• 한국신뢰성학회지:신뢰성응용연구
• /
• 제17권4호
• /
• pp.343-354
• /
• 2017

Purpose: This paper evaluates the reliability of tapered grid couplings and presents test results through performance and life tests. Methods: The performance and life test method were presented by analyzing the failure modes for the tapered grid coupling. Zero failure test time was calculated to evaluate the reliability of tapered grid couplings and the test was performed under accelerated conditions. The nondestructive test and wear analysis using weighing were also carried out to check the failure modes of the field conditions. Conclusion: This study can be provided to improve the product reliability through failure analysis of a tapered grid coupling. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the tapered grid coupling.

• Architectural research
• /
• 제8권1호
• /
• pp.47-56
• /
• 2006

In this research, the analysis of post-buckling behavior of tapered columns has been performed under a combined load of uniformly distributed axial load along the length and concentric axial load at free end by solving the nonlinear differential equation with the differential transformation technique. The buckling load at various slopes at free end of column is calculated and the results of the analysis using the differential transformation technique is verified with those of previous studies. It is also shown through the results that the buckling load of sinusoidal tapered columns is largest, the linear is second largest, and the parabolic is small in the all ranges of slopes at free end and the deflection of parabolic tapered columns in the x coordinates is largest, the sinusoidal is second largest, and the linear is smallest in the range of slope 0 to 140 degrees at free end. However, when the range of the slope is 160 to 176 degrees at the free end, the deflection of sinusoidal tapered columns in the x coordinates is largest, the linear is second largest, and the parabolic is smallest. In addition, for the linear tapered column, the buckling load increases along with the flexural stiffness ratio. Also, for the parabolic and the sinusoidal tapered column, the buckling loads increase and decrease as the flexural ratios increase in the range of flexural stiffness ratio n = 1.0 to n = 2.0. Through this research, it is verified that the differential transformation technique can be applied to solve the nonlinear differential equation problems, such as analysis of post-buckling behavior of tapered columns. It is also expected that the differential transformation technique apply to various more complicated problems in future.

• Current Optics and Photonics
• /
• 제5권3호
• /
• pp.250-260
• /
• 2021

A tapered As₂S₃ photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As₂S₃ PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 ㎛ propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As₂S₃ PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.

• Journal of Chest Surgery
• /
• 제50권1호
• /
• pp.30-35
• /
• 2017

Background: Tapered grafts, which have a smaller diameter on the arterial side, have been increasingly used for arteriovenous fistula (AVF) formation. We compared the outcomes of 4-6-mm tapered and 6-mm straight forearm loop arteriovenous grafts. Methods: A total of 103 patients receiving forearm loop arteriovenous grafts between March 2005 and March 2015 were retrospectively analyzed and separated into 2 groups (group A, 4- to 6-mm tapered grafts, n=78; group B, 6-mm straight grafts, n=25). In each group, complications and patency rates after surgery were assessed. Results: Clinical characteristics and laboratory results, except for cerebrovascular disease history (group A, 7.7%; group B, 28.0%; p=0.014), were similar between the groups. No significant differences were found for individual complications. Kaplan-Meier survival analysis revealed no significant differences in 1-year, 3-year, and 5-year patency rates between groups (61.8%, 44.9%, and 38.5% vs. 62.7%, 41.1%, and 35.3%, respectively). Conclusion: We found no significant differences in complication and patency rates between the tapered and straight graft groups. If there are no differences in complication and patency between the two graft types, tapered grafts may be a valuable option for AVF formation in light of their other advantages.

