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Article
Publication date: 7 September 2012

Kei Sawai, Shigeaki Tanabe, Hitoshi Kono, Tsuyoshi Suzuki and Kuniaki Kawabata

The purpose of this paper is to propose a novel wireless sensor node (SN), with impact resistant capability, for launch deployment into closed areas. In disaster areas…

Abstract

Purpose

The purpose of this paper is to propose a novel wireless sensor node (SN), with impact resistant capability, for launch deployment into closed areas. In disaster areas, gathering disaster area information is crucially important to prevent secondary disasters. However, gathering information is usually associated with the risk of death and/or accident for rescue workers in closed areas. The authors propose the SN for gathering information in dangerous places, inaccessible to rescue workers and robots, by utilizing launch deployment.

Design/methodology/approach

Buffer material is essential when designing an impactresistant structure. The authors adopted the air cushion as general buffer material when considering the directional characteristics of sensor mounting and wireless communication quality and developed the expression for determining the thickness of the air cushion using the parameters of SN size, mass, air pressure and acceleration. The authors developed a sensor node with impact resistant structure by utilizing the proposed determination method of air cushion thickness.

Findings

In the evaluation of impact resistant structure in free fall, launch deployment, the authors verified that the impact resistant structure protected the SN, and the performance of configured devices on the SN. Then, the authors examined the effect of the impactresistant structure on wireless communication between SNs. The structure had no effect on electric field intensity, throughput, or packet jitter, which confirmed that the wireless communication capacity was unaffected by the structure.

Originality/value

In this paper, a new design method is stated for a sensor node with an impactresistant structure by utilizing an air cushion as a general buffer material.

Details

Sensor Review, vol. 32 no. 4
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 8 May 2018

Zdobyslaw Jan Goraj and Kamila Kustron

Bird strike and hail impact resistances are considered in relation to the fulfilment of airworthiness/crashworthiness regulations as specified by appropriate aviation…

Abstract

Purpose

Bird strike and hail impact resistances are considered in relation to the fulfilment of airworthiness/crashworthiness regulations as specified by appropriate aviation authorities. Before aircraft are allowed to go into service, these regulations must be fulfilled. This includes the adaption of the wing leading edge (LE) structure to smart diagnostics and an easy repair. This paper aims to focus on the wing LE, although all forward-facing aircraft components are exposed to the impact of foreign object during the flight. The best practices based on credible simulations which may be appropriate means of establishing compliance with European Aviation safety Agency and Federal Aviation Administration regulations regarding bird strikes, together with the problem of collisions with hailstones, are overviewed in aspect of accuracy and computing cost.

Design/methodology/approach

The best means of evaluating worldwide certification standards so as to be more efficient for all stakeholders by reducing risk and costs (time and money consuming) of certification process are recommended. The very expensive physical tests may be replaced by adequate and credible computer simulations. The adequate credible simulation must be verified and validated. The statistical approaches for modelling the uncertainty are presented in aspect of computing cost.

Findings

The simulation models have simplifications and assumptions that generate an uncertainty. The uncertainty must be identified in benchmarking tests. Instead of using “in house” physical tests, there are scientific papers available in open literature thanks to the new trend in worldwide publication of the research results. These large databases can be efficiently transform into useful benchmark thanks to data mining and knowledge discovery methods and big data analyses. The physical test data are obtained from tests on the ground-based demonstrator by using high-speed cameras and a structural health monitoring system, and therefore, they should be applied at an early stage of the design process.

Originality/value

The sources of uncertainty in simulation models are expressed, and the way to their assessment is presented based on statistical approaches. A brief review of the current research shows that it widely uses efficient numerical analysis and computer simulations and is based on finite element methods, mesh structure as well as mesh free particle models. These methods and models are useful to analyse airworthiness requirements for damage tolerance regarding bird-strike and hail impact and haves been subjected to critical review in this paper. Many original papers were considered in this analysis, and some of them have been critically reviewed and commented upon.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 4
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 31 May 2019

George Bikakis, Nikolaos Tsigkros, Emilios Sideridis and Alexander Savaidis

The purpose of this paper is to investigate the ballistic impact response of square clamped fiber-metal laminates and monolithic plates consisting of different metal…

Abstract

Purpose

The purpose of this paper is to investigate the ballistic impact response of square clamped fiber-metal laminates and monolithic plates consisting of different metal alloys using the ANSYS LS-DYNA explicit nonlinear analysis software. The panels are subjected to central normal high velocity ballistic impact by a cylindrical projectile.

Design/methodology/approach

Using validated finite element models, the influence of the constituent metal alloy on the ballistic resistance of the fiber-metal laminates and the monolithic plates is studied. Six steel alloys are examined, namely, 304 stainless steel, 1010, 1080, 4340, A36 steel and DP 590 dual phase steel. A comparison with the response of GLAss REinforced plates is also implemented.

