• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.215-223
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• 2012

A violet smoke hand grenade(KM18) is used to generate signals. The grenade is considered to fail when its smoke emission time is longer than the specified one so that its smoke concentration becomes lighter. Accelerated degradation test for the grenade was performed, and then failure in smoke emission time was reproduced from the test. Stress for the degradation test was selected as temperature/humidity from the pre-test results. Degraded data of emission time from the accelerated test were analyzed through applying a distibution-based degradation model. Then, Peck Model was applied to predict the storage life under field conditions. In addition, the predicted storage life was compared with that of ASRP(Ammunition Stockpile Reliability Program).

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.735-749
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• 2023

Purpose: The purpose of this study is to derive solutions and prevent similar cases from occurring by analyzing the causes of cracks found in temperature cycling tests of rocket motor. Methods: By combining the results of the current state confirmation test, non-destructive test, domestic and foreign rocket motor comparison test, cutting test, and adhesion test according to the number of times to apply mold release agent, a Cause and Effect Diagram analysis was performed to derive the cause of cracks. Results: Through this study, 26 factors that could cause cracking in rocket motors during temperature cycling tests were identified. Through various additional test results, a total of five causes were identified, including chemical and structural design of the joint between the propellant and stress relief insert, omission of procedure in the manufacturing procedures, natural aging due to temperature, and load accumulation due to temperature changes. The fundamental cause was confirmed to be insufficient consideration of the release properties of the propellant and stress relief insert. Conclusion: During the design process, it was confirmed that this could be solved by structurally or chemically designing the insert so that it does not combine with the propellant, or by applying a mold release agent during the manufacturing process.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.888-896
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• 2011

A white smoke hand grenade, KM8 is used to make smoke screen in order to provide visual field interceptions or signals. The grenade fails when its time to emit smoke is longer than the specified emission time so that the smoke concentration becomes lighter. This paper considered failure in smoke emission time, and evaluated its storage lifetime. The main objective of this paper is to modify the present specification limits of smoke emission time for the efficient process control in manufacturing, through analyzing effect of its specification change on the storage lifetime, based on the lifetime evaluation results. Accelerated degradation test was performed and then failure in smoke emission time was reproduced from the test. And estimated storage lifetimes from the accelerated test results was compared to evaluated lifetimes of grenades using the ASRP data. Past process testing results of the grenade in manufacturing were analyzed in this paper. Then, each storage lifetime for the specifications, ${\pm}3$ and ${\pm}5$ in seconds, extended from the current specification in manufacturing were estimated using the past testing results, and compared to one another.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.300-307
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• 2020

This study examines the reliability evaluation concept and procedure of bulletproof materials (BRP: Bulletproof Reliability Program). ASRP, RAM analysis tasks were utilized for the study. Based on this analysis, the concept, method, performance system, and procedure of BRP were examined. The BRP task execution procedure consists of the following four steps. First, the business (evaluation) planning stage establishes the evaluation plan every year. Second, there is a testing stage that performs the general inspection, functional test, and operational test according to the established plan. Thirdly, there is an evaluation/analysis phase to synthesize/analyze the results and to judge the appropriate grade considering the performance of bulletproof materials. Finally, the follow-up step of each group according to the result. The following criteria are suggested for BRP implementation: BRP testing capability, development of BRP evaluation method, and recognition of the importance of BRP business.