Internal Stress Analysis Of Bolted Joints Composed Of Composte Plate And Aluminum Plate In Thermal Field

Bolts provide primary means of connection in airplane empennage,and alsobehave as the week spots among bolted joints, thus,the analysis of load transfer inbolted joint requires safe and efficient design. Load transfer and internal stressdistribution in bolted joints are obviously affected by ambient temperature. A3Dfinite element model of composite-to-metal bolted joints was founded, when theuniform thermal load was applied to the joint, the longitudinal stress alongcomposite and metal plate and equivalent stress on the bolts were obtainedseperately; Considering different bolt-hole gap arrangment, the effect of gap on loadtransfer distribution was obtained. Bolted joints bearing axial load under differenttemperatures were investigated, the regularity of internal stress distribtion wasobtained: as the temperature rises, stress level on the composite plate goes up, andthat of the aluminum plate goes down; the regularity of load transfer distributionwas also gained: temperature rising improved the non-uniformity, enforcing the loadconcentrated on one bolt. Assuming the gap variation under high temperature as theinitial gap in bolted joint, the results obtained from high temperature and initial gapwere almost the same, thus gaining the mechanism of the thermal effect on internalload distribution: temperature changes the deformation, alters the bolt-hole gap,differs the load tranfer, then varies the internal stress.Experiments on the effect of temperature were conducted, internal stress wasobtained by the strain gage method, the results agreed quite well with that of FEM.The regularities of internal stress and bolt load distribution obtained in this paperhave a guiding significance in the actual applications.