Abstract
A study for fatigue strength of mechanical joints used in composite structures was made on the acquisition and interpretation of S-N data, the evaluation of fatigue life estimation methods and the presentation of fatigue design principle. Through this study the followings came to our knowledge. 1) The ratio of yield life to failure life becomes smaller as loading increases . 2) The effect of loading frequency on S-N data is little for circular hole specimens (no load transfer) but is very large for double shear joints. 3) The optimum clamping torque seems to exist for fatigue life to be longest. 4) The life prediction by use of Linear Residual Strength Reduction Fatigue Model (LRSRFM) gives better estimation than Miner's rule. 5) The scatter factor of composite structures must be 1.5 times larger than that of aluminum structures.
