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Article
Publication date: 9 October 2018

Li Huakang, Kehong Lv, Shen Qinmu, Jing Qiu and Guanjun Liu

This paper aims to reproduce the electrical connector intermittent fault behaviours with step-up vibration stress while maintaining the integrity of the product.

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Abstract

Purpose

This paper aims to reproduce the electrical connector intermittent fault behaviours with step-up vibration stress while maintaining the integrity of the product.

Design/methodology/approach

A dynamic model of an electrical connector under vibration is established for contact resistance analysis. Next, the dynamic characteristics of contact resistance are analysed, and cumulative damage theory is used to calculate the damage under different stresses during the intermittent fault reproduction test. To reduce damage and improve efficiency, the step-up stress is used for the reproduction test.

Findings

The proposed method can reproduce the intermittent fault behaviour, and the step-up stress test is more efficient than the constant stress test.

Research limitations/implications

Step-up stress is used for intermittent fault reproduction, and the quantitative relationships between intermittent fault and product damage can be further studied.

Practical implications

It is expected that the proposed methodology can help engineers to reproduce the intermittent fault behaviours to facilitate the detection and diagnosis of intermittent fault and to improve equipment safety.

Originality/value

The mechanism of electrical connector reproduction is analysed and the step-up stress test is used for intermittent fault reproduction.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 15 March 2013

Xiaodong Tan, Jing Qiu, Guanjun Liu and Kehong Lv

The purpose of this paper is to evaluate the health‐states of unit under test (UUT) in aerospace systems by means of unreliable test outcomes, and the evaluation results can…

219

Abstract

Purpose

The purpose of this paper is to evaluate the health‐states of unit under test (UUT) in aerospace systems by means of unreliable test outcomes, and the evaluation results can provide a guide for engineers to carry out proper maintenance prior to total failure.

Design/methodology/approach

In this paper, the authors formulate the health‐state evaluation (HSE) problem with unreliable test outcomes based on Bayes rule, and develop the Lagrangian relaxation and adaptive genetic algorithm (LRAGA) to solve it. The solution scheme can be viewed as a two‐level coordinated solution framework for the HSE problem. At the top level, the Lagrange multipliers are updated by using AGA. At the bottom level, each of the sub‐problems is solved by using AGA.

Findings

The experimental results show that the HSE model appears promising and the LRAGA can obtain the higher quality solution and converge to it at a faster rate than conventional methods (i.e. Lagrangian relaxation (LR), genetic algorithm (GA), simulated annealing (SA) and Lagrangian relaxation and genetic algorithm (LRGA).

Research limitations/implications

The proposed method for the HSE problem of large‐scale systems which include thousands of faults and tests needs to be verified further.

Practical implications

The HSE results for aerospace systems can help engineers to carry out a schedule for prompt maintenance prior to UUTs' failure, to avoid the consequences of total failure. It is important to improve aerospace systems' safety, reliability, maintainability, affordability, and reduce life cycle cost.

Originality/value

This paper constructs the HSE model with unreliable test outcomes based on the Bayes rule and proposes a method based on LRAGA to solve the HSE problem.

Details

Aircraft Engineering and Aerospace Technology, vol. 85 no. 2
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 6 April 2021

Zhicheng Tao, Shineng Sheng, Zhipei Chen and Guanjun Bao

This paper aims to propose a novel method based on a gesture primitives analysis of human daily grasping tasks for designing dexterous hands with various grasping and in-hand…

258

Abstract

Purpose

This paper aims to propose a novel method based on a gesture primitives analysis of human daily grasping tasks for designing dexterous hands with various grasping and in-hand manipulation abilities, which simplifies the complex and redundant humanoid five-finger hand system.

Design/methodology/approach

First, the authors developed the fingers and the joint configuration with a series of gesture primitives configurations and the modular virtual finger scheme, refined from the daily work gesture library by principal component analysis. Then, the authors optimized the joint degree-of-freedom configuration with the bionic design analysis of the anatomy, and the authors optimized the dexterity workspace. Furthermore, the adaptive fingertip and routing structure were designed based on the dexterous manipulation theory. Finally, the effectiveness of the design method was experimentally validated.

Findings

A novel lightweight three-finger and nine-degree-of-freedom dexterous hand with force/position perception was designed. The proposed routing structure was shown to have the capability of mapping the relationship between the joint space and actuator space. The adaptive fingertip with an embedded force sensor can effectively increase the robustness of the grasping operation. Moreover, the dexterous hand can grasp various objects in different configurations and perform in-hand manipulation dexterously.

Originality/value

The dexterous hand design developed in this study is less complex and performs better in dexterous manipulation than previous designs.

