Je Wook Chae

A Study on the Human Impulse Characteristics with Standing Shooting Posture

The rifle impact on human body is affected by the posture of human for rifling. The interaction human-rifle system influences on a firing accuracy. In this paper, impact analysis of human model for standing posture is carried out. ADAMS code and LifeMOD are used in impact analysis of human model and modeling of the human body, respectively. At the shooting, human model is affected by rifle impact during 0.001 second. Performed simulation time for shooting is 0.3second. Applied constraint condition to human-rifle system is rotating and spherical condition. As the results, displacement of the rifle and transfer path analysis of impact on human model is presented.

A Study on the Measuring Device of Muzzle Velocity Using Magnetic Field Gradient Sensor

In the conventional weapon system, such as gun and small arms, it is a general trend that for maximization of its performance and enhancement of its effectiveness, the fire control system; FCS is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst ammunition is developed in parallel for the maximization of effectiveness. Since setting fuse of the flight time for the air burst ammunition is adapted for next rifle, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy. This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

Impact Path Analysis of Human Body with Three Typical Shooting Postures

The hit rate is affected by the shooting impact of the human-rifle system. The impact response of the human-rifle system is determined mainly by the geometrical parameters and contact boundary conditions. In this study, the height and weight of the considered human model are 170 cm and 60 kg, as these parameters mirror 50 per cent of Korean males in their twenties. The rifle model is applied on the K-2. The impact path analysis of three typical shooting postures: the standing, kneeling and prone shooting postures is performed with experimental impulse-time history during a shooting test. The biomechanical response such as impact transfer path, force history and displacement history are investigated.

Analysis of Elbow Reflexes Using Activation Model for Stretch Reflex

삼두박근 반사는 인체 상지에서 발생하는 대표적인 신장반사이며 경추의 이상 등을 판단하는데 중요한 역할을 수행한다. 본 연구에서는 이를 생체역학적으로 해석하기 위하여 새롭게 정의된 신장반사해석 모델을 이용하여 해석적으로 상완 이두박근과 삼두박근의 근활성도 및 상완의 운동 정보를 예측하였다. 해석을 통해 예측된 운동 정보와 실험 결과가 같도록 하는 근활성도를 구하고, 이를 근전도 실험결과와 비교하여 해석 모델과 방법의 타당성을 검증하였다. 제안된 모델과 실험을 통해 얻은 관절의 각도들의 최소자승오차는 0.056 으로 기존의 모델을 사용하여 얻은 오차의 절반 수준이다. 이것은 제안된 모델이 실제 현상과 잘 부합한다는 것을 나타낸다.

Parametric Shape Modeling of Femurs Using Statistical Shape Analysis

대퇴골(Femur)은 인체의 동작 및 보행 등과 같은 하지의 동역학적 기능을 수행하는데 있어서 필수적인 요소이다. 대퇴골의 형상은Fig. 1 에서와 같이 인체의 골격 중 가장 크고 긴 형태를 나타내며 전체 신장의 약 1/4 가량을 차지한다. 대퇴골의 근위 말단 부에 대퇴골구(Femoral head)는 골반의 관골구(Acetabulum)와 결합하여 고관절(Hip Joint)을 형성한다. 이때 대퇴골의 골조직은 골반과 고관절을 통해 전달되는 하중을 지탱해주는 중요한 역할을 한다. 대퇴골의 원위 말단부에 있는 외측과(Lateral condyle) 및 내측과(Medial condyle)는 경골 Key Words: Parametric Shape Modeling(파라메트릭 형상 모델링), Principal Component Analysis(주성분 분석), Statistical Shape Analysis(통계적 형상 분석), Femur Shape(대퇴골 형상), 초록: 인체 골격의 모델생성과 형상변동을 파악하는 것은 생체역학의 응용분야에서 중요한 부분을 차지한다. 본 논문에서는 3차원 대퇴골 모델의 데이터베이스로부터 대퇴골의 형상변동을 통계적으로 분석하고, 추출된 주요 파라미터를 사용하여 대퇴골의 형상을 직관적으로 모델링 할 수 있는 방법을 제안한다. 이를 위해서 먼저 통계적 기법 중에 하나인 주성분 분석(PCA)을 이용하여 대퇴골의 형상변동을 파악하였다. 주성분 분석을 수행하기 위해서는 3차원 대퇴골 모델 간에 토폴로지(Topology)의 일치가 필요하다. 따라서 대퇴골의 형상에 해부학적 기준점(Landmark)을 정의하여 템플릿 모델이 대상 대퇴골 모델로 변형되기 위한 방향을 결정한 후 곡면 피팅(Surface fitting)을 수행하였다. 다음으로 주성분 분석을 통해 도출된 주성분과 대퇴골의 형상을 대표할 수 있는 해부학적 파라미터와의 상관관계를 정의하였다. 마지막으로 해부학적 파라미터로 대퇴골 모델의 생성 및 형상변동을 가시화 할 수 있는 프로그램을 개발하였다. Abstract: Creation of a human skeleton model and characterization of the variation in the bone shape are fundamentally important in many applications of biomechanics. In this paper, we present a parametric shape modeling method for femurs that is based on extracting the main parameter of variations of the femur shape from a 3D model database by using statistical shape analysis. For this shape analysis, principal component analysis (PCA) is used. Application of the PCA to 3D data requires bringing all the models in correspondence to each other. For this reason, anatomical landmarks are used for guiding the deformation of the template model to fit the 3D model data. After subsequent application of PCA to a set of femur models, we calculate the correlation between the dominant components of shape variability for a target population and the anatomical parameters of the femur shape. Finally, we provide tools for visualizing and creating the femur shape using the main parameter of femur shape variation.

