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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 24, Issue 12 - Dec 2000
Volume 24, Issue 11 - Nov 2000
Volume 24, Issue 10 - Oct 2000
Volume 24, Issue 9 - Sep 2000
Volume 24, Issue 8 - Aug 2000
Volume 24, Issue 7 - Jul 2000
Volume 24, Issue 6 - Jun 2000
Volume 24, Issue 5 - May 2000
Volume 24, Issue 4 - Apr 2000
Volume 24, Issue 3 - Mar 2000
Volume 24, Issue 2 - Feb 2000
Volume 24, Issue 1 - Jan 2000
Selecting the target year
A Development of Hardware-in-the Loop Simulation System For a Electric Power Steering System
Park, Dong-Jin ; Yun, Seok-Chan ; Han, Chang-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2883~2890
DOI : 10.22634/KSME-A.2000.24.12.2883
In this study, a Hardware-In-The-Loop-Simulation(HILS) system for developing a Electric-Power-Steering(EPS) system is designed. To test a EPS by HILS system, a mathematical vehicle model with a steering system model has been constructed. This mathematical model has been constructed. This mathematical model has been downloaded to the Digital-Signal-Processor(DSP) board. To realize the lateral force acting on the front wheel in a real car. the steering wheel angle sensor and vehicle velocity have been used for input signal. The force sensor has been used for a feedback signal. The full vehicle states could by simulated by the HILS system. Consequently, the HILS system could by used to analyze control-parameters of a EPS that contributes to the maneuverability and stability of a vehicle. At the same time, the HILS system can evaluate the whole performance of the vehicle-steering system. Also the HILS system could do test could not be executed in real vehicle. The HILs system will useful for developing the control logic for the EPS system.
Volumetric Error Indentification for Nc Machine Tools Using The Referecne Artifact
Kim, Gyeong Don ; Jeong, Seong Jong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2889~2889
DOI : 10.22634/KSME-A.2000.24.12.2889
Development of Fiber-Optic AE Sensor for On-Line Monitoring System
Nam, Jae-Yeong ; Jeong, Jae-Hyeon ; Choe, Jae-Bung ; Kim, Yeong-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2891~2898
DOI : 10.22634/KSME-A.2000.24.12.2891
The objective of this paper is to develop a fiber-optic acoustic emission(AE) sensor applicable to on-line monitoring systems which is suitable for long-distance signal transmission. An AE sensor was developed by use of a fiber-optic cantilever and an extrinsic Fabry-Perot interferometer(EEPI). The efficiency of signal processing was improved by driving the high frequency AE signals into the low frequency ones. In order to verify the developed sensor, the tensile and the pencil lead fracture(PLF) tests were performed including the experiment showing the Kaiser effect. Form tests, AE signals were successfully detected in the elastic-plastic deformation range, especially higher signals at the crack propagation. The developed sensor was expected to be used for an on-line monitoring of crack propagation in mechanical system.
Volumetric Error Identification for NC Machine Tools Using the Reference Artifact
Kim, Gyeong-Don ; Jeong, Seong-Jong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2899~2908
DOI : 10.22634/KSME-A.2000.24.12.2899
Methodology of volumetric error identification is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geometric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. The proposed method can speed up and simplify volumetric error identification processes.
Effect of Annealing on the Mechanical properties of Fe-6.5wt% Si Alloy
Yun, Yeong-Gi ; Yun, Hui-Seok ; Hong, Seong-Gil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2909~2916
DOI : 10.22634/KSME-A.2000.24.12.2909
6.5wt% Si steel is widely known as an excellent magnetic material because its magnetostriction is nearly zero. The AX magnetic properties as magnetostriction of 6.5% Si steel were evaluated and compared with those of conventional 3% Si steel sheet. In this paper, the fracture behavior of the poly crystals and single crystals of Fe-6.5wt%Si alloy has been observed. Single crystals were prepared by Floating Zone(FZ) method, which melts the alloy by the use of high temperature electron beam in pure argon gas condition. And the single crystals were annealed at 500
respectively and tensile tested at room temperature. According to the result, B2 phase has more good elongation than DO
phase. It was also found that the fracture surfaces of the single crystals have hairline facets in same direction, and the facets change the direction according to the single crystal phase.
