Evaluation of Thermal Stress in Carbon/Glass Hybrid and Glass Nanocomposite under Resistive Heating

Resistive heating of nanocomposite material is proposed for use in many applications because of its light weight and low current requirements. When the nanocomposites are resistively heated, thermal stresses starts arising in it due to mismatch of CTE between the fiber and matrix of the nanocomposite. A nanocomposite material can withstand only limited thermal stress when it is resistively heated. If the thermal load is too high, or combined with other external loads, the nanocomposite can fail by means of delamination, crack formation, warpage and other related modes. Hence, studying the thermal stress that develops in nanocomposites upon resistive heating will help in preventing otherwise unanticipated failures. The objective of this effort was to develop and experimentally validate a Finite Element Method model for evaluation of the thermal stress arising in nanocomposite material upon resistive heating. In order to fill the technology gap of predicting thermal stress in resistively heated nanofiber composites, a finite element method (FEM) model was created. This model was created using ABAQUS® software. To verify the results of the model, the experimental method of hole-drilling was adopted. The nanocomposite considered for the research were a carbon/glass hybrid with epoxy resin and a glass/epoxy composite reinforced with CNT Buckypaper. The experiment was based on the principle of redistribution of stress when the hole is drilled in the composite and the relieved strain is measured by a strain gage rosette. The strain release corresponds to the thermal stress that was present before the drilling the hole. The thermal stress results of hole-drilling method were compared with the FEM model result, validating the model and analysis results. The verified FEM model can be used to predict thermal stresses arising in nanocomposites and preventing failure when the nanocomposite is resistive heated and externally loaded.