• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.139-146
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• 2003

The objective of the presented study is to develop an efficient procedure of proof load testing for existing bridges. By analytical methods, some of these bridges are not adequate to carry normal highway traffic. However, the actual load carrying capacity is often much higher than what can be determined by conventional analysis. Proof load testing can reveal the hidden strength reserve and thus verify the adequacy of the tested bridge. Proof load level required for meaningful tests should be sufficiently higher than legal load. In the state of Michigan, the legal 11-axle truck can weigh up to 685 kN. In this study, a combination of two military tanks and two Michigan 11-axle trucks was used. The proof loads were gradually increased to ensure the safety of the test. After each move, measurements were taken. For the considered bridge, stress levels were rather low compared to pre-test analysis results. This is due to incorrect material strength, structural contribution of nonstructural components such as parapets and railings, and partially fixed supports.

• Journal of Biosystems Engineering
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• v.36 no.5
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• pp.303-313
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• 2011

This study was conducted to investigate the effects of axle weight distribution and inflation pressure of tire on the fuel economy of tractors as well as operational range of tractor engine in terms of engine speed and power when a 4WD tractor of 38.2 kW rated power at 2500 rpm is used for plowing and flooded-field rotavating in paddy fields. (1) Plowing operation required an average engine power of 9.6~13.5 kW which equals 25~35% of rated PTO power. Engine speed ranged from 1,320.4 to 1,737.4 rpm, work velocity from 3.4 to 4.8 km/h, and fuel consumption from 3.2 to 4.2 L/h, respectively. (2) Flooded-field rotavating required an average engine power of 11.5~18.5 kW which equals 30~48.4% of rated PTO power. Out of this 6.2~12.2 kW was used for PTO power. Engine speed ranged from 1,557 to 2,067 rpm, work velocity from 2.5~5.4 km/h and fuel consumption from 3.2~5.5 L/h, respectively. (3) Axle weight distribution, inflation pressure of tire and moisture content of soil did not affect significantly the specific volumetric fuel consumption but affected significantly the fuel consumption per unit area of operation. Fuel savings amounted to 65% in plowing operation and 20% in flooded-field rotavating when the axle weight distribution and inflation pressure of tire were optimally adjusted. (4) Optimal adjustment of axle weight distribution and inflation pressure of tire are expected to save fuel consumption by 10~65% per unit area of operation in plowing and 10~20% in flooded-field rotavating.

• Journal of Drive and Control
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• v.17 no.2
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• pp.9-18
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• 2020

The purpose of this study was to analyze the effect of the soil cone index (CI) on the tractor work load. A load measurement system was constructed for measuring the field data. The field sites were divided into grids (3×3 m), and the cone index was measured at the center of each grid. The work load measured through the plow tillage was matched with the soil cone index. The matched data were grouped at 600 kPa intervals based on the cone index. The work load according to the cone index was analyzed for engine, axle, and traction load, respectively. The results showed that when the cone index increased, engine torque decreased by up to 9%, and the engine rotational speed and brake-specific fuel consumption increased by up to 5% and 3%, respectively. As the cone index increased, the traction and tillage depth were inversely proportional to the cone index, decreasing 7% and 18%, respectively and the traction and tillage depth were directly proportional to the cone index, increasing 13% and 12%, respectively. Thus, it was found that the cone index had a major influence on the engine, axle, and traction loads of the tractor.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.565-575
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• 2009

A forklift (also called a lift truck) is a powered industrial truck that is used to lift and transport materials. It has become an indispensable piece of equipment in manufacturing and warehousing operations. The modem forklift is equipped with automatic transmission to meet the requirement of loading and easy operation of the vehicle. This paper proposes the design of TECU(Transmission Electronic Control Unit) which is applied to PSD322-Axle transmission. Garofalo's control technique is generally used to the automatic transmission. We consider the work quality and market requirement that does not want to control engine throttle. This paper proposes new controller system which guarantees efficient speed changes with simple system. This new system does not control the engine throttle spontaneously. But it has the load of engine and vehicle as a maximum disturbance. The scope of the disturbance is limited to the stoll area of the torque converter. This paper proposes a ideal control commander that converges relative velocity of the input and ouput of a clutch into a zero. We design linear controller to execute the idea control commander. We applied the control algorithm to the forklift of PSD322-Axle type and the performance of this controller was verified.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.356-361
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• 2005

