• Title/Summary/Keyword: contacting stresses

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Degradation Behavior and Micro-Hardness Analysis of a Coolant Rubber Hose for Automotive Radiator (자동차용 냉각기 고무호스의 노화거동과 미소경도분석)

  • Kwak, Seung-Bum;Shin, Sei-Moon;Shin, Wae-Gi;Choi, Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.9
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    • pp.915-923
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    • 2007
  • Rubber hoses for automobile radiators are apt to be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature increased. On account of the penetration of coolant liquid into the skin part influenced by the electro-chemical degradation(ECD) test the weight of the rubber hose increased, whereas their failure strain and IRHD hardness decreased. The hardness of the hose in the side of the negative pole was the most deteriorated at the test site of the hose skin just below the coolant surface.

Characteristic Accelerated Aging Assessment for Coolant Rubber Hose of Automotive Radiator (자동차 냉각기 고무호스의 가속 노화거동 평가)

  • Kwak, Seung-Bum;Choi, Nak-Sam;Kang, Bong-Sung;Shin, Sei-Moon
    • Proceedings of the Korean Reliability Society Conference
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    • 2006.05a
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    • pp.27-31
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    • 2006
  • Rubber hoses for automobile radiators are apt to degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature were large. On account of the penetration of coolant liquid into the skin part the weight of rubber specimens influenced by electro-chemical degradation (ECD) test increased, whereas their failure strain and IRHD hardness decreased. The hardness decreased further as the test site on the hose skin approached to the negative pole.

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Method of Friction Energy Dissipation and Crack Analysis under Partial Slip (부분 미끄럼 상태에서의 마찰에너지 방출 및 균열해석 방법)

  • 김형규
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.06a
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    • pp.38-46
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    • 1999
  • Numerical methods are procured for evaluating the contact stresses, the dissipation of friction energy density and the fatigue cracking emanated from the contact surface under the partial slip condition. A rounded punch is used for the indenter pressing and slipping on the elastic half plane. Plane strain condition is assumed for the present analysis. Several sample calculations are carried out to investigate the effect of the punch roundness, the shear load path, and the crack obliquity and closure on the failure. It is found that the present methods can be a useful tool for studying the physical failure of the of the contacting materials such as fretting wear and fretting fatigue cracking.

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Numerical Study of Thermal Deformations Due to Frictional Heatings in a Mechanical Face Seal (기계평면시일의 마찰열 변형거동에 관한 수치적 연구)

  • 김청균;함정윤
    • Tribology and Lubricants
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    • v.14 no.2
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    • pp.49-56
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    • 1998
  • The thermal deformation of the contact seal components has been analyzed using the finite element method. The temperature distributions, the thermal deformations and contact stresses are solved numerically for the contact surface with wear coning effects. The thermal deformation is always shown to distort the sealing surface along the radius of the seal ring. The results show that the deformations of inner radius side are significant compared with those of outer radius. Thus, the thermal deformation due to thermal heatings may promote the coned face wear or wear related thermal cracks at the contacting face of the seal ring component.

다이케스팅 머신의 구조 해석

  • 윤승원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.813-817
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    • 1995
  • Structural analysis of horizontal cold chamber die casting machine is performed by the FEM. The analyzed model is made up of stationary die platen,movable die platen,link housing platen, C-frame, and tie bar which mainly undertake die locking force and injection force. In modeling, compression gap elements are used for to simulate contacting condition between tie bar and movable die platen, movable die platen and base frame, and link housing and base frame. Unbalanced die locking force imposed on four tie bars are considered. As the results, the deformed shape and the stresses of the die casting machine are given.

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Numerical Study of Thermal Deformations Due to Frictional Heatings in a Mechanical Face Seal (기계평면시일의 마찰열 변형거동에 관한 수치적 연구)

  • 함정윤;김청균
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.149-158
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    • 1998
  • The thermal deformation of the contact seal components has been analyzed using the finite element method. The temperature distributions, the thermal deformations and contact stresses are solved numerically for the contact surface with wear coning effects. The thermal deformation is always shown to distort the sealing surface along the radius of the seal ring. The results show that the deformations of inner radius side are significant compared with those of outer radius. Thus, the thermal deformation due to thermal heatings may promote the coned face wear or wear related thermal cracks at the contacting face of the seal ring component.

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Structural Analysis of Multi-size Power Chuck for Lathes (선반용 멀티사이즈 파워 척의 구조해석)

  • 김문기;유중학;윤영한;국정한;박종권
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.3
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    • pp.107-113
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    • 1999
  • The purpose of this study is to analyze multi-size power chuck which can chuck work pieces having various sizes automatically and be used suitably to an exclusive product line in the field of automotive industry. Gripping force, accuracy, and stiffness about the chuck are especially considered for the analysis. MSC/NASTRAN software is used for FEM analysis. Also, the effects of centrifugal force which occurs when chuck body rotates and compressive stresses which occur at contacting area in between chuck body and collet are estimated.

