Effects of heat accelerated aging on tensile strength of three dimensional braided/epoxy resin composites

Abstract

The tensile tests of three‐dimensional (3Dim) and four‐directional (4Dir) carbon fiber braided/epoxy resin composites and carbon fiber woven plain fabric laminated/epoxy composites after heat accelerated aging at 150 and 180°C for 60, 120, and 180 h were carried out respectively. The reason of the changes of tensile property of these composites after different aging period of time at different high temperature was explained. The results of two‐way ANOVA analyzing indicate that the aging time has a significant effect on tensile strength of these composites. With the increase of accelerated aging period of time at high temperature, the tensile strengths of these composite samples decreased compared with that of composite samples without aging. However the decrease of tensile strength of 3Dim and 4Dir braided composites is less than that of laminated composites. One of the reasons is after aging for a long time at high temperature, the resin is damaged and becomes brittle which make the bonding force between fiber and resin decrease. Another reason is the structure of reinforcement of composites. After aging, the structure of 3Dim and 4Dir braided/epoxy resin composites still keeps the integrity which makes the 3Dim and 4Dir composites have less tensile performance degradation (3Dim and 4 Dir: three‐dimensional and four‐directional). POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Effect of thermo-oxidative aging on three-dimensional and four-directional braided carbon fiber/epoxy composite

“…However, most literatures are confined to thermal oxidation of unidirectional and laminated polymer systems, and there are limited studies on 3D braided composites. Guo et al 25 investigated the effect of thermo-oxidative aging on the tensile strength of 3D and five-direction (5Dir) braided carbon fiber/bismaleimide (carbon fiber/ BMI) composite and noted that the tensile strength decreased after aging for 24 h at 180 C. The observed result of Song and Li 26 was similar to that of Guo et al 25 Song and Li observed that the tensile strength of 3D-4Dir braided carbon fiber/epoxy composite decreased after aging at 150 C and 180 C for 60, 120, and 180 h. It is not difficult to find that past researches are mainly concerned with the effects of thermooxidation on 3D braided composites at the macroscopic scale. However, a systematic study on the thermo-oxidation aging mechanisms of the 3D braided composites has not been performed.…”

Tensile properties of multilayer-connected biaxial weft knitted fabric reinforced composites for carbon fibers

“…To know if there is any statistically significant relationship between the factors (the carbon fiber volume fraction) for response [23] also applied mathematical methods to the analysis of the tensile strength for composite materials, however, the different mathematical model were used. For the results, the two kinds of mathematical models were able to fully explain the relationship between influence factors and tensile strength of composites.…”

“…0°is defined that carbon fiber direction oriented along weft direction, and 90°oriented along warp direction. The samples geometry is 250 mm  25 mm  4 mm [23] see Fig. 3 and Table 1, and five samples were tested in every group.…”

Improved thermo-oxidative stability of three-dimensional and four-directional braided carbon fiber/epoxy hierarchical composites using graphene-reinforced gradient interface layer

“…Compared to conventional laminated composites, the integrated structure of three-dimensional (3D) and fourdirectional (4Dir) braided composites can improve the TOS of the CFPMCs by enhancing the ability of the fibers to bear the external load and resist delamination, despite the deterioration in the matrix resin and interface properties after thermo-oxidative aging (TOA) for long periods of time [5]. Unfortunately, however, the flexural strength (FS) of the 3D-4Dir braided composite decreases significantly when the fiber/matrix interface performance declines extensively after TOA [6].…”