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Abstract

Details

George Spencer Brown's “Design with the NOR”: With Related Essays
Type: Book
ISBN: 978-1-83982-611-5

Book part
Publication date: 8 March 2021

Franz Hoegl

Abstract

Details

George Spencer Brown's “Design with the NOR”: With Related Essays
Type: Book
ISBN: 978-1-83982-611-5

Article
Publication date: 29 April 2014

K. Fellner, P.F. Fuchs, G. Pinter, T. Antretter and T. Krivec

The overall aim of this research work was the improvement of the failure behavior of printed circuit boards (PCBs). In order to describe the mechanical behavior of PCBs under…

Abstract

Purpose

The overall aim of this research work was the improvement of the failure behavior of printed circuit boards (PCBs). In order to describe the mechanical behavior of PCBs under cyclic thermal loads, thin copper layers were characterized. The mechanical properties of these copper layers were determined in cyclic four-point bend tests and in cyclic tensile-compression tests, as their behavior under changing tensile and compression loads needed to be evaluated.

Design/methodology/approach

Specimens for the four-point bend tests were manufactured by bonding 18-μm-thick copper layers on both sides of 10-mm-thick silicone plates. The silicone was characterized in tensile, shear and blow-up tests to provide input data for a hyperelastic material model. Specimens for the cyclic tensile-compression tests were produced in a compression molding process. Four layers of glass fiber-reinforced epoxy resin (thickness 90 μm) and five layers of copper (thickness 60 μm) were applied.

Findings

The results showed that, due to the hyperelastic material behavior of silicone, the four-point bend tests were applicable only for small strains, while the cyclic tensile-compression tests could successfully be applied to characterize thin copper foils in tensile and compression up to 1 percent strain.

Originality/value

Thin copper layers (foils) could be characterized successfully under cyclic tensile and compression loads.

Details

Circuit World, vol. 40 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Book part
Publication date: 20 August 2020

Chloé Germaine Buckley

Cultural perceptions of the zombie have shifted dramatically in the twenty-first century. No longer only associated with anxiety and fear, zombie fiction often appeals to…

Abstract

Cultural perceptions of the zombie have shifted dramatically in the twenty-first century. No longer only associated with anxiety and fear, zombie fiction often appeals to pleasure. One source of pleasure comes from ludification, the process whereby game-like principals and gameful elements shape non-game activities. Increasingly, print fiction borrows from games and uses ludic elements to shape narratives. As such, it has become embedded in convergence culture, a dynamic media ecology where top down processes compete with bottom up processes. This chapter argues that ludified zombie fiction brings this media ecology into sharp relief, revealing ways that gamification and ludification are just as apt to reinforce capitalist processes of commodification and neo-liberal ideologies of power as they are to dismantle them. Through a close reading of three contemporary zombie fictions, this chapter exposes tensions and contradictions in ludification. The dead body of the zombie, the nihilistic landscape of the post-zombie apocalypse and the futility of human endeavour in the face of walking death are all elements of genre that undercut the gamified pursuit of external utility-oriented goals. The chapter explores these knotty ethical and ideological problems, not only considering the zombie apocalypse as a gameful space for rethinking social organisation, but also recognising it as a platform for the promotion of neo-liberal ideologies that perpetuate existing power inequalities through coercive disciplinary regimes.

Details

Death, Culture & Leisure: Playing Dead
Type: Book
ISBN: 978-1-83909-037-0

Keywords

Article
Publication date: 10 May 2013

Peter Filipp Fuchs, Klaus Fellner and Gerald Pinter

The purpose of this paper is to analyse, in a finite element simulation, the failure of a multilayer printed circuit board (PCB), exposed to an impact load, to better evaluate the…

Abstract

Purpose

The purpose of this paper is to analyse, in a finite element simulation, the failure of a multilayer printed circuit board (PCB), exposed to an impact load, to better evaluate the reliability and lifetime. Thereby the focus was set on failures in the outermost epoxy layer.

Design/methodology/approach

The fracture behaviour of the affected material was characterized. The parameters of a cohesive zone law were determined by performing a double cantilever beam test and a corresponding simulation. The cohesive zone law was used in an enriched finite element local simulation model to predict the crack initiation and crack propagation. Using the determined location of the initial crack, the energy release rate at the crack tip was calculated, allowing an evaluation of the local loading situation.

