• 한국산업안전학회:학술대회논문집
• /
• 한국안전학회 1997년도 추계 학술논문발표회 논문집
• /
• pp.31-36
• /
• 1997

Strength test using strain rosette gage have been conducted to investigate safety of an auxiliary tank in a high-pressure air compressor. Thickness of auxiliary tanks in 6063-T5 aluminum at toy are 9mm and 17mm. The result of strength test make a comparison the design in strength of materials by nominal stress and the design in fracture mechanics with consideration of crack size. Summarizing the result: Comparing with the safe working pressure of the strength test and that of the design method in strength of materials by nominal stress with the experimental values, it makes difference 11% and 39% for 9mm and 17mm thickness of auxiliary tanks, respectively, and that of the design method by fracture mechanics, it makes difference 4％ and 5% for them, respectively. It is confirmed that the design by fracture mechanics is more economical and safe design than the design in strength of materials by nominal stress.

• 한국생산제조학회지
• /
• 제21권2호
• /
• pp.221-224
• /
• 2012

This paper presents the strength safety of a hybrid alarm valve by a finite element analysis. The stress and strain of a conventional hybrid alarm valve are calculated for the given maximum test pressure of 2MPa. Especially, the FEM computed maximum stress of a conventional hybrid valve is only 18.6% of yield strength, 370MPa. This means that the conventional valve is designed with a thick thickness of a valve structure. But, new hybrid alarm valve model, which is developed by optimized design method in this study, shows more low level of 43% in maximum stress and strain compared with that of a conventional hybrid valve. These results may recommend the reduction of a weight and a dimension for an optimized hybrid alarm valve.

• 한국정밀공학회지
• /
• 제33권4호
• /
• pp.317-324
• /
• 2016

Stress tests were conducted in the carbody of the railroad car to check the structural strength of the body of the railroad car. The objective of this study was to evaluate safety of the carbody of a railroad car under the maximal strength. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. This study was carried out to analyze the structure of carbody and evaluate safety under maximum vertical load, compressive load, and torsional load. Accordingly, stress tests were conducted on the carbody to measure the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the body structure.

• 한국지반환경공학회 논문집
• /
• 제11권4호
• /
• pp.19-24
• /
• 2010

사면의 거동에 관한 종래의 해석 기법은 사면거동을 시간과 변위의 2차원 크리프로 해석하는 것이었으나, 이러한 해석 기법은 강우에 의한 응력변화를 고려 않고 시간에 따른 변위만을 고려하여, 강우 시 사면의 거동 및 붕괴를 설명하지 못한다. 또한 강우에 의한 이력현상으로 인해 파괴면내의 전단에너지가 감소한다. 크리프 해석은 응력항을, 이력현상 해석은 시간항을 무시한 해석이므로, 두 가지 해석을 결합하여, 사면의 거동을 해석한다면, 응력변화, 변위 및 시간을 모두 고려한 실제 사면의 거동해석이 됨을 알 수 있다. 그러나 응력변화에 관한 항은, 강우로 인한 실제 사면의 침투 및 배수 시, 전단응력의 변화 및 전단강도의 변화를 동시에 유발하므로, 이 두 항을 동시에 고려할 수 있는 안전계수항으로 바꾸어야 한다. 본 논문은 강우의 지반침투 및 배수로 인하여 사면의 단위중량이 변하는 과정에 대한 크리프와 이력현상을 고려할 수 있는 결합해석으로 고찰하고 이에 따른 사면붕괴에 관한 전단응력과 전단강도의 변화 및 안전계수변화를 3차원으로 나타내고자 수행한 결과이다.

• 한국산업융합학회 논문집
• /
• 제9권4호
• /
• pp.269-276
• /
• 2006

Strength Design method for involute spur gears is developed. The developed gear strength design system can design the optimized gear that minimize the number of pinion teeth with face tooth. Method of optimization is matrix form which is developed from this study. Design variables are transmitted power, gear volume, gear ratio, allowable contact stress and allowable bending stress, etc. Gear design method developed this study can be apply to the gears of plants, machine tools, automobiles.

