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This paper dealt with the interface stresses of thin wall box-shaped bolted flanged structures when internal pressure was applied. The flexible flanges were fastened by M8 bolts and nuts with an initial clamping force after being joined with silicone sealant. In the elastic and thermo elastic F.E.A, the effects of bolt pitch distance, bolt positions, flange rigidity and flange thickness were examined. In addition, the effect of the liner thermal expansion coefficient and Young's modulus of the joint in the steady temperature state were also examined. The experimental results were in fairly good agreements with the numerical results. From the results, it was found that the effect of thermal condition is greater than that of internal pressure on the interface stress distributions. In other words, it indicates that thermal conditions are affective on the sealing performance rather than internal pressure application in this case.

It is important to improve the sealing performance of bolted flanged joints subjected to internal pressure. Recently, bolted joints with flexible flanges of stamped steel have been used in an oil-pan structure of automobile from a lightweight viewpoint. However, it is difficult to improve the sealing performance of flexible bolted flanged joints due to the reduction of the interface pressure. In this paper, a liquid sealant is applied to a box-shaped flexible bolted flanged joints such as oil-pan structures subjected to internal pressure in order to improve the sealing performance. In the experiments, an internal pressure when a leakage occurred was measured in the case where box-shaped bolted flanged joints in which liquid sealant was applied to the interfaces between aluminum flexible flanges (the upper) with thickness of 1 and 3mm and the steel (aluminum) flange with 10mm thickness (the lower) and where the bolt positions are changed.

Shrink fit has been used commonly for joining the cylindrical components such as shaft and gears. It is noted recently the shrink fitted joint with anaerobic adhesives is adopted in order to improve it's joint strength. In a reliable design of bonded shrink fitted joints, it is necessary to know the contact stress distributions at the interfaces. In this paper, the interface stress distribution of bonded shrink fitted joint under push-off force is analyzed by using axisymmetric theory of elasticity as four-body contact problem. Analogical test is conducted to determine the relationship between the normal stress and the shear stress. Using the interface stress distribution and analogical test results, a method for estimating the joint strength is proposed. In the numerical calculations, the effect of the outer diameter and Young's modulus of the rings and the engagement length on the contact stress distributions at the interfaces are clarified.

It is important to improve the sealing performance of bolted flanged joints subjected to internal pressure. Recently, bolted joints with flexible flanges of stamped steel have been used in an oil-pan structure of automobile from a lightweight viewpoint. However, it is difficult to improve the sealing performance of flexible flanged bolted joints due to the reduction of the interface pressure. In this paper, a liquid sealant is applied to a box-shape flexible flanged bolted joints subjected to internal pressure in order to improve the sealing performance. In the experiments, a leakage is observed when a box-shape flanged joints in which liquid sealants are applied to the interfaces between aluminum flexible flanges with thickness of 1 and 3 mm and the steel (aluminum) flange with 10 mm thickness. Experiments are also conducted on bolted joints with asbestos gaskets. In addition, the effects of the adjacent bolt distance and bolt preload on the sealing performance are examined.