• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1389-1394
• /
• 2010

This paper describes the evaluation of structural integrity and dynamic characteristic of inertial load test equipments for performance test of railway vehicle propulsion control system. The propulsion control system of railway vehicle has to be confirmed of safety and reliability prior to it's application. Therefore, inertial load test equipments were designed through theoretical equation for performance test of propulsion control system. The structural analysis of inertial load test equipments was conducted using Ansys v11.0 and it's dynamic characteristic was evaluated the designed using Adams. The results showed that the structural integrity of inertial load test equipment was satisfied with a safety factor of 10.2. Also, the structural stability was proved by maximum dynamic displacement of 0.82mm.

• Journal of the Korean Society for Railway
• /
• v.13 no.4
• /
• pp.363-370
• /
• 2010

This paper describes the evaluation of structural integrity and dynamic characteristic of inertial load test equipments for performance test of railway vehicle propulsion control system. The propulsion control system of railway vehicle has to be confirmed of safety and reliability prior to its application. Therefore, inertial load test equipments were designed through theoretical equation for performance test of propulsion control system. The structural analysis of inertial load test equipments was conducted using Ansys v11.0 and the dynamic characteristic was evaluated using Adams. The results showed that the structural integrity of inertial load test equipment was satisfied with a safety factor of 10.2 on the bearing part under combined load. Also, the structural stability of flywheel according to dynamic simulation was secured by the maximum oscillation displacement within 0.83mm.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.8 no.2
• /
• pp.119-126
• /
• 1984

An analysis is presented for the vibration and stability of Beck's column carring a tip mass at its free and subjected there to a follower compressive force by using variational approach. The influence of transverse shear deformation and rotatory inertial of the mass of the column upon the critical flutter load and frequency is considered, and Timoshenko's shear coefficient K' is calculated by Cowper's formulae. It is, moreover, worth noticing that the influence of inertial moment of tip mass upon the flutter load and frequency is investigated. The centroid of a tip mass is offset from the free end of the beam and located along its extended axis of the two cases, one of which has a tip mass increasing as .xi., the tip mass offset parameter, is augmented, the other has a tip mass constant but the inertial moment is variable according to a magnitude of .eta., the tip mass offset parament. This study reveals that the effects of inertial moment of a tip mass and larger value of P are specially remarkable even a tip mass is a same.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.25 no.1
• /
• pp.9-22
• /
• 2022

A fighter performing a reconnaissance mission is equipped with a pod that drives optical/infrared sensors for acquiring and identifying target information on the lower part of the fuselage. Due to the nature of the reconnaissance mission, the fighter performs high speed evasive maneuvers, and the resulting load should be considered importantly for the development of the pod. This paper concerns a numerical investigation into the inertial and aerodynamic loads of the airborne pod of high performance aircrafts. For the aerodynamic load analysis, the pylon and pod shapes are added to the fighter 3D model, and the commercial software was used for static and dynamic analysis. Considering the practical mission conditions, the common/extreme conditions were established respectively in the static and dynamic situations of pods and the driving torque could be tripled under dynamic conditions. In the analysis of inertia load, a 3-DOF model considering roll and turning maneuvers was derived by the Lagrangian method, and then the numerical integration method was applied to the analysis. As a results, it was conformed that the inertia load was generally induced at a low level compared to the aerodynamic load, but depending on the unbalance mass condition of the pod, the inertia load cannot be negligible.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.12
• /
• pp.1395-1401
• /
• 2014

In an effort to develop and implement an inertial balance with high performance, the response characteristics of a load cell, which are some of the critical parameters for optimal system design, were evaluated using a sample object of approximately 100 g under microgravity conditions. To this end, a 15-m drop-tower was used to produce microgravity conditions, and the response characteristics of the load cell were investigated in terms of the variations in the magnitude of the deceleration of the sample object, noting that the mass of a living animal should be determined in microgravity. An analysis of the ratio of the inertial forces clearly demonstrated that the average velocity of a load cell plate should be higher than 0.5 m/s to meet the design requirements.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.6
• /
• pp.529-535
• /
• 2016

This study focuses on the comparison of measured data from 6-DOF motion sensor and strain gauge installed in the IBRV ARAON during 2015 summer voyage in the Arctic. Procedures to calculate the global ice load from MotionPak II inertial measurement system and the local load from stain gauge system are discussed. The ship's speed and peak load are determined in the concept of an ice collision "event". It is found that the peak values in the global ice calculated form whole ship motion analysis fall in the range of 1.5~3 times of the local ice load based in strain gauge measurement.

