방호용 군용차량 플랫폼의 구조 최적화 설계

다국어 초록 (Multilingual Abstract)

In this study, the design optimization of military wheeled vehicle platform under design constraints was studied at conceptual design phase. The multi-design-constraints reflect the characteristics of survivability, mobility and structural stability ; especially, survivability such as ballistic and mine protection is considered most critical in the design fields of the ground weapon systems.
Therefore, in this study, ballistic and mine protections along with the least twist deformation were selected as the multi -disciplinary design constraints, and also the light weight which affects vehicle mobility was included in the purpose function. The final design was optimized according to the four phases.
As the first phase, the reliability of ballistic and mine blast analyses should be proven valid as tools to perform the virtual tests. In order to prove the simulation reliability, the simulation results of ballistic and mine blast were compared with the test results of flat armor plate.
As the second phase, the length, width and height of a base model by reviewing from the dimensions of similar domestic and international combat vehicles were decided. The thickness of front, side, top, rear and bottom of a base model was selected as design variables and then ballistic and mine blast analysis were performed to decide at each thickness level according to the MIL and NATO standard.
As the third phase, the effect analysis was performed to evaluate design variables which affect performance indices such as ballistic protection, mine blast protection, structural strength and stiffness.
The two design variables were extracted from the first five design variables by a main effect analysis and an ANOVA (Analysis of Variance) method. This phase was also divided to four steps, and as the 1st step, the design variables which affect purpose function and design constraints were selected from a base model. As the 2nd step, test cases were decided through DOE (Design of Experiment). As the 3rd step, the numerical analysis for test cases were performed, and then as the 4th step, design variables which affect performance indices were extracted by ANOVA and main effect analysis, and then they were redefined.
As the fourth phase, the 2nd DOE for the two design variables which were extracted from five design variables at the previous phase were executed to minimize test cases, and then the 2nd analysis were also performed.
Finally, the best optimal thicknesses satisfied with the purpose function and three design constraints at each position was decided by the optimal procedure of RSM (response surface method) as a statistical way.
In this study, the optimal design procedure for combat vehicle platform with protection capacity was suggested and an optimized set of plate thicknesses was decided to satisfy the desired condition of three constraints and one purpose function.

국문 초록 (Abstract)

본 논문은 휠 타입의 군용 전투차량 차체 플랫폼 기본설계 단계에서 다분야 설계제한 조건을 고려한 최적화 설계에 대한 연구이다. 다분야 설계제한 조건으로는 생존성, 기동성, 구조 안전성 등 여러 가지 성능조건이 있으며, 특히 생존성 조건인 피탄 및 지뢰폭압 방호는 여러 설계제한 조건 중 지상무기분야 설계에서 가장 중요한 성능으로 분류된다. 따라서, 본 연구에서는 다분야 설계제한 조건을 피탄 및 지뢰폭압 방호와 차량의 내구성에 영향을 주는 최소 비틀림 변위로 정하였고, 또한 차량의 기동성능을 좌우하는 경량화를 목적함수로 정하였다. 최적화 설계는 총 4 단계로 구분하여 수행하였다.
첫 번째 단계는 실험점 수행을 위해서 가상실험 방법인 피탄, 폭압 시뮬레이션의 신뢰성을 확인하는 단계이다. 설계변수 수준을 결정하기 위한 피탄 및 폭압해석 결과의 신뢰성을 검증하기 위해서 기 수행되었던 평판 장갑판재의 피탄 및 폭압 실험과 해석결과 비교를 통한 해석의 신뢰성을 검증하였다.
두 번째 단계는 최적화 차체 플랫폼 설계를 수행하기 위해서 단순화된 기준모델을 결정하는 단계로써, 기 개발되어 상용화 되어 있는 국내 ⋅외 유사 군용 전투차량의 제원을 기준으로 길이, 폭, 높이 등을 결정하였다. 차량 차체의 전면, 측면, 상부, 후면 및 바닥면의 두께를 설계변수(design variables)로 결정하였고, MIL 및 NATO 군사규격 범위내의 설계변수 수준을 정의하기 위해서 피탄 및 폭압해석 등의 충격해석을 수행하였다.
세 번째 단계는 피탄 방호, 지뢰폭압 방호 및 구조 플랫폼 강도, 강성 등의 성능지수에 크게 영향을 미치는 설계변수를 결정하기 위해서 효과 분석 (effect analysis) 수행하는 단계이며, 분산분석 (ANOVA)과 주효과 분석 (main effect analysis)을 통해서 총 5개의 설계 변수로부터 2개의 변수를 추출 하였다. 효과 분석을 수행하는 단계 또한 4 단계로 나누어지는데, 1 단계는 기본모델에서 목적함수와 설계제한조건에 영향을 주는 설계변수를 선택한 후, 2 단계에서 시험계획법 (DOE)을 사용하여 실험점을 생성하였고, 3 단계는 생성된 실험점에 대한 해석을 수행하고, 4 단계에서 해석결과를 이용하여 해석결과에 영향을 주는 인자를 선별하는 방법으로 진행한 후, 주효과 분석과 분산분석을 사용하여 각 해석조건별 성능지수에 유의한 설계변수를 재 정의 하였다.
네 번째 단계는 전 단계에서 재 정의된 유의한 설계변수로 부터 2차 실험계획법을 사용하여 실험점의 수를 최소화하고 각 실험점의 해석을 수행한 후, 최종적으로 통계적인 방법인 반응표면법 (response surface method)의 최적화 절차를 적용하여 설계변수의 최적 두께치수를 결정하였다.
본 연구에서는 연구의 결과로서 목적함수인 차체 경량화, 설계제한 조건인 피탄 방호, 지뢰폭압 방호 및 비틀림 최소 변위 등을 만족시키는 군용 전투차량 차체 플랫폼의 위치별 최적 두께치수를 결정하였고, 방호용 군용 전투차량 차체 최적화 설계방법을 제시하였다.

