Skin-stringer separation in post-buckling of butt-joint stiffened thermoplastic composite panels

Two aeronautical thermoplastic composite stiffened panels are analysed and tested to investigate the buckling behaviour, the skin-stringer separation and the final failure mode. The panels are made of fast crystallising polyetherketoneketone carbon composite, have three stringers with an angled cap on one side, and are joined to the skin by a...

Demonstration of Scalable Series-Connected Submodule of Modular Multilevel Converter-based Arbitrary Wave shape Generator used for High Voltage Testing from Off-the-Shelf Component

To test high-voltage (HV) equipment with increasingly complex transients obtained from various power system studies, this article demonstrates a hardware implementation of a medium-voltage (MV) submodule (SM) to be used in a modular multilevel converter (MMC)-based HV arbitrary wave shape generator (AWG). The MV SM is scalable with its own...

PEM: Perception Error Model for Virtual Testing of Autonomous Vehicles

Even though virtual testing of Autonomous Vehicles (AVs) has been well recognized as essential for safety assessment, AV simulators are still undergoing active development. One particular challenge is the problem of including the Sensing and Perception (S&P) subsystem into the virtual simulation loop in an efficient and effective manner....

Design, analysis and testing of thermoplastic welded stiffened panels to investigate skin-stringer separation in post-buckling

Thermoplastic composite three-stringer panels with omega stiffeners and conduction welded joints are designed, analysed and tested until final failure to investigate the performance of the welded joint in post-buckling. The three-stringer panels are designed to be structurally representative of the fuselage demonstrator of the Clean Sky 2...

Optimal Distributed Composite Testing in High-dimensional Gaussian Models with 1-bit Communication

In this paper we study the problem of signal detection in Gaussian noise in a distributed setting where the local machines in the star topology can communicate a single bit of information. We derive a lower bound on the Euclidian norm that the signal needs to have in order to be detectable. Moreover, we exhibit optimal distributed testing...

A Contribution to the Development of High-Voltage dc Circuit Breaker Technologies: A Review of New Considerations

To promote the integration of renewable energy resources into modern energy systems, high-voltage dc (HVdc) and circuit breaker (CB) technologies have become critical to achieving secure and efficient energy transmission. This article reviews the technical development of the related areas, compares diverse breaker concepts and topologies,...

Safety Performance Boundary Identification of Highly Automated Vehicles: A Surrogate Model-Based Gradient Descent Searching Approach

Highly automated vehicles (HAVs) have been introduced to the transportation system for the purpose of providing safer mobility. Considering the expected long co-existence period of HAVs and human-driven vehicles (HDVs), the safety operation of HAVs interacting with HDVs needs to be verified. To achieve this, HAVs' Operational Design Domain ...

S-Transform based fault detection algorithm for enhancing distance protection performance

This paper presents a new fault detection algorithm based on the Fast Discrete Stockwell Transform. The algorithm can improve the functionality of existing distance protection and resolve shortcomings identified during the fault detection process in case of fault occurrence in systems with a high penetration of power electronics-based generators...

Models over time: Waterloopbos and Mississippi River Basin

The development of knowledge about the mechanism in the delta has had a high dependency on projects and techniques available. During the period from 1930 to 1939, there is a consolidation of the achievements and further development of hydraulic engineering techniques, based on model-based and mathematical analyses and prognoses (Schot et al.,...

Experimental method for investigating wear of porous thermal insulation systems exposed to realistic, hot, turbulent gas flow

A realistic wear test was developed for porous thermal insulation systems exposed to high temperature turbulent gas flow, because it is essential for the development of existing and new concepts of such insulation and therefore also for the performance of processes that depend on such insulation. Wear is crucial and often dominant for the...

Static test of a variable stiffness thermoplastic composite wingbox under shear, bending and torsion

Automated manufacturing of thermoplastic composites has found increased interest in aerospace applications over the past three decades because of its great potential in low-cost, high rate, repeatable production of high performance composite structures. Experimental validation is a key element in the development of structures made using this...

A Theoretical and Empirical Analysis of Program Spectra Diagnosability

Current metrics for assessing the adequacy of a test-suite plainly focus on the number of components (be it lines, branches, paths) covered by the suite, but do not explicitly check how the tests actually exercise these components and whether they provide enough information so that spectrum-based fault localization techniques can perform...

Optimal design, manufacturing and testing of non-conventional laminates

Composite materials are finding increasing application, for example in commercial aircraft. Traditionally fiber angles are restricted to 0°,±45° and 90°. The current work exploits the possibility of using multiple ’non-conventional’ laminates where either fiber steering (‘variable stiffness’), ply drops (‘variable thickness’), or a...

Selecting a suitable battery technology for the photovoltaic battery integrated module

The use of batteries is indispensable in stand-alone photovoltaic (PV) systems, and the physical integration of a battery pack and a PV panel in one device enables this concept while easing the installation and system scaling. However, the influence of high temperatures is one of the main challenges of placing a solar panel close to a battery...

Test Code Quality and Its Relation to Issue Handling Performance

Automated testing is a basic principle of agile development. Its benefits include early defect detection, defect causelocalization and removal of fear to apply changes to the code. Therefore, maintaining high quality test code is essential. This study introduces a model that assesses test code quality by combining source code metrics that...