When using the "dry stringer+wet skin" co-bonding process to manufacture hat stringer stiffened composite panels, the stringer hat often shows collapse deformation and uneven adhesive thickness after bonding. In order to improve the above problems and achieve high precision manufacture of the stiffened panels, the stringer de-formation data before and after bonding and the adhesive thickness data after bonding are collected through manufacture and profile and dimensional measurement of test panels. Free-body force analysis of the hat stringer during bonding is conducted to determine the main causes leading to the deformation of stringer. The analysis is verified by finite element simulation. The results show that the hat stringer does occur collapse deformation after bonding. The main causes of the deformation of the stringer are the pressure difference between inside and outside of the corner of stringer hat top and the insufficient pressure on the flange edge of stringer during bonding. Chamfering the stringer flange edge may reduce the degree of deformation.
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