• 대한기계학회논문집A
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• 제29권9호
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• pp.1191-1198
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• 2005

This paper is concerned with the numerical investigation of the landing impact characteristics of sport shoes to the landing mode. In most court sport activities, jumping and landing are fundamental motions, and the landing motion is largely composed of forefoot and rearfoot landing modes. Since the landing impact may, but frequently, lead to unexpected injuries of players, the investigation of its characteristics and the sport shoes design for reducing it are of a great importance. To investigate the landing impact characteristics to the landing mode, we construct a shoes-leg coupled model and carry out the numerical simulation by an explicit finite element method.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.83-86
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• 2015

Taking the four-wheel bogie landing gear as an example, the force status of truck-like landing gear during the landing impact was analyzed and the simulation model of four-wheel bogie landing gear was established. Firstly, a landing gear prototyping model was established using CATIA and imported to LMS Virtual.lab. Secondly, dynamic analysis of the landing impact was simulated with the established model. Finally, with the help of LMS Virtual.lab's parametric design ability, the effects of landing approach and truck pitch angle on the landing performance, truck motion and truck beam strength were studied. These conclusions will be useful to the design and analysis of the truck.

• Interaction and multiscale mechanics
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• 제5권1호
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• pp.75-90
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• 2012

This paper investigates the effects of sports ground materials on the transfer characteristics of the landing impact force using a coupled foot-shoe-ground interaction model. The impact force resulting from the collision between the sports shoe and the ground is partially dissipated, but the remaining portion transfers to the human body via the lower extremity. However, since the landing impact force is strongly influenced by the sports ground material we consider four different sports grounds, asphalt, urethane, clay and wood. We use a fully coupled 3-D foot-shoe-ground interaction model and we construct the multi-layered composite ground models. Through the numerical simulation, the landing impact characteristics such as the ground reaction force (GRF), the acceleration transfer and the frequency response characteristics are investigated for four different sports grounds. It was found that the risk of injury, associated with the landing impact, was reduced as the ground material changes from asphalt to wood, from the fact that both the peak vertical acceleration and the central frequency monotonically decrease from asphalt to wood. As well, it was found that most of the impact acceleration and frequency was dissipated at the heel, then not much changed from the ankle to the knee.

• 한국운동역학회지
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• 제30권1호
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• pp.37-49
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• 2020

Objective: The purpose of this study was to investigate the injury factors of Taekwondo jumping kick during landing phase according to the experience of injury and to suggest a stable landing movement applicable to free style Poomsae. Method: The participants were non-injury group (NG), n = 5, age: 20.5±0.9 years; height: 171.6±3.6 cm; body weight: 65.7±4.4 kg; career: 5.0±2.7 years. Injury group (IG), n = 9, age: 21.0±0.8 years; height: 170.9±4.6 cm; body weight: 67.1±7.0 kg; career: 8.6±5.0 years. The variables are impact force, loading rate, vertical stiffness, lower limb joint angle, stability, balance, and muscle activity in the landing phase. Results: NG was statistically larger than IG in the gluteus medius (p<.05). The impact force, loading rate and vertical stiffness decreased as the landing foot angle, the ROM of lower limb joint angle and COM displacement increased (p<.05). Conclusion: Based on the results, it means that the landing foot angle plays an important role in the impact reduction during landing phase. It is required the training to adjust the landing foot angle.

• 한국군사과학기술학회지
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• 제11권5호
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• pp.12-22
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• 2008

In this study, the dynamic characteristics for the wheel-type landing gear system of helicopter have been analyzed. Nonlinear multi-body dynamic models of the landing gear system are constructed and the equations of motion, kinematics and internal forces of shock strut are considered. In addition, flexibility effect of the wheel axle with equivalent beam element is taken into account. General purpose commercial finite code, SAMCEF which includes MECANO module is applied. The results of dynamic simulation for various landing and weight conditions are presented and compared with each other. Based on the results, characteristics of impact dynamic behaviors of the landing gear system are practically investigated.

