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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers A
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 29, Issue 12 - Dec 2005
Volume 29, Issue 11 - Nov 2005
Volume 29, Issue 10 - Oct 2005
Volume 29, Issue 9 - Sep 2005
Volume 29, Issue 8 - Aug 2005
Volume 29, Issue 7 - Jul 2005
Volume 29, Issue 6 - Jun 2005
Volume 29, Issue 5 - May 2005
Volume 29, Issue 4 - Apr 2005
Volume 29, Issue 3 - Mar 2005
Volume 29, Issue 2 - Feb 2005
Volume 29, Issue 1 - Jan 2005
Selecting the target year
A Study of Extrusion Process for Al 3003 Condenser Tube
Bae, Jae-Ho ; Lee, Jung-Min ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1043~1050
DOI : 10.3795/KSME-A.2005.29.8.1043
Condenser tube is a component of the heat exchanger in automobile and air conditioning apparatus. It is generally made from the 1000 or 3000 series Al alloys that have good heat efficiency. In the case of 3000 series, these have high strength and hardness but have the disadvantage of low extruability. The development of extruding process in condenser tube with 3000 series Al alloys is studied in this paper. A study on extrusion process is performed through the 3D FE simulation in non-steady state and extrusion experimentation. Also, nano-indentation test is employed to estimate the weldability of tubes. Especially, An evaluation of the weldability using the nano-indentation is accomplished as compared with nano-hardness of welded part and the others in cross-section of tube.
Structural Optimization for Non-Linear Behavior Using Equivalent Static Loads (I)
Park Ki-Jong ; Park Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1051~1060
DOI : 10.3795/KSME-A.2005.29.8.1051
Nonlinear Response Optimization using Equivalent Static Loads (NROESL) method/algorithm is proposed to perform optimization of non-linear response structures. The conventional method spends most of the total design time on nonlinear analysis. The NROESL algorithm makes the equivalent static load cases for each response and repeatedly performs linear response optimization and uses them as multiple loading conditions. The equivalent static loads are defined as the loads in the linear analysis, which generates the same response field as those in non-linear analysis. The algorithm is validated for the convergence and the optimality. The proposed algorithm is applied to a simple mathematical problem to verify the convergence and the optimality.
Structural Optimization for Non-Linear Behavior Using Equivalent Static Loads (II) - Structural Examples -
Park Ki-Jong ; Park Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1061~1069
DOI : 10.3795/KSME-A.2005.29.8.1061
In part I of this papter Nonlinear Response Optimization using Equivalent Static Loads (NROESL) method/algorithm is developed to conduct optimization for nonlinear behavior structures. The method/algorithm is also verified to show its convergency and optimality. In this present paper, the NROESL algorithm is applied to several structural problems with geometric and/or material nonlinearity. Conventional optimization with sensitivity analysis using the finite difference method is also applied to the same examples. The results of the optimizations are compared. The proposed method is very efficient and derives good solutions.
Evaluation of Plastic Collapse Pressure for Steam Generator Tube with Non-Aligned Two Axial Through-Wall Cracks
Moon Seong-In ; Chang Yoon-Suk ; Lee Jin-Ho ; Song Myung-Ho ; Choi Young-Hwan ; Kim Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1070~1077
DOI : 10.3795/KSME-A.2005.29.8.1070
of wall thickness criterion which has been used as a plugging rule is applicable only to a single cracked steam generator tubes. In the previous studies performed by authors, several failure prediction models were introduced to estimate the plastic collapse pressures of steam generator tubes containing collinear or parallel two adjacent axial through-wall cracks. The objective of this study is to examine the failure prediction models and propose optimum ones for non-aligned two axial through-wall cracks in steam generator tubes. In order to determine the optimum ones, a series of plastic collapse tests and finite element analyses were carried out for steam generator tubes with two machined non-aligned axial through-wall cracks. Thereby, either the plastic zone contact model or COD based model was selected as the optimum one according to axial distance between two clacks. Finally, the optimum failure prediction model was used to demonstrate the conservatism of flaw characterization rules for various multiple flaws according to ASME code.
An Evaluation on the Effect of Reversed Plastic Zone on the Fatigue Crack Opening Behavior under 2-D Plane Stress
Choi, Hyeon-Chang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1078~1084
DOI : 10.3795/KSME-A.2005.29.8.1078
The relationship between fatigue crack opening behavior and the reversed plastic zone sizes is studied. An elastic-plastic finite element analysis (FEA) is performed to examine the opening behavior of fatigue crack, where the contact elements are used in the mesh of the track tip area. The smaller element size than reversed plastic zone size is used fer evaluating the distribution of reversed plastic zone. In the author's previous results the FEA could predict the crack opening level, which crack tip elements were in proportion to the theoretical reversed plastic zone size. It is found that the calculated reversed plastic zone size is related to the theoretical reversed plastic zone size and crack opening level. The calculated reversed plastic zone sizes are almost equal to the reversed plastic zone considering crack opening level obtained by experimental results. It can be possible to predict the crack opening level from the reversed plastic zone size calculated by finite element method. We find that the experimental crack opening levels correspond with the opening values of contact nodes on the calculated reversed plastic zone of finite element simulation.
