This study aims to develop a regression model using data from the Ammunition Stockpile Reliability Program (ASRP) to predict the shelf life of 81mm mortar high-explosive shells. Ammunition is a single-use item that is discarded after use, and its quality is managed through sampling inspections. In particular, shelf life is closely related to the performance of the propellant. This research seeks to predict the shelf life of ammunition using a regression model. The experiment was conducted using 107 ASRP data points. The dependent variable was 'Storage Period', while the independent variables were 'Mean Ammunition Velocity,' 'Standard Deviation of Mean Ammunition Velocity,' and 'Stabilizer'. The explanatory power of the regression model was an R-squared value of 0.662. The results indicated that it takes approximately 55 years for the storage grade to change from A to C and about 62 years to change from C to D. The proposed model enhances the reliability of ammunition management, prevents unnecessary disposal, and contributes to the efficient use of defense resources. However, the model's explanatory power is somewhat limited due to the small dataset. Future research is expected to improve the model with additional data collection. Expanding the research to other types of ammunition may further aid in improving the military's ammunition management system.

This study identifies the possibility of alignment discrepancies during mortar firing when using inactive fuzes, which make it impossible to visually observe impact points. To address this issue, we studied a quality assurance method for Sight Alignment after firing. To establish a baseline, we analyzed the pre-firing Sight Alignment and the impact group status during firing for 00 mortars and 000 shells. Based on this analysis, we derived the alignment position information range after firing for 36 mortars, distinguishing between 68% and 95% confidence interval. Finally, considering data characteristics, inspection time requirements, and non-conforming data, we selected the Sight Alignment range after firing based on the 95% confidence interval. This study is expected to contribute to the development of quality assurance methods for munitions by serving as an example of quality assurance in the mass production stage of mortars.

In this paper, the cause of mortar baseplate breakage was analyzed by diving into cross-section, material, process, and design aspects. As a result of observing the fracture surface and non-fracture suface using optical equipment, it was possible to confirm changes in the shape of disconnected line and metal surface at a specific area. In addition, a number of linear defects due to overlap were found. Flow analysis was performed using the Deform program to verify changes during the production process. According to the result, a drop test was performed on each of the lap detection baseplate, undetection baseplate, and removed product to verify the presumptive cause of the rupture of the poplite.

This study presents a systematic causal analysis of the fuel consumption rate reduction phenomenon observed in mortar-carrier tracked vehicles during driving tests. The investigation focused on identifying the root causes and developing effective improvement measures. Through comprehensive inspections and tests of the chassis and power pack components, along with data analysis, the study identified the damage of the engine flywheel housing gasket and the clogging of the transmission exhaust pump strainer as the main causes of the reduced fuel consumption rate. The causal relationship between the two phenomena was empirically proven using material composition analysis and statistical techniques, enhancing the reliability and validity of the diagnosis. Based on the root cause analysis results, improvements were implemented, including the replacement of the engine gasket and the cleaning of the transmission exhaust pump strainer. The effectiveness of the improvements was quantitatively verified, confirming a significant enhancement in fuel consumption rate and cruising range. By employing a systematic and scientific analysis methodology, this study provides a foundation for improving the reliability and maintenance efficiency of similar weapon systems and power transmission systems in general.

This paper is a study on the malfunction that occurred during the power supply logic of the Gunner Display Device during Mortar Functional Firing under low temperature conditions. As a result of the phenomenon reproduction test and its analysis, the cause of the malfunction of the Gunner Display Device was Glitch, which occurred in the process of converting the image signal, and the improved software was applied to the Gunner's Display System by ignoring some of the image signal conversion process that causes Glitch. The improved Gunner Display Device passed the validity test and applied the improvement to the mortars. As a result of this study, several suggestions for power supply and control logic were proposed. It is expected that this study will be used as a reference in the future design of similar weapons systems.

In this paper, dynamic model of 120mm self-propelled mortar is developed, and multi flexible body dynamics analysis is performed to analyze stresses occurring in the mount during mortar fire. For this, vehicle dynamic system, mortar dynamic system, and finite element mount model are proposed. The commercial program Recurdyn is used in the analysis. As a result of the analysis, the maximum stress(146.9MPa) occurred at the mount side plate. In order to analyze the validity of the analysis results, we performed strain measurement tests by selecting three major points, and the errors of results were 7.91%, 11.15%, and 18.23%, respectively. It is confirmed that the tendency of analysis and test is similar.