• Journal of Welding and Joining
• /
• v.13 no.4
• /
• pp.155-162
• /
• 1995

Redistribution of residual stress and its effects during fatigue crack propagates from tensile residual stress region in weldment are investigated. Tests are performed by using welded CCT specimens of structual rolling steel (SS400) and it makes fatigue crack propagate from tensile residual stress region. For this study tension-tension loading type is selected by external loading condition and magnetizing stress indicator is used correctly to measure redistribution of residual stress according to fatigue crack growth and number of loading cycles. From this result, it is proved that redistribution of residual stress is mainly consist of residual stress released by fatigue crack growth. When fatigue crack propagates from tensile residual stress region residual stress are redistributed and it makes fatigue crack growth rate largely increase. Fatigue crack growth rate is low in case of redistributed residual stress compare with initial distributed residual stress.

• Journal of Welding and Joining
• /
• v.33 no.1
• /
• pp.72-79
• /
• 2015

Evaluation of fracture toughness of welded structures has a significant influence on the structural design. However the residual stresses is redistributed while the welded structures is cut for preparing specimens. This study investigated an effect of the welding residual stress redistribution on the impact absorption energy of Charpy specimen. SA516Gr70 steel plate by at the flux cored arc welding (FCAW) and gas tungsten arc welding(GTAW) was cutting. Specimens for Charpy impact testing were taken from the welded plate. Two material removal mechanisms (wire cutting and water jet) were used to make the specimens. Welding residual stress and redistribution residual stress were measured using the XRD (X-Ray Diffraction) method. The amount of redistribution of residual stress depends on the different material removal mechanism. Redistribution of residual stress of reduced the impact absorption energy by 15%.

• Journal of the Korean Society of Safety
• /
• v.10 no.2
• /
• pp.17-23
• /
• 1995

Though the magnitude is decreasing, the compressive residual stress is always distributed during fatigue crack growth near the crack tip. This means that the residual stress is released during fatigue crack growth due to the alternative load. ${\Delta}K_{IV}$ is modified by using the initial residual stress and the redistributed residual stress in uniform and various thickness welded specimens. The former is denoted by ${\Delta}K_{IV.eff.i}$ and the latter is denoted by ${\Delta}K_{IV.eff.i}$. ${\Delta}K_{IV.eff.i}$ gives more accurate relations in da/dN vs. ${\Delta}K_{IV}$ curve, however the difference is very small.

• Journal of Korea Multimedia Society
• /
• v.6 no.4
• /
• pp.620-629
• /
• 2003

Fingerprinting schemes are techniques applied to protect the copyright on digital goods. These enable the merchants to identify the source of illegal redistribution. Let us assume the following situations connectedly happen: As a beginning, buyer who bought digital goods illegally distributed it, next the merchant who found it revealed identity of the buyer/traitor, then the goods is illegally distributed again. After this, we describe it as“The second illegal redistribution”. In most of anonymous fingerprinting, upon finding a redistributed copy, a merchant extracts the buyer's secret information from the copy and identifies a traitor using it. Thus the merchant can know the traitor's secret information (digital fingerprints) after identification step. The problem of the second illegal distribution is that there is a possibility of the merchant's fraud and the buyer's abuse: that is a dishonest employee of the merchant might just as well have redistributed the copy as by the buyer, or the merchant as such may want to gain money by wrongly claiming that the buyer illegally distributed it once more. The buyer also can illegally redistribute the copy again. Thus if the copy turns up, one cannot really assign responsibility to one of them. In this paper, we suggest solution of this problem using two-level fingerprinting. As a result, our scheme protects the buyer and the merchant under any conditions in sense that (1) the merchant can obtain means to prove to a third party that the buyer redistributed the copy. (2) the buyer cannot worry about being branded with infamy as a traitor again later if he never distribute it.

• The Korean Journal of Nuclear Medicine
• /
• v.26 no.2
• /
• pp.355-359
• /
• 1992

The $^{67}Ga$ has somewhat long physical and biological half livies with 78 hours and 600 hours respectively, so we can get $^{67}Ga-scan$ images for 3 or more days after once injection of $^{67}Ga$. Furthermore $^{67}Ga$ scan would be useful to search some residual tumors after surgical removal of the tumors trapped with $^{67}Ga$. However $^{67}Ga$ bound with plasma proteins would be delayed in plasma clearance as approximately 10% of the dose remains in the plasma at 24 hours. If the remained $^{67}Ga$ in the plasma is redistributed into the surgical wound, we wouldn't evaluate the degree of the tumor remained after surgery. So the authors examined the amounts of the remained blood $^{67}Ga$ and the redistribution of the blood $^{67}Ga$ into the artificial wound with S or more centimeters in the diameter at the neck and chest of the rabbits. The results were as follows; 1) The $^{67}Ga$ remained in the plasma were 12%, 5.7%, 4.2% at 24, 48 and 72 hours after $^{67}Ga$ injection respectively. 2) The blood $^{67}Ga$ were redistributed into the artificial wound with 5.9% at 48 hours and 6.9% at 72 hours after $^{67}Ga$ injection.

