Evaluation of debonding strength of single lap joint by the intensity of singular stress field

12th International Conference on Damage Assessment of Structures

Miyazaki, Tatsujiro^1 ; Noda, Nao-Aki^2

University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa

903-0213, Japan^1

Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi, Fukuoka

804-8550, Japan^2

关键词: Adherend thickness;    Adhesive thickness;    Debonding strength;    Intensity of singular stress;    Minimum element size;    Practical method;    Single lap joints;    Singular stress field;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/842/1/012078/pdf
DOI  :  10.1088/1742-6596/842/1/012078

来源: IOP

【 摘 要 】

In this paper, the similarity of the singular stress field of the single lap joint (SLJ) is discussed to evaluate the debonding fracture by the intensity of the singular stress field (ISSF). The practical method is proposed for analyzing the ISSF for the SLJ. The analysis method focuses on the FEM stress at the interface end by applying the same mesh pattern to the unknown and reference models. It is found that the independent technique useful for the bonded plate and butt joint cannot be applied to the SLJ because the singular stress field of the SLJ consists of two singular stress terms. The FEM stress is divided to two FEM stresses by applying the unknown and reference models to different minimum element sizes. Then, the practicality of the present method is examined by applying to the previous tensile test results of the SLJ composed of the aluminum alloy and the epoxy resin. The ISSFs for the SLJ were calculated by changing the adhesive thickness t2and the overlap length l2. In the case of the SLJ with 225 mm in total length and 7 mm in adherend thickness, it was found that the similar singular stress fields are formed in the range of 0.15 mm ≤ t2≤ 0.9mm and 15 mm ≤ l2≤ 50 mm. It is shown that the critical ISSFs at the fracture are constant in the range.