Strength Evaluation and Eailure Analysis of Unidirectional Composites Using Monte-Carlo Simulation
Kim, Jeong-Gyu ; Park, Sang-Seon ; Kim, Cheol-Su ; Kim, Il-Hyeon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2917~2925
DOI : 10.22634/KSME-A.2000.24.12.2917
Tensile strength and failure process of composite materials depend on the variation in fiber strength, matrix properties and fiber-matrix interfacial shear strength. A Monte-Carlo simulation considering variation in these factors has been widely used to analyze such a complicated phenomenon as a strength and simulated the failure process of unidirectional composites. In this study, a Monte Carlo simulation using 2-D and 3-D(square and hexagonal array) model was performed on unidirectional graphite/epoxy and glass/polyester composites. The results simulated by using 3-D hexagonal array model have a good agreement with the experimental data which were tensile strength and failure process of unidirectional composites.
Direct Adaptive Control for Trajectory Tracking Control of a Pneumatic Cylinder
Lee, Su-Han ; Jang, Chang-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2926~2934
DOI : 10.22634/KSME-A.2000.24.12.2926
This study presents a direct adaptive controller which is derived by using Lyapunovs direct methods for trajectory tracking control of a pneumatic cylinder. The structure of the controller is very simple and computationally efficient because it does not use either the dynamic model or the parameter values of the pneumatic system. The bounded stability of the system is shown in the presence of the bounded unmodeled dynamics. The bounded size of tracking errors can be made arbitrarily small without giving andy influences on either input or output variables. The trajectory tracking performance and the stability of the control system is verified experimentally. The results of the experiments show that the proposed controller tracks the given trajectories, sine function and cycloidal function trajectories, more accurately than PD controller does, and it stabilizes the system and adaptive variables.
A Study on Prediction of Temperature Distribution in Pipe Girth Welding by Mapping Theory
Jo, Yeong-Tae ; Na, Seok-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2935~2944
DOI : 10.22634/KSME-A.2000.24.12.2935
Gas tungsten arc(GTA) welding is used to rrpiar the seat ring in swing type check valve in power plant because of its high weld quality. In order to automate the welding process, it is needed to analyze the process of inside pipe girth welding. In this study, the shapes of weld bead on pipe inside and outside were predicted and its validity was investigated. On the assumption that the welding arc had a bivariate gaussian distribution, analytical solution was derived to predict the temperature distribution in pipe weld using mapping under consideration of physical relationships. The size of weld bean could be predicted from this equation and its accuracy was verified by experiments.
Influence of Stacking Sequence Conditions on the Characteristics of Impact Collapse using CFRP Thin-Wall Structures
Kim, Yeong-Nam ; Choe, Hyo-Seok ; Cha, Cheon-Seok ; Im, Gwang-Hui ; Jeong, Jong-An ; Yang, In-Yeong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2945~2951
DOI : 10.22634/KSME-A.2000.24.12.2945
Because of the inherent flexibility in their design for improved material properties, composites have wide applications in aerospace vehicles and automobiles. The purpose of this study is to investigate the energy absorption characteristics of CFRP( Carbon Fiber Reinforced Plastics); tubes on static and impact tests. Static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine)and impact compression tests have been carried out using the vertival crushing testing machine. When such tubes were subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that control the crushing process. The collapse characteristics and energy absorption were examined. Trigger and interlaminar number affect energy absorption capability of CFRP tubes.