• International Journal of Precision Engineering and Manufacturing
• /
• v.9 no.3
• /
• pp.46-50
• /
• 2008

The present status and future prospects of the levitation mass method (LMM), a technique for precision mass and force measurement, are reviewed. In the LMM, the inertial force of a mass levitated using a pneumatic linear bearing is used as the reference force applied to the objects being tested, such as force transducers, materials, or structures. The inertial force of the levitated mass is measured using an optical interferometer. We have modified this technique for dynamic force calibration of impact, oscillation, and step loads. We have also applied the LMM to material testing, providing methods for evaluating material viscoelasticity under an oscillating or impact load, evaluating material friction, evaluating the biomechanics of a human hand, and generating and measuring micro-Newton-level forces.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2015.09a
• /
• pp.63-68
• /
• 2015

This paper presents fatigue analysis of helideck structures located in FPSO. After FPSO is moved to the target position where production of resource is performed, FPSO stays at the target position and performs production of resource, storage and off-loading during the design life. Helideck structure is located in FPSO essentially for the movement of personnel and life rescue at emergency situations by using helicopters. Because inertial load induced by FPSO motion and landing and taking-off load of helicopter occur at helideck structures cyclically, helideck structures should be designed to withstand fatigue loads. Therefore, The fatigue assessment of helideck structures should be performed with fatigue loads. Effect of stress concentration due to misalignment between welded plates is considered in fatigue assessment additionally.

• Structural Engineering and Mechanics
• /
• v.82 no.3
• /
• pp.283-294
• /
• 2022

An inerter is a passive mechanical element whose inertance can be thousands of times its own physical mass. This paper discusses the application of an inerter-based passive control system, termed rotational inertial double-tuned mass damper (RIDTMD), to mitigate human-induced floor vibrations. First, the acceleration frequency response function of the floor with an RIDTMD is first derived. It is then employed to determine the optimal design parameters of the RIDTMD using the extended fixed-points technique. Based on a theoretical analysis, design-oriented empirical functions are proposed for the RIDTMD optimal parameters, whose performance for floor vibration control is evaluated by numerical examples, in which three typical human-induced load types are considered: walking, jumping, and bouncing. The results indicate that the applicability and effectiveness of the RIDTMD for human-induced floor vibration control are robust for various load types, load frequencies, and floor natural frequencies. For the same mass ratio, the RIDTMD is better than the TMD in reducing the floor vibration amplitude and improving the effective frequency suppression bandwidth, and for the same vibration suppression effect, the mass of the RIDTMD is much lighter than that of the TMD.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.8 no.3
• /
• pp.17-26
• /
• 2004

In this paper, power transmission systems converts the shaft power of a Turbo-shaft Engine with Free Power Turbine into the generator power and be composed of a method being supplied in the thrust motor driving a propellers. Being used this, Gas turbine engine works to flat rating about 110 kw (147 shp) that the thrust motor be extremely supplied from the engine of 317shp. In this test equipment, the engine is installed with the flywheel being able to the damping function when happen to the varying load between gas turbine engine output-shaft and generator. Then if the flywheel of inertial moment be not considered, the generator and motor not get the required power from the engine for raising the load. Also it is certified that the engine works the abnormal operation. Hence the flywheel of inertial moment is determined the required range to do the performance analysis with the dynamic transient from the given and tested engine data. This system is able to get the required power after a mounting test with the redesigned flywheel.