• Korean Journal of Computational Design and Engineering
• /
• v.12 no.4
• /
• pp.255-262
• /
• 2007

In the finite element analysis of forming process, objects are described with a finite number of elements and nodes and the approximated solutions can be obtained by the variational principle. One of the shortcomings of a finite element analysis is that the structure of mesh has become inefficient and unusable because discretization error increases as deformation proceeds due to severe distortion of elements. If the state of current mesh satisfies a certain remeshing criterion, analysis is stopped instantly and resumed with a reconstructed mesh. In the study, a new remeshing algorithm using tetrahedral elements has been developed, which is adapted to the desired mesh density. In order to reduce the discretization error, desired mesh sizes in each lesion of the workpiece are calculated using the Zinkiewicz and Zhu's a-posteriori error estimation scheme. The pre-constructed mesh is constructed based on the modified point insertion technique which is adapted to the density function. The object domain is divided into uniformly-sized sub-domains and the numbers of nodes in each sub-domain are redistributed, respectively. After finishing the redistribution process of nodes, a tetrahedral mesh is reconstructed with the redistributed nodes, which is adapted to the density map and resulting in good mesh quality. A goodness and adaptability of the constructed mesh is verified with a testing measure. The proposed remeshing technique is applied to the finite element analyses of forging processes.

• Journal of Welding and Joining
• /
• v.7 no.1
• /
• pp.28-35
• /
• 1989

The fatigue crack growth behavior in GTA butt welded joints of Al-Alloy 5052-H38 was examined using Single Edge Notched(SEN) specimens. It is well known that welding residual stress has marked influence on fatigue crack growth rate in welded structure. In the general area of fatigue crack growth in the presence of residual stress, it is noted that the correction of stress intensity factor (K) to account for residual stress is important for the determination of both stress intensity factor range(.DELTA.K) and stress ratio(R) during a loading cycle. The crack growth rate(da/dN) in welded joints were correlated with the effective stress intensity factor range(.DELTA.Keff) which was estimated by superposition of the respective stress intensity factors for the residual stress field and for the applied stress. However, redistribution of residual stress occurs during crack growth and its effect is not negligible. In this study, fatigue crack growth characteristics of the welded joints were examined by using superposition of redistributed residual stress and discussed in comparison with the results of the initial welding residual stress superposition.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.4
• /
• pp.97-101
• /
• 2021

In this study, Insertion loss according to the structural variant of interposer to Through Silicon Via (TSV) and Redistributed Layer (RDL) was studied through design of experiment. 3-Factors was considered as a variant, TSV depth, TSV diameter, RDL width with factor arrangement method and the response surface method from 400 MHz to 20 GHz. As a result, it was confirmed that as the frequency increased, the effect of RDL width was decreased and the effect of TSV depth and TSV diameter was increased. Also within the analysis range, to increasing RDL width, decreasing TSV depth, and fixing TSV diameter about 10.7 ㎛ was observed optimal result of Insertion loss.

• Journal of Korean Society for Quality Management
• /
• v.17 no.2
• /
• pp.149-157
• /
• 1989

A one-upper warehouse n-lower retailer inventory model is discussed. The probability distribution of demand for a given perod is independent. The inventory holding cost is proportional to the number of unsold units and the cost of shortages is proportional to the number of shortages. In the event of a shortage, units are redistributed with a cost proportional to the number of units from the retailers which are a surplus at the end of the period. The optimum stock levels are obtained and the effects of redistribution are analized.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.388-392
• /
• 2002

Fault tolerant control algorithm for heteropolar magnetic bearings are presented. This fault tolerant control utilizes grouping of currents as C-cores in order to isolate magnetic fluxes. Hardware requirements to maintain fault tolerant control are reduced since decoupling chokes are not required in this control scheme. The currents supplied to each pole are redistributed, if some coils fail suddenly, such that the resultant magnetic forces should remain invariant through coil failure events. Load capacity before magnetic saturation is reduced through coil failures while maintaining the same magnetic forces before and after failure.