# 우레탄 폼 코아 샌드위치 구조물의 피로특성에 미치는 스티칭 사의 영향

• Published : 2000.04.01

#### Abstract

The effects of stitching thread on fatigue characteristics of polyurethane foam cored sandwich structures are investigated. Fatigue test and static test, being used in four point bending test, are performed with various diameters and distances of stitching thread. The Results show that the maximum load for bending tests is similar to each other, but after $1O^6$ fatigue cycles, the stiffness degradation of the stitching thread diameter $\emptyset$ 3mm specimen is a much larger than that of the $\emptyset$ 5mm specimen.