Aluminum material, which has excellent corrosion resistance, durability, and light weight, is widely used in the field of shipbuilding, and welding is an essential technology in shipbuilding. currently, welding is efficiently used to assemble structures of various sizes in the shipbuilding process, but aluminum is a very sensitive material at high temperatures and in a molten state, so appropriate process control is essential. research on aluminum welding has been continuously conducted, but most of the research is on the butt welding method. therefore, in this study fillet welding experiments, which are essentially applied to the internal structure of aluminum ships, were performed and the correlation between welding beads and process variables was identified. for the welding experiment GMA fillet welding was performed on Al5083 material used in the shipbuilding industry, and the influence of the process variable was confirmed by analyzing the correlation through the analysis of the etched fillet weld bead cross section for the test result according to the process variable.

In this study, experiments and simulations were performed for fillet joint friction stir welding according to tool shape and welding conditions. Conventional butt friction stir welding has good weldability because heat is generated by friction with the bottom of the tool shoulder. However, in the case of fillet friction stir welding, the frictional heat is not sufficiently generated at the bottom of the tool shoulder due to the shape of the tool and the shape of the joint. Therefore, it is important to sufficiently generate frictional heat by slowing the welding speed as compared to butt welding. In this study, experiments and simulations were carried out on an aluminum battery housing made by friction stir welding an extruded material with a fillet joint. The temperature of the structure was measured using a thermocouple during welding, and the heat source was calculated through correlation analysis. Thermal elasto-plastic analysis of the structure was carried out using the calculated heat source and geometric boundary conditions. It is confirmed that the experimental results and the simulation results are well matched. Based on the results of the study, the deformation of the structure can be calculated through simulation even if the tool shape and welding process conditions change.

The bead geometry according to the welding conditions was analyzed through the laser fillet welding experiment of 9% Ni steel, and the relationship between the shear strength and the five bead geometry measured by selecting the main bead geometry of the fillet weld was analyzed. Among the welding conditions, the welding conditions that directly affect the penetration depth are welding speed and laser power, and the working angle and beam position have a great influence on the formation of leg of vertical and horizontal members. The bead shape, which greatly affects the shear strength, is the horizontal member length, neck thickness, and weld length, and has a proportional relationship with the shear strength. As a result of confirming the relationship between shear strength and bead shape through the derivation of the trend line, it was confirmed that the length of the vertical member, whose R2 value was 0.92, was most closely related to the shear strength.

Gas welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the fatigue strength of gas-welded joints is considerably lower than that of the parent material due to stress concentration at the weld, the fatigue-strength assessment of gas-welded joints is very important for the reliability and durability of railroad cars and the establishment of a criterion for long-life fatigue design. In this paper, in order to save time and cost for the fatigue design, an accelerated life-prediction method that is based on the theory of statistical reliability was investigated. Its usefulness was verified by comparing the (Δσa)R-Nf relationship that was obtained from actual fatigue test results with the (Δσa)R-(Nf)ALP relationship that was derived from accelerated life testing. And the reliability of the predicted life was evaluated. The reliability of the accelerated life-prediction on the base of actual test data was analyzed to be (81～86)% of the actual test life of the fillet-type gas welded joint.

오스테나이트계 스테인리스강은 우수한 내식성, 내구성 및 내화성을 지닌다. 특히, 오스테나이트계 스테인리스강중의 대표인 STS304에 비해 저탄소를 함유하고 있는 STS304L은 현장용접 후 별도의 열처리 없이 높은 내입계부식성능을 지니고 있어 용접후 내입계 부식이 우려되는 부재접합에 적용할 수 있다. 본 연구에서는 티그(TIG)용접으로 필릿 용접된 STS304L 용접접합부의 용접재(용착금속부) 내력과 파단 메카니즘을 조사하고자 한다. 주요변수인 하중방향에 대한 용접선의 배치에 따라 TFW(하중직각방향 용접), LFW(하중방향용접), FW (하중방향용접과 하중직각방향 용접조합)시리즈의 실험체를 제작하여 인장실험을 실시하였고, 각각 인장파단,전단파단, 블록전단파단(인장 파단과 전단파단의 조합)이 발생하였다. 동일 용접길이에 대해 TFW 시리즈의 접합부가 가장 높은 내력을 나타났으며, 현행기준식( KBC2016/AISC2010)과 기존 연구자의 식에 의한 예측내력과 비교한 결과, TFW와 LFW접합부는 과소평가되었고 FW실험체는 과대평가되었다 .실제 파단 위험단면과 블록전단파단 메카니즘을 고려한 내력식을 제안하였다.

Ultimate behaviors such as ultimate strength and fracture mechanism of fillet-welded connections with TIG(tungsten inert gas) welding have been investigated through test results. Main variables of specimens are weld length and welding direction against loading and ultimate strengths were compared according to the variables. Ultimate strengths were compared with current design predictions and modified design equations were proposed to consider the strength difference according to welding direction.

Austenitic stainless steels have excellent corrosion resistance, durability, aesthetic appeal, fire resistance etc. compared with ferritic stainless steels and so especially 304 stainless steels have been utilized widely in the exterior member of building structure. In this paper, ultimate behaviors such as ultimate strength and fracture mechanism of fillet-welded connections with TIG(tungsten inert gas) welding have been investigated through test results. Main variables of specimens are weld length and welding direction against loading and ultimate strengths were compared according to the variables.

To improve fatigue strength of fillet-welded joints by hammer-peening treatment, fatigue tests were carried out on three types of longitudinal out-of-plane gusset fillet-welded joints and transverse non-load carrying cruciform rib fillet-welded joints: as-welded joints, post-weld hammer peened joints and hammer peened joints at 50% of as-welded joint’s fatigue life. From the test results, the effect of hammer-peening treatment on fatigue behavior of the fillet-welded joints were presented

고등어 fillet 제품의 저장 중 항산화와 기능성을 부여하고 고등어 특유의 비린내를 제거하기 위해 식염 외에 녹차, dill weed, 키토산, 올리고당, 생강을 첨가하여 진공포장한 후 5, , -2에 80일간 저장하면서 제품 특성을 조사하였다. 5에 저장한 고등어 fillet의 휘발성 염기질소 측정 결과는 이들 첨가물을 단독 또는 복합적으로 첨가한 시제품에서 2주 이내에 초기부패에 도달했고, 에서는 4∼7주, -2에서는 저장 80일간 모든

Generally, though we use the vision sensor or arc sensor in welding process, it is difficult to define the welding parameters which can be applied to the weld quality control. Especially, the important Parameters is Arc Voltage, Welding Current, Welding Speed in arc welding process and they affect the decision of weld bead shape, the stability of welding process and the decision of weld quality. Therefore, it is difficult to determine the unique relationship between the weld bead geometry and the combination of various welding condition. Due to the various difficulties as mentioned, we intend to use Fuzzy Logic and Neural Network to solve these problems. Therefore, the combination of Fuzzy Logic and Neural network has an effect on removing the weld defects, improving the weld quality and turning the desired weld bead shape. Finally, this system can be used under what kind of welding recess adequately and help us make an estimate of the weld bead shape and remove the weld defects.