题目：Re-examination of thermal residual stress effects on interfacial properties of thermoplastic matrix microbond test
报告人：Yiu-Wing Mai Centre for Advanced Materials Technology The University of Sydney
As a result of manufacturing processes, thermal residual stresses often occur in fibre reinforced polymer composites and affect the fibre/matrix interface properties, e.g., interfacial shear strength (IFSS), which is commonly evaluated by the microbond test. In thermoplastic matrices, thermal residual stresses can be relieved by annealing. In this talk, we re-examine the effects of thermal residual stresses on IFSS and post-debond friction stress using an example of polyphenylene sulfide/carbon fibre (PPS/CF) composite. Microbond tests on both air-quenched (control) and annealed samples are conducted. By comparing the pullout results of the control to the annealed samples subjected to six different annealing temperatures between 80 oC and 230 oC, it is found that the thermal residual stresses in the fibre axial and radial directions are reduced progressively below 120 oC and can be neglected above this temperature. Thermal residual stresses in the fibre direction can be calculated to explain the microbond test results and construct a master curve for the IFSS. Post-debonding friction stresses can also be analysed in terms of the calculated fibre radial thermal residual stresses and debonded fibre morphologies.
Professor Yiu-Wing Mai received his undergraduate and postgraduate training in mechanical engineering at the University of Hong Kong, China. He worked previously in theUS(UniversityofMichiganand the NIST), theUK(ImperialCollege) and Hong Kong (CityU, HKU, HKUST and PolyU); and now holds a University Chair in Mechanical Engineering at theUniversityofSydney.