Design of Structure Using Orthogonal Array Considering Interactions in Discrete Design Spaces
Hwang, Gwang-Hyeon ; Gwon, U-Seong ; Lee, Gwon-Hui ; Park, Gyeong-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2952~2962
DOI : 10.22634/KSME-A.2000.24.12.2952
The design of experiment(DOE) is getting more attention in the engineering community since it is easy to understand and apply. Recently, engineering designers are adopting DOE with orthogonal arrays when they want to design products in a discrete design space. In this research, a design flow with orthogonal arrays is defined for structural design according to the general DOE. The design problem is defined as a general structural optimization problem. Sensitivity information is evaluated by the analysis of variance(ANOVA), and an optimum design is determined from analysis of means(ANOM). Interactions between design variables are investigated to achieve additivity which should be valid in DOE. When strong interactions exit, a method is proposed. Some methods to consider the problem are suggested.
Variation of the Fracture Resistance Curve with the Change of a Size in the CT Specimen
Seok, Chang-Seong ; Kim, Su-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2963~2971
DOI : 10.22634/KSME-A.2000.24.12.2963
In order to obtain more realistic fracture resistance curve, research is currently underway to introduce new parameter and to quantify the constraint effect. The objective of this study is to investigate the relationship between the constraint effect of a size(plane size and thickness) and the fracture resistance curve. In this paper fracture toughness tests were performed with various plane size and various thickness of specimens in two materials. The test results showed that the effects of plane size in th4 J-R curve were significant and the curve was risen with an increase in plane size. However, relatively weak influence was observed form the change of the specimen thickness and size. The stress fields near the crack tip of th specimen is close to the HRR field according to increasing the plane size and Q stress appears different value according to material properties and the plane size.
A Numerical Study on the Dynamic Characteristics of Power Metal using Split Hopkinson Pressure Bar
Hwang, Du-Sun ; Lee, Seung-U ; Hong, Seong-In ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2972~2979
DOI : 10.22634/KSME-A.2000.24.12.2972
Dynamic characteristics of powder metal is very important to mechanical structures requiring high strength or endurance for impact loading. But owing to distinctive property of powder metal, that is relative, it has been investigated restrictively compared to static characteristics. The objectives of this study is to investigate dynamic characteristics of powder metal and compare it to a fully density material. To find the characteristics, an explicit finite element method is used for simulation of Split Hopkinson Pressure Bar experiment based on the stress wave propagation theory. We obtained a dynamic stress-strain relationship and dynamic behavior of powder metal, as well as the variation of material properties during dynamic deformation.
Depth and Course Controllers Design for Autonomous Underwater Vehicles
Yang, Seung-Yun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2980~2988
DOI : 10.22634/KSME-A.2000.24.12.2980
In this paper, H(sub)
depth and course controllers of autonomous underwater vehicles using H(sub)
servo control are proposed. An H(sub)
servo problem is foumulated to design the controllers satisfying a robust tracking property with modeling errors and disturbances. The solution of the H(sub)
servo problem is as follows; firest, this problem is modified as an H(sub)
control problem for the generalized plant that includes a reference input mode, and than a sub-optimal solution that satisfies a given performance criteria is calculated by LMI(Linear Matrix Inequality) approach, The H(sub)
depth and course controllers are designed to satisfy the robust stability about the modeling error generated from the perturbation of the hydrodynamic coefficients and the robust tracking property under disturbances(was force, wave moment, tide). The performances(the robustness to the uncertainties, depth and course tracking properties) of the designed controlled are evaluated with computer simulations, and finally these simulation results show the usefulness and applicability of the propose H(sub)
depth and course control systems.
A Lubrication Design Optimization of Mechanical Face Seal
Choe, Byeong-Ryeol ; Lee, An-Seong ; Choe, Dong-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2989~2994
DOI : 10.22634/KSME-A.2000.24.12.2989
A mechanical face seal is a tribo-element intended to control leakage of working fluid at the interface of a rotating shaft and its housing. Leakage of working fluid decreases drastically as the clearance between mating seal faces gets smaller. But the very small clearance may result in an increased reduction of seal life because of high wear and heat generation. Therefore, in the design of mechanical face seals a compromise between low leakage and acceptable seal life is important, ant it present a difficult and practical design problem. A fluid film or sealing dam geometry of the seal clearance affects seal lubrication performance very much, and thereby is optimization is one of the main design consideration. in this study the Reynolds equation for the sealing dam of mechanical face seals is numerically analyzed, using the Galerkin finite element method, which is readily applied to various seal geometries, to give lubrication performances, such as opening force, restoring moment, leakage, and axial and angular stiffness coefficients. Then, to improve the seal performance an optimization is performed, considering various design variables simultaneously. For the tested case the optimization ha successfully resulted in the optimal design values of outer and inner seal radii, coning, seal clearance, and balance radius while satisfying all the operation subjected constraints and design variable side-constraints, and improvements of axial and angular stiffness coefficients by 16.8% and 2.4% respectively and reduction of leakage by 38.4% have been achieved.
