Fracture toughness in Mode I (GIC) for ductile adhesives

[摘要] Works carried out in this publication belong to a project that seeks the replacement of welded joints by adhesive joints at stress concentration nodes in bus structures. Fracture toughness in Mode I (GIC) has been measured for two different ductile adhesives, SikaTack Drive and SikaForce 7720. SikaTack Drive is a single-component polyurethane adhesive with high viscoelasticity (more than 100%), whose main use is the car-glass joining and SikaForce 7720 is double-component structural polyurethane adhesive. Experimental works have been carried out from the test called Double Cantilever Beam (DCB), using two steel beams as adherents and an adhesive thickness according to the problem posed in the Project, of 2 and 3 mm for SikaForce 7720 and SikaTack Drive, respectively. Three different methods have been used for measuring the fracture toughness in mode I (GIC) from the values obtained in the experimental DCB procedure for each adhesive: Corrected Beam Theory (CBT), Compliance Calibration Method (CCM) and Compliance Based Beam Method (CBBM). Four DCB specimens have been tested for each adhesive. Dispersion of each GICcalculation method for each adhesive has been studied. Likewise variations between the three different methods have been also studied for each adhesive.

[发布机构] Department of Material Science and Engineering, Universidad Carlos III de Madrid, Avenida de la Universidad 30, Leganés; 28911, Spain^1;Departamento de Engenharia Mecânica, Faculdade de Engenharia, Universidade Do Porto, Portugal^2;Departamento de Engenharia Mecânica, Instituto Superior de Engenharia Do Porto, Instituto Politécnico Do Porto, Portugal^3

[关键词] Adhesive thickness;Bus structures;Calibration method;Corrected beam theory;Double cantilever beam;Ductile adhesives;Polyurethane adhesives;Single components