Reduction in Adhesive Shear Strains at the Ends of Bonded Reinforcements
Abstract
A mathematical model is presented which defines the adhesive shear strain distribution for an adherend with bonded multilayer reinforcements which are stepped at their ends. In this one-dimensional formulation each step is allowed to be of different thickness and modulus, and of variable step length. A procedure is then given to improve the design of such reinforcements through minimising the peak adhesive shear strain which typically occurs near their stepped ends. It is shown that to achieve a 20% reduction in peak adhesive shear strain for a typical stepped patch consisting of unidirectional laminae, the first step adjacent to the patch end needs to be much longer than the remaining Steps. For the case where cross-ply laminae are used in conjunction with unidirectional laminae, the maximum shear strain in the adhesive layer can be reduced by about 60%. The results also indicate that reduced peak adhesive shear strains lead to a smoother transition of load from the plate to the patch. This suggests that a patch design which minimises peak adhesive shear strains will also reduce the undesirable stress concentration in the repaired structure, outside the patched region.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1998
- Accession Number
- ADA342717
Entities
People
- M. Heller
- T. Tran Cong