Earth brush for electrical multiple units(EMUs) is a device through which the current of the EMU load's consumed power fed from the DC 1,500V overhead line (or from the AC 25.000V catenary) flows via axle to the rail(ground) and which prevents the electric corrosion of the axle bearings by preventing the current flow to the axle bearings caused by electric potential from the magnetic field when the bearings rotate together with the earthing function when a thunderbolt falls or a surge comes. The earth brush wear rates among cars, however, shows quite differences when the earth brushes after being separated from the holders are measured with vernier callipers every 6 months of maintenance period. Main causes of the earth brush wear are divided as mechanical, electric arc and electrical one, and the factors can be running speed, current, harmonics, connection state. spring tension, earth brush material, lubricant and so on. but only the earth brushes of the motor(M1) car show the highest wear rate and moreover maintenance difficulty occurs because of the wear rate differences among e earth brushes in one holder. The reason for these preponderant wear comes from the design concept of making preponderant current flow to some particular earth brushes and moreover the heat generated by the harmonics when the inverter starts to operate accelerate the wear. By defining these causes through experiments. I hope that the found results would be helpful for the future EMU design, safety, economy and maintenance.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.423-430
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• 2008

• Journal of Biosystems Engineering
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• v.36 no.3
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• pp.163-170
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• 2011

Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.466-473
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• 1998

LRV(Light Rail Vehicle) is one of the most useful way for urban transit. HDPIC has designed and manufactured the LRV train set for Manila Line 1 expansion. The LRV is composed of two carbody sections which are coupled by a articulated bogie. The articulated bogie and two motorized bogies have slewing rings in order to improve the curving performance and ride quality. Carbody structures are mainly made of low-carbon stainless steel (STS301L), and the carbody bolsters and draft sills are made of rolled steel for welded structures. The authority's specifications specified the design load conditions and weight limits. Design load conditions are vertical load, compressive load and diagonal jacking, and the maximum axle load is 10.7 ton. In order to meet those requirements, the stiffness and strength of carbody structure were predicted using finite element analysis during design stage. The half or full structure is modeled and analyzed with design load conditions, and critical areas are analysed in detail using sub-modeling method. The strength and strength of carbody structure was also verified by the load test. The analysis and test results show a good agreement.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.69-78
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• 2009

Korea has achieved significant economic growth with building the Gyeongbu Expressway. As the number of new road construction projects has decreased, it becomes more important to maintain optimal status of the current road networks. One of the best ways to accomplish it is weight enforcement as active control measure of traffic load. This study is to develop High-speed Weigh-in-motion System in order to enhance efficiency of weight enforcement, and to analyze patterns of overloaded trucks on highways through the system. Furthermore, it is to review possibilities of developing overweight control system with application of the HS-WIM system. The HS-WIM system developed by this study consists of two sets of an axle load sensor, a loop sensor and a wandering sensor on each lane. A wandering sensor detects whether a travelling vehicle is off the lane or not with the function of checking the location of tire imprint. The sensor of the WIM system has better function of classifying types of vehicles than other existing systems by detecting wheel distance and tire type such as single or dual tire. As a result, its measurement errors regarding 12 types of vehicle classification are very low, which is an advantage of the sensor. The verification tests of the system under all conditions showed that the mean measurement errors of axle weight and gross axle weight were within 15 percent and 7 percent respectively. According to the WIM rate standard of the COST-323, the WIM system of this study is ranked at B(10). It means the system is appropriate for the purpose of design, maintenance and valuation of road infrastructure. The WIM system in testing a 5-axle cargo truck, the most frequently overloaded vehicle among 12 types of vehicles, is ranked at A(5) which means the system is available to control overloaded vehicles. In this case, the measurement errors of axle load and gross axle load were within 8 percent and 5 percent respectively. Weight analysis of all types of vehicles on highways showed that the most frequently overloaded vehicles were type 5, 6, 7 and 12 among 12 vehicle types. As a result, it is necessary to use more effective overweight enforcement system for vehicles which are seriously overloaded due to their lift axles. Traffic volume data depending upon vehicle types is basic information for road design and construction, maintenance, analysis of traffic flow, road policies as well as research.

• Structural Engineering and Mechanics
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• v.15 no.1
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• pp.21-38
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• 2003

The formulation of a new bridge-vehicle system using shell with eccentric beam elements has been introduced in a companion paper (Part I). The new system takes into account of the contribution of the twisting and pitching modes of vehicles to the bridge responses. It can also be used to study the dynamic transverse load distribution of a bridge. This paper presents a parametric study on the impact induced by one vehicle or multi-vehicle running across a bridge using the proposed model. Several parameters were considered as variables including the mass ratio, the speed parameter, the frequency ratio and the axle spacing parameter to investigate their effects on the impact factor. A total number of 189 cases were carried out in this parametric study. Within the realistic range of vehicle considered, the maximum impact factors could be 2.24, 1.78 and 1.49 for bridges with spans 10 m, 20 m and 30 m respectively.