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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 21, Issue 12 - Dec 1997
Volume 21, Issue 11 - Nov 1997
Volume 21, Issue 10 - Oct 1997
Volume 21, Issue 9 - Sep 1997
Volume 21, Issue 8 - Aug 1997
Volume 21, Issue 7 - Jul 1997
Volume 21, Issue 6 - Jun 1997
Volume 21, Issue 4 - Apr 1997
Volume 21, Issue 5 - Jan 1997
Volume 21, Issue 3 - Jan 1997
Volume 21, Issue 2 - Jan 1997
Volume 21, Issue 1 - Jan 1997
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A study on the solution stability by the position of internal nodes in hihger order isoparametric elements
Lee, Joon-Hee ; Lim, Jang-Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 1973~1983
DOI : 10.22634/KSME-A.19126.96.36.1993
Higher order isoparametric elements are usually used in the finite element analysis because they can represent easily the geometric shape of a complex structure ad can improve the solution quality. When these elements are used, the position of internal nodes affects greatly on the solution accuracy. Decreasing of the accuracy related to the position of internal nodes is due to non-conformal mapping often results in an unstable Jacobian value. This paper, in order to remove this difficulty, suggests a modified shape function which can establish conformal mapping between two coordinate systems. Numerical experiments with the proposed shape function show that a stable solution can be obtained without respect to the position of internal nodes, and offer convenience that one can take arbitrarily the position of internal nodes considering only the geometric shape of element boundaries.
A study on the characteristics of electrochemical deburring in the governor shaft cross hole
Choi, In-Hyu ; Kim, Jeong-Du ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 1984~1991
DOI : 10.22634/KSME-A.19188.8.131.524
Recently burr technology is rising in the fields of the precision manufacturing and the high quality machining, deburring has treated as a difficult problem on going to the high efficiency, automation in the FMS. Removal of burr with various shapes, dimensions and properties couldn't be standardized and has depended on manual treatment. Especially, deburring for cross hole inside owing to passing through out perpendicular to a main hole is more difficult, the electrochemical method is proper as its solution at practical aspects. Burr elimination in the cross hole drilling of governor shaft used in the automobile engine so far has been worked by a manual post-processing by a skillful worker, which becomes a factor of productivity-down and cost-up so that improvement of machining process is needed. Therefore, for the high efficiency and automation of internal deburring in the cross hole, development of electrochemical deburring technology is needed. So, the new process in the burr treatment is supposed. In this study, characteristics of electrochemical deburring through experiments were identified and factors such as electrolytic gap and electorlytic fluid contributed to removal burr height were analyzed. Also, deburring efficiency and electrolytic performance for cross hole were examined according to electrolytic current and electrochemical deburring condition corresponding to acquired edge quality was found out.
A collision-free path planning using linear parametric curve based on geometry mapping of obstacles
Nam-Gung, In ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 1992~2007
DOI : 10.22634/KSME-A.19184.108.40.2062
A new algorithm for planning a collision-free path is developed based on linear prametric curve. In this paper robot is assumed to a point, and two linear parametric curve is used to construct a path connecting start and goal point, in which single intermediate connection point between start and goal point is considered. The intermediate connection point is set in polar coordinate(
) , and the interference between path and obstacle is mapped into CPS(connection point space), which is defined a CWS GM(circular work space geometry mapping). GM of all obstacles in workspace creates overlapping images of obstacle in CPS(Connection Point Space). The GM for all obstacles produces overlapping images of obstacle in CPS. The empty area of CPS that is not occupied by obstacle images represents collision-free paths in Euclidian Space. A GM based on connection point in elliptic coordinate(
) is also developed in that the total length of path is depend only on the variable .delta.. Hence in EWS GM(elliptic work space geometry mapping), increasing .delta. and finding the value of .delta. for collision-free path, the shortest path can be searched without carring out whole GM. The GM of obstacles expersses all possible collision-free path as empty spaces in CPS. If there is no empty space available in CPS, it indicates that path planning is not possible with given number of connection points, i.e. path planning is failed, and it is necessary to increase the number of connection point. A general case collision-free path planning is possible by appling GM to configuration space obstacles. Simulation of GM of obstacles in Euclidian space is carried out to measure performance of algorithm and the resulting obstacle images are reported.
