• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1009-1014
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• 2007

To improve passenger safety, seatbelt systems with pre-tensioner that tightens seatbelt webbing using explosives just before collision are widely adopted. Even though seatbelt must not be unlatched without passenger's operation, release of a buckle due to explosion of pre-tensioner takes place in some situations resulting in serious injury to passengers. To prevent the unintended unlocking, a pendulum like part called anti-g mass is attached to the buckle to block displacement of release button. In this study, the unlocking conditions of anti-g buckle when pre-tensioner explodes has been theoretically investigated. Through multibody model of the seatbelt system incorporating every detailed part of the buckle, dynamic analysis of the seatbelt system with pre-tensioner has been performed including the driver's body model that interacts with seatbelt system. The simulations results has been validated through actual sled test with driver dummy and the seatbelt system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.141-149
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• 2005

This paper deals with formulations of the energy equilibrium equation by an introduction of the algebraic description, quarternion, which meets conservations of system energy for the equation of motion. Then the equation is discretized to analyze the dynamits analysis of flexible multibody systems in such a way that the work done by the constrained force completely is eliminated. Meanwhile, Rodrigues parameters we used to express the finite rotation lot the proposed method. This method lot the initial essential step to a guarantee of developments of the 3D dynamical problem provides unconditionally stable conditions for the nonlinear problems through the numerical examples.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.185-191
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• 2002

A window-based multibody dynamics program CADyna(Computer Aided Dynamics) is developed and applied for kinematic and dynamic analysis ova steering system. The program is composed oft pre-processor, a main processor, and a post-processor. The pre-processor is developed with Visual C7+ and the post-processor is developed with OpenGL and TeeChart. The main processor generates the equations of motion employing velocity transformation technique. The developed program is customized for the design of an intermediate shaft in a steering system.

• Journal of the Korean Society of Industry Convergence
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• v.11 no.2
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• pp.71-82
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• 2008

In this study, 3 dimensional non-linear race car vehicle model including Chassis, steering and suspension systems were modeled by using Multi-Body Dynamics Simulation Program, DADS 9.5(Dynamic Analysis and Design System),which was used in kinematic and dynamic analysis. A full race car vehicle dynamics model using DADS program was presented and analysis was carried out to estimate the handling characteristics that may be very useful to design a race car in early design stage. The simulation of vehicle handling behavior for step steering input was simulated and compared with different design parameters: torsional stiffness of the front and rear anti roll bars, the motion ratio of the front and rear suspension system, the location of the tie rod joint, in multibody dynamic model. Therefore this simulation model before race car construction in early design step will be helpful for race car designer to save time and limited budget.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.116-122
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• 2011

A realtime simulator using an explicit integration method is introduced to improve the solving performance for the dynamic analysis of a wheeled vehicle. Because a full vehicle system has many parts, the development of a numerical technique for multiple d.o.f. and ground contacts has been required to achieve a realtime dynamics analysis. This study proposes an efficient realtime solving technique that considers the wheeled vehicle dynamics behavior with full degrees of freedom and wheel contact with soft ground such as sand or undersea ground. A combat vehicle was developed to verify this method, and its dynamics results are compared with commercial programs using implicit integration methods. The combat vehicle consists of a chassis, double wishbone type front and rear suspension, and drive train. Some cases of vehicle dynamics analysis are carried out to verify the realtime ratio.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.585-592
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• 2014

In this study, a multibody simulator was developed to analyze the bio-mimetic motion of a lizard robot design. A RecurDyn multibody dynamics model of a lizard was created using a micro-computerized tomography scan and motion capture data. The bio-mimetic motion simulator consisted of a trajectory generator, an inverse kinematics module, and an inverse dynamics module, which were used for various walking motion analyses of the developed lizard model. The trajectory generation module produces spinal movements and gait trajectories based on the lizard's speed. Using the joint angle history from an inverse kinematic analysis, an inverse dynamic analysis can be carried out, and the required joint torques can be obtained for the lizard robot design. In order to investigate the effectiveness of the developed simulator, the required joint torques of the model were calculated using the simulator.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.5
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• pp.109-118
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• 1996

An analysis of handling characteristics of a vehicle is performed for step and pulse steering input, which may be very useful in suspension design stage. Many developed computer programs for vehicle dynamics require test data of compliance effects for proto type car. Therefore, these programs are not suitable for automobile development stage. Using the raw design data of suspension and steering system, we analyze the vehicle behavior for step and pulse steering input with commercial multibody dynamics program, ADAMS. Simulated results are in good agreement with vehicle test results. Vehicle handling characteristics parameters which are very useful in automobile suspension design are evaluated from the analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.686-689
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• 2005

A numerical simulation method is developed to analyze the dynamic response of a cantilever switch, which is driven by electrostatic force and a basic component of electro-mechanical coupled system. First, point-charges model on conductor is proposed as a lumped parameter of electrical part. Then, this model is easily incorporated into a multi-body dynamics analysis algorithm, the generalized recursive dynamics formula previously developed by our research group. The resulting motion of a coupled overall system is formulated as a differential algebraic equation form including electrical and mechanical variables together. The equation is simultaneously solved in every time step. To implement this approach into the useful dynamics analysis tool, we used multibody dynamics software (RecurDyn) based on the generalized recursive formula using relative coordinate. The developed numerical simulation tool is evaluated by applying to many different driving condition and switch configuration. The final analysis model will be added to RecurDyn as a basic module for dynamics analysis of electro-mechanical coupled system.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.421-429
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• 2010

In this paper, in order to analyze the dynamic response of a floating crane when it lifts a heavy cargo, the boom of the floating crane is considered as an elastic beam. The boom is divided into elements based on finite element formulation and the floating frame of reference formulation and nodal coordinates are employed to model the boom as a flexible body. As an extension of the previous study, in order to consider spatial motion in waves, the coupled equations of motions of the 6 degree of freedom (DOF) floating crane and 6 DOF cargo are developed based on the flexible multibody system dynamics. The 3 dimensional deformation of the elastic boom is considered with 18 DOF. The dynamic simulation of the floating crane and the cargo is performed under regular wave conditions with various cargo weights. Finally, the effects of the elastic boom on lifting cargo are discussed by comparing the simulation results between the elastic boom and a rigid boom.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.176-184
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• 2000

Recently, it becomes a very important issue to consider the mechanical systems such as high-speed vehicle and railway train moving on a flexible beam structure. Using general approach proposed in the first part of this paper, it tis possible to predict planar motion of constrained mechanical system and elastic structure with various kinds of foundation supporting condition. Combined differential-algebraic equations of motion derived from both multibody dynamics theory and Finite Element Method can be analyzed numerically using generalized coordinate partitioning algorithm. To verify the validity of this approach, results from simply supported elastic beam subjected to a moving load are compared with exact solution from a reference. Finally, parameter study is conducted for a moving vehicle model on a simply supported 3-span bridge.