목차 (Table of Contents)

• 요약문·············································································ⅰ
• Abstract·········································································ⅲ
• 목 차··············································································ⅴ
• Nomenclatures······························································ⅷ
• List of Tables··································································ⅹ
• List of Figures································································ⅻ
• 제 1 장 서론····································································1
• 1.1 연구배경 및 목적························································1
• 1.2 국내⋅외 연구동향························································2
• 1.3 연구내용···································································4
• 제 2 장 다분야 최적설계 및 고속충격해석의 이론적 배경·····7
• 2.1 실험계획법 (DOE)·····················································7
• 2.2 분산분석 (ANOVA)··················································11
• 2.3 다분야 최적설계·······················································12
• 2.4 피탄해석 모델··························································16
• 2.5 폭압해석 모델 및 방법··············································19
• 제 3 장 해석방법 검증 및 기본모델 형상 결정····················31
• 3.1 해석방법 검증··························································31
• 3.2 기본모델 형상 결정···················································33
• 3.3 차체설계 기준 결정···················································36
• 3.4 차체 두께 결정·························································37
• 3.5 차체 설계 변수 및 목적함수 결정································41
• 제 4 장 효과분석 (effect analysis)···································95
• 4.1 설계기준별 성능지수 결정·········································95
• 4.2 1차 해석 및 효과분석················································95
• 4.3 2차 해석··································································99
• 제 5 장 경량 최적화 수행················································131
• 5.1 반응표면법 적용 개요···············································131
• 5.2 반응표면법을 적용한 최적화 과정······························131
• 제 6 장 결과 및 토론·······················································141
• 제 7 장 결론··································································145
• 참고문헌·······································································146

참고문헌 (Reference)

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2 이수범, "“정/동강성과 충돌성능을 고려한 효과 분석 및 차체 다분야 구속 최적 설계,”", 국민대학교 자동차공학 전문대학원 공학석사학위 논문, 2011

3 김범진, "“다분야 설계 제약조건을 고려한 알루미늄 스페이스 프레임 차체의 최적설계,”", 국민대학교 대학원 공학박사학위 논문, 2004

4 박주호, "“방폭강과 발포알루미늄을 적층한 폭압방호구조 시뮬레이션 과 전투차량 방호분석,”", KAIST 기계항공시스템학부 기계공학 공학 석사학위 논문, 2012

5 김선갑, "“반응표면법을 이용한 스포츠형 자동차 리어 링크모듈의 경 량화를 위한 최적화 설계,”", 동명대학교 대학원 공학석사학위 논문, 2010