scholarly journals Fatigue strength of FRP/metal adhesive joints under low temperature

2008 ◽  
Author(s):  
T. Hattori
Keyword(s):  
Fatigue Strength ◽  
Low Temperature ◽  
Adhesive Joints

Evaluation Method for Fatigue Strength of FRP/Metal Adhesive Joints Considering Mean Stress

2003 ◽  
Vol 125 (4) ◽  
pp. 402-405 ◽  
Author(s):  
Masaaki Iwasa ◽  
Toshio Hattori
Keyword(s):  
Fatigue Strength ◽  
Low Temperature ◽  
Evaluation Method ◽  
Stress Singularity ◽  
Propagation Rate ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Mean Stress ◽  
Lap Joint ◽  
The Relationship

The fatigue strength of two types of FRP/metal adhesive joints at low temperature, a double lap joint and an embedded joint, was evaluated analytically and experimentally. First, the stress singularity parameters of the delamination edges under mechanical and thermal loadings were analyzed by FEM for various delamination lengths. The delamination propagation rate of the double lap joint under mechanical cyclic loadings at room temperature was measured. Using the relationship between the measured propagation rates and the analyzed ranges of stress singularity intensity, we estimated the fatigue strength of the embedded joint, which coincided well with the measured one. Second, we developed an evaluation method that separates the effects of temperature on fatigue strength into two effects: thermal residual stress and low temperature. Third, the fatigue strengths of the double lap joints were measured for various mean stresses. Fatigue limit of adhesive joints was experimentally measured and compared with analytical intensity of stress singularity. A method for evaluating the fatigue strength of adhesive joints by taking mean stress into account was developed.

Fatigue Strength of Metal / FRP Adhesive Joints Under Low Temperature

1995 ◽  
Author(s):  
Toshio Hattori ◽  
Masaaki Iwasa
Keyword(s):  
Fatigue Strength ◽  
Low Temperature ◽  
Residual Stresses ◽  
Adhesive Joint ◽  
Evaluation Method ◽  
Stress Singularity ◽  
Adhesive Joints ◽  
Strength Evaluation ◽  
Thermal Residual Stresses ◽  
Super Conducting

Abstract Fiber reinforced plastics (FRP) have the excellent thermal isolation characteristics, and are used for for cryogenic structures such as super conducting magnets. Generally these FRP materials are connected with metal structures using adhesive joint, as these FRP materials loose strength by the existence of bolt holes. In this metal/FRP adhesive joints high thermal residual stresses occur under cryogenic temperatures as the thermal expansion coefficients of both materials differ large. So, improvement of strength evaluation method of these bi-material adhesive joints under low temperature become indispensable to develop high-reliability super conducting magnet systems such as form Magnetic Levitation Liner Motor Car. In this paper we present a new fatigue strength evaluation method under high thermal residual stresses using following two stress singularity parameters K and λ at bonding edges. τ ( r ) = K / rλ Heat τ(r) is stress (MPa), r is the distance (mm) from the singular point (bonding edge), K is the intensity of stress singularity and λ is the order of stress singularity. And this evaluation method is applied to Stainless-steel/Al2O3 FRP adhesive joint models.

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