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Jefferson Andrew ¹, Vellayaraj Arumugam ¹, Adhithya Plato Sidharth ¹, Benny Thomas ¹

Affiliations
1 Department of Aerospace Engg., Madras Institute of Technology, Anna University, Chennai, IN

Abstract

In this paper, symmetric cross ply CFRP laminates were fabricated using hand layup with LY556 epoxy resin as matrix and the specimens were cut without cut-out, with circular, vertical elliptical and horizontal elliptical cut-outs according to the ASTM D 7137 standard using water jet cutting. The CFRP specimens with and without cut-outs were subjected to compression under controlled condition accompanied by acoustic emission (AE) monitoring. The ultimate compressive strength for specimens with and without cut-outs were determined and compared. The optimum cut-out with lesser reduction in compressive strength was determined. The nature and dominance of different failure modes in each type of cut-out were investigated using AE. Finally the result gives useful information about improved design of laminated composites with cut-outs suitable for different applications.

Keywords

CFRP, Cut-outs, Acoustic Emission, Peak Frequency Analysis, Compression Test.

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C. Ramesh ¹, Joseph Stanley ², Vellayaraj Arumugam ³, Jefferson Andrew ³, S. Arunabharathi ³

Affiliations
1 Dept. of Aeronautical Engg., SKP Engineering College, Tiruvannamalai, IN
2 Dept. of Aeronautical Engg., Hindustan University, Chennai, IN
3 Department of Aerospace Engg., Madras Institute of Technology, Anna University, Chennai, IN

Abstract

In this study, pristine, single impacted and double impacted GFRP specimens were subjected to ageing by immersion in seawater at ambient temperature for different periods of time. The dominating failure mode of the aged specimens was found using acoustic emission monitoring. The water absorption capacity and flexural strength of specimen subjected to ageing were assessed to study the trend of variation. A reduction in residual strength was observed between single and double impacted specimens. Stress cycle plots from AE monitoring indicate that the onset of failure occurs sooner as the ageing time progresses. From those of impacted specimens, it can be seen that the onset of failure and damage initiation occurs sooner in double-impacted specimens than in single-impacted counterparts. Parametric peak frequency analysis shows that fiber-matrix debonding was the predominant mode of failure.

Keywords

GFRP, Epoxy Resin, Drop Weight Impact, Seawater Degradation, Acoustic Emission Monitoring.

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