• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.381-386
• /
• 2000

Simple spring-damper-mass models have been widely used to understand whole-body vertical biodynamic response characteristics of the seated vehicle driver. However, most previous models have not considered about the non-rigid masses(wobbling masses). A simple mechanical model of seated human body developed in this study included the torso represented by a rigid and a wobbling mass. Within the 0.5-20Hz frequency range and for excitation amplitudes maintained below $5ms^{-2}$, this 4-degree-of-freedom driver model is proposed to satisfy the measured vertical vibration response characteristics defined from a synthesis of published data for subjects seated erect without backrest support. The parameters are identified by using the combinatorial optimization technique, simulated annealing method. The model response was found to be provided a closer agreement with the response characteristics than previously published models.

• 한국정밀공학회지
• /
• 제25권5호
• /
• pp.155-163
• /
• 2008

This study investigated biomechanical response through the 3-dimensional virtual skeletal model developed and validated. Ten male subjects in standing posture were exposed to whole body vibrations and measured acceleration on anatomical of interest (head, $7^{th}$ cervical, $10^{th}$ thoracic, $4^{th}$ lumbar, knee joint and bottom of the vibrator). Three dimensional virtual skeletal model and vibration machine were created by using BRG LifeMOD and MSC.ADAMS. The results of forward dynamic analysis were compared with results of experiment. The results showed that the accuracy of developed model was $73.2{\pm}19.2%$ for all conditions.

• 한국군사과학기술학회지
• /
• 제26권3호
• /
• pp.252-261
• /
• 2023

Analysis of dynamic characteristics and flight vibration test for unmanned aerial vehicles was studied by using dummy test body. The FEM model for dummy test body was supplemented by results of modal and random vibration test. The free end boundary condition to simulate flight environments was made by test setup using bungee cable. Prior to the flight vibration test using a dual electric vibration exciters, the test procedure to calculate quantitative vibration level was studied by using military specification. The actual test was successfully done by using the analysis and pretest results. From the analysis results, it was possible to determine the feasibility of the test by predicting the excitation force of the flight vibration test and to get the response of any point which could not be measured by the test. The results of this study will much contribute to the Test and Evaluation of unmanned aerial vehicles.

• 재활복지공학회논문지
• /
• 제8권1호
• /
• pp.33-40
• /
• 2014

본 연구에서는 다양한 스쿼트 자세를 수행할 때 전신진동자극이 하지의 근 활성 변화에 미치는 영향에 대하여 평가하고자 한다. 피험자는 20대 여성 10명(나이 $21{\pm}1.3$년, 키 $160{\pm}2.1cm$, 무게 $52{\pm}4.6kg$)으로 구성되었다. 피험자들은 진동판 위에서 하이스쿼트(HS), 로우스쿼트(LS), 외다리 스쿼트(OS), 뒤꿈치 들고 하이 스쿼트(HU&HS)의 4가지 동작을 수행하였다. 근전도는 하지의 근육(대퇴직근, 외측광근, 중간광근, 내측광근)을 측정하였다. 진동자극은 10초 무자극, 10초 진동자극을 제공하였다. 그 결과 모든 운동 자세와 측정 부위에서 진동 자극을 제공하였을 때 근 활성이 유의하게 증가하는 경향을 보였다(HS +24.8%, LS +23.1%, OS +20.1%, HU&HS +17.9%). 또한 OS 자세는 LS자세나 HU&HS자세보다 근 활성이 유의하게 높은 증가를 보였으며, LS자세는 HU&HS보다 유의하게 높아지는 경향을 보였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.629-630
• /
• 2013

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.85-89
• /
• 2001

Hamiltonian modeling approach has been extensively adopted for rigid body dynamics whereas its usage for deforming flexible continuum dynamics has been limited. A set of Hamilton＇s equations for flexible body motion with finite deformation has been derived and applied for a nonlinear impact problem.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2010년도 춘계학술대회 논문집
• /
• pp.132-133
• /
• 2010

• 소음진동
• /
• 제10권2호
• /
• pp.299-305
• /
• 2000

In this study, the characteristics of transmitted vibration on hand-arm system are examined when operating electric hand tools. Also through the correlation analysis between anthroponetric data and transmitted vibration, and comparison study with appropriate amount of work done based on the ISO criteriaa, the basic data for the ergonomic work design can be presented. The types of electric tools and works for the experiment are drill (general type and impact type), grinder, wire brush and steel to analyze the characteristics of transmitted vibrations, the amount of transmitted vibrations in X, Y and Z direction at tool(T), hand(H), wrist(W), and the joint between foream and upper arm(A) were measured at the frequency range of 6.3∼1000[HZ]. Also, the limit of human exposure to vibration, and the response of frequency were conducted.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 춘계학술대회논문집
• /
• pp.921-924
• /
• 2005

Diesel generator sets with resilient mounts often experience resonances by major excitations which come from diesel engine and their foundation with rigid body modes. Because their natural frequency is determined by moment of inertia and stiffness of resilient mount vibration problems are resolved by changing location and stiffness of resilient mounts. But the calculated natural frequencies are inaccurate due to uncertainty of the inertia and mount stiffness. So this result can be useless on the design stage. In this paper, the stiffness of mount is evaluated on result from mount stiffness test in laboratory and generator set vibration test and a simple calculation method for moment of inertia is proposed. Based on these data, the procedure to select optimized mount stiffness and location on the design stage is set up.

• 한국안전학회지
• /
• 제13권2호
• /
• pp.13-21
• /
• 1998

This is a study on the natural vibration characteristics of Vehicle frame. Nowadays, many trucks freight the over-load, do the car designers consider the over-load about 200% in the design. It's necessary to make the model of a vehicle and simulate it for the test of driving condition, durability and vibration behavior before the vehicle is manufactured. If it is possible to make a simulation using the static and dynamic analysis, this is very useful in accomplishing an optimal design of the vehicle. In this paper, we studied the vibration characteristics of a truck body frame. The automobile body frame model for experiment is made smaller than real size frame with the ratio of 1/10. The vibration characteristics of a frame is considered as one of main factors in analyzing and improving the problem for ride comfort, noise and vibration reduction. Therefore, we experimented two method to neglect the nonlinearity. First is bolting and second is welding at the joint section. We compared computer simulation results and experimental data.