• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.207-216
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• 1997

We developed the durability estimation and design systems to minimize the volume, considering the durability, efficiency, and design requirements of worm gears. That is, we consider each kind of factors affecting on durability on the basis of AGMA Standard for the cylindrical and double-enveloping worm gears. We also estimate input power on the basis of wear and durability, bending strength and deflection of worm shaft, and we developed the durability estimation and design systems of power transmission worm gears introducing the optimal design method on the personal computer to be easily used in field. Also, we developed a method which converts the design variables obtained from the optimal design method to integer values(number of worm threads, number of worm threads, number of worm wheel teeth, etc.,) to be used in real design and production. The developed durability estimation and design method can be easily applied to the design of worm gears used as power transmission devices in machineries and is expected to be used for weight minimization of worm gear unit.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.216-216
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• 1997

We developed the durability estimation and design systems to minimize the volume, considering the durability, efficiency, and design requirements of worm gears. That is, we consider each kind of factors affecting on durability on the basis of AGMA Standard for the cylindrical and double-enveloping worm gears. We also estimate input power on the basis of wear and durability, bending strength and deflection of worm shaft, and we developed the durability estimation and design systems of power transmission worm gears introducing the optimal design method on the personal computer to be easily used in field. Also, we developed a method which converts the design variables obtained from the optimal design method to integer values(number of worm threads, number of worm threads, number of worm wheel teeth, etc.,) to be used in real design and production. The developed durability estimation and design method can be easily applied to the design of worm gears used as power transmission devices in machineries and is expected to be used for weight minimization of worm gear unit.

• International Journal of Automotive Technology
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• v.3 no.4
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• pp.129-135
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• 2002

Durability estimation of a prototype vehicle has traditionally relied heavily on accelerated durability tests using predefined proving grounds or rig tests using a road simulator. By use of those tests, it is very difficult to predict durability failures in actual service environments. This motivated the development of an integrated CAE (Computer Aided Engineering) methodology for the durability estimation of a prototype vehicle in actual service environments. Since expensive computational costs such as computation time and hardware resources are required for a full vehicle simulation in those environments with a very long span of event time, the conventional CAE methodologies have little feasibility. An efficient computational methodology for durability estimations is applied with theoretical developments. The effectiveness of the proposed methodology is shown by the comparison of results of the typical actual service environment such as the city mode with those of the typical accelerated durability test over the Belgian road.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.112-119
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• 1993

A strength and durability estimation system of involute cylindrical gears which are commonly used as power transmission devices is developed on the personal computer, which analyzed and/or evaluates the gear design and the service performance at the point of view of strength and durability. The typical considerations are the bending strength and the sunface durability, and the strength and durability estimations are carried out using the reliable standards of AGMA&ISO. In addition, the finite element analysis (FEM) of tooth bending stress is conducted in order to compare the real maximum stress with the estimaed bending stress by the standard. Therefore, the system is built so that the variables or factors considered differently in those standards and the strength & durability are appraised seperately by each method, and a series of the estimation processes is integrated into the system can be used in the initial design at the view point of strength and durability. And it is useful to the purpose of the trouble-shooting of gear system and the purpose of introducing the methods for maintaining design strength in service, with appraising the strength and durability after design or with appraising the influencing factors, as a whole. Therefore, this strength and durability estimation system can help the aim of automatic design of cylindrical gears.

• Journal of Power System Engineering
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• v.5 no.4
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• pp.61-66
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• 2001

Electro-Rheological(ER) fluids undergo a phase-change when subjected to an external electric field, and this phase-change typically manifests itself as a many-order-of magnitude change in the rheological behavior. This paper presents experimental results on material properties for an ER fluids of arabic gum components subjected to electrical fatigues. As a first step, ER fluids are made of arabic gum 25% of particle weight-concentration. Following the construction of test mechanism for estimated durability of ER fluid, the dynamic yield stress, shear stress and current density of the ER fluids are experimentally distilled as a function of DC electric field. The durability estimation of operated ER fluids are distilled and compared with those of unused ER fluids. In addition, the surface roughness of the employed electrode for copper and aluminum are evaluated as a function of the number of the electric-field cycles.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.4
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• pp.22-32
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• 2001

One of the important considerations in designing a machine tool is the durability. In this study, a durability estimation system for horizontal machining centers is developed to evaluate the effects of structural specification and driving condi-tions on the durability. All loads such as weights, inertial forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flows which can be derived from the structural code of horizontal machining centers. And the external loads applied to the motion elements such as bearings, LM guides, ball screws and ao on, are determined by the equilibrium conditions of force and moment. Especially, the durability of horizontal machining centers is estimated based on the lifes of motion elements operating under the desired driving conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.3-10
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• 1999

One of the important considerations in designing a machine tool is the durability. In this study, a durability estimation systems for horizontal machining centers is developed to evaluate the effects of structural specification and driving conditions on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flows which can be derived from the structural code of horizontal machining centers. And the external loads applied to the motion elements such as bearings, LM guides, ball screws and so on, are determined by the equilibrium conditions of force and moment. Especially, the durability of horizontal machining center is estimated based on the lifes of motion elements operating under the desired driving conditions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.94-101
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• 2004

The purpose of this raper is to assess the benefits of frequency domain fatigue analysis and compare it with more conventional time domain techniques. The multi-body dynamic analysis, FE analysis and fatigue life prediction technique are applied for the frequency domain fatigue analysis. To obtain the dynamic load history used in the frequency domain fatigue analysis, the computer simulations running over typical road Profiles are carried out by utilizing vehicle dynamic model. The fatigue life estimation for the rear suspension system of small-sized passenger car is performed by using resonance durability analysis technique, and the estimation results are compared with the conventional quasi-static durability analysis results. For the pothole simulation, the percent changes, of the fatigue life between the two durability analysis techniques don't exceed 10%. But for the Belgian road simulation because of the resonance effect, the fatigue life using the resonance durability analysis technique are much smaller estimated than the quasi-static durability analysis results.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1211-1219
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• 2001

The electro-rheological(ER) fluids for smart hydraulic system are a class of colloidal dispersion which exhibit large reversible Changes in their rheological behavior when they are subjected to external electrical fields. This paper presents experimental results on material properties of an ER fluids subjected to electrical fatigues. As a first step, ER fluid is made of methyl cellulose(MC) choosing 25% of particle weight-concentration. Following the construction of test mechanism for durability estimation, the dynamic yield shear stress and the current density for the ER fluids of MC component are experimentally distilled as a function of electric field. In addition, the surface roughness of the employed electrode are evaluated as a function of the number of the electric-field cycles.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.460-465
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• 2000

In this study, a durability estimation system of turning centers is developed to systematically evaluate the effects of structural specification and testing condition on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flow which can be derived from the structural code of turning center. And the external loads applying to the moving and rolling elements are determined by using the equilibrium conditions of force and moment. Especially, the durability of turning center is estimated based on the lifes of moving and rolling elements under the required testing condition.