Insulation interface defects are a major cause of cable terminal failure in extreme cold environments, and the stress state at the epoxy resin/silicone rubber interface directly determines the mechanical integrity and the stability of thermal and electrical properties of the cable terminal interface. In this study, a simplified model of the epoxy resin/silicone rubber interface in cable terminals was first designed based on the actual assembly process. The interface stress of this simplified model under extreme cold conditions was calculated using finite element analysis. Then, a quantitative relationship model between the interface stress and the reflection coefficient of epoxy/silicone rubber composite samples was established using an ultrasonic pulse detection system. Finally, a simplified terminal model was fabricated, and ultrasonic pulse detection experiments were carried out under extreme cold environments ranging from 20℃ to -40℃. The interface stresses at different temperatures were inverted using the quantitative model and compared with the simulation results. The results show that the ultrasonic velocity in epoxy resin increases linearly with the decrease of temperature, and the increase rate is 3.446 7 m/(s·℃). During the process of cooling from 20℃ to -40℃, the interface stress of epoxy/silicone rubber decreases significantly due to the loss of interference caused by the temperature drop.The error between the simulation and experimental results remains around 5%, confirming the reliability of the proposed interface stress back-calculation method under extreme cold environments.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |