Papers by Keyword: Curling

Abstract: The curling reversal mode is discussed, with emphasis on the assumptions of the model, many of them unrealistic. The curling mode assumes the Bloch approximation, where a cosine function is approximated by a polynomial of second order. It is argued that if the curling model takes place, this could affect the anisotropy field, and then the anisotropy field would be function of the grain size, but this is not observed. Exchange effects may affect hysteresis curve, as discussed in the SW-CLC model.

Abstract: A human being cannot imagine recent times without technology and digitalization as well as without constant using of computers, computer networks and developed programmes for design and testing assemblies used in various areas of human ́s life. The submitted paper deals with a principle of a stroke. Priority of it is a design of an ideal mechanism for movement of curling machine lower cylinder and creating an analysis to find out its strength during acting of pressure forces.

Abstract: The objective of this paper is to simulate inversion process and prediction of proper parameter to perform process successfully. This research present an investigation of the external inversion of tubes by using available commercial numerical codes. The numerical investigation is verified and assessed by means of existing analytical and experimental results. The numerical results have been compared with existing empirical and analytical results, so the ability of numerical codes to predict the required force to perform the inversion process of the tubes has been examined. The theoretical results correlate well with those obtained through experiments. Finally by use of numerical results and their validation using existing experimental results, a method is available in order to help to predict geometry and loading conditions under which the process is conducted successful.

Abstract: When the sheet metal is curled into the pipe, springback always makes it in poor roundness. Experiments show that the process parameters can influence the springback value. So in this paper it took series of researches to find the regularity of process parameters influence the curling springback. In this paper it designed one set of curling mould, and chose the punch force, material properties, blank thickness and friction condition as the subject studied separately. After experiments it obtained the influence regularity, and then it took an analysis on the phenomenon in this paper. The results will be helpful to decrease the springback value in curling process.

Abstract: Experimental studies for single shear bolted connection of cold-formed ferritic stainless steel fastened with two bolts (2×1 bolt array) and 3.0 mm thick plate has been performed by T.S. Kim etc. End distances parallel to the direction of applied force were considered as the main variables of specimens. Curling (out of plane deformation) was observed in bolted connection with 60mm end distance and it caused abrupt strength reduction. The purpose of this paper is to compare the analysis results with test results and investigate the curling influence on ultimate strength through numerical modelling. FE models with restrained curling were also simulated for strength comparison with the curled specimen. Therefore, the validation of finite element(FE) analysis in predicting ultimate strength and curling behaviour was verified and the strength reduction ratio by the curling was estimated.

Abstract: Stainless steel has been utilized on structural members of building due to significant characteristics in its superior corrosion resistance, durability, aesthetic appeal etc. Recently, structural behaviors and curling effect in single shear bolted connection fabricated with thin-walled plane plates have been studied by T.S. Kim. In this paper, finite element analysis (FEA) has been conducted based on the existing test result of channel bolted connections in austenitic stainless steel. The validation of numerical approach was verified to predict the structural behaviors such as fracture mode, ultimate strength and curling occurrence of bolted connections. Curling (out-of- plane deformation) also occurred in the connections with a long end distance like bolted connections assembled with plane plates. The curling caused the ultimate strength reduction and ultimate strength reduction caused by curling has been estimated quantitatively through the comparison of FEA results of FE models with free edge and restrained curling. Additional parametric analysis for FE models with extended variables has been performed. Therefore, the ultimate strengths were compared with current design strengths and reasonable strength formulae for connections with no curling effect were proposed.

Abstract: Since stainless steel has significant characteristics such as its superior corrosion resistance, durability, aesthetic appeal etc., it has been utilized as structural members in buildings. Recently, ultimate behaviors and curling influence in austenitic stainless steel single shear bolted connections with thin-walled plane plates have been investigated by T.S. Kim. In this paper, finite element analysis (FEA) has been conducted based on the existing test results of angle bolted connections in fabricated with austenitic stainless steel. The validation of the numerical analysis prediction was verified through the comparison of test results for fracture mode, ultimate strength and curling occurrence. Curling (out-of- plane deformation) also observed in the connections with a long end distance. The curling caused the ultimate strength reduction and the ultimate strength reduction ratios (varied from 12% to 25%) caused by curling have been estimated quantitatively through the comparison of FEA results of FE models with free edge and restrained curling.

Abstract: Experiments have been carried out to investigate the ultimate behaviors of single shear bolted connections assembled with four bolts (2 rows×2 columns bolt arrangement) under shear and aluminum alloy plate. End distance parallel to the direction of applied load is considered as main variables. All specimens failed in block shear fracture and curling (out of plane deformation) in the direction parallel to plate thickness was also observed for some bolted connections with a long end distance. The curling led to sudden ultimate strength reduction and test strength was compared with the block shear strength predicted by current design specifications.

Abstract: Numerical simulation is utilized to estimate the structural behaviors such as ultimate strength, fracture mode and curling effect of single shear bolted connections fabricated with aluminum alloys. In the Kim’s previous research, the validity of finite element analysis was verified through the comparison of test results and analysis results. In this paper, curling deformation and strain development between test result and analysis result were investigated. Also, additional parametric studies are performed for bolted connections with other variables of edge distance and end distance, which are not considered in the existing experiment. The conditions of end distance and edge distance for curing occurrence were discussed.

Abstract: The purpose of this study is to investigate the ultimate behaviors of aluminum alloy bolted connections assembled with four bolts. Specimens for single shear bolted connections were tested and finite element analysis based on this test results was conducted. The validity of finite element(FE) analysis for predicting the structural behaviors such as ultimate strength, fracture mode and curling(out-of-plane deformation) occurrence was verified through the comparisons between test results and FE analysis results. It is known that the curling resulted in sudden strength drop. Moreover, FE models with free edge and restrained out-of-plane deformation for curled specimens are analyzed additionally, therefore, the influence of curling on the ultimate strength; strength reduction ratio is estimated.