Mechanical behavior investigation of press-fit connector based on finite element simulation and its reliability evaluation

As the successor of soldering, the press-fit electrical connection is more and more widely used on account of a number of advantages, such as fast assembly. However, in practice, some contact failures were found. Most of the failures are related to the force which the structure bears. Because of complex elastic-plastic deformation characteristic , analyzing the mechanical behavior of the press-fit is challenging. Some studies have been done on the assembly force behavior of the press-fit such as press in force. However, the stress behavior on the assembly is not clearly studied. In this paper, the mechanical behavior of a typical press-fit connector named as eye of needle (EON) was investigated based on finite element (FE) simulation. Firstly, FE models were established and verified. Then, basing on model analysis, the mechanical behaviors (mechanical stress, thermal stress, and contact force) of the EON were obtained, which makes it clear that the relationships between the EON's structural parameters and its work conditions. Finally, the long-term reliability of the EON connector under the stress relaxation and the thermal fatigue was evaluated, respectively. The FE models here are effective on analyzing the press-fit mechanical behavior, which can be adopted to help design and manufacture. • The needle shape obviously influences the contact force. • The maximum stress shows a non-monotonic relationship with the PTH inner diameter. • After the assembly, temperature-rise increases the maximum stress of the barrel. • Different work conditions require different reliability design choices. • Conflicts might appear between function requirement and reliability requirement.