Characterisation of lateral offsets in clinch points with computed tomography and transient dynamic analysis

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

Clinching is a very cost-efficient method for joining two or more sheets made of identical or different materials. However, the current evaluation methods cannot confirm the critical geometrical features of joints such as neck thickness, undercut, and bottom thickness. Furthermore, the effects caused by joining process such as elastic deformation and crack-closure are significant for the joining quality, but often earn insufficient attention. Therefore, computed tomography (CT) and Transient Dynamic Analysis (TDA) as an ultrasonic testing and evaluation procedure are combined to overcome the obstacles mentioned above. In order to have a well-defined and reproducible typical geometrical error in clinching, specimens with a pre-specified lateral offset of the punch with 0.1 mm, 0.2 mm are as well as with no lateral offset are investigated using CT. The specimens are treated with conductive copper varnish in varying intensities to support the two sheets' distinguishability in the CT measurement. The subsequently extracted surfaces from CT-scan data are used to create three-dimensional models for a numerical Transient Dynamic Analysis. Hereby, a harmonic force is applied to one sheet and the transferred energy is determined at the opposite side of the clinch point on the other sheet. The transmitted energy can be used as a quantitative measure for the joining quality. This setup is simulated by means of Finite-Element-Method and the specimens are investigated experimentally using a piezo actuator and a piezo sensor. The novelty of the results presented here is the completely non-destructive investigation of joint specimen by CT of similar materials with a contrast given foil in between the sheets and the subsequent TDA, which can easily detect difference between the specimens by evaluation of the energy dissipation of the joints.

Details

Original languageEnglish
Article number100089
JournalJournal of Advanced Joining Processes
Volume5
Early online date24 Dec 2021
Publication statusPublished - Jun 2022
Peer-reviewedYes

External IDs

Scopus 85121971884
Mendeley a5a1e59d-7e91-3fbc-be99-48014adf6c19
WOS 000821501300004
ORCID /0000-0003-0014-3039/work/142233818
ORCID /0000-0003-1370-064X/work/142243432

Keywords

DFG Classification of Subject Areas according to Review Boards

Keywords

  • Clinching, Non-destructive testing, Transient Dynamic Analysis

Library keywords