PURPOSE: To improve reliability of strength by providing a non-joined zone with a surface sheet in the part of core material side in the case of a frame member facing a surface sheet so as to reduce stress concentration.
CONSTITUTION: A sandwich panel 1 is structured so that a frame member 3 and core material 4 are joined between upper/lower surface sheets 2, 2 with brazing. As its joining state, the frame member 3 and surface sheet 2 are brazed with a brazing filler metal 5 but a non-joined zone having (d) width on the inner peripheral edge part of frame member 3, that is, the side of core material 4 is arranged. The non-joined zone (d) is arranged along the longitudinal direction of frame member 3. In the case the non-joined zone (d) is brazed, that is, the whole surface of frame member 3 facing to the surface sheet 2 is brazed, repeated bending load in the thickness direction is applied to the sandwich panel 1. concentrated stress is generated to part of the surface sheet 2, strength reduction is caused to the sandwich panel 1. However, because the non-joined zone with surface sheet 2 is provided at part of the side of core material 4, a position of stress is dispersed and stress concentration is alleviated.
KAWASAKI TAKESHI
ISHIMARU YASUO