Findings

It is found that the ballistic limits of the panels can be substantially affected by the constituent alloy. The stainless steel based panels offer the highest ballistic resistance followed by the A36 steel based panels which in turn have higher ballistic resistance than the 2024-T3 aluminum based panels. The A36 steel based panels have higher ballistic limit than the 1010 steel based panels which in turn have higher ballistic limit than the 1080 steel based panels. The behavior of characteristic impact variables such as the impact load, the absorbed impact energy and the projectile’s displacement during the ballistic impact phenomenon is analyzed.

Originality/value

The ballistic resistance of the aforementioned steel fiber-metal laminates has not been studied previously. This study contributes to the scientific knowledge concerning the impact response of steel-based fiber-metal laminates and to the construction of impact resistant structures.

Details

International Journal of Structural Integrity, vol. 10 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 4 October 2021

Mitra Salmaninezhad and S. Mahmood Jazayeri Moghaddas

Pier scour is one of the main causes of damage to the columns of the river bridges. It is essential to select the best method among various repair methods based on…

Abstract

Purpose

Pier scour is one of the main causes of damage to the columns of the river bridges. It is essential to select the best method among various repair methods based on different evaluation indices. However, there is no procedure for ranking these repair methods based on their attributes. The present study seeks to set an approach for this ranking.

Design/methodology/approach

In this paper, a multi-attribute decision-making (MADM) model is presented for ranking the repair techniques, in which alternatives are examined using the most important evaluation criteria. In addition, a combination of entropy and eigenvector methods has been proposed for weighting these attributes. A case study is then used to demonstrate the applicability and the validity of the method.

Findings

The execution of the model using two multi-criteria methods yielded similar results, which confirms its accuracy and precision. Moreover, the research findings showed the consistency of the objective and subjective weighting methods and the conformity of the weights obtained for the attributes from the combination of these methods to the nature of the problem.

Originality/value

The selection of the proper method for repairing the bridge columns plays an essential role in success of the bridge restoration. The proposed model introduces an approach for ranking repair methods and selecting the best one that has not been presented so far. Also, the weighing method for attributes is an innovative method for ranking restoration methods that has been proven in a case study.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 19 July 2021

Mohammad Qasim Shaikh, Serena Graziosi and Sundar Vedanarayan Atre

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF3) of Ti-6Al-4V. Additionally, an…

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Abstract

Purpose

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF3) of Ti-6Al-4V. Additionally, an empirical method was presented for the estimation of extrudate deflection in unsupported regions of lattice cells for different geometric configurations.

Design/methodology/approach

Metal-polymer feedstock with a solids-loading of 59 Vol.% compounded and extruded into a filament was used for three-dimensional printing of lattice structures. A unit cell was used as a starting point, which was then extended to multi-stacked lattice structures. Feasible MF3 processing conditions were identified to fabricate defect-free lattice structures. The effects of lattice geometry parameters on part deflection and relative density were investigated at the unit cell level. Computational simulations were used to predict the part quality and results were verified by experimental printing. Finally, using the identified processing and geometry parameters, multi-stacked lattice structures were successfully printed and sintered.

Findings

Lattice geometry required considerable changes in MF3 printing parameters as compared to printing bulk parts. Lattice cell dimensions showed a considerable effect on dimensional variations and relative density due to varying aspect ratios. The experimental printing of lattice showed large deflection/sagging in unsupported regions due to gravity, whereas simulation was unable to estimate such deflection. Hence, an analytical model was presented to estimate extrudate deflections and verified with experimental results. Lack of diffusion between beads was observed in the bottom facing surface of unsupported geometry of sintered unit cells as an effect of extrudate sagging in the green part stage. This study proves that MF3 can fabricate fully dense Ti-6Al-4V lattice structures that appear to be a promising candidate for applications where mechanical performance, light-weighting and design customization are required.

Originality/value

Supportless printing of lattice structures having tiny cross-sectional areas and unsupported geometries is highly challenging for an extrusion-based additive manufacturing (AM) process. This study investigated the AM of Ti-6Al-4V supportless lattice structures using the MF3 process for the first time.

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Article
Publication date: 1 August 1964

In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are…

Abstract

In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are generally classified according to the base or pigment which actively prevents corrosion—e.g. metallic zinc in zinc/epoxy formulations— or by the base which produces a barrier action against corrosion, e.g. bitumen in bituminous paints. Exceptions to this are the etching primers, which are separately classified. About 300 primers are described, the manufacturers' names and addresses being cross‐indexed and listed separately on page 48.

Details

Anti-Corrosion Methods and Materials, vol. 11 no. 8
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 27 November 2018

Zheng Gong, Xinming Qian and Mengqi Yuan

Stab-resistant body armor (SRBA) can protect the human body from injury as a result of stabbing by sharp projectiles. However, in its current design SRBA, it has not been…

Abstract

Purpose

Stab-resistant body armor (SRBA) can protect the human body from injury as a result of stabbing by sharp projectiles. However, in its current design SRBA, it has not been widely adopted for use, because of its weight and poor flexibility. Herein, this paper aims to detail a new type of SRBA that is inspired by the armor plating of mammals and is fabricated using laser sintering (LS) technology.

