# Humidity Aging Effect on Adhesive Strength of Composite Single-lap Joint

• Kim, Myungjun (Graduate School of Aerospace and Mechanical Engineering, Korea Aerospace University) ;
• Kim, Yongha (Graduate School of Aerospace and Mechanical Engineering, Korea Aerospace University) ;
• Kim, Pyunghwa (Graduate School of Aerospace and Mechanical Engineering, Korea Aerospace University) ;
• Roh, Jin-Ho (Department of Aerospace and Mechanical Engineering, Korea Aerospace University) ;
• Park, Jungsun (Department of Aerospace and Mechanical Engineering, Korea Aerospace University)
• Accepted : 2017.02.17
• Published : 2017.03.30

#### Abstract

Because adhesively bonded joints are used in many structural systems, it is important to predict accurate adhesive strengths. Composite aircraft with many joints are easily exposed to low temperatures and high relative humidity. This paper presents a humidity aging effect on the adhesive strength of a composite single-lap joint (SLJ). The adhesive strength of the SLJ is predicted using a finite element analysis with a cohesive zone model (CZM) technique. The humidity aging effect is evaluated based on the adhesive strength and CZM parameters. A lap joint test is carried out on the composite SLJ specimens, which are exposed for four months of 100% R.H. at $25^{\circ}C$. The predicted strengths are in good agreement with experimental data, and the actual crack propagation is satisfactorily simulated using the local CZM technique.

#### Acknowledgement

Supported by : Ministry of Trade, industry & Energy (MOTIE)

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