A Study on Dynamic Analysis and Fatigue Life of the Belt in the OHT Vehicle
Jung Il-Ho ; Kim Chang-Su ; Cho Dong-Hyeob ; Park Joong-Kyung ; Park Tae-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1085~1092
DOI : 10.3795/KSME-A.2005.29.8.1085
The OHT(Over Head Transportation) Vehicle transports heavy products quickly and repeatedly at the industrial workplace. The belt in the OHT vehicle is used to support the weight of the OHT Cage. The fatigue of the belt is caused by the dynamic load during the operation time. Since the fatigue fracture of the belt affects the safety at the workplace, the correct prediction of the dynamic load is necessary to calculate the fatigue life of the belt on the design step. In this paper a computer aided analysis method is proposed for the belt in the early design stage using dynamic analysis, stress analysis, belt tensile test, belt fatigue test and fatigue lift prediction method. From the dynamic load time histories and the stress of the belt FE model, a dynamic stress time history is produced. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The method developed in this paper is used to reduce the time and cost for designing the OHT belt in different environment and condition.
Robust Control of Flexible Structure Using Dynamic Vibration Absorber
Sim Sangdeok ; Kang Hoshik ; Jong Namheui ; Jang Kangseok ; Kim Doohoon ; Song Ohseop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1093~1101
DOI : 10.3795/KSME-A.2005.29.8.1093
Hybrid mass damper systems have recently been introduced as a dynamic vibration absorber to exploit the benefits of both the conventional tuned mass damper system and the active control system. A hybrid system is programmed to function as either a conventional TMD or as an active system according to the wind conditions and the resultant building and damper mass vibration characteristics. This paper deals with the design of the robust controller for the control of the flexible box structure. The control algorithm was devised based on
(LQG) robust control logic with acceleration feedback and to improve the capability of the controller Kalman Filter was accepted for the system. To test the ability of the robust controller using the linear motor damper system, performance tests and simulations were carried out on the full-scale steel frame structure. Through the performance tests, it was confirmed that acceleration levels are reduced down.
Probabilistic Damage Mechanics Assessment of Wall-Thinned Nuclear Piping Using Reliability Method and Monte-Carlo Simulation
Lee Sang-Min ; Yun Kang-Ok ; Chang Yoon-Suk ; Choi Jae-Boong ; Kim Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1102~1108
DOI : 10.3795/KSME-A.2005.29.8.1102
The integrity of nuclear piping systems has to be maintained sufficiently all the times during operation. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis, etc, are required. Up to now, the integrity assessment has been performed using conventional deterministic approach even though there are lots of uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for piping system evaluation. The objectives of this paper are to develop a probabilistic assessment program using reliability index and simulation technique and to estimate the damage probability of wall-thinned pipes in secondary systems. The probabilistic assessment program consists of three evaluation modules which are first order reliability method, second order reliability method and Monte Carlo simulation method. The developed program has been applied to evaluate damage probabilities of wall-thinned pipes subjected to internal pressure, global bending moment and combined loading. The sensitivity analysis results as well as prototypal evaluation results showed a promising applicability of the probabilistic integrity assessment program.
Analysis for Impact Damage Resistance in Filament Wound Composite Pressure Vessel
Park Jae-Beom ; Hwang Tae-Kyung ; Kim Hyoung-Guen ; Kim Jung-Kyu ; Kang Ki-Weon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1109~1117
DOI : 10.3795/KSME-A.2005.29.8.1109
To identify damage that develops in filament wound composite pressure vessels subjected to low velocity impact, a series of impact tests was performed on specimens cutting from the full scale pressure vessel. The resulting damages by the three different impactors were assessed by the scanning acoustic and metallurgical microscope. Based on the impact force history and damage, the resistance parameters were proposed and its validity in identifying the damage resistance of CFRP pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the impactor shape were estimated quantitatively.
