Toward the constitutive modeling of epoxy matrix: Temperature-accelerated quasi-static molecular simulations consistent with the experimental test

Park, Hyungbum; Choi, Joonmyung; Kim, Byungjo; Yang, Seunghwa; Shin, Hyunseong; Cho, Maenghyo

doi:10.1016/j.compositesb.2018.01.018

Cited by 43 publications

(21 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It needs to be noted that the present study only focused on the idealized structure of the epoxy polymers and did not consider the influences of the chain scissions and initial microvoids, which could be critical to the fatigue lives of the amorphous polymers. These issues need to be studied with the aid of large time and spatial scale simulations [ 26,34,44 ] which cannot be achieved by the present full‐atomic simulations. Thus, future investigations will concentrate on the development of the framework that can quantitatively predict the ratcheting behaviors, simultaneously considering aforementioned limitations of the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Other than the stress level, the frequency of the cyclic deformations was also considered as a main variable considering the viscoelastic nature of polymers. [ 26,34 ] In this study, the two different frequency level was studied: 8.33 and 4.17 ns −1 . Based on the abovementioned stress and frequency conditions, a total of 500 cycles was simulated for the considered epoxy polymers (the number of cycles of DGEBA/DETDA at the frequency of 4.17 ns −1 was 480).…”

Section: Methodsmentioning

confidence: 99%

Section: Stress-controlled Compressive Cyclic Loading-unloading Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Effect of molecular structure of curing agents on cyclic creep in highly cross‐linked epoxy polymers

Park

Chung

Cho

2020

Journal of Polymer Science

Self Cite

View full text Add to dashboard Cite

Ratcheting behavior of highly–cross‐linked epoxy polymers was investigated considering the effect of molecular structure of curing agents by molecular dynamics simulations. Cyclic loading–unloading simulations at two different frequencies were conducted using atomistic models for epoxies cured by aliphatic and aromatic curing agents, triethylenetetramine (TETA) and diethyltoluenediamine (DETDA), respectively. Different ratcheting strain evolutions, dihedral angle stress accumulations, and stiffness variations were observed during the cyclic deformation simulations depending on the molecular structure of curing agents. The epoxy cured by DETDA exhibited a more rapid increase of ratcheting strain and a decrease of the stiffness toward the loading direction. Structural analyses were carried out by observing the orientation order parameter of the monomers, radius of gyration, and free volume evolution to understand the ratcheting strain behaviors and stiffness variations at atomistic scale. The structural analyses revealed that irreversible dihedral angle transitions near the benzene ring of the curing agent DETDA were responsible for low ratcheting resistance and stiffness degradation during the cyclic deformations. Whereas, the aliphatic curing agent TETA, which does not exhibit any stress possession by the irreversible dihedral angle change, was revealed to be advantageous for the ratcheting resistance and stiffness variation of the epoxy polymers.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of molecular structure of curing agents on cyclic creep in highly cross‐linked epoxy polymers

Park

Chung

Cho

2020

Journal of Polymer Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…The damage of mechanical properties with increasing temperature is related to the phase transition of the polymer chains from the glassy phase to the rubbery phase. While the flexibility of the polymer chains increases and the non-bonded interaction between the polymer chains is weakened with increasing temperature; the structure could be easily deformed under external loading [ 33 , 34 ]. Plastic deformation contains shear bands and crazes [ 35 ].…”

Section: Discussionmentioning

confidence: 99%

Influence of Thermal Shocks on Residual Static Strength, Impact Strength and Elasticity of Polymer-Composite Materials Used in Firefighting Helmets

et al. 2021

View full text Add to dashboard Cite

The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock occurring during the heat load, it was noticed that the character of a composite damage changes from the elasto-brittle type into the elasto-plastic one. It was also proved that changes in mechanical and elastic properties of the material used in a helmet shell can affect the protective abilities of a helmet.

show abstract

“…PNCs, different from traditional composite materials, exhibit quite complex thermomechanical properties which are strongly related to the physics and chemistry of the inclusion of nanofillers, including nanoparticles, carbon nanotubes (CNTs) [4,8], and graphenes [9,10]. Among all PNCs, the most attractive materials may be those reinforced by carbon nanotubes, due to their practical engineering applications such as aerospace materials, packing, and electromagnetic interference (EMI) shielding [4,11,12].…”

Section: Introductionmentioning

confidence: 99%

Importance of Interface in the Coarse-Grained Model of CNT /Epoxy Nanocomposites

Duan

Wang

et al. 2019

Nanomaterials

View full text Add to dashboard Cite

Interface interactions play a crucial role in determining the thermomechanical properties of carbon nanotubes (CNTs)/polymer nanocomposites. They are, however, poorly treated in the current multi-scale coarse-grained (CG) models. To develop suitable CG models of CNTs/polymer nanocomposites, we demonstrate the importance of two aspects for the first time, that is, preserving the interfacial cohesive energy and reproducing the interface load transfer behavior of all-atomistic (AA) systems. Our simulation results indicate that, for CNTs/polymer nanocomposites, the interface cohesive energy and the interface load transfer of CG models are generally inconsistent with their AA counterparts, revealing significant deviations in their predicted mechanical properties. Fortunately, such inconsistency can be “corrected” by phenomenologically adjusting the cohesive interaction strength parameter of the interface LJ potentials in conjunction with choosing a reasonable degree of coarse-graining of incorporated CNTs. We believe that the problem studied here is general for the development of the CG models of nanocomposites, and the proposed strategy used in present work may be applied to polymer nanocomposites reinforced by other nanofillers.

show abstract

Toward the constitutive modeling of epoxy matrix: Temperature-accelerated quasi-static molecular simulations consistent with the experimental test

Cited by 43 publications

References 59 publications

Effect of molecular structure of curing agents on cyclic creep in highly cross‐linked epoxy polymers

Effect of molecular structure of curing agents on cyclic creep in highly cross‐linked epoxy polymers

Influence of Thermal Shocks on Residual Static Strength, Impact Strength and Elasticity of Polymer-Composite Materials Used in Firefighting Helmets

Importance of Interface in the Coarse-Grained Model of CNT /Epoxy Nanocomposites

Contact Info

Product

Resources

About