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Stress Analysis on the Cam-Roller Contact Parts in a Marine Diesel Engine (박용 디젤기관 캠-롤러 접촉부의 응력 해석)

  • 김형자;임우조;조용주;구영필
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.2
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    • pp.174-180
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    • 2002
  • The subsurface stress field beneath the roller's contacting surface due to the contact pressure in lubricating condition has been calculated. Main purpose of this study in view of engineering is to prove the validity of the numerical profile roller presented by Koo et al. The Love's rectangular patch solution was used to obtain the subsurface stress field. The stress field of the numerical profile roller was compared with the one of the existing dub-off profile roller The analysis results show reduced subsurface stresses for the numerical profile roller.

Finite element analysis of peri-implant bone stresses induced by root contact of orthodontic microimplant (치근접촉이 마이크로 임플란트 인접골 응력에 미치는 영향에 대한 유한요소해석)

  • Yu, Won-Jae;Kim, Mi-Ryoung;Park, Hyo-Sang;Kyung, Hee-Moon;Kwon, Oh-Won
    • The korean journal of orthodontics
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    • v.41 no.1
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    • pp.6-15
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    • 2011
  • Objective: The aim of this study was to evaluate the biomechanical aspects of peri-implant bone upon root contact of orthodontic microimplant. Methods: Axisymmetric finite element modeling scheme was used to analyze the compressive strength of the orthodontic microimplant (Absoanchor SH1312-7, Dentos Inc., Daegu, Korea) placed into inter-radicular bone covered by 1 mm thick cortical bone, with its apical tip contacting adjacent root surface. A stepwise analysis technique was adopted to simulate the response of peri-implant bone. Areas of the bone that were subject to higher stresses than the maximum compressive strength (in case of cancellous bone) or threshold stress of 54.8MPa, which was assumed to impair the physiological remodeling of cortical bone, were removed from the FE mesh in a stepwise manner. For comparison, a control model was analyzed which simulated normal orthodontic force of 5 N at the head of the microimplant. Results: Stresses in cancellous bone were high enough to cause mechanical failure across its entire thickness. Stresses in cortical bone were more likely to cause resorptive bone remodeling than mechanical failure. The overloaded zone, initially located at the lower part of cortical plate, proliferated upward in a positive feedback mode, unaffected by stress redistribution, until the whole thickness was engaged. Conclusions: Stresses induced around a microimplant by root contact may lead to a irreversible loss of microimplant stability.

FINITE ELEMENT STRESS ANALYSIS OF IMPLANT PROSTHESIS WITH INTERNAL CONNECTION BETWEEN THE IMPLANT AND THE ABUTMENT (임플란트와 지대주간 내측 연결을 갖는 임플란트 보철의 유한요소 응력분석)

  • Ahn, Jong-Kwan;Kay, Kee-Sung;Chung, Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
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    • v.42 no.4
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    • pp.356-372
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    • 2004
  • Statement of problom: In the internal connection system the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. Purpose: The purpose of this study was to assess the loading distributing characteristics of 3 implant systems with internal connection under vertical and inclined loading using finite element analysis. Material and method: Three finite element models were designed according to the type of internal connection of ITI(model 1), Friadent(model 2), and Bicon(model 3) respectively. This study simulated loads of 200N in a vertical direction (A), a $15^{\circ}$ inward inclined direction (B), and a $30^{\circ}$ outward inclined direction (C). Result: The following results have been made based on this numeric simulations. 1. The greatest stress showed in the loading condition C of the inclined load with outside point from the centric cusp tip. 2. Without regard to the loading condition, the magnitudes of the stresses taken at the supporting bone, the implant fixture, and the abutment were greater in the order of model 2, model 1, and model 3. 3. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture, and lower stress was taken at the cancellous bone. 4. The stress of the implant fixture was usually widely distributed along the inner surface of the implant fixture contacting the abutment post. 5. The stress distribution pattern of the abutment showed that the great stress was usually concentrated at the neck of the abutment and the abutment post, and the stress was also distributed toward the lower part of the abutment post in case of the loading condition B, C of the inclined load. 6. In case of the loading condition B, C of the inclined load, the maximum von Misess stress at the whole was taken at the implant fixture both in the model 1 and model 2, and at the abutment in the model 3. 7. The stress was inclined to be distributed from abutment post to fixture in case of the internal connection system. Conclusion: The internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, and the abutment according to the abutment connection form had differenence among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the a butment post.