Abstract
Interference connection is an effective method for improving the fatigue life of bolt connections. In this paper, a new method of interference connection was designed based on the shape memory effect of shape memory alloy. Using the method of numerical simulation, a finite element model was established to analyze the stress–strain rule of the bolt and the hole wall under different interference fit sizes. The results show that the stress concentration is formed at the orifice of the connecting plate. When the interference fit size is less than 1%, the connection hole has elastic deformation. When the interference fit size is 1.5%, the hole wall has plastic deformation. When the interference fit size is 2.5%, the maximum stress on the connecting plate is close to the tensile limit of the material. If the interference fit size continues to increase, the strength of the connection structure will be damaged. The connection experiments with different interference fit size were designed, and the interference force was calculated by the pull-out force. The experimental results were compared with the numerical simulation results. The change trend of the interference force with the interference fit size is consistent, which verifies the rationality of the finite element simulation.
Highlights
The design idea of interference connection based on shape recovery characteristics of shape memory alloy (SMA) was proposed
The results show that the maximum stress appeared at the root of the bolt rod, which is due to the axial restoring force of NiTiNb SMA after heating between the bolt head and the connecting plate
The interference connection of 6061-T651 aluminum alloy with NiTiNb SMA was studied by means of a constitutive model, finite element simulation, and experimental verification
Summary
It is easy for stress concentration to form near the bolt hole of a bolt connection, which can reduce the fatigue life of the connection structure. In order to enhance the fatigue resistance of structural parts and improve their fatigue life, it is necessary to strengthen the weak parts [2]. As an effective fatigue strengthening technology, interference connection has been widely used in the aircraft manufacturing industry. The interference connection can strengthen the key parts of the structure without increasing the weight of the connection structure or changing its form and material. Compared with the ordinary connection, due to the interference prestress, it can significantly reduce the stress concentration at the edge of the hole, strengthen the fitting surface, inhibit the initiation of fatigue cracks, and improve the fatigue life of the connection structure, which has good economy [3]
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