• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.107-112
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• 1998

A great deal of time and effort are required to evaluate the safety and durability of a vehicle structure in the vehicle development stage. It is difficult to find the reasons for cracks which occur in the body and frame of a vehicle during tests. Recently computer aided engineering techniques have been utilized to solve the problems of safety and durability of vehicles. In this study, a dynamic stress analysis is performed on the frame of the vehicle by rigid and flexible multibody dynamics techniques. The result of the analysis is compared to that of the actual test. The full vehicle dynamic models for the rigid and flexible bodies are developed by DADS package. The modal coordinate system is used to save time for the dynamic stress analysis. The flexible multibody dynamic models have 12 normal modes considering the flexibility of the frame. Dynamic stresses arc calculated by relating the stress influence coefficients and the applied forces.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2615-2625
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• 2011

Recently in worldwide and Korea domestically, the LRT vehicles are introduced as reputable urban transit system, in a view of energy saving, punctuality and eco-friendly as well as transport efficiency. At first time in Korea, the Busan metro Line 4 was applied with AGT system which is a kind of LRT using the Rubber tired AGT vehicle and developed from 1999 to 2004 in charge of Korean government. Busan selected the AGT system for Metro Line 4 as the solution of traffic jam and networking the intercity. At present, Busan Metro Line 4 has been running since opened at March 30, 2011. The vehicle of Busan metro line 4 is aiming the maximization of LRT vehicle advantage that is the lightness of vehicle size and vehicle weight. So, it did size downed and weight downed by lightened the weight of car frame and bogies and by the compactness of electrical on-board equipments. The study carried out the structure analysis to verify and safety and performance of car body and bogie frame of Busan Metro Line 4 vehicles. In this study, it was analyzed the stress of main load and verified the fatigue strength. And measured the dynamic stress sending to body structure and bogie frame while running on main line and analyzed the fatigue stress. As a result, it verified the safety and life cycle of car body and bogie frame.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.122-129
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• 2012

This study investigates structural and vibration analyses according to the thickness of bicycle frame tube. The model of bicycle frame has the dimension as length of 862mm, width of 100mm and hight of 402.5mm. There are 3 kinds of models with tubes of top, down and seat at bicycle frame as thicknesses of 10, 15 and 20mm. The maximum displacement and stress occur at the center part of seat stay and at the installation part of rear wheel respectively. Maximum displacements become 0.031936, 0.029159 and 0.027984mm in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 20mm among 3 cases, maximum displacement becomes lowest. But maximum stresses become 10.019, 8.5492 and 9.2511MPa in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 15mm among 3 cases, maximum stress becomes lowest. There is no resonance at practical driving conditions and natural frequency remains almost unchanged along the change of thickness. In case of the displacement due to vibration mode, the displacement difference at thickness between 15mm and 20mm becomes 1/2 times than that between 10mm and 15mm. Design at bicycle frame tube becomes most economical and durable effectively in case of thickness of 15mm among 3 cases.

• Korean Architects
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• no.11 s.82
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• pp.22-25
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• 1975

The aim of this study is the introduction of simplified method for the design stress analysis of multi-span gable frame structures with crane supports. Under the author's assumptions made previously for the same structures of single span, simplified stress analysis and exact computer analysis are excuted for some multi-span sample structures. Comparing the results of both stress analysis and with some modifications, a feasible simplified method for the design stress analysis of multi-span gable frame structures with crane supports is established.

• Journal of Welding and Joining
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• v.13 no.2
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• pp.82-95
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• 1995

This paper discusses distribution of thermal stress, strain at near the joint and investigates the reliability of solder joints of electronic devices on a printed circuit board. As Electronic devices are composed of different materials, thermal stresses generate at near the interface, such as solder joints and interface between lC device and lead frame pad due to the differences of thermal expansion coefficients, As results of thermal stress, strain, micro crack often occurs thermal fatigue fracture at the interface of different materials, The initiation and propagation of micro crack depend on the environmental conditions, such as storage temperature and thermal cycling. Finally, this paper experimentally shows a way to suppress micro cracks by using Fe-Ni alloy clad lead frame, and investigates crack and thermal fatigue fracture of TSOP(Thin small outline package) type on printed circuit board.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.98-103
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• 2002

In this paper, static analysis of eddy current brake's frame, which is one of key structural components of brake system for high speed train, was performed in order to evaluate the design by computer simulation. Calculation was carried out in general for the driving modes 'braking' and 'frame in upper position(Brakes inactive)'. Several yield stress load cases and fatigue load cases were analysed for each of the driving modes. The fatigue load resulting from the Multi Body System simulation was also taken into consideration. The simulation results shows that some of structural part should be improved for more increasing reliability of frame.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.144-148
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• 2005

Cylinder frame manufactured by casting is assembled with the components such as cylinder head, cylinder liner and main bearing cap, etc. The mechanical contact between all of the neighboring components due to bolt tightening was taken into consideration. The loads used in structural analysis were the bolt tightening forces induced by hydraulic jack and the dynamic forces calculated from kinematic analysis. The difference of forces between the neighboring cylinders was taken into account. The maximum stress, stress amplitude and mean stress calculated from the results of structural analyses were used to evaluate the static and fatigue strength. Gray cast iron which is material of cylinder frame has the material characteristics of very small elongation and different strength in tension and compression. Based on such an material characteristics, the strength evaluation of cylinder frame was carried out with in-house program developed internally.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.15-21
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• 2022

Collision analysis involving a vehicle frame that includes a battery and a battery case was performed using a carbon fiber composite material (CFRP) and a glass fiber-reinforced plastic (GFRP), which are lightweight materials. Three types of collisions were analyzed: frontal collisions, partial frontal collisions, and side collisions. The maximum stress and deformation levels were measured for each case. To evaluate the stability of ignition and explosion potential of the battery, the maximum stress of the frame was measured before measuring the direct stress to confirm whether the collision energy was sufficiently absorbed. The deformation level of the battery case was measured to confirm whether the battery case affects the battery directly.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.1-5
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• 2013

In order to evaluate fatigue endurance for an MTB(mountain bike) frame, FEM(finite element method) analysis was performed. For evaluating the fatigue endurance of the MTB frame, the S-N data for Al-6061 fillet weldment were compared with the stress analysis results through FEM analysis of the frame. Three loading condition, pedalling, horizontal and vertical loading conditions were considered for fatigue endurance evaluation. Horizontal loading(+1200 N) condition was found to be the most severe to the frame. The maximum von Mises stress of the frame under horizontal loading(+1200 N) condition was determined 294 MPa through FEM analysis of the frame. Conclusively, on the basis of fatigue strength of 200 MPa at the number of cycles of 50,000, the MTB frame has an improper safety factor of approximately 0.25, suggesting that this frame needs reinforcement.

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.1-8
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• 2005

A new design of shoulder straps and frame of backpack is proposed for reducing compression and fatigue of shoulder. The stress reduction effects of a backpack equipped with the newly designed shoulder straps and frame have been analyzed statistically through various experiments. We show that the newly designed shoulder straps(wider than the conventional ones) is superior to existing shoulder straps in respect of RPE, task performance measure and physiological measure. The new frame is also proven to be superior to existing frame in respect of RPE and task performance measure. In conclusion, the proposed shoulder straps and frame are shown to enhance the task performance of soldiers.