• Structural Engineering and Mechanics
• /
• 제87권4호
• /
• pp.391-403
• /
• 2023

In this study, a new type of self-centering beam-column joint with tapered steel plate links is proposed. Firstly, mechanical property of the basic joint (with the prestressed steel strands only, to provide the self-centering ability) and the combined joint (with both the prestressed steel strands and tapered steel plate links, to provide self-centering and energy dissipation simultaneously) is theoretically analyzed. Then, three joints with different dimensions and combinations of tapered plate links are designed and tested through a series of quasi-static cyclic loading tests. Test results show that a nearly bilinear elastic moment-rotation relationship for the basic joint is obtained. With the addition of tapered steel plate links, typical flag-shape hysteretic curves are obtained, which indicates good self-centering and energy dissipating ability of the combined joint. By installing multiple tapered plate links, stiffness and bearing capacity of the beam-column joint can be enhanced. The theoretical moment-rotation relationships agree well with the test results. A simplified macro model of the proposed joint is developed using OpenSees, which simulates reasonably well its hysteretic behavior.

• Structural Engineering and Mechanics
• /
• 제90권3호
• /
• pp.273-285
• /
• 2024

Tapered girders emerged as an economical remedy for the challenges associated with constructing long-span buildings. From an economic standpoint, these systems offer significant advantages, such as wide spans, quick assembly, and convenient access to utilities between the beam's shallow sections and the ceiling below. Elastic-local buckling is among the various failure modes that structural designers must account for during the design process. Despite decades of study, there remains a demand for efficient and comprehensive procedures to streamline product design. One of the most pressing requirements is a better understanding of the tapered web plate girder's local buckling behavior. This paper conducts a comprehensive numerical analysis to estimate the critical buckling coefficient for simply supported tapered steel web plates, considering loading conditions involving compression and bending stresses. An eigenvalue analysis was carried out to determine the natural frequencies and corresponding mode shapes of tapered web plates with varying geometric parameters. Additionally, the study highlights the relative significance of various parameters affecting the local buckling phenomenon, including the tapering ratio of the panel, normalized plate length, and ratio of minimum to maximum compressive stresses. The regression analysis and optimization techniques were performed using MATLAB software for the results of the finite element models to propose a separate formula for each load case and a unified formula covering different compression and bending cases of the elastic local buckling coefficient. The results indicate that the proposed formulas are applicable for estimating the critical buckling coefficient for simply supported tapered steel web plates.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.402.1-402
• /
• 2002

A linearly tapered beam immersed partially in other material is considered and is modelled as a linearly tapered Bernoulli-Euler beam fixed at the bottom with a concentrated mass at the top. Its governing equations is derived and its free vibration analysis is performed for various boundary conditions. And the rotatory inertia of the eccentric lumped tip mass is considered. (omitted)

• Structural Engineering and Mechanics
• /
• 제3권6호
• /
• pp.611-622
• /
• 1995

This paper is concerned with inelastic load carrying capacity of tapered steel members with or without accumulated plastic strains resulted from previous loading histories. A finite element program is developed using stiffness matrices of tapered members and is applicable for analyses with material and geometric nonlinearity. Results of analyses are compared with other available solutions and with experimental results.

• 기계저널
• /
• 제16권2호
• /
• pp.100-107
• /
• 1976

Stress analysis of tapered cylinder of reactor vessels is investigated by means of the intersection method. The tapered cylinder is approximated into three models-average cylinder, conical frustum, and ring. The results are compared with those of the finite element method program and an experiment. In this paper, the following results are obtained: (1) the best aproximation has been obtained by the ring model analysis: (2) the intersection analysis of the tapered cylinder by the ring model shows a sufficient accuracy for the stress analysis of reactor vessels.

• Applied Science and Convergence Technology
• /
• 제23권5호
• /
• pp.284-288
• /
• 2014

We present tapered nanostructures fabricated on a selective area of gallium phosphide substrates for advanced optoelectronic device applications. A lithography-free fabrication process was accomplished by dry etching of metal nanoparticles. Thermal dewetting of micro-patterned metal thin films provides etch masks for tapered nanostructures. This simple process also allows the formation of plasmonic surfaces with corrugated shapes. Rigorous coupled-wave analysis calculations provide design guidelines for tapered nanostructures on gallium phosphide substrates.