국회도서관 서비스 이용에 대한 안내를 해드립니다.
검색결과 (전체 1건)
원문 있는 자료 (1)열기
원문아이콘이 없는 자료는 국회도서관에 방문하여 책자로만 이용이 가능합니다.
목차보기더보기
표제지
ABSTRACT
목차
Nomenclature 8
1. 서론 15
1.1. 연구 동기 15
1.2. 연구 동향 16
1.3. 연구 개요 18
2. 충돌 해석을 위한 유한요소모델 19
2.1. 골프 공의 설계 19
2.2. 반발계수 20
2.3. 골프 클럽의 설계 21
2.4. 접촉 조건 22
3. 충돌 해석 32
3.1. 이론적인 충돌 계산 32
3.2. 유한요소해석 36
4. 여러 가지 충돌 해석 58
4.1. 마찰이 없을 경우 충돌 해석 58
4.2. 공의 강성에 따른 충돌 해석 59
4.3. 클럽 초기 속도, 로프트 각도를 변화시켰을 때 충돌 해석 61
4.4. 클럽이 공에 비스듬히 맞았을 경우 충돌 해석 62
4.5. 클럽의 무게중심에서 일정거리 떨어졌을 때 충돌 해석 64
5. 결론 82
참고문헌 85
부록 88
A.1. 궤적 운동 방정식 88
A.2. 항력, 양력, 항모멘트계수 89
A.3. 정면 충돌에서 공의 궤적, 회전 량 변화 및 최적화 91
A.4. 여러 가지 충돌의 궤적 계산 91
감사의 글 102
Table 2.1. Material property of golf ball and club head 25
Table 2.2. Mooney-Rivlin constants 25
Table 2.3. Coefficient of friction between club head and ball at impact 25
Table 3.1. Inconsistent results on contact forces at impact between ball and club head 43
Table 4.1. Velocities and spin rates of ball with club open angle(γ) varied 66
Table 4.2. Velocities and spin rates of ball for off-center hit with eccentricity (h) 66
Table A.1. Reference parameters at impact 93
Table A.2. Ball flight and trajectory 93
Table A.3. Effect of club head speed (V) on the ball flight 94
Table A.4. Effect of loft angles (Ψ) on ball flight 94
Figure 2.1. Golf ball model 26
Figure 2.2. Bouncing of golf ball 27
Figure 2.3. Coefficient of restitution vs. ball impact speed 28
Figure 2.4. Club head model and coordinates: (a) top and (b) side views 29
Figure 2.5. Dynamics of ball and club head after impact for the ball contact line (a) above, (b) through and (c) below the club head mass center 30
Figure 2.6. Contact method by FEM 31
Figure 3.1. Vector of club and ball at impact 44
Figure 3.2. The realistic velocity of the moving frame 44
Figure 3.3. Golf club head and ball models: (a) overview and (b) cut-view 45
Figure 3.4. Ball and head velocity at impact: (a) launch angle and (b) ball and head velocity 46
Figure 3.5. Normal and tangential forces at impact 47
Figure 3.6. (a) Normal and tangential forces and (b) tangential force compared to Moriyama data 48
Figure 3.7. Normal and tangential forces during contact 49
Figure 3.8. Slip and roll of ball 54
Figure 3.9. Ball spin rate at impact: (a) method to compute spin rate and (b) ball spin rate compared to FEM result 55
Figure 3.10. Tangential force, tangential velocity and spin rate at impact 56
Figure 3.11. Effective radius of deformed ball at impact: (a) node plot at minimum radius and (b) radius vs. time 57
Figure 4.1. Normal and tangential forces: no friction 67
Figure 4.2. Tangential forces along the undeformed and deformed club faces: (a) deformed club faces and (b) tangential force vs. time 68
Figure 4.3. (a) Tangential forces and (b) spin rates for elastic club head with ball stiffness varied 69
Figure 4.4. (a) Tangential forces and (b) spin rates for rigid club head with ball stiffness varied 70
Figure 4.5. Ball velocity, launch angle, spin rate and compression factor for club initial velocity and loft angle varied 71
Figure 4.6. (a) Coordinates and (b) side spin rate for zero loft angle 72
Figure 4.7. Impact for open club face: (a) side and (b) top views 73
Figure 4.8. Normal (Fn) and tangential forces (Ft1, Ft2) for open club face with (a) 5 and (b) 15 degrees(이미지참조) 74
Figure 4.9. Tangential forces (Ft1, Ft2) with the club face open angle(γ) varied(이미지참조) 75
Figure 4.10. Ball spin rate components for the club face open angle γ=10° 76
Figure 4.11. Resultant spin axis with the club face open angle (γ) varied 77
Figure 4.12. (a) Coordinates and (b) tangential forces (Ft1, Ft2) for the off-center hit with eccentricity (h)(이미지참조) 78
Figure 4.13. Ball spin rate components for h= 10 mm 79
Figure 4.14. Gear effect 80
Figure 4.15. Spin rate axis vs. eccentricity (h) 81
Figure A.1. Coordinates for golf ball trajectory 95
Figure A.2. Dimples of golf ball 96
Figure A.3. Drag and lift coefficients of ball 96
Figure A.4. Ball trajectory 97
Figure A.5. Decrease of ball spin rate in flight 97
Figure A.6. Maximum ball distance (x) vs. upper blow angle (η) 98
Figure A.7. Ball trajectory vs. club head speed (V) 99
Figure A.8. Ball trajectory vs. loft angle (ψ) 99
Figure A.9. Ball trajectory vs. club open angle (γ) 100
Figure A.10. Ball trajectory vs. eccentricity (h) 101
초록보기 더보기
It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and contact force.
Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Moriyama (2004) conjectured that the positive and negative tangential forces create and reduce the back spin rate, respectively, without mentioning the mechanism of ball spin creation during impact. The mechanism of ball spin creation has not yet been discussed in detail in the literature.
In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and the contact time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.
원문구축 및 2018년 이후 자료는 524호에서 직접 열람하십시요.
도서위치안내: / 서가번호:
우편복사 목록담기를 완료하였습니다.
* 표시는 필수사항 입니다.
* 주의: 국회도서관 이용자 모두에게 공유서재로 서비스 됩니다.
저장 되었습니다.
국회전자도서관에 오신 것을 환영합니다. 로그인을 하시려면 아이디와 비밀번호를 입력해주세요. 모바일 간편 열람증으로 입실한 경우 회원가입을 해야합니다.
공용 PC이므로 한번 더 로그인 해 주시기 바랍니다.
아이디 또는 비밀번호를 확인해주세요
