Application of bonded patch and sleeve to cracked hole repair under biaxial load
Abstract
This paper presents the use of both bonded sleeve and bonded composite patches to repair a crack emanating from a fastener hole in a relatively thick plate subjected to biaxial load. Proper design requires that the reinforcing patch and the steel sleeve absorb an appreciable fraction of the load to reduce the stress intensity near the crack tip. Also, the patch may not fail or detach from the structure under load cycling. All results obtained from three-dimensional finite element computation are analyzed to illustrate the application of fracture mechanics to the repair technology. It is shown that, for all loading conditions, the mode 1 and 2 stress intensity factors are significantly reduced by using the bonded sleeve and bonded patches separately or together. In general, the direction of composite fibres, being stiffer, could be orientated in the direction perpendicular to the crack in pure mode I to satisfy the design guidelines. In mixed-mode conditions, however, both the loading state and crack geometry should be considered to find the most effective ply orientation. The results show that the optimum ply orientation should be selected to coincide with the axis of principal tensile stress.
- Publication:
-
Engineering Fracture Mechanics
- Pub Date:
- July 1994
- Bibcode:
- 1994EnFM...48..515C
- Keywords:
-
- Crack Propagation;
- Crack Tips;
- Elastic Properties;
- Finite Element Method;
- Fracture Mechanics;
- Holes (Mechanics);
- Load Distribution (Forces);
- Sleeves;
- Steels;
- Stress Analysis;
- Stress Intensity Factors;
- Structural Design;
- Crack Geometry;
- Ply Orientation;
- Tensile Stress;
- Structural Mechanics