Optimization On Stress Distribution Of Adhesive Single Lap Steel Joint

In this dissertation, the optimizations on stress distribution of adhesively bonded single lap joint had been systematically investigated by finite element method based on a review of its current states and developing tendency from a worldwide view.Finite element software ANSYS is applied to optimize the adhesively bonded single lap joint topologically for the first time. The results showed that the threshold values 0.2 and 0.3 are appropriate for joint under low load and large load respectively. The rational gap length reduced the volume of adhesive effectively and the highest reduction ratio was 60%. Compared with continuous mid-bondline joint, the peak value of shear stress in mid- bondline has a 10% increase. The rational configurations of overlap regions and fillets are S-form and arc respectively. The stress distribution became more even in optimized joint and low stress region became smaller on a large scale.The stress distributions of adhesively bonded single lap joint with unbalanced rigidity were first investigated considering the prerequisite of joint non-linearity and glue-line elasto-plasticity. It showed that recessing could optimize the stress distribution at mid-bondline. The clearance sites had influence not on the peak values of shear stress, peel stress and equivalent stress, but on the occurrence point of those items. While gap was sufficiently close to the overlap end of large rigidity, the maximum value of shear stress appeared in the same way, which could help to control the failure point of joint. Under low load, the minimum volume of adhesive was 35mm3, which accounted for 28% of the volume of continuous joint. Gap played an important role in reducing cost of joint under low load.Combination of reliability with finite element method is applied in analyzing reliability design of bonded structure. The results showed finite element could be effective tool for predicting reliability of bonded joint based on limited experiments. It also showed the thicknesses of adherend and mid-bondline influenced the strength of joint greatly. A reliability of 0.93 was calculated within 100 specimens.Stress distribution of bonded single lap eccentric-joint and bonded single lap coaxial-joint are investigated. The results showed that the peak values of normal stress and equivalent stress in bonded single lap coaxial-joint are merely one third of those in bonded single lap eccentric-joint. The peak value of shear stress in mid-bondline of bonded single lap coaxial-joint is merely one second of that in bonded single lap eccentric-joint. Bonded...