Determination of residual stresses in GFRP composite using incremental slitting method by the aid of strain gauge

Residual stresses are those stresses which exist in the specimen even before the specimen has been loaded. Chemical Shrinkage of matrix and the thermal mismatch between the components of the composites during curing are main sources for residual stresses in polymer composite. Residual stresses may add up to the external loads and cause premature failure of the structure. The presence of residual stresses effects the structural integrity of the structure and should be investigated and quantified. Unidirectional (UD) woven Glass fiber was coated with epoxy resin using manual draw down method and then composite laminate was made using hand lamination technique which was cured under room temperature and then post cured at 180 °C for 3 hours The main objective of this work is to experimentally determine the cure induced residual stresses in glass fiber reinforced polymer (GFRP) composite using incremental slitting method. The technique compromises of introducing a thin slit using a CNC milling from the top surface of the specimen in the form of incremental cuts while the corresponding released strains are recorded from strain gauge bonded on the bottom surface of the specimen for every incremental cut. The results obtained display a high values of residual stresses inherited during the curing process. The original version of this article supplied to AIP Publishing contained an error in the affiliation for G. B. Veeresh Kumar. The author’s affiliation was corrected in the updated and re-published version of this article on 11 March 2019.