여자 축구선수의 사이트 커팅 동작 시 방향 예측과 피로가 하지 관절의 부하에 미치는 영향

박은정 ( Eun Jung Park ),이용석 ( Yong Seuk Lee ),임비오 ( Bi O Lim ),김용운 ( Yong Woon Kim ),이기광 ( Ki Kwang Lee ) 대한스포츠의학회 2011 대한스포츠의학회지 Vol.29 No.1

To investigate effect of fatigue and anticipation on lower extremity joint load during a side-cutting maneuver in female collegiate soccer players, thirteen female collegiate soccer players whose right leg dominant participated in this study. Three dimensional motion analysis system and a force plate were used to record the 45˚ side cutting maneuver. In the first, anticipated and unanticipated cutting were measured in the pre-fatigue condition. Second, participations performed the fatigue protocol by the squat exercise with weight lifting. And then, two different type of cutting task were measured again after fatigue condition. The cutting direction let known before start their running in case of the anticipated cutting, the random signal of cutting direction were presented in the unanticipated condition. In the results, the most influential variable was anticipation factor. Lower limb angles represented significantly flexed posture during unanticipated cutting than anticipated condition. Maximum knee flexion moment represented significantly higher in unanticipated cutting than anticipated cutting. Adduction and internal rotation moment of lower limb joint decreased in unanticipated cutting. Fatigue factor was influenced by the initial contact angles of the ankle joint. Lower limb angles at the initial ground contact indicated more erect posture in post-fatigue condition. The unanticipation factor had more effect on locomotors ability of lower limb in this study. Therefore, the sensory-motor training to adapt to unanticipated situation should be considered for the injury prevention training program.

엔드밀 가공시 절삭조건이 비절삭력계수에 미치는 영향

이신영 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.6

For improvement of productivity and cutting tool life, cutting force in end milling needs to be predicted accurately. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. Specific cutting force coefficients of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, feed, axial depth, and radial depth of cut. The effects of the cutting conditions on the specific cutting force constants in milling were studied. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments.

밀링가공시 절삭조건이 비절삭력계수에 미치는 영향 분석

이신영 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

A reasonable analysis of cutting force in end milling may give much advantage to improvement of productivity and cutting tool life. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. Specific cutting constants of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, feed, axial depth, and radial depth of cut. The effects of the cutting conditions on the specific cutting force constants in milling were studied. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments.

밀링가공시 절삭조건이 비절삭력계수에 미치는 영향 분석

이신영(Sin-Young Lee) 한국생산제조학회 2004 한국생산제조시스템학회 학술발표대회 논문집 Vol.2004 No.4

A reasonable analysis of cutting force in end milling may give much advantage to improvement of productivity and cutting tool life. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. Specific cutting constants of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, feed, axial depth, and radial depth of cut. The effects of the cutting conditions on the specific cutting force constants in milling were studied. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments.

엔드밀 가공의 절삭력 예측 및 실험

이신영,임용묵 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.4

A reasonable analysis of cutting force in end milling may give much advantage to improvement of productivity and cutting tool life. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. The specific cutting constants of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, feed, axial depth, and radial depth of cut. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments. The results showed good agreement and from that we could predict reasonably the cutting forces in end milling.

앤드밀 가공의 절삭력 예측 및 실험

이신영,임용묵 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

A reasonable analysis of cutting force in end milling may give much advantage to improvement of productivity and cutting tool life. In order to analyze cutting force, the cutting dynamics was modelled mathematically by using chip load, cutting geometry, and the relationship between cutting forces and the chip load. Specific cutting constants of the cutting dynamics model were obtained by average cutting forces, tool diameter, cutting speed, feed, axial depth, and radial depth of cut. The model is verified through comparisons of model predicted cutting forces with measured cutting forces obtained from machining experiments. The results showed good agreement and from that we could predict reasonably the cutting forces in end milling.

CNC 머시닝센터의 스핀들부하를 이용한 법선방향 절삭력 추정

김재혁,윤주성,이동윤 한국생산제조학회 2019 한국생산제조학회지 Vol.28 No.6

The cutting force closely reflects the physics of material removal processes, therefore, much attention has been paid to its measurement. Various sensors have been examined and their feasibilities have been analyzed by many researchers. This study proposes an indirect cutting force estimation method with spindle loads acquired from computer numerical control (CNC). The characteristic of a spindle motor is carefully investigated and the tangential cutting forces are estimated based on spindle loads. Experiment results show that estimation errors depend on the spindle rotation speed and the magnitude of the cutting force. The proposed method can be practically applied to the field, where the magnitude of cutting force is needed but sensors cannot be attached.

Performance Prediction of TBM Disc Cutting on Marble Rock under Different Load Cases

Qing Tan,Liang Yi,Yi-Min Xia 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.4

A series of disc cutting tests was conducted with a single disc cutter (216 mm diameter) and a single rock type (a marble) byapplying different loads. Normal, rolling and side forces were measured for a series of spacings and penetrations, from which othercutting parameters also were calculated. The rock chips and fines were carefully collected and analyzed. Specific Energy (SE)considerations indicate that the optimum cutting condition is existed with the ratio of S/P between 9 and 12 when applying the staticloading. However, when the combination of static and impact loading is applied, the optimum cutting conditions was estimated withthe ratio of S/P between 16 and 19. It shows that the optimal spaces become larger after adding the combination of static and impactloading. The relationship between rolling force and normal force is close and consistent: whether applying the static loading or thecombination of static and impact loading, a nearly linear rise of the ratio of rolling force to normal force with increased penetration,and, conversely, a nearly unchanged ratio with increases in spacing. The grain size distribution curves show that larger chip size andlesser fines are produced when applying the combination of static and impact loading and the degree of crushing size tends to beuniform distribution.

Specific Cutting Force Coefficients Modeling of End Milling by Neural Network

Lee, Sin-Young,Lee, Jang-Moo The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.6

In a high precision vertical machining center, the estimation of cutting forces is important for many reasons such as prediction of chatter vibration, surface roughness and so on. The cutting forces are difficult to predict because they are very complex and time variant. In order to predict the cutting forces of end-milling processes for various cutting conditions, their mathematical model is important and the model is based on chip load, cutting geometry, and the relationship between cutting forces and chip loads. Specific cutting force coefficients of the model have been obtained as interpolation function types by averaging forces of cutting tests. In this paper the coefficients are obtained by neural network and the results of the conventional method and those of the proposed method are compared. The results show that the neural network method gives more correct values than the function type and that in the learning stage as the omitted number of experimental data increase the average errors increase as well.

The effect of zirconia framework design on the failure of all-ceramic crown under static loading

Pakamard Taenguthai,Somchai Urapepon 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.2

PURPOSE This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.