• 한국기계가공학회지
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• 제10권5호
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• pp.38-43
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• 2011

This study was carried out to evaluate the structural stability of hybrid type fan heater. The evaluation of structural safety of hybrid fan heater was conducted by using Ansys Workbench and CFX-11 under the design condition. The hybrid fan heater was operated by heat transfer for heat source supplied from electric heater and combustion gas. According to result of structural analysis, the maximum equivalent stress of hybrid fan heater was 150MPa when the temperature of heat transfer fluids was $150^{\circ}C$. It was found that the hybrid fan was structurally safe because the value of maximum equivalent stress was smaller than that of yield stress of the material.

• 한국기계가공학회지
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• 제7권3호
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• pp.36-40
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• 2008

This study is analyzed by the simulation of automotive steering system. The maximum equivalent stress of $2.2418{\times}109Pa$ and the maximum total displacement of 0.014929m are shown at the universal joint and its lower part respectively. As the minimum cycle of 34.047 is shown at the universal joint in case of fatigue analysis, it is possible to have greatest damage at this part. In case of natural frequency analysis at vibration, its frequency of 47 to 59Hz is occurred generally. The maximum total displacement of 0.5m is shown at handle on the natural frequency of 57 to 58Hz. And the displacement over 2m is shown at the lower part of universal joint on the natural frequency of 58 to 59Hz. As the basis of the simulation analysis of steering system, passenger's comfort of car body can be improved in the design of practical part and the design effect necessary to safe driving can be promoted.

• 한국기계가공학회지
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• 제6권2호
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• pp.3-8
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• 2007

Nonlinear property and contact matter are analyzed about the pipe applied with internal pressure through this study. The weakest part and its safety can be examined. Maximum equivalent stress is shown at the contact surface between bolt and nut. The value of contact stress with the pressure of 12MPa is increased 1.4 times as large as that with no pressure. The maximum contact pressure is shown at the clamp corner of the external surface on pipe. The value of contact pressure with the pressure of 12MPa is increased 1.4 times as large as that with no pressure. The radial deformation with no pressure is also increased greatly at the middle part of internal surface on pipe. But this maximum deformation on pipe with the pressure of 12MPa is shown at the part far away the support of pipe. This value is increased 5.7 times as large as that value with no pressure. As contact status, the sticking occurs most at the external surface of pipe. It also tends to occur at the contact surface between bolt and nut. At the external surface of pipe, the sticking in case of the pressure of 12MPa occurs more than that in case of no pressure.

• 대한치과기공학회지
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• 제43권3호
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• pp.99-105
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• 2021

Purpose: This study aims to examine the stress distribution effect of tightening torques of different abutment screws in a custom-abutment implant system on the abutment-fixture connection interface stability using finite element analysis. Methods: The custom-abutment implant system structures used in this study were designed using CATIA program. It was presumed that the abutment screws with a tightening torque of 10, 20, and 30 N·cm fixed the abutment and fixture. Furthermore, two external loadings, vertical loading and oblique loading, were applied. Results: When the screw tightening torque was 10 N·cm, the maximum stress value of the abutment screw was 287.2 MPa that is equivalent to 33% of Ti-6Al-4V yield strength. When the tightening torque was 20 N·cm, the maximum stress value of the abutment screw was 573.9 MPa that is equivalent to 65% of Ti-6Al-4V yield strength. When the tightening torque was 30 N·cm, the maximum stress value of the abutment screw was 859.6 MPa that is similar to the Ti-6Al-4V yield strength. Conclusion: As the screw preload rose when applying each tightening torque to the custom-abutment implant system, the equivalent stress increased. It was found that the tightening torque of the abutment influenced the abutment-fixture connection interface stability. The analysis results indicate that a custom-abutment implant system should closely consider the optimal tightening torque according to clinical functional loads.

• 터널과지하공간
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• 제22권6호
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• pp.462-470
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• 2012

일반화된 Hoek-Brown 암반파괴조건식을 Mohr-Coulomb 파괴조건에 기초한 암반구조물 해석법에 적용시키기 위해서는 등가 마찰각과 등가 점착력을 계산하는 과정이 필요하다. Balmer(1952)이론에 기초한 기존의 접선 순간마찰각과 순간점착력 계산식은 최소주응력 ${\sigma}_3$의 함수로 표시되므로 등가 강도정수의 정수압 의존성 및 응력경로 의존성을 이해하는 데 적합지 않다. 이 연구에서는 응력불변량을 이용하여 일반화된 Hoek-Brown식의 접선 순간마찰각과 순간점착력 계산하는 방법을 제시하여 기존의 방법이 갖는 단점을 극복하였다. 제시된 방법을 이용한 예제 해석을 통해 접선 순간마찰각과 순간점착력의 정수압 의존특성 및 파괴곡면의 팔면체 단면에서 Lode각의 의존성을 고찰하였다. 접선 순간마찰각은 삼축신장 응력조건에서 가장 크며, 접선 순간점착력은 삼축압축 응력조건에서 가장 큰 것으로 나타났다. 접선 순간마찰각과 순간점착력의 정수압 및 Lode각 의존성은 GSI 값이 큰 양호한 암반에서 상대적으로 큰 것으로 나타났다.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권3호
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• pp.411-419
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• 2017