Design/methodology/approach

This new type of SRBA was fabricated using LS technology. The laser sintered SRBA was subjected to a stab resistance performance test that conformed to the GA 68-2008 Chinese National Standard. The stab resistance response of the novel structured, stab resistance test plates in this study was analyzed using the using the AUTODYN explicit module in ANSYS-Workbench.

Findings

The structure of the novel stab resistance plate was designed and the optimum structural parameters were tested, discussed and achieved. The mechanism of dissipation of the impact energy by the pyramidal structures of the novel SRBA was studied, and it was found that this structure dispersed the kinetic energy of the knife and minimized the structural damage to the plate. Interlinks inspired by the pangolin hierarchy structure were designed and used to fabricate a large piece of laser sintered body armor.

Originality/value

High-performance laser sintered stab resistance plate was produced via the material and structure studies, which could reduce 40 per cent weight on the stab resistance body armor and increase the wearability.

Details

Rapid Prototyping Journal, vol. 25 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 4 April 2019

Brahmadev Panda and N.M. Leepsa

Previous empirical evidence scrutinizing the impact of the institutional ownership on the firm performance has produced inconclusive results and mostly concentrated in the…

Abstract

Purpose

Previous empirical evidence scrutinizing the impact of the institutional ownership on the firm performance has produced inconclusive results and mostly concentrated in the developed market. Hence, the purpose of this paper is to assess the impact of the ownership engagement by pressure-resistant, pressure-sensitive and foreign institutions on the corporate financial performance in a developing market like India post US financial crisis.

Design/methodology/approach

This study considers a panel data set of 361 Indian listed firms from National Stock Exchange (NSE) 500 index for a period of eight years from financial year (FY) 2008-2009 to FY 2015-2016. The panel data regression (pooled ordinary least square [OLS], fixed-effect [FE] and random-effect [RE]) and simultaneous equation modeling are used by considering the institutional ownership engagement as both exogenous and endogenous variable.

Findings

The test results show that institutional ownership engagement by the pressure-resistant and foreign institution have a robust and positive effect, while ownership engagement by the pressure sensitive institution has an adverse impact on the financial performance of the Indian listed firms.

Research limitations/implications

The findings will boost the monitoring activities of the institutional owners in the developing markets. The investment from pressure-resistant and foreign institutions needs to be augmented in Indian firms to improvise their governance functions and performance.

Originality/value

This research will enrich the governance literature of the developing economies as the studies on institutional ownership engagement are limited in the developing world. Further, this study adds value by capturing two emerging institutional ownership category such as the pressure-resistant and pressure-sensitive, which are still untouched in the Indian context. Next, the consideration of the institutional ownership as both exogenous and endogenous is also novel to the Indian literature.

Details

International Journal of Law and Management, vol. 61 no. 2
Type: Research Article
ISSN: 1754-243X

Keywords

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Book part
Publication date: 19 September 2014

Nikolaos Kavadis and Xavier Castañer

To show that differences in the extent to which firms engage in unrelated diversification can be attributed to differences in ownership structure.

Abstract

Purpose

To show that differences in the extent to which firms engage in unrelated diversification can be attributed to differences in ownership structure.

Methodology/approach

We draw on longitudinal data and use a panel analysis specification to test our hypotheses.

Findings

We find that unrelated diversification destroys value; pressure-sensitive Anglo-American owners in a firm’s equity reduce unrelated diversification, whereas pressure-resistant domestic owners increase unrelated diversification; the greater the firm’s free cash flow, the greater the negative effect of pressure-sensitive Anglo-American owners on unrelated diversification.

Research limitations/implications

We contribute to corporate governance and strategy research by bringing in owners’ institutional origin as a shaper of owner preferences in particular with regards to unrelated diversification. Future research may expand our investigation to more than one home institutional context, and theorize on institutional origin effects beyond the dichotomy between Anglo-American and non-Anglo-American (not oriented toward shareholder value maximization) owners.

Practical implications

Policy makers, financial analysts, owners, and managers may want to reflect about the implications of ownership structure, as well as promoting or joining corporations with particular ownership configurations.

Social implications

A shareholder value-destroying strategy, such as unrelated diversification has adverse consequences for society at large, in terms of opportunity costs, that is, resources could be allocated to value-creating activities instead. Promoting an ownership configuration that creates value should contribute to social welfare.

Originality/value

Owners may not be exclusively driven by shareholder value maximization, but can be influenced by normative beliefs (biases) stemming from the institutional context they originate from.

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Article
Publication date: 1 December 2004

George K. Stylios

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…

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Abstract

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 16 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

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