Evaluation of Material Degradation Using Electrical Resistivity Method
Seok, Chang-Seong ; Kim, Dong-Jung ; Bae, Bong-Guk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 2995~3002
DOI : 10.22634/KSME-A.2000.24.12.2995
The remaining life estimation for the aged components in power plants as well as chemical plants are very important beacuse mechanical properties of the components are degraded with time of service exposure in high temperature. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components nondestructive techniques are needed to estimate the degradation. In this study, test materials with 4 different degradation levels were prepared by isothermal aging heat treatment at 630
. And the DC potential drop method and destructive methods such as tensile, K(sub)IC and hardness tests were used in order to evaluate the degradation of 1-Cr-1Mo-0.25V steels. The objective of this study is to investigate the possibility of the application of DCPD method to estimated the material degradation, and to analyse the relationship between the electrical relationship between the electrical resistivity and the degree material degradation.
Optimal Interpolation Functions of 2-None Hybrid-Mixed Curved Beam Element
Kim, Jin-Gon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3003~3009
DOI : 10.22634/KSME-A.2000.24.12.3003
In this paper, we propose a new efficient hybrid-mixed C(sup)0 curved beam element with the optimal interpolation functions determined from numerical tests, which gives very accurate locking-free two-node curved beam element. In the element level, the stress parameters are eliminated from the stationary condition and the nodeless degrees of freedom are also removed by static condensation so that a standard six-by-six stiffness matrix is finally obtained. The numeri cal benchmark problems show that the element with cubic displacement functions and quadratic stress functions is the most efficient.
A Study on the Compliance of a Compact Tension Test Specimen
Jeong, Gi-Hyeon ; Seok, Chang-Seong ; Yang, Won-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3010~3017
DOI : 10.22634/KSME-A.2000.24.12.3010
For integrity evaluation of cracked or damaged structures, fracture toughness test results in ASTM are widely used. The fracture toughness values of the structures are used as an effective design criterion in nuclear plants and aircraft structures. Sometimes the difference of P-
curve trend during the unloading /reloading cycle in the fracture toughness test using partial unloading compliance was observed. The phenomenon as a possible source of error in determining fracture toughness may be caused by the residual stress during unloading work-hardening and bucking of a specimen. Therefore, we evaluate the effect of bucking and compressive residual stress during the K-R and J-R testing using a finite element method.
A Study of an Effect of Tool Offset on Cutting Precision Considering Cutting Force in Polyurethane Foam Cutting
Min, Se-Hong ; Kim, Hui-Song ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3018~3025
DOI : 10.22634/KSME-A.2000.24.12.3018
It is possible to shorten developing process by making model using polyurethane foam in the area of automobile development process, etc. However, this skill is too difficult to be of practical use because machining is not easy due to characteristic of polyurethane foam. Domestic and foreign automobile company use clay, polyurethane foam. etc,, those are easy to handle and to make model after completing design sketch. But these materials is difficult to the machined and be worked by humans hand, There are so many difficult problem for machining by making model using polyurethane foam since cutting of elastic body like polyurethan foam has never been studied. Therefore, in this study, it is investigated to measured cutting force that is generated in case of polyurethane foam machining, and to make systematize tool compensation of polyurethane foam cutting work on automobile model by modification of tool offset method on existing steel.
