• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.8-13
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• 2013

This study analyzes about poclain bucket through fatigue durability analysis. Maximum equivalent stress and total deformation are shown at the lower of bucket and edge part respectively. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of -10000Pa to 5000MPa and the amplitude stress of 0 to 6000MPa, the possibility of maximum damage becomes 3%. This stress state can be shown with 5 or 6 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of poclain bucket by investigating prevention and durability against fatigue damage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.3
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• pp.33-37
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• 2009

Manifold could apply stainless steel with light weight and durability to improve fuel efficiency at automotive industry. This study is analyzed and compared by heat transfer and deformation according to the materials of cast iron and stainless steel. The heat transfer at manifold of cast iron at the distribution of heat temperature is more than that of stainless steel. But the value of maximum heat deformation in case of stainless steel is 1.5 times as great as that in case of cast iron. The value of maximum heat equivalent stress in case of stainless steel is 2.7 times as great as that in case of cast iron. This maximum stress at manifold is shown at the part assembled with engine body.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.733-740
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• 2012

This paper studies with structural and vibration analysis to evaluate the structural safety according to the types of steering wheels. This study models are two, three and four spoke types. As the number of spokes increases, the maximum equivalent stress becomes smaller but the maximum total deformation becomes a little higher. The natural frequency at three models are shown from 180 to 230Hz as the maximum deformation. The frequency responses as maximum amplitude displacement are happened at 200Hz, 500Hz and 500Hz respectively. In this study, the steering wheel with three spoke type is shown to become suitable at durability and production.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.963-971
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• 2000

Gerotor is a planar mechanism consisting of a rotor and lobes which form a closed space, namely a chamber. As active contact points between a rotor and lobes are subjected to very high contact stresses, wear in one or both of the rotor and lobe cannot be avoided. Therefore, in the design of Gerotor used in hydraulic motors a compromise between high torque output and contact stress is of great importance and a thorough analysis of design parameters should be conducted to achieve this compromise. In this study, a contact point is modelled as a linear spring in consideration of equivalent curvature to analyze the contact stress. As the contact stress calculation in this problem is a statically indeterminate type, a numerical iterative scheme has been adopted to obtain the solution. To fully understand the influence of design parameters on the contact stress, the relationship between pressure force, equivalent curvature, contact force and contact stress are analyzed. It is shown that the equivalent curvature of the contact point is a dominant factor that affects the maximum contact stress.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.188-195
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• 2004

In this paper we analyzed the mechanical behavior with respect to the thickness variation of elastic foundation(fatty tissue) in end-to-end anastomosis. This study considered the preliminary deformed shape induced by suturing in the anastomosis of coronary artery and PTFE with different diameters using simplified suturing model and the fatty tissue surrounding heart and coronary artery for more accurate result using finite element method. Area compliance(CA) was used to analyze the final deformed shape of the anastomotic part with respect to the thickness variation of fatty tissue under mean blood pressure, 100mmHg(13.3㎪). And Equivalent and circumferential stresses in the anastomosis were also analyzed with respect to the change of initial diameter ratio( $R_1$) and fatty tissue thickness( $T_{F}$). The results obtained were as follows : 1 When the elastic foundation, assumed to be incompressive material, surrounded the grafts in anastomosis, the compliance mismatch of artery and PTFE was reduced by 47 -72%. 2. As the initial diameter ratio( $R_1$) became larger, the higher difference of compliance was induced in spite of elastic foundation surrounding grafts. 3. The maximum nondimensional circumferential stress is twice or three times as high as the maximum nondimensional equivalent stress in the anastomotic part.t.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.6
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• pp.68-74
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• 2014

This study analyzes structural stress and fatigue about three types of automotive wheels. As maximum equivalent stresses at 1, 2 and 3 types become lower than the yield stress of material and deformations become minute, theses types are thought be safe on durability. Type 2 model has the most fatigue life among three kinds of types and the rest of models with fatigue lives are shown in the order of type 1 and 3. As the most fatigue frequency of type 2 model happens at the state of average stress and amplitude stress on the stress range narrower than type 1 or 3, type 2 model becomes most stable. In case of type 2 with the state near the average stress of 0 MPa and the amplitude stress of 300MPa, the possibility of maximum damage becomes 30%. This stress state can be shown as the most damage possibility. These study results can be effectively utilized with the design on automotive wheel by anticipating and investigating prevention and durability against its damage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.761-764
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• 2002

This paper deals with the stress concentration of the rotating disc in detail. We studied maximum stress of rotating disc with respect to the various parameter of circular hole such as position, size, number of the hole, then the mollified effect of maximum stress due to pin-hole around circular hole, using FEM, the results are as follows: 1. The more the number of circular hole and the further from the center, the maximum equivalent stress reduces. 2. When the pin-hole is located 60$^{\circ}$ from the x-axis, the maximum stress reduces significantly due to the effect of interference.

• Computers and Concrete
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• v.8 no.2
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• pp.207-227
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• 2011

In flexural strength design of unconfined reinforced concrete (RC) members, the concrete compressive stress-strain curve is scaled down from the uni-axial stress-strain curve such that the maximum concrete stress adopted in design is less than the uni-axial strength to account for the strain gradient effect. It has been found that the use of this smaller maximum concrete stress will underestimate the flexural strength of unconfined RC members although the safety factors for materials are taken as unity. Herein, in order to investigate the effect of strain gradient on the maximum concrete stress that can be developed in unconfined flexural RC members, several pairs of plain concrete (PC) and RC inverted T-shaped specimens were fabricated and tested under concentric and eccentric loads. From the test results, the maximum concrete stress developed in the eccentric specimens under strain gradient is determined by the modified concrete stress-strain curve obtained from the counterpart concentric specimens based on axial load and moment equilibriums. Based on that, a pair of equivalent rectangular concrete stress block parameters for the purpose of flexural strength design of unconfined RC members is determined.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.70-76
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• 2013

This study investigates structural durability through the analyses of stress, fatigue life and vibration damage at bike carrier basket. As model 2 has less stress and deformation than model 1 on static structural analysis, model 2 becomes more durable than model 1. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. The amplitude deformations become highest at maximum response frequency of 2400Hz in cases of models 1 and 2. As the values of maximum equivalent stresses become within the allowable material stresses at two holes at the upper parts on models 1 and 2, these models become safe. The structural result of this study can be effectively utilized with the design of bike carrier basket by investigating prevention and durability against fatigue or vibration damage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.36-44
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• 2013

This study investigates life, damage and durability through the analyses of fatigue load and vibration on disk brake models of A, B and C. Maximum equivalent stress is happened at the inside of disk brake on these models. As there are A, B and C models by order of life, model A has the most stable strength on fatigue analysis, The deformations at 3 kinds of models become nearly same on natural frequency analysis. The maximum total deformation and equivalent stress is shown at 1617Hz by harmonic vibration analysis on these models. As there are A, B and C models by order of deformation and stress, model A becomes lowest and safest. This study result can be effectively utilized with the design of brake disk in order to improve durability and prevention against its fatigue damage and vibration.