Free vibration analysis of double split beams
Han, B.K ; Lee, S.H ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2008~2018
DOI : 10.22634/KSME-A.19220.127.116.118
In this study, free vibration analysis of double through-the-width split beam is studied based on the author's earlier work. Each segment which constructs double through-the-width split beam is considered as Timoshenko beam. The effect of coupling between longitudinal and transverse vibration on the natural frequencies of split beams is considered. Data acquisition and modal test of double split beam for clamped-free boundary condition are carried out. Experimental and numerical results obtained by ANSYS were compared with the calculated data by present theory and their comparisons give good agreement with one another. The influences of the size and location of double split, shear deformation, and boundary conditions on the natural frequencies are demonstrated for illustrative purpose. Effects of double split on the dynamic characteristics of beams can be used to detect the size and the location of damages in structures.
Investigation of rolling resistance and surface damage of rolling elements
Cha, Kum-Hwan ; Kim, Dae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2019~2028
DOI : 10.22634/KSME-A.1918.104.22.1689
It has been well established that resistant force and wear that occur during rolling motion depend on several factors such as material type, hardness, subsurface microstructure, applied load, and speed. The purpose of this work is to investigate the effect of microstructure and the state of deformed layer on the rolling contact characteristics in dry and lubricated rolling contacts. The results of this work show that the rolling resistance behavior depends on the state of the deformed layer. Also, lubrication can reduce the plastic flow at the surface but may still have an effect on the subsurface strain. The cross-sectional view of the microstructure shows that surface traction has a difinite effect on the morphology of the surface region. That is, significant slip seems to have taken place between the ball than those of the dry rolling case. The surface generation effects were significantly less compared to the case of dry rolling contact.
A nonlinear PID control of winding tension using contact roll
Shin, K.H ; Kim, K.T ; Cheon, S.M ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2029~2037
DOI : 10.22634/KSME-A.1922.214.171.1249
In a web winding process, the contact roll plays many important roles including air-entrainment control and WIT(Wound In Tension) regulation. The behavior of contact roll significantly affects the winding tension characteristics specifically at the time of contact when the speeds of contact roll and the winding roll are not synchronized. A mathematical model for the web, the winding roll, and the contact roll is derived. By using the model derived, a nonlinear PID(NPID) controller is designed to control the winding tension at the time of contact and separation between the contact roll and the winding roll. Computer simulation study showed that the performance of the winding system with the NPID controller significantly improved compared with that of a system with PID controller.
Instability caused by interaction between a rotating disk and a mass-spring-damper system
Kim, C.B ; Han, D.H ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2038~2046
DOI : 10.22634/KSME-A.19126.96.36.1998
In this paper the instability of the system which has a disk and a mass-spring-damper system interacting through a medium having stiffness and damping is analyzed. To solve the equations of motion of this systme, it is assumed that the solution consists of the eigenfunctions which are the products of the Bessel functions and sine or cosine functions. The former represents the radial characteristics of the disk and the latter represents the circumferential characteristics. Using this assumed solution and the orthogonality of the eigenfunctions, the equations of motion can be transformed into a set of equations of motion with variables dependent only on the time. After this set is changed to the state equation, the eigenvalue problem can be made. Once the eigenvalues are calculated according to the angular velocity of the disk, the dynamic characteristics ofthis system is obtained. Because the thickness of the disk and the element characteristics of the mass-spring-damper system have important effects on the stability of the system, it will be understood how these factors affect the system and then a method to ameliorate the stability of the system with a disk will be presented.
Development of electronic shearography for vibration analysis
Kang, Young-June ; Kwon, Yong-Ki ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2047~2054
DOI : 10.22634/KSME-A.19188.8.131.527
This paper describes a measuring method of vibration mode shapes by the Electronic Shearography. This method called the speckle interferometer has many merits in practical use, such as low sensitivity to environmental noise, low limit of coherent-length and simple optical configuration. In this study, we developed Michelson-type shearing interferometer provided with a phase stepping mirror and with a bias modulation mirror to quantify the vibration gradient fields. Results of application to a simple cantilever plate show that the vibration amplitude fields obtained are in good agreement with those of the electronic speckle pattern interferometry (ESPI).
Three dimensional multi-step inverse analysis for optimum design of initial blank in sheet metal forming
Lee, Choong-Ho ; Huh, Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2055~2067
DOI : 10.22634/KSME-A.19184.108.40.2065
Values of process parameters in sheet metal forming can be estimated by various one-step inverse methods. One-step inverse methods based on deformation theory, however, cause some amount of error. The amount of error is generally increased as the deformation path becomes more complex. As a remedy, a new three dimensional multi-step inverse method is introduced for optimum design of blank shapes and strain distributions from desired final shapes. The approach extends a one-step inverse method to a multi-step inverse method in order to reduce the amount of error. The algorithm developed is applied to square cup drawing to confirm its validity by demonstrating reasonably accurate numerical results. Rapid calculation with this algorithm enables easy determination of an initial blank of sheet metal forming.
development of an ear-muff with active noise control for selective noise attenuation
Kim, Dong-Gyun ; Kim, Ok-Hyeon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2068~2072
DOI : 10.22634/KSME-A.19220.127.116.118
Acoustic noise has become an increasingly important issue, especially in the industrial environment. Nowadays home and office are not exceptional, mainly due to the increase in the usage of machinery. Active Noise Control(ANC) becomes efficiently an available tool for the noise suppression with rapid advances of solid state electronics. In this study an ANC system is developed for audio headphone to work as a noise protector, so called an ear-muff. The system is developed to kill a certain frequency band noises selectively which is purposed to suppress only the dominant ambient noise such that normal numan conversation is not disturbed with wearing the ear-muff. For the purpose, an ANC design strategy is suggested and implemented with an analogue control circuit. The performance is evaluated by frequency response test, which shows well consistence with theoretical one. The results are so satisfactory that noise of 640 Hz, which is aimed to suppress, is reduced by 20db without significant distortion in other frequency band.
Optimization of the tool geometry of PSST using taguchi's orthogonal matrix
Kim, Yeong-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2073~2080
DOI : 10.22634/KSME-A.1918.104.22.1683
Recently, the plane strain puch stretching test(called PSST) has been developed and used successfully in the evaluation of the press formability of automotive steel sheets. In this paper, the optimum punch geometry of the original PSST tool was investigated by the FEM analysis. The puch length, crown and corner radius are chosen to be optimized according to the Taguchi's experiment technique with the
Control of throttle actuator system based on time delay control
Song, Jae-Bok ; Byeon, Kyeong-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2081~2089
DOI : 10.22634/KSME-A.1922.214.171.1241
Accurate positioning of the throttle valve of a gasoline engine is required to implement various systems such as traction control system(TCS), cruise control system and drive-by-wire system. In this research, position control system has been developed for the throttle actuator system that uses one throttle actuation for small volume and DC servo motor for fast response. In order to drive the DC motor, PWM signal generator and PWM amplifier were built and interfaced to the motor and controller. Also, time delay control(TDC) law has been used as a basic control algorithm. A method of varying the reference model of the TDC according to the size of change in target throttle angle is proposed here. The simulation and experimental results show that both overshoot prevention and fast response are achieved by the TDC technique with this variable reference model.
Fracture toughnesses of thin sheet materials by using CT specimens
Lee, Eok-Seop ; Lee, Yun-Pyo ; Gang, In-Mo ; Kim, Seon-Yong ; Kim, Seung-Gwon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2090~2095
DOI : 10.22634/KSME-A.19126.96.36.1990
The plane stress fracture toughness for thin aluminum alloy(2024-T3 and 7075-T6) specimens are characterized by using compact-tension (CT) specimens. Anti-buckling plates were fabricated on both sides of the thin CT specimens to prevent the buckling phenomena which caused by the 45.deg. C plastic yielding at the crack tip under the plane stress condition. The plane stress fracture toughnesses determined by three different procedures are compared with each others. The plane stress fracture toughnesses are also compared with a few published values which were determined by using center-cracked panel specimens.
Finite element analysis of strip rolling process using distributive parallel algorithm
Gwon, Kie-Chan ; Youn, Sung-Kie ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2096~2105
DOI : 10.22634/KSME-A.19188.8.131.526
A parallel approach using a network of engineering workstations is presented for the efficient computation in the elastoplastic analysis of strip rolling process. The domain decomposition method coupled with the frontal solver for elimination of internal degrees of freedom in each subdomain is used. PVM is used for message passing and synchronization between processors. A 2-D plane strain problem and the strip rolling process are analyzed to demonstrate the performance of the algorithm and factors that have a great effect on efficiency are discussed. In spite of much communication time on the network the result illustrates the advantages of this parallel algorithm over its corresponding sequential algorithm.
Lateral vibration characteristics of a rotor system supported by hydrodynamic journal bearings considering the effect of a bearing width
Han, Dong-Chul ; Choi, Sang-Hyun ; Kim, Woo-Jeong ; Cho, Myung-Rae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2106~2113
DOI : 10.22634/KSME-A.19184.108.40.2066
This paper presents the characteristics of lateral vibrations of rotor system supported by hydrodynamic journal bearings. Finite element model is developed for the dynamic analysis of rotor system. Hydrodynamic bearings are modeled with the distributed springs and dampers in shape of the 2nd order polynomials in the direction of bearing width. Experiments are conducted to measure the natural frequency, and experimental results are compared with the theoretical results that are calculated using the point model and distributed model. Theoretical results using the distributed model agrees better with the measured results as bearing width increases. Also, this method is applied to actual three-stage turbo blower model. Then, critical speed and forced vibration analysis are performed.
machining of sculptured surfaces using partition machining method
Lee, Tae-Whi ; Lee, Sang-Joe ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2114~2120
DOI : 10.22634/KSME-A.19220.127.116.114
This paper presents precision machining of sculptured surfaces with a flat end cutter as follows; tool path generation using partition machining method and elimination interference. These days many researchers are getting interested in flat end cutter having a good cutting performance as machine tool for machining sculptured surfaces. It can get low curvature surfaces and have a much better material removal rates and longer tool life. Partition machining method is the first submitted in this paper. It is a new method of tool path generation, which means the way to map surfaces under the normal vector and then to cut them partially.
Finite element analysis for 3-D self-contact problems of C.v.joint rubber boots
Lee, Hyeong-Uk ; Kim, Se-Ho ; Lee, Chung-Ho ; Huh, Hun ; Lee, Jong-Hwa ; Oh, Seung-Tak ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2121~2133
DOI : 10.22634/KSME-A.1918.104.22.1681
A finite element code is developed for 3-D self-contact problems, using continuum elements with a SRI(Selective Reduced Integration) scheme to prevent locking phenomenon by the incompressibility of rubber. Contact treatment is carried out in two ways : using the displacement constraints in case of rigid contact ; and imposing the same contact forces on two contact boundaries in case of self-contact. The finite element code developed is applied to the deformation analysis of C.V.joint boots which maintain lubrication conditions and protect the C.V.joint assembly from impact and dust. The boot accompanies large rotation depending on the rotation of the wheel axis and leading to the self-contact phenomena of the boot bellows. Since this contact phenomenon causes wear of the product and has great influence on the endurance life of the product, it is indispensable to carry out stress analysis of the rubber boots. In case of self-contact, various methods for determining contact forces have been suggested with an appropriate contact formulation. Especially, the types of penetration in self-contact are modularized to accelerate conputation with a contact algorithm.
Development of Intelligent Design System for Embodiment Design of Machine Tools(I)
Cha, Joo-Heon ; Park, Myon-Woong ; Park, Ji-Hyung ; Kim, Jong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2134~2145
DOI : 10.22634/KSME-A.1922.214.171.1244
We present a framework of an intelligent design system for embodiment design of machine tools which can support efficiently and systematically the machine design by utilizing design knowledge such as objects(part), know-how, public, evaluation, and procedures. The design knowledge of machining center has been accumulated through interview with design experts of machine tool companies. The processes of embodiment design of machining center are established and represented by the IDEF0 model from the field surveys. We also introduce a hybrid knowledge representation so that the system can easily deal with various and complicated design knowledge. The intelligent design system is being developed on the basis of object-oriented programming, and all parts of a design object, machining center, are also classified by the object-oriented modeling.
Kinematic analysis of the wire parallel mechanism for robot pose measurement
Jeong, Jae-Won ; Kim, Soo-Hyun ; Kwak, Yoon-Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2146~2155
DOI : 10.22634/KSME-A.19126.96.36.1996
This paper presents the Wire Parallel Mechanism for robot pose measurement which can be used to robot calibration. It is constructed with six parallel links using wire. The position and orientation of the end effector of a robot are calculated from the wire length that measured by the encoder. The unique solution is obtained from a Newton-Raphson method and geometric configuration of the mechanism, also the method to estimate a measuring space is presented. Through the simulations, it is verified that the proposed mechanism can measure a robot pose, and has a large measuring space. In conclusion, it can be used effectively in a robot pose measurement with little cost and effort.
Dynamic analysis of constrained multibody systems using Kane's method
Park, Jeong-Hun ; Yu, Hong-Hui ; Hwang, Yo-Ha ; Bae, Dae-Seong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2156~2164
DOI : 10.22634/KSME-A.19188.8.131.526
A new formulation for the dynamic analysis of constrained multibody systems is presented in this paper. The formulation employs Kane's method along with the null space method. Kane's method reduces the dimension of equations of motion by using partial velocity matrix introduced in this study : it can improve the efficiency of the formulation. Three numerical examples are given to demonstrate the accuracy and efficiency of the formulation.
Development of new fracture parameter for rigid inclusion with crack shape in creep material
Lee, Kang-Yong ; Kim, Jong-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2165~2171
DOI : 10.22634/KSME-A.19184.108.40.2065
The analysis model is the infinite power law creep material containing the rigid inclusion with crack shape. The present analysis is performed using the complex pseudo-stress function method. The strain rate intensity factor is developed as new fracture mechanics parameter which represents the stress and strain rate distribution near a crack tip in power law creep material. The strain rate intensity factor is developed in terms of Kolosoff stress functions.
Development of diamond wheel for ultra precision and high performance grinding of difficult-to-materials
Heo, Seong-Jung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2172~2178
DOI : 10.22634/KSME-A.19220.127.116.112
Development of diamond wheel with fine grains and multi-pore structures were newely attempted. Wheels, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, must have both performances to remove tool marks efficiently and to contact elastically with curved surfaces. Diamond grains were bonded firmly by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures were developed to increase the flexibility of the wheel, and to induce active self-sharpening by increasing contact pressure between the wheel and work surfaces. In this paper, melamine-bonded diamond wheels are trial manufactured, then the forming method of wheels are suggested, and the grinding characteristics of wheels are also illustrated.
Control of Semi-active Suspensions for Passenger Cars(I)
Jo, Yeong-Wan ; Lee, Gyeong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2179~2186
DOI : 10.22634/KSME-A.1918.104.22.1689
In this paper, the performance of a semi-active suspension system for a passenger car has been investigated. Alternative semi-active suspensions control laws has been compared via simulations. The control laws investigated in this study are : sprung mass velocity feedback control law, sky-hook damping control law, and state feedback control law. Simulation results show that a semi-active suspension has potential to improve ride quality of automobiles.
Control of Semi-active Suspensions for Passenger Cars(II)
Jo, Yeong-Wan ; Lee, Gyeong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2187~2195
DOI : 10.22634/KSME-A.1922.214.171.1247
A semi-active suspension test system was designed and built for the experimental study. Vehicle parameters were estimated through tests and a quarter-car model was validated by comparing computer simulation results and laboratory test results. Alternative semi-active suspension control laws have been tested using the test system. Modulable damper used in this study is a "reverse" damper with 42 states which is controlled by a stepper motor. Experimental results have shown that semi-active suspensions have potential to improve ride quality of automobiles.tomobiles.
Magnetically levitated transport system for a controller-free carrier
Son, Yeong-Uk ; Park, Gi-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2196~2208
DOI : 10.22634/KSME-A.19126.96.36.1996
In this work, a magnetic levitation (maglev) system is developed to transport a wafer between semiconductor fabrication process modules in clean rooms to take advantages of eliminating particle and oil contamination that normally exist in conventional transport systems due to contact motion of mechanical components. A main feature of the maglev system developed in this work is that a controller and power supplying part are not mounted on the moving carrier but on the stationary track, which is defined a controller-free carrier, to reduce carrier's weight. Iron-core electromagnets and irons are used for levitation, and air-core electromagnets and permanent magnets are used for stabilization. Analysis, design, and modeling of the magnetically levitated transport system are presented. The performance of the maglev system is experimentally demonstrated.
High strain rate tensile test of sheet metals with a new tension split hopkinson bar
Kang, Woo-Jong ; Cho, Sang-Soon ; Huh, Hoon ; Jung, Dong-Taek ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 12, 1997, Pages 2209~2219
DOI : 10.22634/KSME-A.19188.8.131.529
A split hopkinson bar could be used for obtaining the high strain rate material properties of sheet metals for an autobody. In high speed tensile tests of sheet matals, a new design of a tension split Hopkinson bar apparatus is needed. The design of grips and an anvil length are numerically analyzed with ABAQUS/Explicit for the new apparatus of split Hopkinson bars. From the experiments with the new apparatus, the material properties of SPCEN in the high strain rate state have been acquired and compared with quasi-static experimental results. The material properties of SPCEN as well as other sheet metals in an autobody are indispensible for the analysis of crashworthness. Nevertheless the experiment of sheet metal in the high strain rate state has not been done or reported.