INFLUENCE OF TEMPERATURE-DEPENDENT RESIN BEHAVIOR ON NUMERICAL PREDICTION OF EFFECTIVE CTES OF 3D WOVEN COMPOSITES

2021 ◽  
Author(s):  
KOSTIANTYN VASYLEVSKYI ◽  
BORYS DRACH ◽  
IGOR TSUKROV

3D woven composites are well known for their high strength, dimensional stability, delamination, and impact resistance. They are often used in aerospace, energy, and automotive industries where material parts can experience harsh service conditions including substantial variations in temperature. This may lead to significant thermal deformations and thermally-induced stresses in the material. Additionally, 3D woven composites are often produced using resin transfer molding (RTM) technique which involves curing the epoxy resin at elevated temperatures leading to accumulation of the processing-induced residual stress. Thus, understanding of effective thermal behavior of 3D woven composites is essential for their successful design and service. In this paper, the effective thermal properties of 3D woven carbon-epoxy composite materials are estimated using mesoscale finite element models previously developed for evaluation of the manufacturing-induced residual stresses. We determine effective coefficients of thermal expansion (CTEs) of the composites in terms of the known thermal and mechanical properties of epoxy resin and carbon fibers. We investigate how temperature sensitivity of the thermal and mechanical properties of the epoxy influences the overall thermal properties of the composite. The simulations are performed for different composite reinforcement morphologies including ply-to-ply and orthogonal. It is shown that even linear dependence of epoxy’s stiffness and CTE on temperature results in a nonlinear dependence on temperature of the overall composite’s CTE.

1996 ◽  
Vol 23 (2) ◽  
pp. 511-517 ◽  
Author(s):  
T. T. Lie ◽  
V. K. R. Kodur

For use in fire resistance calculations, the relevant thermal and mechanical properties of steel-fibre-reinforced concrete at elevated temperatures were determined. These properties included the thermal conductivity, specific heat, thermal expansion, and mass loss, as well as the strength and deformation properties of steel-fibre-reinforced siliceous and carbonate aggregate concretes. The thermal properties are presented in equations that express the values of these properties as a function of temperature in the temperature range between 0 °C and 1000 °C. The mechanical properties are given in the form of stress–strain relationships for the concretes at elevated temperatures. The results indicate that the steel fibres have little influence on the thermal properties of the concretes. The influence on the mechanical properties, however, is relatively greater than the influence on the thermal properties and is expected to be beneficial to the fire resistance of structural elements constructed of fibre-reinforced concrete. Key words: steel fibre, reinforced concrete, thermal properties, mechanical properties, fire resistance.


2012 ◽  
Vol 525-526 ◽  
pp. 73-76 ◽  
Author(s):  
Daisei Abe ◽  
Omar Bacarreza ◽  
M.H. Aliabadi

Textile composites have increasingly been used as a structural material because of their balanced properties, higher impact resistance, and easier handling and fabrication compared with unidirectional composites. However, the complex architecture of textile composites leads to difficulties in predicting the response in spite of the fact that there is the need to determine mechanical properties in product design. Micromechanical analysis, using the Finite Element Method, was conducted in order to evaluate the effective mechanical properties of plain woven and 3D woven composites. In this study, numerical models of unit cells were used and it is shown that the predicted values of homogenized mechanical properties using the developed procedure were in good agreement with experimental results.


2021 ◽  
pp. 50533
Author(s):  
Yasmine N. Baghdadi ◽  
Lucia Youssef ◽  
Kamal Bouhadir ◽  
Mohammad Harb ◽  
Samir Mustapha ◽  
...  

2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.


e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Morteza Ghorbanzadeh Ahangari ◽  
Abdolhosein Fereidoon ◽  
Seyfolah Saedodin

AbstractIn the present work, the effect of different acid treatment times of singlewalled carbon nanotubes (SWNTs) on the mechanical and thermal properties of polypropylene (PP)/maleated polypropylene (PP-g-MA) nanocomposites was investigated. The acid treatment process was based on a mixture of concentrated sulphuric and nitric acids. The SWNTs were treated with the acid mixture for 1, 3, and 6 h. FTIR, Raman spectroscopy and TEM revealed the values of carboxylic groups, graphitization and morphology of acid treated SWNTs, respectively. The thermal and mechanical properties and the morphology of nanocomposites were investigated by tensile tests, DMTA, DSC, and SEM.


2012 ◽  
Vol 24 (6) ◽  
pp. 470-477 ◽  
Author(s):  
Sandi G. Miller ◽  
Gary D. Roberts ◽  
Justin L. Bail ◽  
Lee W. Kohlman ◽  
Wieslaw K. Binienda

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1075 ◽  
Author(s):  
Liming Zhu ◽  
Lihua Lyu ◽  
Xuefei Zhang ◽  
Ying Wang ◽  
Jing Guo ◽  
...  

Conventionally laminated spacer composites are extensively applied in many fields owing to their light weight. However, their impact resistance, interlaminar strength, and integrity are poor. In order to overcome these flaws, the zigzag-shaped 3D woven spacer composites were rationally designed. The zigzag-shaped 3D woven spacer fabrics with the basalt fiber filaments tows 400 tex (metric count of yarn) used as warp and weft yarns were fabricated on a common loom with low-cost processing. The zigzag-shaped 3D woven spacer composites were obtained using the VARTM (vacuum-assisted resin transfer molding) process. The three-point bending deformation and effects of damage in zigzag-shaped 3D woven spacer composites were studied both in experiment and using the finite element method (FEM). The bending properties of zigzag-shaped 3D woven spacer composites with different direction, different numbers of weaving cycle, and different heights were tested in experiments. In FEM simulation, the geometrical model was established to analyze the deformation and damage based on the 3D woven composite structure. Compared with data obtained from the experiments and FEM simulation, the results show good agreement and also prove the validity of the model. Based on the FEM results, the deformation, damage, and propagation of stress obtained from the model are very helpful in analyzing the failure mechanism of zigzag-shaped 3D woven composites. Furthermore, the results can significantly guide the fabrication process of real composite materials.


2017 ◽  
Vol 30 (10) ◽  
pp. 1159-1168 ◽  
Author(s):  
Animesh Sinha ◽  
Nazrul Islam Khan ◽  
Subhankar Das ◽  
Jiawei Zhang ◽  
Sudipta Halder

The effect of reactive (polyethylene glycol) and non-reactive (toluene) diluents on thermal and mechanical properties (tensile strength, hardness and fracture toughness) of diglycidyl ether of bisphenol A epoxy resin (cured by triethylenetetramine) was investigated. The thermal stability and mechanical properties of the epoxy resin modified with reactive and non-reactive diluents at different wt% were investigated using thermo-gravimetric analyser, tensile test, hardness test and single-edge-notched bend test. A minor variation in thermal stability was observed for epoxy resin after addition of polyethylene glycol and toluene at 0.5 wt%; however, further addition of reactive and non-reactive diluents diminished the thermal stability. The addition of 10 wt% of polyethylene glycol in epoxy resin significantly enhances the tensile strength (∼12%), hardness (∼14%) and fracture toughness (∼24%) when compared to that of neat epoxy resin. In contrast, major drop in mechanical performance was observed after addition of toluene in epoxy. Furthermore, fracture surfaces were investigated under field emission scanning electron microscope to elucidate the failure mechanism.


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