The Development and Performance Analysis of Beam Rotating Actuator for Multi-Beam Disk Drive
Kim, Byeong-Jun ; Kim, Su-Hyeon ; Gwak, Yun-Geun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3026~3032
DOI : 10.22634/KSME-A.2000.24.12.3026
To enhance the effective data transfer rate the multi-beam optical disk drive is presented. The Beam rotating actuator is necessary for putting multi-beam on more than one track. Ray tracing was also executed for real system set-up. The beam Rotating Actuator is made up of piezoelectric material, high stiffness wire hinge and dove prism. The actuator has about 1kHz natural frequency and suitable operational range. The dynamic equation for the actuator is derived for the control real system.
Determination of Deformation Behavior of the Al6060-T6 under high Strain Rate Tensile Loading Using SHPB Technique
Lee, Eok-Seop ; Kim, Gwan-Hui ; Hwang, Si-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3033~3039
DOI : 10.22634/KSME-A.2000.24.12.3033
Mechanical properties of the materials used for transportations and industrial machinery under high stain rate loading conditions have been required to provide appropriate safety assessment to these mechanical structures. The Split Hopkinson Pressure Bar(SHPB) technique with a special experimental apparatus can be used to obtain the material properties under high strain rate loading condition. There have been many studies on the material behavior under high strain rate compressive loading compared to those under tensile loading. In this paper, mechanical properties of the aluminum alloy, Al6061-T6, under high strain rate tensile loading were determined using SHPB technique.
Progressive Quadratic Approximation Method for Effective Constructing the Second-Order Response Surface Models in the Large Scaled System Design
Hong, Gyeong-Jin ; Kim, Min-Su ; Choe, Dong-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3040~3052
DOI : 10.22634/KSME-A.2000.24.12.3040
For effective construction of second-order response surface models, an efficient quad ratic approximation method is proposed in the context of trust region model management strategy. In the proposed method, although only the linear and quadratic terms are uniquely determined using 2n+1 design points, the two-factor interaction terms are mathematically updated by normalized quasi-Newton formula. In order to show the numerical performance of the proposed approximation method, a sequential approximate optimizer is developed and solves a typical unconstrained optimization problem having 2, 6, 10, 15, 30 and 50 design variables, a gear reducer system design problem and two dynamic response optimization problems with multiple objectives, five objectives for one and two objectives for the other. Finally, their optimization results are compared with those of the CCD or the 50% over-determined D-optimal design combined with the same trust region sequential approximate optimizer. These comparisons show that the proposed method gives more efficient than others.
Development of an Efficient Optimization Technique for Robust Design by Approximating Probability Constratints
Jeong, Do-Hyeon ; Lee, Byeong-Chae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3053~3060
DOI : 10.22634/KSME-A.2000.24.12.3053
Alternative formulation is presented for robust optimization problems and an efficient computational scheme for reliability estimation is proposed. Both design variables and design parameters considered as random variables about their nominal values. To ensure the robustness of objective performance a new cost function bounding the performance and a new constraint limiting the performance variation are introduced. The constraint variations are regulated by considering the probability of feasibility. Each probability constraint is transformed into a sub-optimization problem and then is resolved with the modified advanced first order second moment(AFOSM) method for computational efficiency. The proposed robust optimization method has advantages that the mean value and the variation of the performance function are controlled simultaneously and the second order sensitivity information is not required even in case of gradient based optimization. The suggested method is examined by solving three examples and the results are compared with those for deterministic case and those available in literature.
