Effect of Isothermal Aging on Ultimate Strength of High-Temperature Composite Materials for SST Structures

Abstract

The objective of this experimental study was to evaluate the effect of iso-thermal aging on the ultimate strength of three kinds of carbon/high-temperature composite materials, i.e., G40-800/5260 and MR50K/MR2000N bismaleimide composites and T800H/PI-SP amorphous thermoplastic polyimide composite. These materials are current candidate structural materials for a supersonic transport of the next-generation. The hole-notched and unnotched panels, before being machined to specimens, were isothermally aged at 120°C and 180°C for up to 15,000 hours. Static tests at room and elevated temperatures before and after thermal aging provided the open-hole tensile, open-hole compressive, and short beam shear strengths. Moreover, the effects of five oxidation resistant treatments on open-hole compressive strength at 180°C were investigated after isothermal aging of 5,000 hours at 180°C. The test results clarified the effects of isothermal aging on ultimate strengths and oxidation resistant treatments on open-hole compressive strength. Moreover, the possibility of developing an accelerated aging test method is discussed using a modified Larson-Miller type equation.

Effect of thermal cycling and open-hole size on mechanical properties of polymer matrix composites

“…Shimokawa et al [12] evaluated the effect of isothermal aging on the ultimate strength of composite materials. The hole-notched and un-notched panels, before being machined to specimens, were isothermally aged at 120°C and 180°C for up to 15,000 hours.…”

Experiments and numerical analysis of compression after impact (CAI) behavior of CF/PIXA stiffened panels for HSCT structure

“…The major critical strengths as composite coupon levels were evaluated at room and elevated temperatures up to 230 • C previously [2,3] by the authors including compression strength after impact (CAI) using SACMA method at 6.7 J/mm impact energy, and open hole compression (OHC) of quasi-isotropic laminates with 38.1 mm width and 6.35 mm diameter. Long-term exposure tests at high temperature air followed by the same size OHC tests as above have been being conducted [4] for one family of resin composites by another group in NAL, Japan. These basic tests demonstrated the great potential of this composite system for HSCT structure.…”

The effect of long-term exposure to high temperature atmosphere on weight change and damage progress in carbon fiber-reinforced polycyanate ester composites

“…The weight change q i was a function of the fiber orientation angle θ and obtained from Equations (4)- (6). For most outer layers of specimen, the A z is top or bottom surface areas, and the other layers, the A z is actually zero.…”

“…Hence, many researchers have conducted investigation, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] such as isothermal test, to clarify thermal stability of PMCs in high temperature thermo-oxidative environment. Because it is easier than conducting strength test, weight measurements have been well conducted to evaluate thermal stability of PMCs under the thermo-oxidative environment for a long term.…”