• 한국군사과학기술학회지
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• 제21권3호
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• pp.342-348
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• 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.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.70-78
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• 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.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1108-1114
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• 2006

Underwater acoustic transducers can be exposed to a underwater explosive shock caused by various types of underwater weapon. So, a robust anti-shock design is required for transducers to endure the underwater explosive shock. To check the anti-shock characteristics of a transducer, underwater explosive shock test is needed. The conditions of underwater explosive shock test are set up referring to various oversea explosive shock test specifications, and the explosive shock pressure values are calculated according to those conditions. Transient analyses art: carried out for two kinds of underwater acoustic transducer model to verify the anti-shock characteristics. The applied model has robust anti-shock characteristics enough to endure the explosive shock up to 2300 psi. In the future, the transducer design should be certified through the fields test, and modified if needed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.940-944
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• 2001

Shock environments are generally classified two categories; One is mechanical shock environments encountered in handling, transportation, and service environments. The other is pyrotechnic shock (or pyroshock) environments generally initiated by firing of an ordnance item to separate or release a structural member of fastener. The objective of this paper is to present a set of shock test methods - specific characteristics induced by many shock test devices, test objects properties, and shock environments. In addition, it is introduced the application of shock test in Korean aerospace development program and others with shock test facilities of Korea Aerospace Research Institute.

• 한국정밀공학회지
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• 제33권10호
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• pp.805-811
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• 2016

Prior to installation in a navy ship, shipboard equipment should be qualified by shock test requirements. The multi-function console mounted on the elastic platform of the ship should also withstand given shock loads. In this study, both real shock test methods, as well as numerical computer simulations using the finite element method were used to verify structural durability under shock load conditions. First, we used domestic test facilities to perform possible shock tests, including an impact hammer test, a drop table test and a shaker shock test. Full model tests satisfying the shock response spectrum level were performed. Thereafter, an analytical model of the complex console structure was built by the finite element method. Finally, numerical results were verified by modal test results of the real product and an FEA analysis was also performed with a full model transient response analysis.

• 대한조선학회논문집
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• 제40권4호
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• pp.66-74
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• 2003

In non-contact underwater explosion shock test of a real naval ship, measurement of shock loadings and responses should require onboard system to be able to safely trigger an explosive and to simultaneously and successfully measure scores of shock signals in the deteriorated environment. For this purpose, we have developed a shock-hardened measurement system resistible to 170g peak acceleration having 4 msec duration by resiliently mounting general purpose measurement instruments in racks. The system can simultaneously measure and record 200 signals to evaluate shock leadings and responses of the test ship by triggering an explosive and measurement instruments at the same time. We prove the performance of the developed system by introducing the signal acquisition results from of a real ship underwater shock test, firstly performed in Korea.

• Journal of Biosystems Engineering
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• 제35권5호
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• pp.323-329
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• 2010

Physical damages on fruits may be caused by shock and vibration inputs that transmitted from the transporting vehicle through the packaging and cushioning materials to the fruit. In this study, both half sine shock test and trapezoidal shock test were performed by MIL-STD-810F specification in order to investigate and represent the shock response properties such as peak acceleration and shock amplification factors of the pear according to packaging and cushioning materials for optimal packaging design during transportation. Shock excitation data that had been measured on the vehicle operating on the real road were used. Shock response properties measured by half sine shock test were smaller than those measured by trapezoidal shock test. Results represent that corrugation shapes and thickness can significantly affect the cushioning performance than the paper configurations of cushioning pad and showed that fruits may be damaged seriously while transported on the unpaved road without the properly cushioned packaging practices.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2583-2588
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• 2009

본 논문에서는 반정현파 형태의 충격을 받는 HDD에 대한 충격해석을 수행하고, 그 타당성을 실험적으로 검증하였다. 일반적으로 센서를 이용한 제품의 충격실험을 통해서는 제한적인 정보만을 얻을 수 있지만, 컴퓨터를 이용한 해석기술은 제품의 파손현상을 규명하는데 필요한 보다 광범위하고 상세한 정보를 제공할 수 있는 장점을 가진다. 하지만, 이러한 해석결과는 여러 요인들에 따라 매우 민감하기 때문에 그 타당성을 검증하는 것이 중요하다. 따라서 본 연구에서는 200G/1ms의 전자기 충격실험과 300G/2ms의 낙하충격실험을 통하여 HDD의 조립단계별로 LS-DYNA를 이용한 유한요소해석의 신뢰성을 검증하였다.

• 한국세라믹학회지
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• 제49권4호
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• pp.385-396
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• 2012

Thermal shock test methods and thermal shock parameters for ceramics were reviewed from the following viewpoints: (1) The test methods should be based on the precise estimation of both temperature and thermal stress distributions in a specimen taking into account the temperature-dependent thermo-mechanical properties; (2) The thermal shock parameters must be defined as a physical property of the materials and described as a function of temperature at the fracture point of the specimen; (3) The relation between the strength and fracture toughness of brittle ceramics under a thermal shock load must be the same as the relation under a mechanical load. In addition, appropriate thermal shock parameters should be defined by the thermal shock strength and thermal shock fracture toughness based on stress and energy criteria, respectively. A constant heat flux method is introduced as a testing technique suitable for estimating these thermal shock parameters directly from the electric power charged.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.588-593
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• 2012

Nowadays, various forms of electro-optical rifle scope have been developed and used in order to enhance the accuracy of small arms. However, firing shock acceleration has characteristics of pyroshock having a big acceleration value with very short duration time, which the electro-optical scopes should be designed to sustain. In this paper, the firing shock acceleration, which is transmitted to the electro-optical scope, was measured and SRS (Shock Response Spectrum) analysis was performed by using the measured firing shock acceleration. Furthermore, a shock test condition using a drop-table shock tester, which can simulate the actual firing shock acceleration, was devised. The devised shock test condition will be utilized to test the electro-optical scope itself before attaching it to the small arms.