초록 ▼

1. 신(新)구조 PCM 단위셀 형상설계 및 제조 기술 개발
1) 트러스 PCM코어 샌드위치 판재 해석 기술 개발
◦ Full model 및 Equivalent model을 이용한 truss 코어 샌드위치 판재 굽힘해석 및 결과 분석 완료
2) 면내이방성 최소화를 위한 신(新)구조 PCM 단위셀 형상설계
◦ Hexagonal truss 구조 설계
◦ FEM을 이용한 인장, 전단물성예측을 통한 압축강도의 동등성 및 전단강도의 면내이방성 감소확인.
3) 신(新)구조 PCM용 금형 설계 및 제조
◦

1. 신(新)구조 PCM 단위셀 형상설계 및 제조 기술 개발
1) 트러스 PCM코어 샌드위치 판재 해석 기술 개발
◦ Full model 및 Equivalent model을 이용한 truss 코어 샌드위치 판재 굽힘해석 및 결과 분석 완료
2) 면내이방성 최소화를 위한 신(新)구조 PCM 단위셀 형상설계
◦ Hexagonal truss 구조 설계
◦ FEM을 이용한 인장, 전단물성예측을 통한 압축강도의 동등성 및 전단강도의 면내이방성 감소확인.
3) 신(新)구조 PCM용 금형 설계 및 제조
◦ Hexagonal truss 제조를 위한 다점 핀 금형설계 및 제작
4) 신(新)구조 PCM코어 샌드위치 판재 제조 및 정적 특성 평가
◦ 2차원 그물망 형상 가공
◦ 3차원 truss PCM 성형 및 접합
◦ 압축, 전단, 굽힘특성평가
2. 개방형 폼의 멀티스케일 해석 기술 개발
1) 연속체 기반 해석 모델 적용
◦ 연속체 기반 해석 모델 및 관련 물질 상수 확보
2) 충돌 해석 기술 결과 검증
◦ 충돌 시험 및 해석 결과 비교 검증
3) 충돌 성능 분석
◦ 충돌 성능 향상을 위한 미세 구조 디자인 제시

Abstract ▼

Metallic sandwich panels based on a PCM (Periodic cellular metal) core structure have been developed for a wide range of potential applications with their lightweight and multi-functionality. However, industrial applications of PCMs are limited to some parts for aerospace and military purpose due to

Metallic sandwich panels based on a PCM (Periodic cellular metal) core structure have been developed for a wide range of potential applications with their lightweight and multi-functionality. However, industrial applications of PCMs are limited to some parts for aerospace and military purpose due to high manufacturing cost. Successful implementation relies not only on their mechanical or thermal properties, but also on additional attributes, such as low manufacturing cost, small limitation in the formation of designed shape and environmental durability etc. The main goal of the paper is the development of the novel fabrication technology that can eliminate the limiting factors which obstruct for PCMs to be implemented. In order to achieve this goal, a new fabrication process, perforation-stretching method using multiple pin die, have been developed. The process enables to fabricate new type of truss PCM(ie. hexagonal truss) which has higher mechanical properties than that by the conventional perforation-bending process. Through some experimental investigations for the structural performance evaluation such as compression, shear and three-point bending tests, it is verified that the sandwich panel with the hexagonal truss PCM fabricated has over or equal mechanical properties compared to the one reported previously.
To reduce vehicle weights while maintaining or even increasing the crashworthiness, metal foam inserts have been tried for the thin-walled crash members. For design and analysis of the foam-filled crash member, accurate description of the foam behavior is essential. Foams, however, are not easy to be characterized using standard material testing methods such as the tensile test. In addition, pressure-sensitivity of the foam makes the material modeling even more complex. To circumvent the difficulties of experiments, a representative volume element (RVE) of an open-cell aluminum alloy foam was constructed and virtual tests were conducted for the RVE. The structure of the open-cell foam was recorded using the X-ray microtomography (micro-CT) and the finite element model was constructed. By comparing the compressive response of the RVE with the measurement, the property of the bulk aluminum alloy was inversely estimated. The RVE was then subject to various stress states, such as uniaxial, biaxial, and shear loading, to characterize the behavior of the foam. The homogenized material model was then incorporated into the impact test of the foam-filled crash member. The impact tests of the foam-filled and thin-walled crash member were conducted. The predicted decelleration compared well with the measurements, which confirms that the material model characterized by the RVE represents well the behavior of the open-cell foam under impact loading. In order to investigate the effect of foam contents on the impact performance, the foam structures with different volume fractions were generated using the image processing technique and their effective mechanical behavior was calculated. Then, the impact performance of the crash members with the same weight but with different foam contents was compared. The results showed that the crash member made of the aluminum foam with a higher volume fraction has better impact performance than the hollow structure made of the steel sheet.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 초록 ... 3
• 요약문 ... 4
• SUMMARY ... 6
• CONTENTS ... 7
• 목차 ... 8
• 제 1 장 연구개발과제의 개요 ... 9
• 제 1 절 연구개발의 필요성 ... 9
• 제 2 절 연구개발의 목표 및 내용 ... 11
• 제 2 장 국내외 기술개발 현황 ... 13
• 제 3 장 연구개발수행 내용 및 결과 ... 14
• 제 1 절 신(新)구조 PCM 단위셀 형상설계 및 제조 기술 개발 ... 14
• 제 2 절 개방형 폼의 Multiscale 해석 기술 개발 ... 19
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 25
• 제 1 절 연구목표 달성도 ... 25
• 제 2 절 연구결과의 기대효과 ... 27
• 제 5 장 연구개발결과의 활용계획 ... 28
• 끝페이지 ... 29