기하학적으로 급격히 변화되는 부분의 응력집중은 봉에 작용하는 평균응력 보다 큰 응력이 작용하여, 봉의 파손을 발생시키는 원인 중 하나이다. 구멍과 단이 있는 봉이 비틀림 하중을 받았을 경우, 응력집중 변화에 대해 구멍의 위치에 따른 관계를 규명하였다. 본 논문에서는 범용 유한요소 소프트웨어인 ANSYS Workbench를 통해 구멍의 위치가 다른 봉의 응력을 해석하였다. 해석된 결과, 필렛과 구멍이 서로 가까울수록 응력이 증가되는 것으로 나타났다. 또한, 본 해석에 사용된 모델에서는 구멍이 필렛으로부터 특정거리(L : -100 mm ~ 300 mm) 이상에서는 구멍과 필렛에서 발생한 최대 등가응력이 거의 일정하였다. 반면에, 구멍이 필렛으로부터 특정거리(L : -100 mm ~ 300 mm) 이하에서는 구멍과 필렛에서 발생한 최대 등가응력이 급격하게 증가 및 감소하는 변화를 보였다. 그리고 특정거리(L : -100 mm ~ 300 mm) 이하에서 구멍과 필렛에서 발생한 등가응력의 차이가 발생하는 지점을 확인할 수 있었다. 본 논문의 해석 결과는 비틀림을 받는 단이 있는 봉에서 구멍 위치를 선정할 때, 사용 될 수 있다.

• Journal of Welding and Joining
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• 제10권3호
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• pp.54-62
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• 1992

Large steel water pipes are joined prevalently by bell and method and welded at inside and outside of lapped parts. According to the Korean Standard(KS) for fabrication of water pipes, the weldments are designed to have the length of leg which is same as or larger than the thickness of the pipe. It is recently pointed out that the standard size of weldments is too large, which results in an excessive consumption of material and labor. In this study, several cases of weldments having different sizes were investigated to reduce the length of leg to the effective size. For each case, the analysis of stresses was carried out to evaluate the safety of the welded pipes by using a package program, ANSYS, under the consideration of the loading condition of water pipes which includes the soil pressure on the pipe, the load over the road, and temperature change of the pipe. The results of this study revealed that the weldment which has the length of leg of the size over 0.7*thickness of the pipe could provide a stress level below the yield strength. Especially when the length of leg is 85% of the wall thickness, the maximum equivalent stress is only slightly higher than that of the leg of fillet of the size of 1.0*pipe thickness.

• 한국기계가공학회지
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• 제8권1호
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• pp.18-23
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• 2009

This study analyzes the thermal stress at automotive radiators on steady and transient states. The maximum displacement is shown at the lower corner of upper tank with the value of 0.51mm. The displacement becomes smaller at the center of radiator and it becomes larger at this edge. The maximum thermal stress with the value of 62 MPa is shown at the contact between upper tank and cooling plate. Thermal maximum stress with the transient state at the elapsed time of 10 second is lower than that at steady state as much as 0.7%.

• 한국생산제조학회지
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• 제21권5호
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• pp.747-754
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• 2012

A solar power generator is usually installed outdoors and it is exposed to extreme environments such as snow weight and wind loading. The solar tracker structure should be designed to have sufficient stiffness and strength against such loads. In this paper, simulations are performed by varying the parameters such as wind directions, wind speeds and the pose of the solar panel to evaluate the effects of extreme wind on solar tracker. As the effects of wind load, maximum displacement and maximum equivalent stress in the solar tracker are calculated. Finite element stress analysis is carried out by using the pressure distribution that is obtained by prior wind load analysis due to the flow around the solar tracker. The stress analysis of solar tracker to check and/or improve structural robustness provides some useful instructions for structural design or revision of solar tracker.

• 한국기계가공학회지
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• 제11권2호
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• pp.137-143
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• 2012

This study analyzes flywheel through the analyses of stress, fatigue and vibration. Maximum equivalent stress is 15.271MPa at the mid round shape and maximum deformation is 0.02264mm at the outer teeth. 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 -$10^4$MPa and the amplitude stress of 1000 to 2900MPa, the possibility of maximum damage becomes 30%. This stress state can be 20 times greater than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The range of natural frequencies becomes 200 to 820Hz and the values of these deformations are not more than 10mm. The structural result of this study can be effectively utilized with the design of flywheel by investigating prevention and durability against its damage.