Abstract
The paper presents a study of the fatigue and post-fatigue behavior of a hybrid carbon–glass biaxial fabric reinforced epoxy composite manufactured by the resin transfer molding (RTM) and the hand lay-up (HL) processes, with the main objective of assessing whether a material characterization run at the prototype level of a handicraft technology could be significant for a mass production technology and whether a comparison on static properties (a viable task at an industrial level) could ensure the same level of agreement for the fatigue life and residual properties. Tensile and flexural static tests as well as displacement-controlled bending fatigue tests (R ratio of 0.10) were conducted on two sets of standard specimens, having fiber orientation parallel to the loading direction (on-axis specimens) and at 45° to the loading direction (off-axis specimens). Specimens were subjected to different fatigue loading, with the maximum load level up to 60% of the average ultimate flexural strength, and damage in the laminate was continuously monitored through the loss of bending moment during cycling. After 106 cycles, the fatigue test was stopped and residual properties were measured. Micrographs of sample sections revealed some voidage for HL specimens while resin rich areas were observed for RTM specimens. Results of the static tensile and flexural tests pointed out lower mechanical properties for the RTM specimens when tested on-axis and slightly higher properties when tested off-axis. Regardless of specimen fiber orientation, the fatigue and post-fatigue performance of RTM samples was inferior to that of HL specimens with the gap increasing for increasing fatigue load levels. The result was ascribed to the presence in RTM samples of resin-rich areas, which are reported to have limited influence on the laminate static properties but which may act as initiation sites for fatigue cracks.
Similar content being viewed by others
References
Abraham D, Matthews S, Mcllhagger R (1998) Compos Part A 29(7):795
Bannister M, Herszberg I, Nicolaidis A, Coman F, Leong KH (1998) Compos Part A 29:293
Carvelli V, De Angelis D, Poggi C, Puoti R (2002) Key Eng Mater 221–222:109
Moura Branco C, Ferreira JM, Fael P, Richardson MOW (1995) Int J Fatigue 18(4):255
Gamstedt EK, Redon O, Brøndsted P (2002) Key Eng Mater 221–222:35
Hou M, Ye L, Mai YW (1997) J Mater Process Technol 63:334
ASTM D3039 (1995) Standard test method for tensile properties of polymer matrix composite materials. American Society for Testing Materials
ASTM D790 (1998) Flexural properties of unreinforced and reinforced plastics and electrical insulating materials. American Society for Testing Materials
Belingardi G, Cavatorta MP (2006) Int J Fatigue 28(8):815
Shan Y, Liao K (2002) Int J Fatigue 24:847
Van Paepegem W, Degrieck J (2002) Int J Fatigue 24:747
Hwang W, Han KS (1986) J Compos Mater 20:154
Acknowledgments
The research was funded by the European Union within the COMPASS project, under contract no G5RD-CT-2001-00575. Thanks are due to Italdesign Giugiaro and Centro Ricerche Fiat for the supply of the specimens.
The author wishes to thank Prof. Giovanni Belingardi and Roberto Doglione for the valuable discussions and for performing the micrographs, respectively, and to acknowledge former graduated student C. Frasca for helping with the testing activity.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Cavatorta, M.P. A comparative study of the fatigue and post-fatigue behavior of carbon–glass/epoxy hybrid RTM and hand lay-up composites. J Mater Sci 42, 8636–8644 (2007). https://doi.org/10.1007/s10853-007-1847-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10853-007-1847-8