• 한국생산제조학회지
• /
• 제20권4호
• /
• pp.401-406
• /
• 2011

This study presents the stress safety analysis of a cylinder, which is manufactured by a tempered ASTM D2, tempered SM45C and normalized SM45C materials, respectively. The inner diameter of three cylinder models are 85mm, 95mm, and 11 Omm and the total length of a cylinder is 2,365mm for a high pressure injection molding machine. The FEM computed results show that the inner diameter of 85mm with a thick thickness of 62.5mm may produce the injection pressure of 325MPa and the inner diameter of 110mm with 50mm thickness reduces up to the injection pressure of 220MPa because of a reduced thickness of a cylinder. These injection pressures are enough for a high pressure injection molding machine assembled by ASTM D2 cylinder. And also, an injection cylinder manufactured by a tempered SM45C material in which is low priee may produce 225MPa injection molding pressure and this may sufficiently endure stress safety compared to that of ASTM D2 cylinder material. Thus, this study recommends that tempered SM45C cylinder is appropriated for a mild injection molding machine as an alternative cylinder material when the safety strength and low prices are considered. But the normalized SM45C cylinder material does not meet a stress safety of yield strength in general.

• 대한기계학회논문집A
• /
• 제26권11호
• /
• pp.2421-2428
• /
• 2002

In this study, the failure probability of the degraded LP turbine blade steel was performed using the Monte Carlo simulation to apply variation of applied stress and strength. For this purpose, applied stress under the service condition of steady state was obtained by theoretical stress analysis and the maximum Von-Mises stress was 219MPa. The fatigue strength under rotating-bending load was evaluated by the staircase method. Furthermore, 3-parameter Weibull distribution was found to be most appropriate among assumed distributions when the probabilistic distributions of tensile and fatigue strength were determined by the proposed analysis. The failure probability with various loading conditions was derived from the strength-stress interference model and the characteristic factor of safety was also estimated.

• 해양환경안전학회지
• /
• 제2권1호
• /
• pp.143-143
• /
• 1996

Recent Class requirements and IMO recommendations concerning Hull Strength Monitoring (HSM) have prompted an increasing number of shipowner to adopt monitoring systems on bulk carriers and tanker. Such systems are designed to give warning when stress levels and the frequency and magnitude of ship motions approach levels which require corrective action. When fitted these systems provide enhanced operational safety and efficiency. This paper describes a development beyond the standard BMT HSM system through the integration of stress, motion and radar-based sea state monitoring with powerful, on-board, artificial intelligence (AI) tools. The latter utilises conceptual clustering techniques as an aid to pattern recognition in stress, fatigue. motion and sea state data clusters. This, in turn, provides additional operational guidance for ship's staff. Feedback from applications of the standard BMT HSM and extended HSM systems on board the British Steel Bulk Shipping fleet is described.

• 한국안전학회지
• /
• 제23권4호
• /
• pp.19-24
• /
• 2008

This paper presents and discusses the experimental results on the F10T high strength bolts used in the T-flange joint structure. The experimental works were carried out for the parameters which are flange web thickness, the distance between bolts, prying ratio. The results show that the working stress imposed to bolts decreases as the flange web thickness increases on the other hand the imposed stress to the bolts increases as the distance between two bolts increases. In other words the strength of the T-flange joint increased as the web flange thickness increases and the distance between two bolts decreases. The prying ratio is increased as the distance between two bolts increases and as the flange web thickness decreases However, the degree of stress decrease in flange thickness variation is not that high as the distance variation between two bolts. Finally the equation for predicting the failure stress in T-flange joint structure using F10T high strength bolts was suggested.

• 한국산업융합학회 논문집
• /
• 제26권2_2호
• /
• pp.285-291
• /
• 2023

In this paper, in order to secure the safety and productivity of pine cone harvest, modeling and structural analysis of the hammering system for pine cone harvest drone that can easily access pine cone of Pinus koraiensis and collide with them to harvest them was performed. It calculate the equivalent stress for the structure of the hammering system and the yield strength of the applied material by applying the shear force of the stalk at which the pine cone is separated from the branch, and it is to verify the safety of the structure and propose an optimal design through appropriate factor of safety and design change. The shear force of the stalk at which the pine cone was separated from the branch was 468 N, and was applied to both ends of the hammering system. The yield strength of SS400 steel used in the hammering system is 245 ㎫, and the design change and structural analysis were performed so that the Von Mises stress could be less than 122.5 ㎫ by applying the factor of safety of 2.0 or more. As a result of the structural analysis of the frist modeling, the Von Mises stress was 220.3 ㎫, the factor of safety was 1.12, and the stress was concentrated in the screw fastening holes. As a result of the design change of the screw fastening holes, the Von Mises stress was 169.4 ㎫, the factor of safety was 1.45, and the stress was concentrated on the side part. As a result of the design change by changing screw fastening holes and adding ribs, the Von Mises stress was 121.6 ㎫, and the factor of safety was 2.02. The safety of the hammering system was secured with an optimal design with little change in mass. There was no deformation or damage as a result of experimenting on pine cone harvest by manufacturing the hammering system with an optimal design.