Fracture mechanic properties are determined by using optimized standard specimen:
- Peeling strength of Double Cantilever Beam (DCB) specimen
Shear strength via End-Notched Flexure Specimen (ENF)
The specimen geometry (of the part in question) can be adapted with regard to the substrate material, the manufacturing process, type and thickness of bonding, as well as the dimensions.
Bondline characterization comprises tests on static stability - including the determination of critical energy release rates - as well as operational stability tests under repeated strain, in order to determine crack propagation rates.
Leichtwerk AG has often detected bondings that have displayed high crack propagation rates upon repeated strain in cases of very high critical energy release rates and related static strength
A special testing machine with a customized control program was developed to carry out the specimen trials.