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

Abstract

Compression after impact (CAI) behavior of stiffened panels using T-shaped stringers made of heat resistant thermoplastic composites, CF/PIXA, was obtained by tests at room temperature and 180 • C. Excellent impact resistance in terms of delamination area was verified for the present composite panels due to the special fusion bonding film. Room temperature CAI strengths of the stiffened panels were found to be better than CF/PEEK panels in a rough comparison, without regard to differences in stacking sequence and geometry. Relationships between temperature and CAI strengths for CF/PIXA stiffened panels were compared with the results for flat plates (SACMA) and a compatibility between flat plate and stiffened panel data was observed. It is clarified that damage tolerance properties of CF/PIXA stiffened structure are so remarkable at room temperature that compression strengths are quite insensitive to relative impact energy. Its damage tolerance capability is also excellent at high temperature for High Speed Civil Transport structures. Linear and nonlinear buckling analyses based on simple models without delamination and interlaminar stresses were conducted using a finite element code. The results agreed well basically with experimental results. In the case of prediction of the final strength, several points of improvement are identified. The present prediction provides the initial step to discuss the possibility of post-buckling strength design at high temperature stiffened panels.

Compressive property degradation of composite stiffened panel due to debonding and delaminations

“…The first and second buckling loads were very similar to each other. The numerical results explained satisfactory the experimental results obtained by Ishikawa et al [1], where the average buckling load was about 290 kN and the buckling modes observed in the plate with uniform skin thickness and slightly tapered skin were 5-wave pattern and 4-wave pattern, respectively. Considering the efficiency of the calculation we basically adopted two layer models for convenience when further subdivision was not necessary to model the damaged portion.…”

“…We considered a blade-stiffened panel [1] made of carbon fiber and a high toughness and high thermal resistant resin (PIXA) as shown in Fig Table 1, where the 0 • direction is horizontal (x-axis) and transverse to the load as shown in Fig. 1.…”

“…A stiffened panel of composite material using a high toughness and high thermal resistant resin as its matrix (CF/PIXA) has been developed by the joint efforts of the Japan Aerospace Exploration Agency, Fuji Heavy Industry Co. and Mitsui Chemical Company [1]. A series of compression tests were conducted on the stiffened panels with and without impact damage at the flange portion.…”

“…The effect of damage on the compressive behavior of stiffened panels has been studied by several researchers. Ishikawa et al carried out a careful experimental study on the compressive problem of stiffened panels with impact damage and showed interesting results [1,8]. Suemasu et al studied the effects of edge delamination on the stiffener portion through Rayleigh-Ritz approximation and experiment [9,10].…”

Compressive fracture of layered composites caused by internal instability

“…The effect of stiffeners on stress distribution around a hole, as well as on buckling and failure characteristics of lightweight composite panels, is the subject of the survey by Leissa (1987). More recently this subject was addressed in Degenhardt et al (2007), Diamanti, Soutis, and Hodgkinson (2007), Falzon, Davies, andGreenhalgh (2001), Found, Howard, andParan (2002), Greenhalgh and Hiley (2003), Greenhalgh and Garcia (2004) and Ishikawa, Matsushima, Hayashi, and Scott (2005) and numerous other publications mentioned in this chapter.…”