Understanding residual stresses in polymer matrix composites

Shokrieh, M.M.; Safarabadi, Majid

doi:10.1016/b978-0-12-818817-0.00011-1

Cited by 3 publications

(2 citation statements)

References 104 publications

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“…Residual temperature stresses in polymers and composites are formed due to specific reasons and mechanisms. These are explained in monographs [16][17][18][19][20][21], as well as in review and research publications [22][23][24][25][26]. These factors include temperature variations through structures, different thermal expansions of polymer components, curing process conditions, polymer shrinkage, and interaction with tools.…”

Section: Introductionmentioning

confidence: 99%

Cyclic Thermomechanical Loading of Epoxy Polymer: Modeling with Consideration of Stress Accumulation and Experimental Verification

Mishnev,

Korolev,

Zadorin

et al. 2024

Polymers

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Developing a viscoelastic model for the cyclic thermomechanical loading of thermosetting polymers is the main goal of this study. The model includes memory for residual thermal stresses and can consider stress accumulation across many loading cycles. By considering stress accumulation, we can improve predictions and understand how thermosetting polymers’ stress–strain state changes under cyclic thermomechanical loading. This approach was validated through experimental verification to ensure its applicability in practical engineering scenarios. The experiment showed that the thermosetting polymer can accumulate stress during cycles of heating and mechanical loading during use. The results of the modeling and experiment are compared. The results have led to corrections in the way this model is applied to thermosetting polymers like the epoxy resin in this study. The corrected results matched well with the experimental measurements of stress under cyclic thermomechanical load, with a difference of only 1 to 6%.

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Section: Introductionmentioning

confidence: 99%

Cyclic Thermomechanical Loading of Epoxy Polymer: Modeling with Consideration of Stress Accumulation and Experimental Verification

Mishnev,

Korolev,

Zadorin

et al. 2024

Polymers

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show abstract

“…The main reasons and mechanisms of formation of residual temperature stresses in polymers and composites are summarized in monographs [1][2][3][4][5][6], review and research publications [7][8][9][10][11]. These include temperature gradients along the thickness of structures, different (including anisotropic) thermal expansion of polymer composites components, features of technological modes of curing, chemical shrinkage of polymer matrix, interaction with technological tools and others.…”

Section: Introductionmentioning

confidence: 99%

Cyclic thermomechanical loading of thermoset polymer: experiment and modeling considering accumulation residual stress

Mishnev,

Korolev,

Zadorin

et al. 2023

Preprint

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The paper presents the results of experimental studies and mathematical modeling of the effect of stress accumulation in thermosetting epoxy polymer "hot" curing on anhydride hardener. Stress accumulation occurs under cyclic thermomechanical action in a locked rod, similar effects are observed, for example, in thermoplastic elements subjected to the combined effect of mechanical loads and variable temperatures. Experimental results have shown that under cyclic thermomechanical loading during exploitation it is possible to accumulate residual stresses in the thermosetting polymer. A multi-element structural mathematical model with memory for thermomechanical load, which allows to consider the accumulation of residual thermal stresses, has been proposed. The results of modeling and experiment are compared. Based on the results, corrections are made in the approach to the application of this model to thermosetting polymers such as the epoxy resin under study. Considering the corrections, a good agreement (the difference is from 1 to 6%) with the results of experimental determination of stresses under complex cyclic thermomechanical load was obtained.

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Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process

2022

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Vinyl ester (VE) resin has strong environmental tolerance and is the matrix commonly used in the composite materials of fiber-reinforced plastics (FRP). VE resin is often combined with glass fiber in different maritime structures, such as wind turbine blades, spinner cases, and nacelle cases. However, VE resin exhibits exothermic reactions and shrinkage during curing, which often generates residual strain in large structures and those with a high stacking number. This study explored the exothermic reaction and shrinkage of VE resin and glass fiber during the vacuum-assisted resin transfer molding process, as measured using a fiber Bragg grating sensor. The experiment results verified the relationship between the stacking number and residual strain shrinkage. In addition, the symmetric laminate method was used to prevent the bending–twisting coupling effect and subsequent warping deformation of the FRP laminated plate during curing. The experiment results also verified that the bottom layers of the FRP laminated plates produced using VE resin were closer to the mold, and exhibited more shrinkage as the stacking number increased. In addition, this study discovered that during the experiment, the symmetry layer of the FRP laminated plate had a higher exothermic temperature than the bottom layer as a result of the symmetry layer’s ineffective heat dissipation. Therefore, the curing shrinkage of the symmetry layer resin was measured. The experiment results indicated that if the stacking number was between 10 and 30, the residual strain shrinkage of the symmetry layer was greater than that of the surface layer. However, because of the symmetric laminate, the residual strain of the symmetry layer did not increase when the temperature increased. Therefore, the greatest residual strain occurred at the surface of the bottom layer of the laminated plate with a stacking number of 40.

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Understanding residual stresses in polymer matrix composites

Cited by 3 publications

References 104 publications

Cyclic Thermomechanical Loading of Epoxy Polymer: Modeling with Consideration of Stress Accumulation and Experimental Verification

Cyclic Thermomechanical Loading of Epoxy Polymer: Modeling with Consideration of Stress Accumulation and Experimental Verification

Cyclic thermomechanical loading of thermoset polymer: experiment and modeling considering accumulation residual stress

Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process

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