Details

Industrial Robot: the international journal of robotics research and application, vol. 48 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 19 January 2015

Guanjun Bao, Kun Li, Sheng Xu, Pengcheng Huang, Luan Wu and Qinghua Yang

This paper aims to avoid the precise modeling and controlling problems of rigid structures of hand recovery device, by proposing a hand rehabilitator based on flexible pneumatic…

446

Abstract

Purpose

This paper aims to avoid the precise modeling and controlling problems of rigid structures of hand recovery device, by proposing a hand rehabilitator based on flexible pneumatic actuator with its safety and adaptability.

Design/methodology/approach

The hand rehabilitator is designed based on a flexible pneumatic bending joint. The recovery training program for an injured finger is developed via forearm sEMG (surface electromyogram) sampling, analysis, classification and motion consciousness identification. Four typical movement models of the index finger and middle finger were defined and the corresponding sEMG signals were sampled. After simulation and comparative analysis, autoregressive (AR) model back propagation (BP) network was selected for sEMG analysis and hand recovery planning because of its best recognition performance. A verification test was designed and the results showed that the soft hand rehabilitator and recovery conception are feasible.

Findings

AR model BP network can identify the index finger and middle finger movement intention via an sEMG analysis. The developed flexible pneumatic hand rehabilitator is safe and suitable for finger recovering therapy.

Research limitations/implications

Because of the limitation of experimental samples, the prototype rehabilitator of this work may lack generalizability for other situations. Therefore, for further study and application, systematic structure revising, experiments, data and training are necessary to improve the performance.

Practical implications

The paper includes implications for the development and application of a new style, safe and dexterous hand rehabilitator.

Originality/value

The paper tries a new approach to design a safe, flexible and easily controlled hand rehabilitator.

Details

Industrial Robot: An International Journal, vol. 42 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 3 March 2020

Vitus Mwinteribo Tabie, Chong Li, Wang Saifu, Jianwei Li and Xiaojing Xu

This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.

1545

Abstract

Purpose

This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.

Design/methodology/approach

Following a brief introduction of titanium (Ti) alloys, this paper considers the near-α group of Ti alloys, which are the most popular high-temperature Ti alloys developed for a high-temperature application, particularly in compressor disc and blades in aero-engines. The paper is relied on literature within the past decade to discuss phase stability and microstructural effect of alloying elements, plastic deformation and reinforcements used in the development of these alloys.

Findings

The near-a Ti alloys show high potential for high-temperature applications, and many researchers have explored the incorporation of TiC, TiB SiC, Y2O3, La2O3 and Al2O3 reinforcements for improved mechanical properties. Rolling, extrusion, forging and some severe plastic deformation (SPD) techniques, as well as heat treatment methods, have also been explored extensively. There is, however, a paucity of information on SiC, Y2O3 and carbon nanotube reinforcements and their combinations for improved mechanical properties. Information on some SPD techniques such as cyclic extrusion compression, multiaxial compression/forging and repeated corrugation and straightening for this class of alloys is also limited.

Originality/value

This paper provides a topical, technical insight into developments in near-a Ti alloys using literature from within the past decade. It also outlines the future developments of this class of Ti alloys.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

Available. Open Access. Open Access
Article
Publication date: 28 August 2021

Slawomir Koziel and Anna Pietrenko-Dabrowska

A novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three…

710

Abstract

Purpose

A novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios.

Design/methodology/approach

The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels that render good initial designs, as well as an initial estimate of the antenna response sensitivities. Subsequent design refinement is realized using an iterative prediction-correction loop accommodating the discrepancies between the actual and target design specifications.

Findings

The presented framework is capable of yielding optimized antenna designs at the cost of just a few full-wave electromagnetic simulations. The practical importance of the iterative correction procedure has been corroborated by benchmarking against gradient-only refinement. It has been found that the incorporation of problem-specific knowledge into the optimization framework greatly facilitates parameter adjustment and improves its reliability.

Research limitations/implications

The proposed approach can be a viable tool for antenna optimization whenever a certain number of previously obtained designs are available or the designer finds the initial effort of their gathering justifiable by intended re-use of the procedure. The future work will incorporate response features technology for improving the accuracy of the initial approximation of antenna response sensitivities.

Originality/value

The proposed optimization framework has been proved to be a viable tool for cost-efficient and reliable antenna optimization. To the knowledge, this approach to antenna optimization goes beyond the capabilities of available methods, especially in terms of efficient utilization of the existing knowledge, thus enabling reliable parameter tuning over broad ranges of both operating conditions and material parameters of the structure of interest.

Details

Engineering Computations, vol. 38 no. 10
Type: Research Article
ISSN: 0264-4401

Keywords

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