The joint structure refers to the structural form in which the end of the composite insulator is connected with the core rod, and mainly has three types of bonding type, wedge type and pressure type. Since the joint shield is usually used to cause a certain degree of stress concentration on the mandrel in the joint area, the joint structure is a weak link in the mechanical properties of the composite insulator. The new joints with improved joint structure and excellent design performance are effective means to improve the overall mechanical properties of the insulator. At present, all major foreign manufacturers only use crimp joints. In 1999, China also cooperated with insulator manufacturers to develop successful crimp-type insulator products.

   As a new joint structure, the crimp joint has the practical features of low cost and high work efficiency. At the same time, it has its unique advantages in terms of mechanical properties: good long-term and short-term static load performance, dynamic load performance and possible improvements in the end seal. At present, although the crimping process has been widely used in foreign countries, there are few published documents, and there is almost no public report on how to apply the detection technology to ensure the crimping effect in the crimping process.