Evaluation of the Crack Initiation of Curved Compact Tension Specimens of a Zr-2.5Nb Pressure Tube Using the Unloading Compliance and Direct Current Potential Drop Methods
Jeong, Hyeon-Cheol ; Ahn, Sang-Bok ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1118~1122
DOI : 10.3795/KSME-A.2005.29.8.1118
The direct current potential drop (DCPD) method and the unloading compliance (UC) method with a crack opening displacement gauge were applied simultaneously to the Zr-2.5Nb curved compact tension (CCT) specimens to determine which of the two methods can precisely determine the crack initiation point and hence the crack length for evaluation of their fracture toughness. The DCPD method detected the crack initiation at a smaller load-line displacement compared to the UC method. As a verification, a direct observation of the fracture surfaces on the curved compact tension specimens was made on the CCT specimens experiencing either 0.8 to 1.0 mm load line displacement or various loads from
of the maximum peak load, or
. The DCPD method is concluded to be more precise in determining the crack initiation and fracture toughness, J in Zr-2.5Nb CCT specimens than the UC method.
The Development of a Sliding Joint for Very Flexible Multibody Dynamics
Seo Jong-Hwi ; Jung Il-Ho ; Sugiyama Hiroyuki ; Shabana Ahmed A. ; Park Tae-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1123~1131
DOI : 10.3795/KSME-A.2005.29.8.1123
In this paper, a formulation for a spatial sliding joint, which a general multibody can move along a very flexible cable, is derived using absolute nodal coordinates and non-generalized coordinate. The large deformable motion of a spatial cable is presented using absolute nodal coordinate formulation, which is based on the finite element procedures and the general continuum mechanics theory to represent the elastic forces. And the non-generalized coordinate, which is neither related to the inertia forces nor external forces, is used to describe an arbitrary position along the centerline of a very flexible cable. In the constraint equation for the sliding joint, since three constraint equations are imposed and one non-generalized coordinate is introduced, one constraint equation is systematically eliminated. Therefore, there are two independent Lagrange multipliers in the final system equations of motion associated with the sliding joint. The development of this sliding joint is important to analyze many mechanical systems such as pulley systems and pantograph/catenary systems for high speed-trains.
Formulation of Tearing Energy for Fatigue Life Evaluation of Rubber Material
Kim, Heon-Young ; Kim, Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1132~1138
DOI : 10.3795/KSME-A.2005.29.8.1132
Fatigue life of metal material can be predicted by the use of fracture theory and experimental database. Although prediction of fatigue life of rubber material uses the same way as metal, there are many reasons to make it almost impossible. One of the reasons is that there is not currently used fracture criteria for rubber material beacuse of non-standardization, various way of composition process of rubber and so on. Tearing energy is one of the fracture criteria which can be applied to a rubber. Even if tearing energy relaxes the restriction of rubber composition, it is also not currently used because of complication to apply in. Research material about failure process of rubber and tearing energy was reviewed to define the process of fatigue failure and the applicability of tearing energy in estimation of fatigue life for rubber. Also, 1file element formulation of tearing energy which can be used in FE analysis was developed.
A Theoretical Investigation of Forming Limits of Voided Anisotropic Sheet Metals
You Bongsun ; Yim Changdong ; Kim Youngsuk ; Won Sungyeun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1139~1145
DOI : 10.3795/KSME-A.2005.29.8.1139
Most failures of ductile materials in metal forming processes occurred due to material damage evolution - void nucleation, growth and coalescence. In this paper, the modified yield function of Liao et al in conjunction with the Hosford's yield criterion is studied to clarify the plastic deformation characteristic of voided anisotropic sheet metals. The void growth of an anisotropic sheet under biaxial tensile loading and damage effect of void growth on forming limits of sheet metals are investigated. Also the characteristic length defining the neck geometry is introduced in M-K model to incorporate the effect of triaxial stress in necked region on forming limits. The forming limits theoretically predicted are compared with experimental data. Satisfactory agreement was obtained between the predictions and experimental data.
FE Simulation of Extrusion Process for Al Multi Cell Tube According to the Changes of the Porthole Shape
Lee Jung Min ; Kim Dong Hwan ; Ho Jo Hyung ; Kim Byung Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1146~1152
DOI : 10.3795/KSME-A.2005.29.8.1146
Recently, multi cell tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce multi cell tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.
Performance Evaluation for the Methods of Spot Weld Modeling Considering Durability
Byun Hyung-Bae ; Lee Byung-Chai ; Joo Byung-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 8, 2005, Pages 1153~1160
DOI : 10.3795/KSME-A.2005.29.8.1153
Many methods of spot weld modeling have been developed to increase efficiency and guarantee the robustness fer the CAE analysis. In this research they are introduced and the performance is compared in a viewpoint of stiffness and durability. For evaluating the performance a multi-spot welded specimen as well as two single welded specimen is used. The results show that the CWELD element considering 'patch to patch' is stiffer than other modeling methods in stiffness and more conservative in durability. It also offers simple modeling and since it is much easier to maintain the orrhogonality of the BAR element expressing a nugget, we can obtain more exact reaction forces and moments in a nugget. Therefore the CWELD element is the most excellent in the assessment of durability.