Effect of Preforming Adherends on Static and Fatigue Strength of Bonded Composite Single-Lap Joints.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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An analytical and experimental investigation was conducted on bonded composite single-lap joints with the adherends preformed to reduce the angle between the line of action of the applied in-plane force and the bondline. A classical closed-form solution was used to analyze the composite joints with various preform angles and overlap lengths. The adherends of the test specimens were preformed before bonding, during the layup and curing process. Static tests were conducted for preform angles of 0 deg, 5 deg, 10 deg, and 15 deg and overlap lengths of 0.75, 1.75, 2.75, and 3.75 in. A limited fatigue study was conducted for specimens with a 2.75-in. overlap and a preform angle of 5 deg. Results of the analysis showed that preforming the adherends of bonded composite single-lap joints significantly reduced the shear and peel stress concentrations in the adhesive. Experimental results showed that preforming the adherends significantly increased their static and fatigue strength and thus increased the load level for which bonded composite single-lap joints can be designed. MM
- Adhesives, Seals and Binders
- Laminates and Composite Materials
- Couplers, Fasteners and Joints