Estimation of Human Lower-Extremity Muscle Force Under Uncertainty While Rising from a Chair

Biomechanical models are often used to predict muscle and joint forces in the human body. For estimation of muscle forces, the body and muscle properties have to be known. However, these properties are difficult to measure and differ from person to person. Therefore, it is necessary to predict the change in muscle forces depending on the body and muscle properties. The objective of the present study is to develop a numerical procedure for estimating the muscle forces in the human lower extremity under uncertainty of body and muscle properties during rising motion from a seated position. The human lower extremity is idealized as a multibody system in which eight Hill-type muscle force models are employed. Each model has four degrees of freedom and is constrained in the sagittal plane. The eight muscle forces are determined by minimizing the metabolic energy consumption during the rising motion. Uncertainty analysis is performed using a first-order reliability method. The one-standard-deviation range of agonistic muscle forces is calculated to be about 150–300 N. § 이 논문은 2014년도 대한기계학회 신뢰성부문 춘계학술대회 (2014. 2. 26.-28., 제주대) 발표논문임 † Corresponding Author, hhyoo@hanyang.ac.kr C 2014 The Korean Society of Mechanical Engineers 조영남 · 강문정 · 채제욱 · 유홍희 1148 P f : 수동요사가 발생시키는 수축력 φ : 우모각 t F : 건의 수축력 e : 건의 변형률

Study of Prediction of Reliability of Barrel in Small Arms by Dispersion Anlaysis

Key Words: Reliability(신뢰성), Barrel(총열), Dispersion(분산도), Small Arms(소구경화기)초록: 본연구는소구경화기의총열수명신뢰성분석에대한내용이다 연구의진행은총열의잔여수명을예측할수있는변수를선정하는것에서출발하였으며기존의예측기법인총열의내경을 계측을통해확인하여마모정도를측정하는방법과는달리 야전에서사용가능한분산도와사격량과의관계를예측하여총열의신뢰성및잔여수명예측에대한가설을설정하고연구를진행하였다 실사격을통해수행한선행시험을통해나온결과를바탕으로회귀분석기법을통해적합한실험식을유도한이후검증시험을통해수식이사용가능함을확인하였으며 사용군의운용시험을통해검증하고결과를분석하였다Abstract: This study proposes a method for predicting the reliability of the barrel in small arms by analyzingthe dispersion. The periodicity with which the barrel needs to be changed can be determined by detecting theinner surface directly or by inspecting scratches inside the barrel using an optical sensor. However, soldiersand directors in the logistics command need a more easy way to check the periodicity of barrel. Therefore,this study focuses on the relation between the firing round and the dispersion. A simple equation can beexperimentally derived from pre-tests and analyses. This equation is confirmed through firing tests. In thissense, it can be easily applied to determine the periodicity with which the barrel of small arms needs to bechanged in the field army.

Structural Human Impact Analysis on Shooting: Experimental and Simulation

On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The muscle-skeleton model was developed by the finite element method using beam and spar elements. In this study, a structural analysis has been performed in order to investigate the human body impact by firing a 5.56mm small caliber machine gun. The firing experiments with a standing shooting posture were performed to verify analytical results. The result of this study shows analytical displacements of the human-rifle system and experimental displacements of real firing. In the results, the analytical displacement on the human body is presented.

A Study on Bore-Sighting for the Error Reduction of the XK11

This study is launched to get exact bore-sighting value in the process of assembly for XK11. Image processing method with Charged Coupled Device camera is chosen for the Error reduction of bore-sighting. The results of this method by using a CCD camera and the Testing Target Method are described in this paper. After we confirm the performance of the Dual-Barrel Weapon and that of the Firing Control System in the Dual Barrel Weapon System, the bore-sighting which is a part of the process in the system assembly is accomplished. In this process, the position of the barrel is identified by using the Testing Target Method that is an existing bore-sighting method. Then the fixing line of the Firing Control System is checked by a Day-Optical part. The precision of the boresighting is required within 1 mil, however the manual method using the human eyes makes it worse. Therefore CCD camera is installed in the eyepieces. Next, we can get the image of the sighting and the center coordinate values of the laser-pointer from each barrel by image processing method. Required bore-sighting value is calculated from the eccentricity of the center coordinate. Finally, we will plan to adopt this result in the assembly process of XK11.

A Study on the Surface Treatments of the Barrel of Small Arms under the Firing Condition

This paper includes a study on the surface treatments of the barrel of small arms with an aim at improving resistance of corrosion and wear. The inner surface of the barrel is Cr plated or nitrided to improve the performance under the firing. The endurance test was conducted to compare the wear resistance of standard barrel (the non surface treatment barrel), the Cr plating barrel and the nitriding barrel. The wear resistance is evaluated by inner diameter of the barrel, muzzle velocity and dispersion during the firing. And the salt water immersion test was conducted to estimate the corrosion resistance. As the results of the tests, the Cr plating barrel is superior to the NST barrel and the nitriding barrel in a view of corrosion and wear.