Findings

A good concurrence between the simulated and the experimentally observed failure pattern was observed. Calculating the energy release rate of two example PCBs, the significant influence of the chosen type on the local failure behaviour was proven.

Originality/value

The work presented in this paper allows for the simulation and evaluation of failure in the outermost epoxy layers of printed circuit boards due to impact loads.

Article
Publication date: 1 May 2006

Brian P. DeJong, Eric L. Faulring, J. Edward Colgate, Michael A. Peshkin, Hyosig Kang, Young S. Park and Thomas F. Ewing

Sets out to discuss lessons learned from the creation and use of an over‐the‐internet teleoperation testbed.

Abstract

Purpose

Sets out to discuss lessons learned from the creation and use of an over‐the‐internet teleoperation testbed.

Design/methodology/approach

Seven lessons learned from the testbed are presented.

Findings

This teleoperation interface improves task performance, as proved by a single demonstration.

Originality/value

In helping to overcome time‐delay difficulties in the operation, leading to dramatically improved task performance, this study contributes significantly to the improvement of teleoperation by making better use of human skills.

Details

Industrial Robot: An International Journal, vol. 33 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 6 November 2017

Guozeng Wu and Quanlin Dong

The purpose of this paper is to improve the stability of high voltage DC power supply and reduce the ripple.

Abstract

Purpose

The purpose of this paper is to improve the stability of high voltage DC power supply and reduce the ripple.

Design/methodology/approach

The study was conducted using the simulation analysis model and numerical calculation.

Findings

By increasing the output arm capacitance, the expression of ripple and times of the output arm capacitance and the auxiliary arm capacitance is derived. The output ripple is determined by the value of the output arm capacitance. Finally, the correctness of the method and the formula are verified using circuit simulation.

Originality value

This paper presents a method to improve the power supply stability.

Article
Publication date: 3 August 2023

Zuraihana Bachok, Aizat Abas, Hehgeraj A/L Raja Gobal, Norwahida Yusoff, Mohamad Riduwan Ramli, Mohamad Fikri Mohd Sharif, Fakhrozi Che Ani and Muhamed Abdul Fatah Muhamed Mukhtar

This study aims to investigate crack propagation in a moisture-preconditioned soft-termination multi-layer ceramic capacitor (MLCC) during thermal reflow process.

Abstract

Purpose

This study aims to investigate crack propagation in a moisture-preconditioned soft-termination multi-layer ceramic capacitor (MLCC) during thermal reflow process.

Design/methodology/approach

Experimental and extended finite element method (X-FEM) numerical analyses were used to analyse the soft-termination MLCC during thermal reflow. A cross-sectional field emission scanning electron microscope image of an actual MLCC’s crack was used to validate the accuracy of the simulation results generated in the study.

Findings

At 270°C, micro-voids between the copper-electrode and copper-epoxy layers absorbed 284.2 mm/mg3 of moisture, which generated 6.29 MPa of vapour pressure and caused a crack to propagate. Moisture that rapidly vaporises during reflow can cause stresses that exceed the adhesive/substrate interface’s adhesion strength of 6 MPa. Higher vapour pressure reduces crack development resistance. Thus, the maximum crack propagation between the copper-electrode and copper-epoxy layers at high reflow temperature was 0.077 mm. The numerical model was well-validated, as the maximum crack propagation discrepancy was 2.6%.

Practical implications

This research holds significant implications for the industry by providing valuable insights into the moisture-induced crack propagation mechanisms in soft-termination MLCCs during the reflow process. The findings can be used to optimise the design, manufacturing and assembly processes, ultimately leading to enhanced product quality, improved performance and increased reliability in various electronic applications. Moreover, while the study focused on a specific type of soft-termination MLCC in the reflow process, the methodologies and principles used in this research can be extended to other types of MLCC packages. The fundamental understanding gained from this study can be extrapolated to similar structures, enabling manufacturers to implement effective strategies for crack reduction across a wider range of MLCC applications.

Originality/value

The moisture-induced crack propagation in the soft-termination MLCC during thermal reflow process has not been reported to date. X-FEM numerical analysis on crack propagation have never been researched on the soft-termination MLCC.

