• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.1
• /
• pp.70-78
• /
• 2021

Naval surface ships and submarines could be exposed to non-contact underwater explosion(UNDEX) environment. Equipment installed on the ships and submarines could be damaged by shock load generated by UNDEX environment. Therefore, shock survivability of equipment generally evaluated by shock tests. Ground based shock test machine such as Light weight shock test machine(LVSM) is developed to simulate shock load caused by UNDEX environment. In this study, linear dynamic model of LVSM is proposed and evaluated to improve shock test design procedure. Parameters of the model are decided by optimizing time domain response compared to zero payload experiment. Proposed model is verified by comparing simulation results and test results of maximum payload experiment. Finally, shock test design using the model is described for various test equipment weight.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.3
• /
• pp.342-348
• /
• 2018

The important issue of equipment installed in maritime weapon system is shock survivability against underwater explosion(UNDEX). If the shock survivability of equipment should not be guaranteed, the successful mission also could not be achieved. For that reason, the shock-resistance of each equipment under UNDEX environment should be demonstrated before deployment at combat field. However, the actual UNDEX test on the ocean is too expensive to conduct. Also, it has diverse dangerous factors. The main characteristic of UNDEX is a dual-pulse shock. The vertical shock test machine able to simulate dual pulse shock signal on the ground will be introduced in this paper. The dual-pulse shock signal presented in certain shock standard was achieved with this shock-test machine on the ground. The analytical procedure to set a test condition was verified by comparing simulation result with experiment result.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1149-1153
• /
• 2000

All critical equipment installed aboard naval ships and submarines is required to be shock-qualified by tests on the MIL-S-901 shock test machines where testing is practical. The intent of the shock requirements is to produce combat vessels which are resistant to the underwater explosion weapon attack. To efficiently design equipment for passing a series of shock tests, the shock environment of the shock test machine should be clearly identified. In this paper, the shock characteristics of the MIL-S-901 Medium Weight Shock Machine(MWSM) are reviewed, based on the existing test data. An analytical model for the MWSM is also discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.750-754
• /
• 2001

All critical equipment installed aboard naval ships and submarines is required to be shock-qualified by tests on the MIL-S-901D shock test machines where testing is practical. The intent of the shock requirements is to produce combat vessels which are resistant to the underwater explosion weapon attack. To efficiently design equipment for passing a series of shock tests, the shock environment of the shock test machines should be clearly identified. In this paper, the shock characteristics of the MIL-S-901D Light Weight Shock Machine(LWSM) are reviewed, based on the existing test data.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.6
• /
• pp.663-668
• /
• 2014

Mechanical and electrical devices in various forms are used in many different fields. These can be exposed to external environmental factors such as shock. Therefore, a shock test machine is commonly used to test these devices and evaluate their shock resistance. In this test, the break-down or permanent deformation and malfunction of inner parts due to a high stress or acceleration can be evaluated. As part of a shock test machine, a velocity generator is needed to create shocks between objects. In this study, a hydraulic velocity generator was conceptually designed and an AMESim model was developed to simulate the velocity under different conditions. Simulation results using this model were compared with the test results from a reduced-size velocity generator, and we designed a velocity generator that fits the target payload and velocity using the simulation results.

• Journal of the Korean Society of Safety
• /
• v.26 no.5
• /
• pp.13-16
• /
• 2011

The vibration and shock of the opto-electronic protective device was induced mechanical failure or fail to work correctly. In order to identify the exciting frequency components of vibration and shock, vibration signals are measured and analyzed from the mechanical power press. In addition, the modal test for the opto-electronic protective device was performed to investigate the dynamic characteristics. Some FEM simulations were carried out and then anti vibration mount was made for opto-electronic protective device. Based on the results of simulations, some kind of rubber mounts were tested to demonstrate the reduction of vibration and shock. It was verified by the test that a considerable amount of vibration and shock were reduced.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.6 no.1
• /
• pp.37-40
• /
• 2000

This study was carried out to investigate dropping shock of household electric appliances during materials handling. Microwave oven($18{\ell}$), TV(16") and washing machine(6.2kg) were singled out as the study items. From the results of dropping test by KS A 1026(General Rules of Performance Testing for Packaged Freights), relative equations were gained as follow : y=0.0863x+10.032 for microwave oven, y=0.136x+7.85 for TV and y=0.214x+5.8 for washing machine (where y is G-factor and x is Dropping height). The maximum values of dropping shock during materials handling were measured to be $11{\sim}14G$ for microwave oven, $12{\sim}15G$ for TV and $10{\sim}12G$ for washing machine. The maximum shocks of microwave oven, TV and washing machine during materials handling were corresponding to dropping shocks of dropping height 45.98cm, 52.57cm and 28.97cm by KS A 1026.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1154-1160
• /
• 2000

This paper reports the development of a special impact fatigue test machine for high pressure vessels. The targeted vessels are subjected to shock pressures equivalent of explosions. This severe loading condition brings many difficulties to the design of test machine. Unfortunately, there are very rare such test machine in the world, and more worse, the machine is not opened and sold.

• Journal of Applied Reliability
• /
• v.15 no.1
• /
• pp.60-66
• /
• 2015

In this paper, The infrastructure case for reproduction or analysis of the mechanism on the fire or the electrics shock of the electrical appliances is proposed. The various electrical appliances(Washing machine, Ballast, Electric heaters, Electronic switches, Mobile phone chargers) used in the home can be tested on the high voltage and over current test through the implementation of the infrastructure. The electrical tests of fire and electric shock consists of the high voltage of maximum 5000 V and over current test of 3 steps(90 A, 60 A, 40 A) and noise test. The mechanism of the fire and the electric shock tests reproduced are analyzed through the monitoring system and the oscilloscope. The electronics manufacturers can prevent accidents through the tests of the electronics factor reproduced and the analysis of the infrastructure designed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.581-586
• /
• 2000

Explosively activated pyro-technic device is used to release exhausted rocket booster or payloads at prescribed times in the rocket's flight. It creates pyro-shock environment that rocket or payload components must survive. With the shock spectra acquired from flight data, laboratory test should be performed before flight to check whether all of component can sustain the shock environment. The pyro-shock environment simulation was created by the resonance fixture response to a projectile impact. Desired shock spectra is realized by adjusting the natural frequency of resonance plate and the velocity of impact hammer. This paper describes the development process of Pyro-shock testing machine, which is designed and tested by Korean engineers, to verify components of Korean Sounding Rocket(KSR-3) and the other Korean space vehicle. Both analytical and experimental techniques are introduced in this paper.