• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.912-918
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• 2004

Main vibration problems of a transaxle type forklift truck are caused by the resonance of engine excitation force and natural mode shade of major components such as engine-mount system, mast, and main frame. But, it is well known that the reduction of vibration is very difficult because of the limitation of structural modifications. In this paper, the vibration characteristics of engine-mast system including engine mount were firstly identified by the experimental and simplified numerical methods. And also, the free and forced vibration characteristics of a whole forklift truck were surveyed with modal test and ODS(operation deflection shape) measurement. Based on these results, the reliable finite element model was developed. Finally, various countermeasures were considered and applied to a real forklift truck and then its effects were confirmed.

• 대한안전경영과학회지
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• 제15권2호
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• pp.167-184
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• 2013

A cross docking operation involves multiple inbound trucks that deliver items from suppliers to a distribution center and multiple outbound trucks that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. The objective of this study is to find the best truck spotting sequence for both inbound and outbound trucks in order to minimize total operation time of the cross docking system under the condition that multiple visits to the dock by a truck to unload or load its consignments is allowed. The allocations of the items from inbound trucks to outbound trucks are determined simultaneously with the spotting sequences of both the inbound and outbound trucks.

• 한국직업건강간호학회지
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• 제29권2호
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• pp.106-113
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• 2020

Purpose: This study aimed to analyze industrial accident compensation insurance coverage and industrial accidents among concrete mixer truck drivers. Methods: Original data on industrial accidents from 2012 to 2017 were analyzed through descriptive statistics. Results: Industrial accident compensation insurance coverage was 44.6% in 2017. Most concrete mixer truck drivers were affiliated with small businesses. A total of 61 industrial accidents occurred in 2012, 65 in 2014, and 80 in 2017. The major types of industrial accident were falls, slips, and crushes. Conclusion: Because concrete mixer truck drivers are at high risk for industrial accidents, industrial accident compensation insurance coverage and industrial accident prevention should be strongly enforced.

• 한국철도학회논문집
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• 제5권2호
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• pp.55-60
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• 2002

This study proposes the post-processor simulator construction of ultrasonic signal for integrity evaluation of railway truck. For these purposes, the ultrasonic signals for defects(crack) of weld zone in frames are acquired in the type of time series data and echo strength. The detection of the natural defects in railway truck is performed using the characteristics of echodynamic pattern in ultrasonic signal. The constructed post-processor simulator agree fairly well with the measured results of test block(defect location, beam propagation distance, echo strength, etc). Proposed post-processor simulator construction of ultrasonic in this study can be used for the integrity evaluation of railway truck.

• 동력기계공학회지
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• 제17권4호
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• pp.23-30
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• 2013

In this paper, the payload condition is considered and computer simulation is carried out to analyze the dynamic behavior of the middle-sized truck under the condition with different weight and location. The computer model for the truck is established and ADAMS/Car is employed to simulate the truck vehicle. A single lane change and bump-pass simulation are performed to evaluate the performance according to the weight and the position of it. Effects of the location and weight of commercial vehicle are analyzed. According to the simulation results, the front deck is preferred as the load location.

• 대한안전경영과학회지
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• 제25권2호
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• pp.85-90
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• 2023

The delivery truck is traveled around the delivery area for a long time. Truck drivers cause traffic accidents because of long hours of driving, fatigue, and speeding, etc. In this study, we will test the factors for preventing accidents of drivers. We would like to find factors that affect accidents and improve that can prevent accidents. As in the results of the study, accidents occur when traffic increases and profits increase among driver age, career, and profit factors. In addition, if the volume of traffic increases during the season, the number of accidents increases further. Therefore, in order to prevent truck accidents, a stable cargo quantity must be allocated to truck and cargo must be delivered.

• 한국도로학회논문집
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• 제16권2호
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• pp.53-59
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• 2014

PURPOSES : This study estimated an asphalt pavement internal behavior under uphill lanes considering reducing speed of heavy truck on uphill slope. METHODS : Truck performance curve which has been adapted to "Korea Highway Capacity Manual" was analyzed. And asphalt pavement internal behaviors were estimated with Multi-layered elastic analysis using KPRP(Korea Pavement Research Program) dynamic modulus prediction equations. RESULTS : As a result, it is shown that when the standard truck drives 2.0 km at a speed of 80 km/h in 8% climbing slope, it's speed reduced to 25.4 km/h, at same time frequency in asphalt layer decrease to 67.2% and it's dynamic modulus degrades to 30.9%. Based on these results, internal behavior as decreasing vehicle speed on uphill lanes were estimated. CONCLUSIONS : From the results of Multi-layered elastic analysis, internal behavior showed that when the standard truck drives 2.0 km at a speed of 80 km/h in 8% slope on uphill lanes, vertical strain was increased to 44.4% at the bottom of surface course, and lateral tensile strain was increased to 20.5% at the bottom of base course.

• 대한기계학회논문집A
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• 제29권2호
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• pp.270-276
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• 2005

This paper develops the flexible computational model of a heavy truck by interfacing the frame modeled as a flexible body to the heavy truck's computational model composed of rigid bodies. The frame is modeled by the finite element method. Three torsional modes and three bending modes of the frame are considered for the interface of the heavy truck's computational model. The actual vehicle test is conducted off road with a velocity of 20km/h. The vertical accelerations at the cab and front axle are measured in the test. For the verification of the developed computational model, the measured vertical acceleration profiles are compared with the simulation results of the heavy truck's flexible computational model. E grade irregular road profile of ISO is used as an excitation input in the simulation. The verified flexible computational model is used to compare the vibration characteristics of a front suspension system having a multi-leaf spring and that having a tapered leaf spring. The comparison results show that the front suspension having a tapered leaf spring has a higher vertical acceleration at the front axle but a lower vertical acceleration at the cab than the suspension system having a multi-leaf spring.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.128-134
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• 2008

In this paper, a hydropneumatic modeling and analysis of a heavy truck cabin air suspension system is presented. Cabin air suspension system is a system which improves ride comfort of a heavy truck and it can reduce vibration between truck frame and cabin. The components of the system, air spring, shock absorber, leveling valve and full cabin system are mathematically modelled using AMESim software. Simulation results of components and full cabin system are compared with experimental data of components and test results of a cabin using 6 axis simulation table. It is found that the simulation results are in good agreements with test results, and the hydropneumatic model can be used well to predict dynamic characteric of heavy truck cabin air suspension system.

• 전력전자학회논문지
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• 제9권1호
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• pp.25-29
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• 2004

본 연구는 최근 관심이 높아지고 있는 스위치드 릴럭턴스 전동기(SRM)를 적용한 소형 지게차의 구동시스템 개발에 관한 연구이다. SRM은 스위칭 전원에 적절한 전동기구로서, 전력전자기술의 발달에 힘입어 최근 연구가 활발히 이루어지고 있다. 본 연구에서는 기존 소형 전기지게차에 사용되어지고 있는 직류직권 전동기를 경제적이고 고효율, 견고성, 넓은범위의 속도제어가 가능한 스위치드 릴럭턴스 전동기(Switched Reluctance Motor, 이하 SRM)로 대체하기 위해 저전압용 전동기를 설계하고 이 전동기를 구동하기 위한 구동 시스템을 개발하였다. 또한 실제 전기 지게차에 적용하기 위하여 구동시스템의 운전특성을 확인하였다.