Densification Behavior of Titanium Alloy Powder Under Hot Pressing
Yang, Hun-Cheol ; Kim, Gi-Tae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3061~3071
DOI : 10.22634/KSME-A.2000.24.12.3061
Densification behavior of titanium alloy powder was investigated under hot pressing at various pressures and temperatures. Experimental date were obtained for densification of titanium alloy powder under an instantaneous loading and subsequent creep deformation during hot pressing. The constitutive models of Fleck et al. and the modified Gurson were employed for thermo-phastic deformation under the instantaneous loading and that f Abouaf and co-workers for creep deformation of titanium alloy powder during hot pressing. By implementing these constitutive equations into a finite element program(ABAQUS), finite element results were compared with experimental data during hot pressing. To investigate the effect of friction between the power and die wall, density distributions of power compacts were measured and compared with finite element calculations. Finite element results from the models of Fleck et al. and the modified Gurson agreed reasonably good with experimental data for densification and density distribution of titanium alloy powder under the instantaneous loading during hot pressing. Finite element results from the model of Abouaf and co-workers, however, somewhat overestimate experimental data for creep deformation of power compacts during hot pressing.
Control of a Two-Arm Robot System for Assembly in Highy Uncertain Environment
Jeong, Seong-Yeop ; Gang, Gyeong-Dae ; Lee, Du-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3072~3079
DOI : 10.22634/KSME-A.2000.24.12.3072
Assembly tasks are often performed by one robot with fixtures. This type of assembly system has low flexibility in terms of the variety of parts and the part-presentation the system can handle. This paper addresses assembly without fixtures using two-manipulator robot. An active method using force feedback is proposed for the peg-in-hole assembly in highly uncertain environment. Assembly states are defined as status having unique motion constraints and events are modeled as variation of the environmental force. The states are recognized through identification of the events using two 6-d. o. f. force/moment sensors. The proposed method is verified and evaluated by experiments with round peg-in-hole assembly.
Mathematical Model of Hard Disk Drive Actuator System
Gwon, Sun-Eok ; Park, No-Yeol ; Kim, Jun-O ; Jeong, Tae-Geon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3080~3087
DOI : 10.22634/KSME-A.2000.24.12.3080
We obtain the mathematical model of the hard disk drive actuator system the system response data of the finite element analysis or experimental results. The model is base on the Rayleigh-Ritz method to approximate the dynamic response of the actuator system. The basic idea is to use the curve-fit technique to obtain the approximation coefficients. It allows the dynamic analysis of the actuator system without resort to the repetitive finite element modeling work. Even though the dynamic characteristics of the system of the system are affected somewhat by the structural modification and the change of the material properties, we can use the modified size and dynamic properties of the actuator system in the mathematical model to some extent. In this study, we express the mathematical model of the simplified rectangular plate first and then proceed to the actual hard disk drive actuator system.
Creep-Fatigue Crack Growth at CrMo Steel Weld Interface
Baek, Un-Bong ; Yun, Gi-Bong ; Lee, Hae-Mu ; Seo, Chang-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3088~3095
DOI : 10.22634/KSME-A.2000.24.12.3088
Creep-fatigue crack growth behavior was experimentally measured particularly when a crack was located in the heat affected region of lCr-5Mo steel. Load hold times of the tests for trapezoidal fatigue waveshapes were varied among 0, 30, 300 and 3,600 seconds. Time-dependent crack growth rates were characterized by the
parameter. It was found that the crack growth rates were the highest when the crack path was located along the fine-grained heat affected zone(FGHAZ). Cracks located in other heat affected regions had a tendency to change the crack path eventually to FGHAZ. Creep-fatigue crack growth law of the studied case is suggested in terms of (da/dt)
for residual life assessment.
An Experimental Study on High Temperature Material Properties of Welded Joint
Baek, Un-Bong ; Yun, Gi-Bong ; Seo, Chang-Min ; Lee, Hae-Mu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 24, issue 12, 2000, Pages 3096~3103
DOI : 10.22634/KSME-A.2000.24.12.3096
High temperature material properties of a welded joint were experimentally studied. Tensile and creep properties were measured for each part of weld metal. HAZ(heat affected zone) and parent metal at 538
. HAZ metal was obtained by a simulated heat treatment. Results showed that the order of tensile strength is weld>HAZ> parent both at 24
and at 538
. Creep resistance was also the highest for weld metal and lowest for parent metal. Creep rupture life curves were obtained and converted to Monkman-Grant relation which is useful for life assessment. Use of the data obtained in this study is discussed.