Design Criteria For Components Research Articles

Novel Modified High Step-Up DC/DC Converters with Reduced Switch Voltage Stress

This paper presents the improved switched inductor unit and new step-up DC/DC converters with reduced switch voltage stress and high voltage gain. The proposed switching-inductor unit is composed of 1 switch, 2 diodes, and 2 inductors, which can realize the step-up function. Through comparison, the better topology is selected from the proposed converters, which is named the double-switch high step-up (DS-HS) converter. The CCM operating principles and voltage gain of the DS-HS converter are analyzed. Then, the influences of nonideal components, efficiency analysis, small signal modeling and control, and design criteria of components are discussed. The comparison of the converters is given, and the loss of the DS-HS converter is lower through theoretical derivation, which shows that the DS-HS converter has the advantages of high voltage gain, low voltage stress, and high efficiency. Finally, in order to verify the effectiveness of the DS-HS converter, simulation and experimental results are given, and the efficiency of the DS-HS converter can reach 96.15%.

Fault location in low‐voltage direct current network based on auxiliary injection unit

Fault location plays an important role in accelerating fault clearance and grid recovery, which greatly improves the reliability and robustness of low-voltage direct current distribution network. A fault location method based on auxiliary injection unit (AIU) is proposed in this study with respect to its basic structure and principle. With single terminal information, the proposed method allows low requirement of sampling frequency and enhances the tolerance to fault resistance by utilising the characteristic of AIU. Furthermore, design criteria of components in AIU are discussed in detail. Optimised parameters contribute to better performance in estimating fault distance. Numerous simulations demonstrate that the proposed method can realise accurate fault location with fault distance and fault resistance varying in a wide range.

Hydrogen susceptibility of nano-sized oxide dispersed austenitic steel for fusion reactor

Effects of hydrogen on the mechanical properties and fracture patterns of nano-sized yttria (Y2O3) dispersed 316L austenitic steel usually mentioned as oxide dispersed strengthened (ODS) steel was studied from in situ tensile test using small specimens under high-pressure hydrogen gas, and the steel’s hydrogen desorption properties were quantified using thermal desorption spectra analysis. The steel samples were prepared using powder metallurgy from precursor powders with 5μm and 150μm particle size, then processed by mechanical alloying and hot isostatic press. The original powder size affected mechanical properties and hydrogen embrittlement. Type-316L ODS steel with fine grain size showed the robust tensile property under gaseous hydrogen and less hydrogen susceptibility. Yttria-doped 316L steel is a candidate for use as a structural component exposed to hydrogen in nuclear fusion reactors, so these results will be useful to material and component design criteria.

Structural Design and Analysis of the Model Coil for the Hybrid Magnet Superconducting Outsert

A model coil developed at the High Magnetic Field Laboratory, Chinese Academy of Sciences, will be wound with a Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn cable-in-conduit conductor (CICC). In this paper, we first introduce the model coil structure and its design requirements and then explicate the important components of the model coil structure, such as the preload structure, joint, cooling circuit, etc. Stress analyses of the preload structure, lead-in and lead-out CICC, joint, transitive CICC, and some supporting structures are performed, and the results are compared with the International Thermonuclear Experimental Reactor metallic and composite structural component design criteria.

Fatigue performance of glass/polyester laminates and the monitoring of material degradation

Experiments are performed on glass/polyester composites under fatigue loading. The stiffness degradation is recorded as an indirect measure of material damage. The stiffness decrease rate is described by a power dependence on stress; this relationship allows the fatigue law to be derived. Stiffness-controlled fatigue curves are generated and presented in an S-N-diagram based on normalized stress (equivalent to strain). Such stiffness controlled fatigue curves can be used as a basis for design criteria for components.

The Uses of Composite Materials in the Design and Manufacture of Formula 1 Racing Cars

In recent years a new application for advanced composite materials has been in the construction of load-bearing components for Formula 1 racing cars. Their use has been progressively extended and they currently comprise a major part of the vehicle assembly for all competing Formula 1 designs. Here the experiences gained with these materials at Williams Grand Prix Engineering are described. The initial interest in this technology was for optimization of structural efficiency. A wide range of component design criteria are covered and advantages have also been found in the areas of strength, impact performance, geometric accuracy and speed of manufacture.

Considerations of probability-based fatigue design for marine structures

Fatigue is a major failure modelin marine structures which respond dynamically to random wave and wind loading. Oscillatory stresses produce fatigue at points of stress concentration, typically the welded joints. Because all fatigue design factors are subject to significant uncertainty, a reliability approach to management of such uncertainty seems appropriate. This article summarizes some studies in fatigue reliability research and demonstrates how reliability methods can be effectively utilized by designers to avoid fatigue in marine structural components. Included are (1) a description of fatigue damage under variable amplitude stresses employing the characteristics S-N and fracture mechanics models, (2) models for reliability assessment relative to fatigue and the use of these models to derive design criteria, and (3) an elementary application of system fatigue reliability analysis to establish component design criteria.

Fatigue Design Criteria for TLP Tendons

A framework for the development of fatigue design criteria for components (joints) of tendons of tension leg platforms (TLP) is presented. Two approaches are considered. First, a target reliability for the tendon (as an element) is specified from which a component target reliability, β0, is derived. The second approach requires that a maximum probability of replacing any tendon during the service life be specified; β0 is derived from elementary system analysis. The safety check format proposed requires that linear fatigue damage, D, computed by conventional methods using nominal values, be less than a target damage level, Δ0, and derived from β0. A simplified approach to the computation of the probability of progressive tendon failure is presented as a mechanism to ensure that β0 is chosen to be sufficiently large to avoid loss of platform. No specific recommendation is made herein regarding target reliabilities. However, the suggestion is made that the choice of Δ0 not be made without consideration of ul...

力覚センサの弾性要素の設計指針と信号処理

力覚センサの弾性要素の設計指針と信号処理

Liquid fluorine feed system component design criteria

Liquid fluorine feed system valves, seals and seats, discussing design criteria for flight weight components