Control of the discharge path in adhesive for separation of the bonding structure

Masataka Kondo, Taketoshi Koita, Soowon Lim, Takao Namihira, Chiharu Tokoro

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Recently, the easy disassembly of bonding structures used in lightweight automobile bodies is needed. This is because these bonding structures are difficult to separate efficiently as there are joints using chemicals with a high adhesive strength and are commonly separated manually. In this study, we applied a pulsed discharge for the separation of bonding structures consisting of two adherends bonded by epoxy adhesive. The separation was carried out by controlling the discharge path inside the adhesive with a notch punched on the adherend and peeling the adhesive by the explosive force caused by the discharge. The discharge path in the adhesive was generated by the concentration of electric field at the tip of the notch. The effect of notch geometry on the electric field strength was studied by simulation with the AC/DC module of COMSOL Multiphysics. Simulation results indicated that the notch height affected the electric field concentration, and likewise, that the electric field strength at the notch was higher than the one at the edge of the adhered material. The discharge path of the bonding structure with the notch was visualized using the shadowgraph method. The fracture surfaces of structure without and with the notch after the pulsed discharge were also observed to confirm the discharge crater. The visualized images indicated that the discharge path occurred inside the adhesive from the tip of the notch and that the structure was separated by the expansion of gasified adhesive caused by the discharge when the notch was punched to the structure. A discharge crater was observed in the adhesive surface near the notch. In the case of the structure without a notch, the discharge luminescence appeared not in the adhesive but at the edge of the adherend because of the electric field concentration at the edge, resulting in non-separation due to surface discharge in the structure. These results indicated that the notch was responsible for controlling the discharge path inside the adhesive and caused the separation of the bonding structure.

Original languageEnglish
Title of host publication2021 IEEE Pulsed Power Conference, PPC 2021
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781665433471
Publication statusPublished - 2021
Event2021 IEEE Pulsed Power Conference, PPC 2021 - Denver, United States
Duration: 2021 Dec 122021 Dec 16

Publication series

NameIEEE International Pulsed Power Conference
ISSN (Print)2158-4915
ISSN (Electronic)2158-4923


Conference2021 IEEE Pulsed Power Conference, PPC 2021
Country/TerritoryUnited States


  • Bonding structure
  • Electric field
  • Notch
  • Pulsed discharge
  • Separation

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology


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