element homogenization results and the predictions made using the determined parameters. The simulated warpage of the molded part also agrees well with the experimental measurements. The developed dual‐scale model can be used to predict the effective thermomechanical properties of composites. Moreover, it can also be integrated into numerical tools for structural design and process optimization of thermoplastic composites.

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Section: Temperature Dependent Viscoelastic Constitutive Modelmentioning

confidence: 99%

“…Time–temperature superposition principle is generally used to evaluate properties of polymers at different temperatures, [ 36,37 ] namely the mechanical behavior

C

of the material at temperature

T

can be derived by shifting its property

{boldC}^{ref}

at the reference temperature

T^{ref}

as:

C (t; T) = {boldC}^{ref} (\frac{t}{a_{T}}; T^{ref}),

where,

a_{T}

denotes the shift factor. When the temperature is within the glass transition temperature

T_{g}

and

T_{g} + 100 ° C

, [ 38 ] the Williams‐Landel‐Ferry (WLF) model is commonly used to mathematically describe

a_{T}

, [ 39 ] which is expressed as:

\log a_{T} = - \frac{C_{1} (T - T_{ref})}{C_{2} + (T - T_{ref})},

where,

C_{1}

and

C_{2}

denote universal constants.…”

Section: Introductionmentioning

confidence: 99%

A dual‐scale three‐dimensional thermo‐viscoelastic model for the hot stamping simulation of thermoplastic composites

et al. 2022

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“…The composite displayed noticeable creep in the fiber direction when the temperature approached the T g value, and it showed a nonlinear viscoelastic behavior beyond threshold stress of 13 ksi at 700 °C. Sayyidmousavi et al [10] conducted creep tests on polyimide resin-based carbon fiber composite at 180, 220, and 270 °C. Increased temperature resulted in softening and acceleration of the creep strain.…”

Section: Introductionmentioning

confidence: 99%

Stress Dependency of Creep Response for Glass/Epoxy Composite at Nonlinear and Linear Viscoelastic Behavior

Nosrati

Zabett

Sahebian

2022

International Journal of Polymer Science

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This research is aimed at comparing the stress dependency of creep viscoelastic behavior for glass/epoxy composite and neat epoxy close to the glass transition temperature and room temperature. Long-term creep performance of quasi-unidirectional composites and quasi-isotropic stacking sequence composites is modeled based on the time-stress superposition principle (TSSP). Linearity and nonlinearity of viscoelastic behavior and stress-dependence correlations were investigated for quasi-isotropic stacking sequence composite at 25°C and 50°C (near the glass transition temperature). Stress dependency of creep stages (primary, secondary, and tertiary) of neat epoxy was evaluated at this range of temperature. The prediction results of composite at room temperature show that the raising of the stress levels leads to the acceleration of viscoelastic strain values, but the creep compliance does not present any dependency. Besides, the reduction of viscoelastic ability is realized by measuring less amount of creep compliance at higher stress level in the glass transition temperature. These observations confirmed the linearity and nonlinearity of viscoelastic behavior at room and glass transition temperature, respectively. Similar results of neat epoxy revealed that the increase in the stress level accelerates the strain values at room temperature and decreases the creep resistance at glass transition temperature. Failure morphologies of epoxy sample fractured at room temperature are included scarp, cusp, and river line; however, close to the glass transition temperature, more expansive mirror zones appeared. Fiber architecture significantly affected the secondary stage regime by providing load-bearing ability. Thereby, creep rate reduction and enhancement of creep lifetime and creep resistance would be reported using unidirectional reinforcing in contrast to those of the multilayer sequence one.

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“…Figure7 6. shows the creep response of the composite material at 180 o C for 30% of the UTS compared to the experimental results.…”

mentioning

confidence: 99%

Investigation of creep and fatigue in high temperature polymer matrix composites using a micromechanical approach

Sayyidmousavi¹

2021

Preprint

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Polymer matrix composites (PMC’s) are widely used in critical aerospace structures due to their numerous advantageous mechanical properties. Recently, PMC’s have been considered for high temperature applications where viscoelasticity arising from the time dependent nature of the polymer matrix becomes an important consideration. This inherent viscoelasticity can significantly influence deformation, strength and failure response of these materials under different loading modes and environmental factors. With a potentially large number of plies of different fiber directions and perhaps material properties, determining a fatigue failure criterion of any degree of generality through experiments only, may seem to be an unrealistic task. This difficult situation may be mitigated through the development of suitable theoretical micro or macro mechanical models that are founded on considering the fatigue failure of the constituting laminas. The micro‐approach provides a detailed examination of the individual failure modes in each of the constituent materials i.e. fiber, matrix. In this work, a micromechanical approach is used to study the role of viscoelasticity on the fatigue behavior of polymer matrix composites. In particular, the study examines the interaction of fatigue and creep in polymer matrix composites. The matrix phase is modeled as a vicoelastic material using Schapery’s single integral constitutive equation. Taking viscoelsticity into account allows the study of creep strain evolution during the fatigue loading. The fatigue failure criterion is expressed in terms of the fatigue failure functions of the constituent materials. The micromechanical model is also used to calculate these fatigue failure functions from the knowledge of the S‐N diagrams of the composite material in longitudinal, transverse and shear loadings thus eliminating the need for any further experimentation. Unlike the previous works, the present study can distinguish between the strain evolution due to fatigue and creep. The results can clearly show the contribution made by the effect of viscoelasticity to the total strain evolution during the fatigue life of the specimen. Although the effect of viscoelsticity is found to increase with temperature, its contribution to strain development during fatigue is compromised by the shorter life of the specimen when compared to lower temperatures.

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Investigation of the viscoelastic response of high temperature AS4‐12K/RP46 composites using a micromechanical approach

Cited by 6 publications

References 32 publications

A dual‐scale three‐dimensional thermo‐viscoelastic model for the hot stamping simulation of thermoplastic composites

A dual‐scale three‐dimensional thermo‐viscoelastic model for the hot stamping simulation of thermoplastic composites

Stress Dependency of Creep Response for Glass/Epoxy Composite at Nonlinear and Linear Viscoelastic Behavior

Investigation of creep and fatigue in high temperature polymer matrix composites using a micromechanical approach

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