Improved consistency of bond-line thickness when conducting single lap-shear joint tests

Joe Flanagan,Lorcan Byrne,Joseph Mohan,Barry Twomey,Kenneth T Stanton

doi:10.1016/j.mex.2019.09.002

Abstract

This article details a method for improving the consistency of bond-line thickness during lap-shear sample preparation. This includes the schematic for a lap-shear sample test rig and consideration for controlled variation of the bond-line thickness for up to ten pairs of samples at a time. Concerns regarding the curing of the samples when held on a large heat reservoir are addressed through direct measurement of the bond-rig temperature in combination with the cure chamber temperature. Additionally, the application of a release coating to the bond-rig has been demonstrated to improve ease of sample removal for the bond-rig, minimizing potential damage to the lap-shear sample set before testing. The release coating provides a clean surface for subsequent sets of samples, ensuring an even surface and reducing cleaning and degradation of the machined geometries of the rig. Overall, the proposed bond-rig provides:•Increased bond-line uniformity•Up to ten samples prepared in a batch•Option to apply a release coating to improve usability and minimize cleaning

Highlights

The SLJ test configuration is often criticized due to the number of setup parameters that can negatively affect the consistency of the test results unless controlled
A bond-rig was designed which was able to accommodate ten bonded lap shear samples per test
The design ensured that the fillet at the edge of the adhesive joint are the same dimensions from batch-to-batch ensuring that the geometric parameters that may influence bond strength of each bonded sample are kept consistent. `As can be seen from the CAD model of the new bond-rig in Fig. 1, the bond overlap length was controlled at 12.7 mm as per ASTM D1002-10 [3]

Summary

Method Article

Improved consistency of bond-line thickness when conducting single lap-shear joint tests. Joe Flanagana,*, Lorcan Byrneb, Joseph Mohanb, Barry Twomeyb, Kenneth T. Stantona a School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland b ENBIO Ltd., DCU Alpha Innovation Campus, Glasnevin, Dublin 11, Ireland

Method details

Findings

Conclusion