Details

Soldering & Surface Mount Technology, vol. 35 no. 5
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 2 June 2023

Saeed Mahjouri, Rasoul Shabani and Martin Skote

The first touchdown moment of aircraft tyres on a runway is the critical phase where maximum of the vertical and horizontal ground loads is produced. Some valuable drop tests have…

Abstract

Purpose

The first touchdown moment of aircraft tyres on a runway is the critical phase where maximum of the vertical and horizontal ground loads is produced. Some valuable drop tests have been performed at Langley research centre to simulate the touchdown and the spin-up dynamics. However, a long impact basin and a huge power source to accelerate and decelerate the landing gear mechanism have been used. Based on a centrifugal mechanism, the purpose of this paper is to propose the conceptual design of a new experimental setup to simulate the spin-up dynamics.

Design/methodology/approach

A schematic view of the proposed mechanism is presented, and its components are introduced. Operating condition of the system and the test procedure are discussed in detail. Finally, tyre spin-up dynamics of Boeing 747 is considered as a case study, and operating condition of the system and the related test parameters are extracted.

Findings

It is shown that the aircraft tyre spin-up dynamics can be simulated in a limited laboratory space with low energy consumption. The proposed setup enables the approach velocity, sink rate and vertical ground load to be adjusted by low power actuators. Hence, the proposed mechanism can be used to simulate the tyre spin-up dynamics of different types of aircraft.

Research limitations/implications

It is important to note that more details of the setup, including the braking and actuating mechanisms together with their control procedures, should be clarified in practice. In addition, the curved path introduced as the runway will cause errors in the results. Hence, a compromise should be made between the tyre pressure, path curvature, the induced error and the cost of the experimental setup.

Practical implications

The proposed experimental setup could be constructed in a limited space and at a relatively low cost. Low power actuators are used in the proposed system. Hence, in addition to the performance tests, fatigue tests of the landing gear mechanism will also be possible.

Originality/value

Based on a centrifugal mechanism, the conceptual design of a new experimental setup is presented for simulating the tyre spin-up dynamics of aircraft. Considering that the drag load developed during tyre spin-up following initial touchdown is an important factor governing the design of the landing gear mechanism and aircraft structure, the authors hope this paper encourages engineers to continuously make efforts to increase the transparency of the touchdown process, enabling optimisation of landing gear design.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 8
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 7 May 2024

Job Maveke Wambua, Fredrick Madaraka Mwema, Stephen Akinlabi, Martin Birkett, Ben Xu, Wai Lok Woo, Mike Taverne, Ying-Lung Daniel Ho and Esther Akinlabi

The purpose of this paper is to present an optimisation of four-point star-shaped structures produced through additive manufacturing (AM) polylactic acid (PLA). The study also…

Abstract

Purpose

The purpose of this paper is to present an optimisation of four-point star-shaped structures produced through additive manufacturing (AM) polylactic acid (PLA). The study also aims to investigate the compression failure mechanism of the structure.

Design/methodology/approach

A Taguchi L9 orthogonal array design of the experiment is adopted in which the input parameters are resolution (0.06, 0.15 and 0.30 mm), print speed (60, 70 and 80 mm/s) and bed temperature (55°C, 60°C, 65°C). The response parameters considered were printing time, material usage, compression yield strength, compression modulus and dimensional stability. Empirical observations during compression tests were used to evaluate the load–response mechanism of the structures.

Findings

The printing resolution is the most significant input parameter. Material length is not influenced by the printing speed and bed temperature. The compression stress–strain curve exhibits elastic, plateau and densification regions. All the samples exhibit negative Poisson’s ratio values within the elastic and plateau regions. At the beginning of densification, the Poisson’s ratios change to positive values. The metamaterial printed at a resolution of 0.3 mm, 80 mm/s and 60°C exhibits the best mechanical properties (yield strength and modulus of 2.02 and 58.87 MPa, respectively). The failure of the structure occurs through bending and torsion of the unit cells.

Practical implications

The optimisation study is significant for decision-making during the 3D printing and the empirical failure model shall complement the existing techniques for the mechanical analysis of the metamaterials.

Originality/value

To the best of the authors’ knowledge, for the first time, a new empirical model, based on the uniaxial load response and “static truss concept”, for failure mechanisms of the unit cell is presented.

Details

Rapid Prototyping Journal, vol. 30 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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