In this study, the regression equation was suggested to predict of the shot ball velocity according to blade shapes based on discrete element (DE) analysis. First, the flat type blade DE model was used in the analysis, the validity of the DE model was verified by giving that the velocity of the shot ball almost equal to the theoretical one. Next, the DE analyses for curved and combined blade models was accomplished, and their analytical velocities of shot ball were compared with the theoretical one. The velocity of combined blade model was greatest. From this, the regression equation for velocity of shot ball according to the blade shape based on the DE analysis was derived. Additionally, the wind speed measurement experiment was carried out, and the experimental result and analytical one were the same. Ultimately, it was confirmed that the prediction method of the velocity of shot ball based on DE analysis was effective.

ABSTRACT
 1. 서 론
 2. 숏볼의 이론적 투사속도
  2.1 평면형 블레이드에서의 투사속도
  2.2 곡면형 블레이드에서의 투사속도
 3. 이산요소해석에 기초한 투사성능
  3.1 이산요소해석 모델의 유효성
  3.2 곡면형 블레이드 모델에서의 투사속도
  3.3 혼합형 블레이드 모델에서의 투사속도
 4. 투사속도 회귀방정식 및 실험적 검증
  4.1 이산요소해석에 기초한 투사속도 예측식
  4.2 풍속측정 실험을 통한 투사성능의 유효성
 5. 결 론
 References

• 김태형(Cheongju University,) | Tae-Hyung Kim Corresponding Author
• 이승호(Gyeonggi College of Science & Technology) | Seung-Ho Lee
• 정찬기(Daewon Applied Eng. Co.) | Chan-Gi Jung