• 한국항공우주학회지
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• 제30권4호
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• pp.114-122
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• 2002

착륙장치 시스템의 개발은 설계특성상 충격흡수 성능에 대한 설계 파라메터, 최소한의 작동공간, 복잡성 및 중량과 비용 등의 복합적인 관계를 가지고 있다. 특히 항공기 착륙에 따른 지상충격하중 및 동적거동은 착륙장치 자체 구성품 뿐만 아니라 장착구조물의 설계 하중으로 적용되는 중요한 설계분야이다. 본 연구에서는 T-50 착륙장치를 모델로 ADAMS를 이용하여 지상 충격하중 및 동적거동을 해석할 수 있는 프로그램을 개발하였다. 항공기 운용/환경조건을 고려한 충격흡수특성 해석은 다양한 설계경험을 토대로 수행하였다. 설계변수 설정, 완충기에 작용하는 내력정의, 운동방정식을 유도하여 착륙 수직속도, 착륙 자세, 착륙 수평속도, 완충효율, 장착위치 작용하중 등을 고려한 해석결과와 동적거동 특성을 분석하고 제시하였다. 이러한 해석 결과를 바탕으로 향후 새로운 착륙장치 개발시 범용적인 해석이 용이할 뿐만 아니라 지상/비행시험의 문제점 발생시 고장탐구 해결에 활용할 수 있다.

• 한국운동역학회지
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• 제19권2호
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• pp.217-225
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• 2009

최근 들어 부강을 방지하고 경기력을 향상시킬 수 있는 스포츠화를 개발하기 위해 신체운동학과 생체역학을 반영한 연구가 전세계적으로 활발히 수행되고 있다. 하지만, 이러한 연구의 성골 여부는 스포츠화와 발의 동적 거동, 특히 착지 충격 특성 평가의 신뢰성에 절대적으로 좌우된다. 그 이유로는 코트 스포츠운동에 있어서 착지충격력이 예상치 못한 부상과 경기력의 주요한 요인이기 때문이다. 이 연구는 맨발과 대표적인 코트 스포츠화의 착지충격 특성을 평가하기 위해 유한요소 해석을 적용하였다. 사람의 발과 신발사이의 연계효과를 정확히 반영하기 위해 별도의 실험 데이터에 의존하지 않는 완전한 3차원 발-신발 FEM 모델을 생성하였다. 수치 시뮬레이션을 통해 FEM 모델의 신뢰성을 평가함과 동시에 여러 가지 스포츠화의 GRF, MIF 및 주파수 응답과 같은 착지충격 특성들을 분석하였다.

• 제어로봇시스템학회논문지
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• 제11권6호
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• pp.543-549
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• 2005

This paper deals with modeling and analysis fer the landing motion of a human-body model. First, the dynamic model of a floating human body is derived. The external impulse exerted on the ground as well as the internal impulse experienced at the joints of the human body model is analyzed. Second, a motion planning algorithm exploiting the kinematic redundancy is suggested to ensure stability in terms of ZMP stability condition during a series of landing phases. Four phases of landing motion are investigated. In simulation, the external and internal impulses experienced at the human joints and the ZMP history resulting from the motion planning are analyzed for two different configurations. h desired landing posture is suggested by comparison of the simulation results.

• 대한기계학회논문집A
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• 제28권12호
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• pp.1974-1981
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• 2004

This paper is concerned with the numerical investigation of the transfer characteristics of the landing impact force exerted on court sport shoes to the sport surface condition. The reaction force occurred by the impact between court sport shoes and sport surface is absorbed by shoes to some extent, but the remaining impact force is to transfer the human body from the sole of a foot. We consider four surface conditions, asphalt, urethane, clay and wood court surfaces. For the dynamic response analysis, we construct a coupled leg-shoes FEM model and create the multi-layered composite surface model. The numerical simulations are performed by an explicit nonlinear finite element method. Through the numerical experiments, we examine the transfer characteristics of the landing impact force to the surface condition.

• 국제물리치료학회지
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• 제2권1호
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• pp.222-228
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• 2011

With comparison of maximum vertical reaction force and lower limb on drop landing between normal and flat foot group, this study is to provide fundamental data of the prevention of injury and the treatment of exercise which are frequently occurred on flat foot group's drop landing. The surface electrodes were sticked on lateral gastrocnemius muscle, medial gastrocnemius muscle, tibialis anterior and the drop landing on a force plate of 40cm was performed with a normal group who had no musculoskeletal disease and a flat foot group of 9 people who had feet examinations. Vertical reaction force were significantly statistically different between two groups(p<.001). Muscle activity of lower limbs in all three parts were not statistically different but showed high tendency on average in the flat foot group. The flat foot group had difficulties in diversification of impact burden and high muscle activity. Therefore, it was suggested that muscular strengthening of knee joints and plantar flexions of foot joints which were highly affected in impact absorption will be required.